Localization of lattice dynamics in low-angle twisted bilayer graphene.

Twisted bilayer graphene is created by slightly rotating the two crystal networks in bilayer graphene with respect to each other. For small twist angles, the material undergoes a self-organized lattice reconstruction, leading to the formation of a periodically repeated domain1-3. The resulting superlattice modulates the vibrational3,4 and electronic5,6 structures within the material, leading to changes in the behaviour of electron-phonon coupling7,8 and to the observation of strong correlations and superconductivity9. However, accessing these modulations and understanding the related effects are challenging, because the modulations are too small for experimental techniques to accurately resolve the relevant energy levels and too large for theoretical models to properly describe the localized effects. Here we report hyperspectral optical images, generated by a nano-Raman spectroscope10, of the crystal superlattice in reconstructed (low-angle) twisted bilayer graphene. Observations of the crystallographic structure with visible light are made possible by the nano-Raman technique, which reveals the localization of lattice dynamics, with the presence of strain solitons and topological points1 causing detectable spectral variations. The results are rationalized by an atomistic model that enables evaluation of the local density of the electronic and vibrational states of the superlattice. This evaluation highlights the relevance of solitons and topological points for the vibrational and electronic properties of the structures, particularly for small twist angles. Our results are an important step towards understanding phonon-related effects at atomic and nanometric scales, such as Jahn-Teller effects11 and electronic Cooper pairing12-14, and may help to improve device characterization15 in the context of the rapidly developing field of twistronics16.

Intra-genotypic variability in elite parent lines of papaya.

This study aimed to characterize papaya lines via microsatellite markers, and select genotypes based on the fixation index in order to promote the genetic purification of important commercial hybrids parent lines. Overall, 400 genotypes from three parental lines (JS-12, SS-72/12, and Sekati) were genotyped. Expected (HE), observed (HO) heterozygosity, and fixation index (F), were estimated. Genetic distances were estimated using an unweighted index, which was graphically presented via cluster analysis using the UPGMA and PCoA. Intra-genotypic variability was detected in both JS-12 and Sekati lines, while an absence of it was observed in SS-72/12. Such variability may positively contribute to the fitting of 'UENF/Caliman 01' and 'UC-10' hybrids into the traits of commercial interest how size and weight fruit. Regarding the fixation index, 293 genotypes showed maximum values (F=1) facilitating the genotypes selection process. Concerning population analysis, a close proximity between heterotic group 'Formosa' lines was observed, while a greater distance among 'Solo' group ones, and this enables systematic exploitation of such material. The fixation index maximum enabled the 80 genotypes selection thereby contributing to the parents genetic purification, since, the selected genotypes will be used in future hybridization steps to generate hybrids fitted into the traits of commercial interest.

Methamphetamine Enhances Cryptococcus neoformans Melanization, Antifungal Resistance, and Pathogenesis in a Murine Model of Drug Administration and Systemic Infection.

Methamphetamine (METH) is a major public health and safety problem in the United States. Chronic METH abuse is associated with a 2-fold-higher risk of HIV infection and, possibly, additional infections, particularly those that enter through the respiratory tract or skin. Cryptococcus neoformans is an encapsulated opportunistic yeast-like fungus that is a relatively frequent cause of meningoencephalitis in immunocompromised patients, especially in individuals with AIDS. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. l-3,4-Dihydroxyphenylalanine (l-Dopa) is a natural catecholamine that is frequently used to induce melanization in C. neoformans. l-Dopa-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents, and heavy metals. Using a systemic mouse model of infection and in vitro assays to critically assess the impact of METH on C. neoformans melanization and pathogenesis, we demonstrated that METH-treated mice infected with melanized yeast cells showed increased fungal burdens in the blood and brain, exacerbating mortality. Interestingly, analyses of cultures of METH-exposed cryptococci supplemented with l-Dopa revealed that METH accelerates fungal melanization, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms.

Lessons Learned from Studying Histoplasma capsulatum Extracellular Vesicles.

