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1.
Dalton Trans ; 52(27): 9301-9314, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37347124

RESUMO

ZnAl2-xCrxO4 (x = 0 and 0.05) samples were synthesized via a high-temperature solid-state reaction method. The structure, photoluminescence properties, EPR measurements, thermal stability, and chromaticity diagram of the far-red phosphor ZnAl1.95Cr0.05O4 were investigated. These measurements have enabled us to study the Cr3+ transitions and the site symmetry of Cr3+ in the ZnAl2O4 host lattice and examine the suitability of ZnAl1.95Cr0.05O4 for plant growth application. According to optical and EPR measurements, Cr3+ ions substitute Al3+ ions with D3d symmetry in the ZnAl2O4 host. PLE measurement indicates that upon excitation at 390 nm and 530 nm, the far-red phosphor ZnAl1.95Cr0.05O4 exhibited bright far-red emission around 687 nm. Photoluminescence phenomena show a sharp R line origin from the sublevels of the 2Eg(2G) → 4A2(4F) transition in Cr3+ ions. The 2Eg level was split into 2Eg (Eg) and 2Eg (2Ag) levels in the distorted crystal field environment, and the sharp R line in the ZnAl2O4 matrix was split into R1 and R2 lines. In this paper, the temperature-dependent luminescence characteristics of ZnAl1.95Cr0.05O4 have been investigated. As the temperature increased from 300 K to 440 K, a slight decrease in the intensity of the R1 and R2 lines was observed under excitation at 390 nm. The experimental results show that the ZnAl1.95Cr0.05O4 phosphors exhibit a nearly zero-thermal-quenching behavior. The CIE chromaticity coordinates of the ZnAl1.95Cr0.05O4 phosphor were located at the boundary of the chromaticity diagram, signifying that the phosphors possessed high color purity. The emissions of the ZnAl1.95Cr0.05O4 phosphor match well with the PFR absorption of phytochromes in plants. The investigation indicates that ZnAl1.95Cr0.05O4 is a potential far-red phosphor matching ultraviolet (UV) LED chips for plant growth applications.

3.
Sci Rep ; 12(1): 9697, 2022 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-35690606

RESUMO

We investigate the interplay of magnetization and lattice vibrations in rare-earth orthoferrites RFeO3, with a specific focus on non-symmetry-breaking anomalies. To do so, we study the magnetization, magnon excitations and lattice dynamics as a function of temperature in NdFeO3, TbFeO3, EuFeO3 and GdFeO3. The magnetization shows distinct temperature anomalous behavior for all investigated rare-earth orthoferrites, even in the compounds with no phase transitions occurring at those temperatures. Through spin-phonon coupling, these magnetic changes are mirrored by the FeO6 rotation mode for all the studied RFeO3, revealing a common magnetostructural effect associated with the octahedra rotations. The R3+ oscillation modes evidence a Fe3+/R3+ spins cross-talk for the NdFeO3 and TbFeO3 cases. Our work sheds light into the common magnetostructural coupling in rare-earth orthoferrites, and the important role of magnetic anisotropy and spin-orbit coupling strength of the R-Fe interactions on the spin-reorientation transition at high temperatures.

4.
Orthod Craniofac Res ; 24(1): 1-16, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32608091

RESUMO

OBJECTIVE: To assess scientific evidence of the association between temporomandibular joint (TMJ) disorders and facial asymmetry (FA). METHODS: A systematic review was performed in accordance with the PRISMA checklist. A search strategy was developed in electronic databases including MEDLINE, Scopus, Web of Science, Virtual Health Library and Cochrane Library until January 2020. Eligibility criteria included observational studies that investigated the occurrence of FA among patients with and without signs and symptoms of TMJ disorders. Risk of bias of individual studies was analysed after study selection and data collection processes according to Fowkes and Fulton guidelines. Four meta-analyses (MA) were performed to evaluate the association between TMJ disorders and linear/angular menton deviation, subgrouping the studies into unilateral and bilateral cases. The evidence was certainty-tested using the GRADE approach. RESULTS: The search retrieved 2371 studies, 31 of which were eligible for full-text reading. Seven cross-sectional clinical studies met the eligibility criteria and were included in the qualitative synthesis, comprising a total of 621 subjects (345 with TMJ disease and 276 in control group), four of which were classified as being methodologically sound. Five studies were eligible for quantitative synthesis. Linear and angular menton deviation was greater in individuals with unilateral TMJ disorders than controls (MD = 2.41 [0.33, 4.50] P = .02; I2  = 86% and MD = 2.68 [0.99, 4.38] P = .002; I2  = 0%, respectively). CONCLUSIONS: Despite the low certainty in evidence, the present study indicated that unilateral TMJ disorders are associated with FA. However, longitudinal studies with greater certainty of evidence should be conducted to achieve a stronger estimate of this association.


