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1.
Geohealth ; 8(6): e2024GH001024, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38912225

RESUMO

Many infectious disease forecasting models in the United States (US) are built with data partitioned into geopolitical regions centered on human activity as opposed to regions defined by natural ecosystems; although useful for data collection and intervention, this has the potential to mask biological relationships between the environment and disease. We explored this concept by analyzing the correlations between climate and West Nile virus (WNV) case data aggregated to geopolitical and ecological regions. We compared correlations between minimum, maximum, and mean annual temperature; precipitation; and annual WNV neuroinvasive disease (WNND) case data from 2005 to 2019 when partitioned into (a) climate regions defined by the National Oceanic and Atmospheric Administration (NOAA) and (b) Level I ecoregions defined by the Environmental Protection Agency (EPA). We found that correlations between climate and WNND in NOAA climate regions and EPA ecoregions were often contradictory in both direction and magnitude, with EPA ecoregions more often supporting previously established biological hypotheses and environmental dynamics underlying vector-borne disease transmission. Using ecological regions to examine the relationships between climate and disease cases can enhance the predictive power of forecasts at various scales, motivating a conceptual shift in large-scale analyses from geopolitical frameworks to more ecologically meaningful regions.

2.
Phys Rev Lett ; 132(12): 126502, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38579201

RESUMO

LiCu_{3}O_{3} is an antiferromagnetic mixed valence cuprate where trilayers of edge-sharing Cu(II)O (3d^{9}) are sandwiched in between planes of Cu(I) (3d^{10}) ions, with Li stochastically substituting Cu(II). Angle-resolved photoemission spectroscopy (ARPES) and density functional theory reveal two insulating electronic subsystems that are segregated in spite of sharing common oxygen atoms: a Cu d_{z^{2}}/O p_{z} derived valence band (VB) dispersing on the Cu(I) plane, and a Cu 3d_{x^{2}-y^{2}}/O 2p_{x,y} derived Zhang-Rice singlet (ZRS) band dispersing on the Cu(II)O planes. First-principle analysis shows the Li substitution to stabilize the insulating ground state, but only if antiferromagnetic correlations are present. Li further induces substitutional disorder and a 2D electron glass behavior in charge transport, reflected in a large 530 meV Coulomb gap and a linear suppression of VB spectral weight at E_{F} that is observed by ARPES. Surprisingly, the disorder leaves the Cu(II)-derived ZRS largely unaffected. This indicates a local segregation of Li and Cu atoms onto the two separate corner-sharing Cu(II)O_{2} sub-lattices of the edge-sharing Cu(II)O planes, and highlights the ubiquitous resilience of the entangled two hole ZRS entity against impurity scattering.

3.
Parasit Vectors ; 16(1): 200, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37316915

RESUMO

BACKGROUND: Mosquitoes in the genus Culex are primary vectors in the US for West Nile virus (WNV) and other arboviruses. Climatic drivers such as temperature have differential effects on species-specific changes in mosquito range, distribution, and abundance, posing challenges for population modeling, disease forecasting, and subsequent public health decisions. Understanding these differences in underlying biological dynamics is crucial in the face of climate change. METHODS: We collected empirical data on thermal response for immature development rate, egg viability, oviposition, survival to adulthood, and adult lifespan for Culex pipiens, Cx. quinquefasciatus, Cx. tarsalis, and Cx. restuans from existing literature according to the PRISMA scoping review guidelines. RESULTS: We observed linear relationships with temperature for development rate and lifespan, and nonlinear relationships for survival and egg viability, with underlying variation between species. Optimal ranges and critical minima and maxima also appeared varied. To illustrate how model output can change with experimental input data from individual Culex species, we applied a modified equation for temperature-dependent mosquito type reproduction number for endemic spread of WNV among mosquitoes and observed different effects. CONCLUSIONS: Current models often input theoretical parameters estimated from a single vector species; we show the need to implement the real-world heterogeneity in thermal response between species and present a useful data resource for researchers working toward that goal.