Histoplasma capsulatum is a major endemic mycosis. Our laboratories have demonstrated that H. capsulatum produces extracellular vesicles (EV) that are loaded with diverse compounds that influence virulence. We have further shown that H. capsulatum dynamically regulates the loading and release of fungal EV in response to stimuli and growth conditions. This chapter details the current knowledge of EV biology in H. capsulatum and the impact of this information on our understanding of this important process that is closely linked to pathogenesis.

Host cell membrane microdomains and fungal infection.

Lipid microdomains or lipid rafts are dynamic and tightly ordered regions of the plasma membrane. In mammalian cells, they are enriched in cholesterol, glycosphingolipids, Glycosylphosphatidylinositol-anchored and signalling-related proteins. Several studies have suggested that mammalian pattern recognition receptors are concentrated or recruited to lipid domains during host-pathogen association to enhance the effectiveness of host effector processes. However, pathogens have also evolved strategies to exploit these domains to invade cells and survive. In fungal organisms, a complex cell wall network usually mediates the first contact with the host cells. This cell wall may contain virulence factors that interfere with the host membrane microdomains dynamics, potentially impacting the infection outcome. Indeed, the microdomain disruption can dampen fungus-host cell adhesion, phagocytosis and cellular immune responses. Here, we provide an overview of regulatory strategies employed by pathogenic fungi to engage with and potentially subvert the lipid microdomains of host cells. TAKE AWAY: Lipid microdomains are ordered regions of the plasma membrane enriched in cholesterol, glycosphingolipids (GSL), GPI-anchored and signalling-related proteins. Pathogen recognition by host immune cells can involve lipid microdomain participation. During this process, these domains can coalesce in larger complexes recruiting receptors and signalling proteins, significantly increasing their signalling abilities. The antifungal innate immune response is mediated by the engagement of pathogen-associated molecular patterns to pattern recognition receptors (PRRs) at the plasma membrane of innate immune cells. Lipid microdomains can concentrate or recruit PRRs during host cell-fungi association through a multi-interactive mechanism. This association can enhance the effectiveness of host effector processes. However, virulence factors at the fungal cell surface and extracellular vesicles can re-assembly these domains, compromising the downstream signalling and favouring the disease development. Lipid microdomains are therefore very attractive targets for novel drugs to combat fungal infections.

A Perspective of the Urinary Microbiome in Lower Urinary Tract Infections - A Review.

PURPOSE OF REVIEW: Greater availability of sequencing methods has broadened the knowledge of the urinary microbiome in an environment previously believed to be sterile. This review discusses internal and external influences that promote either a balance or a dysbiosis of the urinary tract and the future perspectives in understanding lower urinary tract infections. RECENT FINDINGS: Efforts have been made to identify a "core" urinary microbiome in which Firmicutes and Bacteroidetes account for most of the bacterial representations. A shift to a Proteobacteria-dominant representation shapes the fingerprint of the infectious urinary microbiome; furthermore, the virome and the mycobiome are important modulators of the urinary microbiome, which have been recently explored to determine their role in the health-disease process of the lower urinary tract. A disturbance of bacterial representation and diversity triggers a transition from health to disease; conversely, a functional cooperative interplay between the host and microbiome allows for basic metabolic and immune functions to take place.

Essential Oils from Different Myrtaceae Species from Brazilian Atlantic Forest Biome - Chemical Dereplication and Evaluation of Antitrypanosomal Activity.

Chagas Disease (CD), caused by flagellate protozoan Trypanosoma cruzi, is a Neglected Tropical Diseases (NTD) that affect approximately seven million people worldwide with a restrict therapeutical arsenal. In the present study, the essential oils from 18 Myrtaceae species were extracted, chemically dereplicated, and evaluated in vitro against T. cruzi. From these, eight essential oils were considered promising (IC50 <10 µg/mL and SI>10) against the protozoan: Eugenia florida, E. acutata, E. widgrenii, Calyptranthes brasilienses, C. widgreniana, Plinia cauliflora, Campomanesia xanthocarpa, and Psidium guajava. Multivariate data analysis pointed out (E)-caryophyllene, α-humulene, limonene, caryophyllene oxide, and α-copaene playing an important role in the anti-T. cruzi activity. The obtained results demonstrated the potential of essential oils of Myrtaceae species as valuable sources of bioactive compounds against T. cruzi.