Assuntos
Assimetria Facial , Transtornos da Articulação Temporomandibular , Estudos Transversais , Humanos , Estudos Longitudinais
5.
Sci Rep ; 9(1): 18755, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31822738

RESUMO

A previously unreported tetragonal phase has been discovered in a epitaxially strained GdMnO3 thin films deposited on (001)-oriented SrTiO3 substrates by radio frequency (RF) magnetron sputtering. The tetragonal axis of the films grown up to a 35 nm thickness is perpendicular to the film surface and the basal lattice parameters are imposed by the cubic structure of the substrate. Furthermore, the emergence of a spontaneous electric polarization below ~32 K points to the stabilization of an improper ferroelectric phase at low temperatures, which is not observed in bulk GdMnO3. This work shows how strain engineering can be used to tailor the structure and properties of strongly correlated oxides.

6.
J Pediatr Urol ; 15(4): 421-422, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31431350

RESUMO

Ureteropelvic junction (UPJ) stenosis is the most common cause of pathological neonatal hydronephrosis. UPJ obstruction may be treated conservatively in some cases, but surgery is indicated if symptoms occur or renal function deteriorates. Pyeloplasty is the procedure of choice for UPJ stenosis. Pyeloplasty can be performed by open laparoscopic or robotic technique. The laparoscopic technique is safe and may be associated with shorter length of hospital stay and reduced complications. Lately, robotic pyeloplasty has been performed with similar results, adding the benefits of easier suturing maneuverability, but with increased costs. Flexdex® is a laparoscopic articulating needle driver that improves maneuverability and ergonomics. In this video, a laparoscopic pyeloplasty with the Flexdex® needle drive is described. The case was treated without any intraoperative complications and with no significant blood loss, and the patient was discharged the day after the procedure. After 90 days of follow-up, there were no complications reported.


Assuntos
Pelve Renal/cirurgia , Laparoscopia/métodos , Procedimentos de Cirurgia Plástica/métodos , Robótica/instrumentação , Obstrução Ureteral/cirurgia , Procedimentos Cirúrgicos Urológicos/métodos , Criança , Desenho de Equipamento , Humanos
7.
Artigo em Inglês | MEDLINE | ID: mdl-31336318

RESUMO

The main aim of this study was to define the optimal adsorption and elution conditions for the purification of human immunoglobulin G (IgG) by mixed-mode chromatography using the multimodal resin Capto MMC. To this end, Central Composite Experimental Design (ED) was performed for both the adsorption and desorption stages. In the first case, the conditions were systematically studied in batch mode while in the latter case, these were performed in column. For both studies, the experimental design was conducted using high-purity human IgG samples. Buffer pH and concentration as well as the salt concentration were the parameters under study in the ED. Adsorption kinetics and equilibrium experiments were performed under the best conditions defined in the ED (phosphate buffer 60 mmol/L, pH 6.75, no salt). The equilibrium experimental data were fit to the Langmuir equation, with maximum uptake qmax equal to 549.2 mg/g. The qmax value found for IgG in Capto MMC was quite high as compared to other chromatographic techniques that employ single modes of interaction. Regarding elution, the best conditions were obtained with acetate buffer (56.40 mmol/L), pH 5.2 and 0.2 mol/L NaCl. An ultimate recovery of 46.96% for high-purity IgG was achieved. Thus, the effectiveness of Capto MMC for IgG adsorption and recovery could be confirmed. Moreover, electrophoretic runs in the human serum indicated that although co-elution of HSA and IgG proteins occurs, substantial HSA removal and a high IgG recovery were achieved in the elution step.


Assuntos
Cromatografia/métodos , Imunoglobulina G/isolamento & purificação , Adsorção , Cromatografia/instrumentação , Humanos , Imunoglobulina G/química , Cinética , Projetos de Pesquisa
8.
Phys Rev Lett ; 121(25): 253602, 2018 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-30608797

RESUMO

We exploit a time-resolved pump-probe spectroscopic technique to study the out-of-equilibrium dynamics of an ultracold two-component Fermi gas, selectively quenched to strong repulsion along the upper branch of a broad Feshbach resonance. For critical interactions, we find the rapid growth of short-range anticorrelations between repulsive fermions to initially overcome concurrent pairing processes. At longer evolution times, these two competing mechanisms appear to macroscopically coexist in a short-range correlated state of fermions and pairs, unforeseen thus far. Our work provides fundamental insights into the fate of a repulsive Fermi gas, and offers new perspectives towards the exploration of complex dynamical regimes of fermionic matter.