Assuntos
Culex , Culicidae , Características de História de Vida , Vírus do Nilo Ocidental , Animais , Feminino , Mosquitos Vetores , Temperatura
4.
Phys Rev Lett ; 129(24): 246404, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36563241

RESUMO

The electronic structure of Weyl semimetals features Berry flux monopoles in the bulk and Fermi arcs at the surface. While angle-resolved photoelectron spectroscopy (ARPES) is successfully used to map the bulk and surface bands, it remains a challenge to explicitly resolve and pinpoint these topological features. Here we combine state-of-the-art photoemission theory and experiments over a wide range of excitation energies for the Weyl semimetals TaAs and TaP. Our results show that simple surface-band-counting schemes, proposed previously to identify nonzero Chern numbers, are ambiguous due to pronounced momentum-dependent spectral weight variations and the pronounced surface-bulk hybridization. Instead, our findings indicate that dichroic ARPES provides an improved approach to identify Fermi arcs but requires an accurate description of the photoelectron final state.

5.
Anim Microbiome ; 4(1): 45, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35908068

RESUMO

Microbiomes are essential to a host's physiology and health. Despite the overall importance of microbiomes to animal health, they remain understudied in wildlife. Microbiomes function as physical barriers to invading pathogens, and changes in the diversity or composition of microbes within a host may disrupt this barrier. In order to use microbiomes in wildlife ecology, knowledge of the natural variation within and among species is essential. We compare the diversity and composition of two avian species that share the same habitat and niche in our study area, the western screech-owl (Megascops kennicottii) and the whiskered screech-owl (M. trichopsis). We used a targeted 16S sequencing method to improve the taxonomic resolution of microbiomes. We found similar measures of alpha diversity between species and sample types (cloacal samples vs. fecal samples). However, there were significant differences in bacterial species richness among nestlings from different nest boxes, and the composition differed between the two bird species and among nestlings from different nest boxes. Western screech-owls had more variation in alpha diversity and composition and had fewer bacterial species in their core microbiome than whiskered screech-owls. Siblings are likely to yield similar findings for microbiomes; thus, sampling nestlings from different nests may be most informative for monitoring population-level changes.

6.
J Theor Biol ; 545: 111145, 2022 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-35490763

RESUMO

The many respiratory viruses that cause influenza-like illness (ILI) are reported and tracked as one entity, defined by the CDC as a group of symptoms that include a fever of 100 degrees Fahrenheit, a cough, and/or a sore throat. In the United States alone, ILI impacts 9-49 million people every year. While tracking ILI as a single clinical syndrome is informative in many respects, the underlying viruses differ in parameters and outbreak properties. Most existing models treat either a single respiratory virus or ILI as a whole. However, there is a need for models capable of comparing several individual viruses that cause respiratory illness, including ILI. To address this need, here we present a flexible model and simulations of epidemics for influenza, RSV, rhinovirus, seasonal coronavirus, adenovirus, and SARS/MERS, parameterized by a systematic literature review and accompanied by a global sensitivity analysis. We find that for these biological causes of ILI, their parameter values, timing, prevalence, and proportional contributions differ substantially. These results demonstrate that distinguishing the viruses that cause ILI will be an important aspect of future work on diagnostics, mitigation, modeling, and preparation for future pandemics.


Assuntos
Epidemias , Influenza Humana , Viroses , Vírus , Humanos , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , Rhinovirus , Viroses/epidemiologia
7.
Phys Rev Lett ; 125(21): 216402, 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-33274982

RESUMO

Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of a chiral crystal. We have studied by spin- and angle-resolved photoelectron spectroscopy its unconventional electronic structure and unique spin texture. We identify Kramers-Weyl, composite, and accordionlike Weyl fermions, so far only predicted by theory, and show that the spin polarization is parallel to the wave vector along the lines in k space connecting high-symmetry points. Our results clarify the symmetries that enforce such spin texture in a chiral crystal, thus bringing new insight in the formation of a spin vectorial field more complex than the previously proposed hedgehog configuration. Our findings thus pave the way to a classification scheme for these exotic spin textures and their search in chiral crystals.