Mechanisms of altered skeletal muscle action potentials in the R6/2 mouse model of Huntington's disease.

Huntington's disease (HD) patients suffer from progressive and debilitating motor dysfunction for which only palliative treatment is currently available. Previously, we discovered reduced skeletal muscle Cl- channel (ClC-1) and inwardly rectifying K+ channel (Kir) currents in R6/2 HD transgenic mice. To further investigate the role of ClC-1 and Kir currents in HD skeletal muscle pathology, we measured the effect of reduced ClC-1 and Kir currents on action potential (AP) repetitive firing in R6/2 mice using a two-electrode current clamp. We found that R6/2 APs had a significantly lower peak amplitude, depolarized maximum repolarization, and prolonged decay time compared with wild type (WT). Of these differences, only the maximum repolarization was accounted for by the reduction in ClC-1 and Kir currents, indicating the presence of additional ion channel defects. We found that both KV1.5 and KV3.4 mRNA levels were significantly reduced in R6/2 skeletal muscle compared with WT, which explains the prolonged decay time of R6/2 APs. Overall, we found that APs in WT and R6/2 muscle significantly and progressively change during activity to maintain peak amplitude despite buildup of Na+ channel inactivation. Even with this resilience, the persistently reduced peak amplitude of R6/2 APs is expected to result in earlier fatigue and may help explain the motor impersistence experienced by HD patients. This work lays the foundation to link electrical changes to force generation defects in R6/2 HD mice and to examine the regulatory events controlling APs in WT muscle.

Host membrane glycosphingolipids and lipid microdomains facilitate Histoplasma capsulatum internalisation by macrophages.

Recognition and internalisation of intracellular pathogens by host cells is a multifactorial process, involving both stable and transient interactions. The plasticity of the host cell plasma membrane is fundamental in this infectious process. Here, the participation of macrophage lipid microdomains during adhesion and internalisation of the fungal pathogen Histoplasma capsulatum (Hc) was investigated. An increase in membrane lateral organisation, which is a characteristic of lipid microdomains, was observed during the first steps of Hc-macrophage interaction. Cholesterol enrichment in macrophage membranes around Hc contact regions and reduced levels of Hc-macrophage association after cholesterol removal also suggested the participation of lipid microdomains during Hc-macrophage interaction. Using optical tweezers to study cell-to-cell interactions, we showed that cholesterol depletion increased the time required for Hc adhesion. Additionally, fungal internalisation was significantly reduced under these conditions. Moreover, macrophages treated with the ceramide-glucosyltransferase inhibitor (P4r) and macrophages with altered ganglioside synthesis (from B4galnt1-/- mice) showed a deficient ability to interact with Hc. Coincubation of oligo-GM1 and treatment with Cholera toxin Subunit B, which recognises the ganglioside GM1, also reduced Hc association. Although purified GM1 did not alter Hc binding, treatment with P4 significantly increased the time required for Hc binding to macrophages. The content of CD18 was displaced from lipid microdomains in B4galnt1-/- macrophages. In addition, macrophages with reduced CD18 expression (CD18low ) were associated with Hc at levels similar to wild-type cells. Finally, CD11b and CD18 colocalised with GM1 during Hc-macrophage interaction. Our results indicate that lipid rafts and particularly complex gangliosides that reside in lipid rafts stabilise Hc-macrophage adhesion and mediate efficient internalisation during histoplasmosis.

Response to the letter to the editor: "Score risk scale as a prognostic factor after sudden sensorineural hearing loss".

We appreciate the opportunity to comment the observations on our paper entitled "Score risk scale as a prognostic factor after sudden sensorineural hearing loss", by Capuano et al. This letter highlights several important points, including the role of hyperbaric oxygen therapy and the possible association between patent foramen ovale and sudden sensorineural hearing loss (SSHL). Further research is needed to strengthen the association between cardiovascular risk and SSHL. We thank the authors for their insights into our paper and for adding their experience and observations on the potential role of cardiovascular risk in the etiology of SSHL.