9.
Phys Chem Chem Phys ; 19(2): 1335-1341, 2017 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-27973632

RESUMO

This study provides a comprehensive insight into the effects of controlled off-stoichiometry on the structural and multiferroic properties of the hexagonal manganite LuMn1-xO3+δ (x = 0.02; δ ∼ 0), supported by neutron powder diffraction measurements confirming single phase P63cm symmetry and evidencing a relevant ferromagnetic component, below TN ∼ 90 K, which breaks the archetypal geometrically frustrated antiferromagnetic state typically ascribed to LuMnO3. The perturbations in the triangular disposition of spins prompt an additional electric polarization contribution and a clear enhancement of the magnetoelectric coupling which are in good agreement with the results of first principles calculations. In addition, Raman spectroscopy, dielectric permittivity, pyroelectric current and magnetic measurements as a function of temperature point out the precursor effects of the magnetic phase transitions involving a strong coupling between spins, lattice and electric order, even above the Néel temperature.

10.
J Nanosci Nanotechnol ; 16(3): 2608-12, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27455677

RESUMO

In this work silver-rich and sulfur-rich silver sulfide (Ag2S) thin films were fabricated using a diversified set of experimental methods, namely ion beam deposition and atmosphere- and solution-based sulfurizations. The composition of the Ag2S thin films was studied using X-ray diffraction, Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. We found that it strongly depends on the fabrication conditions, such as sulfurization time and temperature. These conditions, in turn, affect the electrical characteristics of the thin films, namely the resistivity and resistive switching. We were able to control the Ag2S stoichiometry and infer its dependence on the fabrication parameters for all the followed methods.


Assuntos
Compostos de Prata/química , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Análise Espectral Raman , Difração de Raios X
11.
Phys Chem Chem Phys ; 18(19): 13519-23, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27140064

RESUMO

This study explores controlled off-stoichiometric LuMn1+zO3+δ (|z| < 0.1) compounds, intended to retain the utter LuMnO3 intrinsic hexagonal symmetry and ferroelectric properties. X-ray powder diffraction measurements evidenced a single phase P63cm structure. Thermo-gravimetric experiments show a narrow impact of oxygen vacancies while a distinguishable gas exchange at ∼700 K, a surprisingly lower temperature when compared to perovskite systems. A comparison of different nominal ceramics revealed pertinent structural and magnetic property variations owing to subtle self-doping effects. Deviations from the archetypal antiferromagnetic state were detected below ∼90 K suggesting local rearrangements of the nominal Mn(3+) ions matrix, breaking the ideal geometrical spin frustration, leading to a non-compensated magnetic structure.

12.
ACS Appl Mater Interfaces ; 7(44): 24741-7, 2015 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-26480219

RESUMO

We report polycrystalline BaTiO3 with cooperative magnetization behavior associated with the scarce presence of about 113 atomic ppm of Fe ions, clearly displaying magnetoelectric coupling with significant changes in magnetization (up to ΔM/M ≈ 32%) at the ferroelectric transitions. We find that Fe ions are segregated mostly at the interfaces between grain boundaries and an Fe-rich phase, forming a self-composite with high magnetoelectric coupling above room temperature. We compare our results with ab initio calculations and other experimental results found in the literature, proposing mechanisms that could be behind the magnetoelectric coupling within the ferroelectric matrix. These findings open the way for further strategies to optimize interfacial magnetoelectric couplings.

13.
J Phys Condens Matter ; 26(21): 215401, 2014 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-24787139

RESUMO

We report perturbed angular correlation measurements with (111m)Cd/(111)Cd and (111)In/(111)Cd probes, at the ISOLDE-CERN facility, in the manganite compounds BaMnO3, with the 6H and 15R polymorphs, and SrMnO3, with the 4H polymorph. The electric field gradient (EFG) is measured, and found approximately constant in a large temperature range for all the compounds. The EFG is also calculated from first principles with density functional theory, and compared with experimental results by considering diluted substitutional Cd impurities. Based on the results, we assign as sites for the probes the Ba (for BaMnO3-6H, 15R) and Sr (for SrMnO3-4H) sites, apart from fractions of undetermined origin in the case of BaMnO3-6H. We predict the hyperfine parameters in the recently synthesized multiferroic manganite Sr(0.5)Ba(0.5)MnO3, and its variation with the structure and electric polarization, which is found to be very small.