8.
Phys Rev Lett ; 125(7): 076401, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32857568

RESUMO

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correlations between Dirac quasiparticles. Here we investigate the electronic structure of ZrSiSe, by combining time- and angle-resolved photoelectron spectroscopy with ab initio density functional theory (DFT) complemented by an extended Hubbard model (DFT+U+V) and by time-dependent DFT+U+V. We show that electronic correlations are reduced on an ultrashort timescale by optical excitation of high-energy electrons-hole pairs, which transiently screen the Coulomb interaction. Our findings demonstrate an all-optical method for engineering the band structure of a quantum material.

9.
J Appl Microbiol ; 125(2): 513-527, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29624801

RESUMO

AIMS: Straw wine is a highly valuable oenological production, affected by relevant economical losses due to proliferation of spoilage micro-organisms during drying grapes, after being harvested. In this work, ozone was evaluated as a tool to preserve grapes during drying, in terms of both qualitative and quantitative changes induced in the epiphytic microflora. In addition, the alteration exerted by ozone on grapes' chemical composition was analysed. METHODS AND RESULTS: Grapes from four vine varieties were treated with ozone produced by a cold plasma generator during the entire drying period (6 weeks). The microflora was quantified weekly by plate counts and characterized by 454-pyrosequencing, and was compared with identical, untreated grape samples. At the end of drying, an extensive chemical characterization of the whole mass of grapes by FT-IR and GC-MS was performed. Ozone counteracted the growth of microflora by reducing the microbial population up to 3 log units. From the qualitative point of view, ozone reduced the incidence of spoilage micro-organisms, such as Acetobacter and Botrytis cinerea, among the microbiota of grapes. CONCLUSIONS: The statistical analysis discriminates grape samples based on the residual epiphytic microflora at the end of drying and not on their chemical composition. These evidences confirmed that ozone did control spoilage micro-organisms without altering the volatile profile of grapes. Chemical analysis revealed that untreated grapes are less suitable for winemaking owing to the deprivation of some valuable compounds during the microbial proliferation. SIGNIFICANCE AND IMPACT OF THE STUDY: Ozone is an emerging tool in winemaking, recently applied for controlling spoilage micro-organisms in winery. The present study describes a new application of ozone as an effective and safe alternative to chemical preservatives which are actually involved in the control of microbial alterations of grapes.


Assuntos
Manipulação de Alimentos/métodos , Microbiota/efeitos dos fármacos , Ozônio/farmacologia , Vitis , Vinho , Vitis/química , Vitis/efeitos dos fármacos , Vinho/análise , Vinho/microbiologia
10.
J Viral Hepat ; 25(7): 870-873, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29316001

RESUMO

An important subgroup of people who inject drugs (PWID) receiving opioid agonist therapy (OAT) cannot be treated in the setting of a hepatology centre and would not regularly ingest their medication when handed to them for self-administration. Our hypothesis was that chronic hepatitis C in these patients could be ideally managed if modern, interferon-free regimens were administered together with OAT under direct observation of a physician or nurse at a low-threshold facility. In this open-label, noninterventional, proof-of-concept study (ClinicalTrials.gov number, NCT02638233), 40 PWID at risk of nonadherence to direct-acting antivirals (DAA) and previously untreated chronic hepatitis C virus genotype 1 infection without cirrhosis were treated with ledipasvir/sofosbuvir for 8 weeks. Patients received antiviral treatment together with OAT under direct observation of a physician or nurse at a low-threshold facility. By following the concept of directly observed therapy, excellent adherence to antiviral therapy was achieved as follows: only 0.16% (95% CI: 0.03-0.47) of scheduled dates for ingestion of the antiviral therapy in combination with OAT were missed by the 40 patients. The rate of sustained virological response 12 weeks after end of therapy was 100% (95% CI: 91.2-100.0). Between week 12 and week 24 of follow-up reinfections were recorded in 2 of 40 patients (5%). Directly observed therapy of chronic hepatitis C is highly effective in PWID at risk of nonadherence to DAA. By this new concept, a group of difficult-to-treat patients can be cured, who could not have been treated in settings of studies published so far.