The putative flippase Apt1 is required for intracellular membrane architecture and biosynthesis of polysaccharide and lipids in Cryptococcus neoformans.

Flippases are responsible for the asymmetric distribution of phospholipids in biological membranes. In the encapsulated fungal pathogen Cryptococcus neoformans, the putative flippase Apt1 is an important regulator of polysaccharide secretion and pathogenesis in mice by unknown mechanisms. In this study, we analyzed the role of C. neoformans Apt1 in intracellular membrane architecture and synthesis of polysaccharide and lipids. Analysis of wild type (WT), apt1Δ (mutant) and apt1Δ::APT1 (complemented) strains by transmission electron microscopy revealed that deletion of APT1 resulted in the formation of irregular vacuoles. Disorganization of vacuolar membranes in apt1Δ cells was accompanied by a significant increase in the amounts of intra-vacuolar and pigment-containing vesicles. Quantitative immunogold labeling of C. neoformans cells with a monoclonal antibody raised to a major capsular component suggested impaired polysaccharide synthesis. APT1 deletion also affected synthesis of phosphatidylserine, phosphatidylethanolamine, inositolphosphoryl ceramide, glucosylceramide and ergosterylglycoside. These results reveal novel functions of Apt1 and are in agreement with the notion that this putative flippase plays an important role in the physiology of C. neoformans.

SCORE risk scale as a prognostic factor after sudden sensorineural hearing loss.

INTRODUCTION: Sudden sensorineural hearing loss (SSHL) is an otologic urgency whose treatment is still controversial. Its etiology remains largely unknown in most cases and predicting its prognosis is still a challenge. Cardiovascular risk factors (CVRF) have been implicated in the etiopathogenesis of this entity. OBJECTIVES: Application of the SCORE (Systematic Coronary Risk Evaluation) risk scale in patients with SSHL and evaluation of its potential prognostic value in recovery in patients with CVRF. MATERIALS AND METHODS: Prospective analysis of patients with SSHL admitted for protocol treatment including intravenous corticosteroid therapy associated to weekly intratympanic injection in the event of therapeutic failure or severe hearing loss at admission. Demographic, audiometric, clinical and imaging data were assessed. The SCORE risk scale was applied and the audiometric recovery was compared among different risk groups. RESULTS: Our overall complete and partial recovery rates were 35.9% and 26%, respectively. More than a half of our patients had at least one CVRF. Of these, overweight/obesity, hyperlipidemia and hypertension were the most common. In our sample, patients with CVRF and higher SCORE risk presented higher PTA at admission and also worse hearing outcome, although these results were not statically significant. CONCLUSION: This preliminary study could not confirm the validity for SCORE scale for cardiovascular risk assessment in predicting audiometric recovery in patients with SSHL with multiple comorbidities. Further research with larger samples are needed to elucidate the etiology of SSHL and the exact role of cardiovascular risk factors in the pathophysiology of SSHL. LEVEL OF EVIDENCE: 4.

Ethnic Identity Development and Acculturation Preferences Among Minority and Majority Youth: Norms and Contact.

This article tests a longitudinal model of the antecedents and consequences of changes in identification with indigenous (Mapuche) among indigenous and nonindigenous youth in Chilean school contexts over a 6-month period (633 nonindigenous and 270 Mapuche students, Mages  = 12.47 and 12.80 years, respectively). Results revealed that in-group norms supporting contact and quality of intergroup contact at Time 1 predicted student's changes in Mapuche identification at Time 2, which in turn predicted changes in support for adoption of Chilean culture and maintenance of Mapuche culture at Time 2; some of the relationships between these variables were found to be moderated by age and ethnicity. Conceptual and policy implications are addressed in the Discussion.