Assuntos
Compostos de Bário/química , Radioisótopos de Cádmio/química , Radioisótopos de Índio/química , Compostos de Manganês/química , Estrôncio/química , Eletricidade , Estrutura Molecular , Teoria Quântica , Temperatura
14.
Biomed Res Int ; 2013: 350289, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24371821

RESUMO

BACKGROUND: Heart failure (HF) patients with higher systolic blood pressure (SBP) survive longer. Diabetes mellitus (DM) is a frequent comorbidity in HF. We evaluated the prognostic significance of low SBP according to DM in acute HF. METHODS: We prospectively recruited 589 patients admitted with acute HF. DM was defined according to the 2011 American Diabetes Association recommendations. Patients were followed for 6 months and HF-death was the endpoint. A multivariate Cox-regression model was used to assess the prognostic impact of SBP. A stratified analysis according to DM was performed. RESULTS: Median patients' age was 79 years and DM was present in 50.8%. Ischemic aetiology HF and hypertension history were more common in diabetics. Diabetic patients had worse renal function and lower total cholesterol and were more often discharged with antiplatelet therapy and statin. During followup, 89 patients died due to HF. The multivariate-adjusted HR for the 6-month HF death in non-diabetic patients with an admission SBP < 115 mmHg (1st quartile) was 2.94 (95% CI: 1.49-5.79), while lower admission SBP was not associated with HF mortality in diabetics. CONCLUSIONS: The blood pressure paradox in HF is only observed in non-diabetic HF patients. Diabetic patients seem to be a particular subgroup of HF patients.


Assuntos
Pressão Sanguínea , Complicações do Diabetes/patologia , Insuficiência Cardíaca/patologia , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus/patologia , Feminino , Insuficiência Cardíaca/complicações , Humanos , Masculino , Prognóstico , Resultado do Tratamento
15.
J Phys Condens Matter ; 25(23): 235602, 2013 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-23676206

RESUMO

This work is focused on the phase diagrams and physical properties of Y-doped and Lu-doped EuMnO3. The differences in the corresponding phase boundaries in the (x,T) phase diagram could be overcome by considering a scaling of the Y(3+) and Lu(3+) concentrations to the tolerance factor. This outcome evidences that the tolerance factor is in fact a more reliable representative of the lattice deformation induced by doping. The normalization of the phase boundaries using the tolerance factor corroborates previous theoretical outcomes regarding the key role of competitive FM and AFM exchanges in determining the phase diagrams of manganite perovskites. However, significant differences in the nature and number of phases at low temperatures and concentrations could not be explained by just considering the normalization to the tolerance factor. The vertical phase boundary observed just for Lu-doped EuMnO3, close to 10% Lu, is understood by considering a low temperature Peierls-type spin-phonon coupling, which stabilizes the AFM-4 phase in Lu-doped EuMnO3.

17.
J Phys Condens Matter ; 24(43): 436002, 2012 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-23032964

RESUMO

In this work we investigate the magnetic field dependence of A(g) octahedra rotation (tilt) and B(2g) symmetric stretching modes frequencies at different temperatures. Our field-dependent Raman investigation at 10 K is interpreted by an ionic displacive nature of the magnetically-induced ferroelectric phase transition. The increasing frequency of the A(g) tilt mode with magnetic field gives evidence for the increase of the MnO(6) tilt angle, which in turn leads to a weakening of the ferromagnetic exchange interaction, yielding the necessary conditions for the onset of ferroelectricity on the basis of the inverse Dzyaloshinskii-Moriya interaction. The frequency change of the B(2g) symmetric stretching mode at the ferroelectric phase transition enables one to estimate the shift of oxygen ion positions and the corresponding spontaneous polarization of 480 µC m(-2) in magnitude, which is of the same order as earlier reported values in single crystals.