Assuntos
Antivirais/administração & dosagem , Benzimidazóis/administração & dosagem , Terapia Diretamente Observada , Fluorenos/administração & dosagem , Hepatite C Crônica/tratamento farmacológico , Sofosbuvir/administração & dosagem , Abuso de Substâncias por Via Intravenosa/complicações , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Genótipo , Hepacivirus/classificação , Hepacivirus/genética , Hepacivirus/isolamento & purificação , Humanos , Masculino , Adesão à Medicação , Pessoa de Meia-Idade , Resposta Viral Sustentada , Resultado do Tratamento , Adulto Jovem
11.
Nat Commun ; 8: 15176, 2017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28474681

RESUMO

A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic structure. Here we provide-using angle-resolved photoemission electron spectroscopy-the band structure of the paramagnetic insulating phase of Ca2RuO4 and show how it features several distinct energy scales. Comparison to a simple analysis of atomic multiplets provides a quantitative estimate of the Hund's coupling J=0.4 eV. Furthermore, the experimental spectra are in good agreement with electronic structure calculations performed with Dynamical Mean-Field Theory. The crystal field stabilization of the dxy orbital due to c-axis contraction is shown to be essential to explain the insulating phase. These results underscore the importance of multi-band physics, Coulomb interaction and Hund's coupling that together generate the Mott insulating state of Ca2RuO4.

13.
Phys Rev Lett ; 118(17): 176404, 2017 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-28498707

RESUMO

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu_{2}O_{2}, a mixed-valence cuprate where planes of Cu(I) (3d^{10}) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d^{9}) chains. We find that the Cu(I)- and Cu(II)-derived electronic states form separate electronic subsystems, in spite of being coupled by bridging O ions. The valence band, of the Cu(I) character, disperses within the charge-transfer gap of the strongly correlated Cu(II) states, displaying an unprecedented 250% broadening of the bandwidth with respect to the predictions of density functional theory. Our observation is at odds with the widely accepted tenet of many-body theory that correlation effects generally yield narrower bands and larger electron masses and suggests that present-day electronic structure techniques provide an intrinsically inappropriate description of ligand-to-d hybridizations in late transition metal oxides.

14.
Nat Commun ; 8(1): 13, 2017 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-28408739

RESUMO

Anatase TiO2 is among the most studied materials for light-energy conversion applications, but the nature of its fundamental charge excitations is still unknown. Yet it is crucial to establish whether light absorption creates uncorrelated electron-hole pairs or bound excitons and, in the latter case, to determine their character. Here, by combining steady-state angle-resolved photoemission spectroscopy and spectroscopic ellipsometry with state-of-the-art ab initio calculations, we demonstrate that the direct optical gap of single crystals is dominated by a strongly bound exciton rising over the continuum of indirect interband transitions. This exciton possesses an intermediate character between the Wannier-Mott and Frenkel regimes and displays a peculiar two-dimensional wavefunction in the three-dimensional lattice. The nature of the higher-energy excitations is also identified. The universal validity of our results is confirmed up to room temperature by observing the same elementary excitations in defect-rich samples (doped single crystals and nanoparticles) via ultrafast two-dimensional deep-ultraviolet spectroscopy.Here the authors combine steady-state angle-resolved photoemission spectroscopy, ellipsometry and ultrafast two-dimensional ultraviolet spectroscopy to examine the role of many-body correlations in anatase TiO2, revealing the existence of strongly bound excitons in single crystals and nanoparticles.

15.
HNO ; 65(8): 671-679, 2017 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-28271168

RESUMO

BACKGROUND: Age-related hearing loss is one of the most common chronic sensory impairments in the older population. This chronic condition is associated with bio-psychosocial consequences such as cognitive decline, depression, withdrawal, isolation, and reduced wellbeing. OBJECTIVE: This study aimed to investigate the perception of hearing problems among older women and men (≥55 years) with age-related hearing loss. Furthermore, the association between functional hearing loss and perceived hearing problems was examined. Lastly, this study undertook a detailed investigation of subjective experiences in order to better understand the consequences of age-related hearing loss for daily life. MATERIALS AND METHODS: With the aid of mixed methods, quantitative data were gathered from 65 participants with age-related hearing impairment in Austria using the Hearing Handicap Inventory for the Elderly (HHIE). Moreover, qualitative data regarding experiences with hearing problems were collected by performing semi-structured problem-centered interviews and analyzing the results of a further 14 older adults with hearing loss. RESULTS: On average, participants assessed their hearing handicap as mild and perceived consequences on emotional, social, and communication levels. Moreover, feelings of insecurity were evident. In addition, the findings indicate a relationship but also a discrepancy between hearing loss and hearing handicap, i. e., not all participants perceived a hearing handicap. CONCLUSION: Patient-centered care encompassing (1) objective and self-report measures for assessing hearing problems, (2) involvement of family members and significant others, (3) counseling and exchange of information, and (4) a shared decision-making approach could enhance quality of life and quality of care.