HOLD study (Home care Obstructive Lung Disease): natural history of patients with advanced COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the fourth cause of death in western countries. Its final stage has clearly been forgotten by medical research in recent years. There exists consensus regarding the need to integrate palliative care in assisting these patients, but the difficulty in establishing a prognosis for the disease, establishing limits for life support measures, the lack of information about the disease's natural course and ignorance as to the most effective health-care structure for these patients' palliative treatment may be responsible for their late inclusion or non-inclusion in specific programmes. The main purpose of this work is to find out the natural background of patients with stage IV COPD and the main prognostic factors that influence these patients' survival. METHODS/DESIGN: Prospective observational study of a home patient cohort with stage IV COPD sent from Neumology consultations and Palliative Care Unit in La Paz Hospital in Madrid and Primary Care Health Centres in the area to the palliative care home support team. The goal is to study socio-demographic variables, prognosis, nutritional status, use of health resources, perceived quality of life, functionality, main symptomatology, use and effectiveness of opioids, adherence to treatment, prognostic information regarding the disease, information given by professionals, advance directives, social backup requirements and overburden level of the main caregiver. DISCUSSION: The HOLD study is a project aimed at finding out the prognostic factors and evolution of the disease COPD in its most advanced stage. The final goal is to improve the health and quality of life, in a personalised, integral way up to end of life and explore and foster communication with patients, as well as their participation and collaboration in decision-taking. The HOLD study can help us better understand what these patients' real palliative and care needs are, in order to more efficiently organise their treatment at end of life.

Probiotic Saccharomyces cerevisiae strains as biotherapeutic tools: is there room for improvement?

The probiotic yeast Saccharomyces cerevisiae var boulardii is widely used as a low cost and efficient adjuvant against gastrointestinal tract disorders such as inflammatory bowel disease and treatment of several types of diarrhea, both in humans and animals. S. boulardii exerts its protective mechanisms by binding and neutralizing enteric pathogens or their toxins, by reducing inflammation and by inducing the secretion of sIgA. Although several S. cerevisiae strains have proven probiotic potential in both humans and animals, only S. boulardii is currently licensed for use in humans. Recently, some researchers started using S. boulardii as heterologous protein expression systems. Combined with their probiotic activity, the use of these strains as prophylactic and therapeutic proteins carriers might result in a positive combined effort to fight specific diseases. Here, we provide an overview of the current use of S. cerevisiae strains as probiotics and their mechanisms of action. We also discuss their potential to produce molecules with biotherapeutic application and the advantages and hurdles of this approach. Finally, we suggest future directions and alternatives for which the combined effort of specific immunomodulatory effects of probiotic S. cerevisiae strains and ability to express desired foreign genes would find a practical application.

Why can organic liquids move easily on smooth alkyl-terminated surfaces?

The dynamic dewettability of a smooth alkyl-terminated sol-gel hybrid film surface against 17 probe liquids (polar and nonpolar, with high and low surface tensions) was systematically investigated using contact angle (CA) hysteresis and substrate tilt angle (TA) measurements, in terms of their physicochemical properties such as surface tension, molecular weight/volume, dielectric constant, density, and viscosity. We found that the dynamic dewettability of the hybrid film markedly depended not on the surface tensions but on the dielectric constants of the probe liquids, displaying lower resistance to liquid drop movement with decreasing dielectric constant (ε < 30). Interfacial analysis using the sum-frequency generation (SFG) technique confirmed that the conformation of surface-tethered alkyl chains was markedly altered before and after contact with the different types of probe liquids. When probe liquids with low dielectric constants were in contact with our surface, CH3 groups were preferentially exposed at the solid/liquid interface, leading to a reduction in surface energy. Because of such local changes in surface energy at the three-phase contact line of the probe liquid, the contact line can move continuously from low-surface-energy (solid/liquid) areas to surrounding high-surface-energy (solid/air) areas without pinning. Consequently, the organic probe liquids with low dielectric constants can move easily and roll off when tilted only slightly, independent of the magnitude of CAs, without relying on conventional surface roughening and perfluorination.

Polymeric Semiconductor in Field-Effect Transistors Utilizing Flexible and High-Surface Area Expanded Poly(tetrafluoroethylene) Membrane Gate Dielectrics.