18.
Clin Oral Implants Res ; 23(12): 1404-13, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22092925

RESUMO

OBJECTIVES: This study aimed to analyse the association between polymorphisms in the IL1 gene cluster and failure of dental implants in a Portuguese population. MATERIAL AND METHODS: A total of 155 Caucasian Portuguese subjects were divided into two groups: 100 with successful dental implants and 55 with unsuccessful dental implants. DNA was obtained through an oral mucosa scraping. PCR was used to identify the polymorphisms: single nucleotide changes in positions -889 of IL1A gene and +3953 of IL1B gene. RESULTS: The prevalence of the polymorphisms -889IL1A gene and +3953IL1B gene, determined by the positive result of TGP (Genetic Test for Periodontitis; CGC, Genetics, Portugal), in the studied population rehabilitated with dental implants was of 33.50%. Allele 1 of the IL1B gene was the most prevalent (62.20%), followed by allele 1 of the IL1A gene (54.80%) and the least frequent was allele 2 of IL1B gene (37.40%). Success of dental implants was mainly associated with a negative TGP result, whereas no success was found to be related to a positive result. There were no statistically significant differences between the alleles 1 and 2 of the genes IL1A and IL1B and the tobacco and alcohol consumption for the success or no success of the dental implants. CONCLUSIONS: The alleles 1 and 2 of IL1A gene and the alleles 1 and 2 of IL1B gene were statistically associated with the success or no success of the dental implants. Tobacco habit and alcohol consumption showed no statistically significant association with success or no success of the dental implants.


Assuntos
Implantes Dentários , Falha de Restauração Dentária , Interleucina-1alfa/genética , Interleucina-1beta/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Consumo de Bebidas Alcoólicas/epidemiologia , Alelos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Portugal/epidemiologia , Fatores de Risco , Fumar/epidemiologia , Inquéritos e Questionários
19.
Genes Immun ; 13(2): 197-201, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21866115

RESUMO

Non-Hodgkin lymphoma (NHL) has been associated with immunological defects, chronic inflammatory and autoimmune conditions. Given the link between immune dysfunction and NHL, genetic variants in toll-like receptors (TLRs) have been regarded as potential predictive factors of susceptibility to NHL. Adequate anti-tumoral responses are known to depend on TLR9 function, such that the use of its synthetic ligand is being targeted as a therapeutic strategy. We investigated the association between the functional rs5743836 polymorphism in the TLR9 promoter and risk for B-cell NHL and its major subtypes in three independent case-control association studies from Portugal (1160 controls, 797 patients), Italy (468 controls, 494 patients) and the US (972 controls, 868 patients). We found that the rs5743836 polymorphism was significantly overtransmitted in both Portuguese (odds ratio (OR), 1.85; P=7.3E-9) and Italian (OR, 1.84; P=6.0E-5) and not in the US cohort of NHL patients. Moreover, the increased transcriptional activity of TLR9 in mononuclear cells from patients harboring rs5743836 further supports a functional effect of this polymorphism on NHL susceptibility in a population-dependent manner.


Assuntos
Linfoma não Hodgkin/genética , Polimorfismo Genético , Receptor Toll-Like 9/genética , Feminino , Genética Populacional , Humanos , Linfoma não Hodgkin/epidemiologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco
20.
ACS Appl Mater Interfaces ; 3(7): 2289-99, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21615151

RESUMO

This work reports the synthesis and characterization of mesoporous silica nanoparticles (MSNs) functionalized with tridecafluorooctyltriethoxysilane (F13) and their in situ incorporation onto cotton textiles. The hybrid MSNs and the functional textiles were prepared by a one-pot co-condensation methodology between tetraethylorthosilicate (TEOS) and F13, with hexadecyltrimethylammonium chloride (CTAC) as the template and triethanolamine as the base. The influence of the F13 to TEOS molar ratio (1:10, 1:5 and 1:3) on the nanoparticle morphology, porosity, degree of functionalization, and hydro/oleophobic properties is discussed. The hybrid nanosilicas presented high colloidal stability and were spherical and monodispersed with average particle size of ∼45 nm. They also showed high surface areas, large pore volumes, and a wormhole-type mesoporous structure. The increase in the organosilane proportion during the co-condensation process led to a more radially branched wormhole-like mesoporosity, a decrease in the surface area, pore volume, and amount of surface silanol groups, and an enrichment of the surface with fluorocarbon moieties. These changes imparted hydrophobic and oleophobic properties to the materials, especially to that containing the highest F13 loading. Cotton textiles were coated with the F13-MSNs through an efficient and less time-consuming route. The combination between surface roughness and mesoporosity imparted by the MSNs, and the low surface energy provided by the organosilane resulted in superhydrophobic functional textiles. Moreover, the textile with the highest loading of fluorocarbon groups was superamphiphobic.


Assuntos
Fibra de Algodão , Nanopartículas , Dióxido de Silício/química , Microscopia Eletrônica de Varredura , Difração de Pó
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