Assuntos
Auxiliares de Audição , Perda Auditiva , Idoso , Áustria , Feminino , Testes Auditivos , Humanos , Masculino , Qualidade de Vida , Inquéritos e Questionários
17.
Allergy ; 72(5): 754-763, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27753449

RESUMO

BACKGROUND: Allergen-specific IgE antibodies are a hallmark of type I allergy. The aim of this cross-sectional study was to analyze the sensitization profiles of an Austrian adolescent population utilizing molecule-based IgE diagnosis. METHODS: Serum samples of 501 nonselected pupils from Salzburg, Austria, were tested in ImmunoCAP ISAC® for IgE reactivity to 112 single allergens. Sensitization profiles were assessed and statistically coordinated with reported allergies. RESULTS: In the population aged 12-21 years, 53.5% showed IgE reactivity to at least one allergen tested. The highest prevalence was found for Phl p 1 from grass pollen (26.5%), group 2 mite allergens (18.2%), Bet v 1 from birch pollen (16.3%) and Fel d 1 from cat (14.4%). The majority of participants showed a complex sensitization profile and reacted on average to 9 allergens. Pollen sensitization was highly prevalent (41.7%) and mainly driven by group I grass and PR-10 allergens of the Betulaceae family, while Pla l 1 represented the most relevant weed. Diagnosed and self-reported allergies were noted in 21.9% and 45.5% of participants, respectively, and correlated well with in vitro results. Among atopic individuals, 71.4% reported to suffer from at least one allergy; concordance was found for grass and cat sensitization, while venom- and weed pollen-positive individuals were frequently asymptomatic. CONCLUSIONS: More than half of the tested adolescent population had already established an atopic status presenting a complex IgE reactivity profile dominated by pollen sensitization. Detailed molecule-based analysis allows determining relevant biomarkers and monitoring of the atopic status in populations.


Assuntos
Alérgenos/imunologia , Hipersensibilidade/epidemiologia , Hipersensibilidade/imunologia , Imunoglobulina E/imunologia , Adolescente , Adulto , Áustria/epidemiologia , Criança , Estudos Transversais , Feminino , Humanos , Hipersensibilidade/diagnóstico , Hipersensibilidade Imediata/epidemiologia , Hipersensibilidade Imediata/imunologia , Masculino , Prevalência , Adulto Jovem
18.
Epidemiol Infect ; 144(8): 1748-55, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27125574

RESUMO

Vancomycin-resistant enterococci (VRE) infections are a public health threat associated with increased patient mortality and healthcare costs. Antibiotic usage, particularly cephalosporins, has been associated with VRE colonization and VRE bloodstream infections (VRE BSI). We examined the relationship between antimicrobial usage and incident VRE colonization at the individual patient level. Prospective, weekly surveillance was undertaken for incident VRE colonization defined by negative admission but positive surveillance swab in a medical intensive care unit over a 17-month period. Antimicrobial exposure was quantified as days of therapy (DOT)/1000 patient-days. Multiple logistic regression was used to analyse incident VRE colonization and antibiotic DOT, controlling for demographic and clinical covariates. Ninety-six percent (1398/1454) of admissions were swabbed within 24 h of intensive care unit (ICU) arrival and of the 380 patients in the ICU long enough for weekly surveillance, 83 (22%) developed incident VRE colonization. Incident colonization was associated in bivariate analysis with male gender, more previous hospital admissions, longer previous hospital stay, and use of cefepime/ceftazidime, fluconazole, azithromycin, and metronidazole (P < 0·05). After controlling for demographic and clinical covariates, metronidazole was the only antibiotic independently associated with incident VRE colonization (odds ratio 2·0, 95% confidence interval 1·2-3·3, P < 0·009). Our findings suggest that risk of incident VRE colonization differs between individual antibiotic agents and support the possibility that antimicrobial stewardship may impact VRE colonization and infection.