Organic field-effect transistors (OFETs) were fabricated using three high-surface area and flexible expanded-poly(tetrafluoroethylene) (ePTFE) membranes in gate dielectrics, along with the semiconducting polymer poly[2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2':5',2″:5″,2‴-quaterthiophen-5,5‴-diyl)] (PDPP4T). The transistor behavior of these devices was investigated following annealing at 50, 100, 150, and 200 °C, all sustained for 1 h. For annealing temperatures above 50 °C, the OFETs displayed improved transistor behavior and a significant increase in output current while maintaining similar magnitudes of Vth shifts when subjected to static voltage compared to those kept at ambient temperature. We also tested the response to NO2 gas for further characterization and for possible applications. The ePTFE-PDPP4T interface of each membrane was characterized via scanning electron microscopy for all four annealing temperatures to derive a model for the hole mobility of the ePTFE-PDPP4T OFETs that accounts for the microporous structure of the ePTFE and consequently adjusts the channel width of the OFET. Using this model, a maximum hole mobility of 1.8 ± 1.0 cm2/V s was calculated for the polymer in an ePTFE-PDPP4T OFET annealed at 200 °C, whereas a PDPP4T OFET using only the native silicon wafer oxide as a gate dielectric exhibited a hole mobility of just 0.09 ± 0.03 cm2/V s at the same annealing condition. This work demonstrates that responsive semiconducting polymer films can be deposited on nominally nonwetting and extremely bendable membranes, and the charge carrier mobility can be significantly increased compared to their as-prepared state by using thermally durable polymer membranes with unique microstructures as gate dielectrics.

Epidemiology and Burden of Ventilator-Associated Pneumonia among Adult Intensive Care Unit Patients: A Portuguese, Multicenter, Retrospective Study (eVAP-PT Study).

Ventilator-associated pneumonia (VAP) is a prevailing nosocomial infection in critically ill patients requiring invasive mechanical ventilation (iMV). The impact of VAP is profound, adversely affecting patient outcomes and placing a significant burden on healthcare resources. This study assessed for the first time the contemporary VAP epidemiology in Portugal and its burden on the healthcare system and clinical outcomes. Additionally, resource consumption (duration of iMV, intensive care unit (ICU), hospital length of stay (LOS)) and empirical antimicrobial therapy were also evaluated. This multicenter, retrospective study included patients admitted to the hospital between July 2016 and December 2017 in a participating ICU, who underwent iMV for at least 48 h. Patients with a VAP diagnosis were segregated for further analysis (n = 197). Control patients, ventilated for >48 h but without a VAP diagnosis, were also included in a 1:1 ratio. Cumulative VAP incidence was computed. All-cause mortality was assessed at 28, 90, and 365 days after ICU admission. Cumulative VAP incidence was 9.2% (95% CI 8.0-10.5). The all-cause mortality rate in VAP patients was 24.9%, 34.0%, and 40.6%, respectively, and these values were similar to those observed in patients without VAP diagnosis. Further, patients with VAP had significantly longer ICU (27.5 vs. 11.0 days, p < 0.001) and hospital LOS (61 vs. 35.9 days, p < 0.001), more time under iMV (20.7 vs. 8.0 days, p < 0.001) and were more often subjected to tracheostomy (36.5 vs. 14.2%; p < 0.001). Patients with VAP who received inappropriate empirical antimicrobials had higher 28-day mortality, 34.3% vs. 19.5% (odds ratio 2.16, 95% CI 1.10-4.23), although the same was not independently associated with 1-year all-cause mortality (p = 0.107). This study described the VAP impact and burden on the Portuguese healthcare system, with approximately 9% of patients undergoing iMV for >48 h developing VAP, leading to increased resource consumption (longer ICU and hospital LOS). An unexpectedly high incidence of inappropriate, empirical antimicrobial therapy was also noted, being positively associated with a higher mortality risk of these patients. Knowledge of the Portuguese epidemiology characterization of VAP and its multidimensional impact is essential for efficient treatment and optimized long-term health outcomes of these patients.