Assuntos
Antibacterianos/uso terapêutico , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Uso de Medicamentos , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Enterococos Resistentes à Vancomicina/isolamento & purificação , Adulto , Idoso , Monitoramento Epidemiológico , Feminino , Humanos , Incidência , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
19.
Br J Anaesth ; 116(3): 405-12, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26865133

RESUMO

BACKGROUND: Ultrasound guidance allows for the use of much lower volumes of local anaesthetics for nerve blocks, which may be associated with less aberrant spread and fewer complications. This randomized, controlled study used contrast magnetic resonance imaging to view the differential-volume local anaesthetic distribution, and compared analgesic efficacy and respiratory impairment. METHODS: Thirty patients undergoing shoulder surgery were randomized to receive ultrasound-guided interscalene block by a single, blinded operator with injection of ropivacaine 0.75% (either 20 or 5 ml) plus the contrast dye gadopentetate dimeglumine, followed by magnetic resonance imaging. The primary outcome was epidural spread. Secondary outcomes were central non-epidural spread, contralateral epidural spread, spread to the phrenic nerve, spirometry, ultrasound investigation of the diaphragm, block duration, pain scores during the first 24 h, time to first analgesic consumption, and total analgesic consumption. RESULTS: All blocks provided fast onset and adequate intra- and postoperative analgesia, with no significant differences in pain scores at any time point. Epidural spread occurred in two subjects of each group (13.3%); however, spread to the intervertebral foramen and phrenic nerve and extensive i.m. local anaesthetic deposition were significantly more frequent in the 20 ml group. Diaphragmatic paralysis occurred twice as frequently (n=8 vs 4), and changes from baseline peak respiratory flow rate were larger [Δ=-2.66 (1.99 sd) vs -1.69 (2.0 sd) l min(-1)] in the 20 ml group. CONCLUSIONS: This study demonstrates that interscalene block is associated with epidural spread irrespective of injection volume; however, less central (foraminal) and aberrant spread after low-volume injection may be associated with a more favourable risk profile. CLINICAL TRIAL REGISTRATION: This study was registered with the European Medicines Agency (Eudra-CT number 2013-004219-36) and with the US National Institutes' of Health registry and results base, clinicaltrials.gov (identifier NCT02175069).


Assuntos
Anestésicos Locais/farmacocinética , Meios de Contraste , Imageamento por Ressonância Magnética , Bloqueio Nervoso , Nervo Frênico/efeitos dos fármacos , Ultrassonografia de Intervenção , Adolescente , Adulto , Idoso , Amidas/farmacocinética , Plexo Braquial/diagnóstico por imagem , Plexo Braquial/efeitos dos fármacos , Espaço Epidural , Feminino , Gadolínio DTPA , Humanos , Aumento da Imagem , Masculino , Pessoa de Meia-Idade , Ropivacaina , Ombro/cirurgia , Distribuição Tecidual , Adulto Jovem
20.
J Phys Condens Matter ; 27(45): 455502, 2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26490303

RESUMO

We report an investigation of the structural and electronic properties of a Pb monolayer (ML) grown on Ag(1 0 0), by combining x-ray photoelectron diffraction (XPD) and angle resolved photoelectron spectroscopy (ARPES). The Pb atoms are found to arrange in a pseudo-hexagonal adlayer commensurate to the underlying square Ag substrate, resulting in a coincidence cell with c([Formula: see text]) periodicity. The electronic structure of the Pb ML in proximity of the Fermi level consists in three p-derived bands, which show different degrees of hybridization with the substrate for their different orbital characters. In particular, we report that the p xy states disperse without forming energy gap, in contrast to previous ARPES studies of the Pb ML on different metallic substrates. We attribute the absence of energy gap to the commensurability between substrate and adlayer, resulting in a higher two-dimensionality of the Pb ML.

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