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1.
BMJ Open Respir Res ; 11(1)2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38479821

RESUMO

BACKGROUND: The rate of pulmonary tuberculosis (TB) recurrence is substantial. Identifying risk factors can support the development of prevention strategies. METHODS: We retrieved studies published between 1 January 1980 and 31 December 2022 that assessed factors associated with undifferentiated TB recurrence, relapse or reinfection. For factors reported in at least four studies, we performed random-effects meta-analysis to estimate a pooled relative risk (RR). We assessed heterogeneity, risk of publication bias and certainty of evidence. RESULTS: We included 85 studies in the review; 81 documented risk factors for undifferentiated recurrence, 17 for relapse and 10 for reinfection. The scope for meta-analyses was limited given the wide variety of factors studied, inconsistency in control for confounding and the fact that only few studies employed molecular genotyping. Factors that significantly contributed to moderately or strongly increased pooled risk and scored at least moderate certainty of evidence were: for undifferentiated recurrence, multidrug resistance (MDR) (RR 3.49; 95% CI 1.86 to 6.53) and fixed-dose combination TB drugs (RR 2.29; 95% CI 1.10 to 4.75) in the previous episode; for relapse, none; and for reinfection, HIV infection (RR 4.65; 95% CI 1.71 to 12.65). Low adherence to treatment increased the pooled risk of recurrence 3.3-fold (95% CI 2.37 to 4.62), but the certainty of evidence was weak. CONCLUSION: This review emphasises the need for standardising methods for TB recurrence research. Actively pursuing MDR prevention, facilitating retention in treatment and providing integrated care for patients with HIV could curb recurrence rates. The use of fixed-dose combinations of TB drugs under field conditions merits further attention. PROSPERO REGISTRATION NUMBER: CRD42018077867.


Assuntos
Infecções por HIV , Tuberculose Pulmonar , Humanos , Reinfecção , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/prevenção & controle , Tuberculose Pulmonar/tratamento farmacológico , Fatores de Risco , Recidiva , Combinação de Medicamentos
2.
Cancers (Basel) ; 16(6)2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38539440

RESUMO

BACKGROUND: The current standard of local treatment for patients with localized breast cancer (BC) includes whole breast irradiation (WBI) after breast-conserving surgery (BCS). Ultrahypofractionated WBI schemes (1-week treatment) were shown not to be inferior to the standard WBI. Tumor bed boost using photon intraoperative radiotherapy (IORT) is safe and feasible in combination with standard WBI. The aim of the present study is to assess, for the first time, the feasibility and safety of combining photon IORT with ultrahypofractionated WBI. METHODS: Patients diagnosed with low-risk early BC candidates for BCS were included in this prospective study. IORT was administered at a dose of 20 Gy to the surface's applicator, and WBI was administered 3-5 weeks after surgery at a total dose of 26 Gy in five consecutive days. RESULTS: From July 2020 to December 2022, seventy-two patients diagnosed with low-risk early BC and treated in our institution were included in this prospective study. All patients completed the proposed treatment, and no severe acute or late grade 3 toxicity was observed 3 and 12 months after WBI, respectively. CONCLUSIONS: Our results confirm for the first time that the combination of ultrafractionation WBI and photon-IORT after BCS is a feasible and safe option in patients with early BC.

3.
Materials (Basel) ; 17(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38541569

RESUMO

This study explores the optical and electrochemical properties of a ZnO coating layer deposited on a nanoporous alumina structure (NPAS) for potential multifunctional applications. The NPAS, synthesized through an electrochemical anodization process, displays well-defined nanochannels with a high aspect ratio (~3000). The ZnO coating, achieved via atomic layer deposition, enables the tuning of the pore diameter and porosity of the NPAS, thereby influencing both the optical and electrochemical interfacial properties. A comprehensive characterization using photoluminescence, spectroscopy ellipsometry and impedance spectroscopy (with the sample in contact with NaCl solutions) provides insights into optical and electrochemical parameters, including the refractive index, absorption coefficient, and electrolyte-ZnO/NPAS interface processes. This research demonstrates potential for tailoring the optical and interfacial properties of nanoporous structures by selecting appropriate coating materials, thus opening avenues for their utilization in various technological applications.

5.
Acta Otolaryngol ; 143(10): 845-848, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38059470

RESUMO

BACKGROUND: Inner ear hemorrhage (IEH) is an increasingly recognized cochlear lesion that can cause sensorineural hearing loss (SNHL). Magnetic resonance imaging (MRI) is known to be the best imaging modality for clarifying the causes of SNHL and providing images that point to those causes. AIMS: Evaluate the lesional patterns in patients with presumed Inner ear hemorrhage (IEH) from radiological and functional aspects. MATERIAL AND METHODS: We retrospectively reviewed 10 patients performed in our institution from 2014 to 2020, with suspected labyrinthine hemorrhage based on radiological and functional examination. RESULTS: We included 8 patients with IEH and sensorineural hearing loss (SNHL). The median age was 55 years (range: 3 months - 78 years). The results from the MRI and functional tests were compared for each end-organ. Only three cases (37.5%) showed a correlation between signal abnormalities and dysfunction in the labyrinthine apparatus. CONCLUSIONS: In patients with SNHL inner ear hemorrhage needs to be ruled out in the differential diagnosis, so specific MRI sequences should be requested. It represents a way to a better understanding of the disorder and the variety of findings claim for a complete auditory and vestibular testing.


Assuntos
Otopatias , Orelha Interna , Perda Auditiva Neurossensorial , Perda Auditiva Súbita , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Perda Auditiva Súbita/diagnóstico , Orelha Interna/diagnóstico por imagem , Otopatias/complicações , Perda Auditiva Neurossensorial/diagnóstico por imagem , Perda Auditiva Neurossensorial/etiologia , Imageamento por Ressonância Magnética/métodos , Hemorragia/diagnóstico por imagem , Hemorragia/complicações
6.
ACS Omega ; 8(43): 40087-40098, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37929086

RESUMO

In the current energy crisis scenario, the development of renewable energy forms such as energy storage systems among the supercapacitors is an urgent need as a tool for environmental protection against increasing pollution. In this work, we have designed a novel 3D nanostructured silver electrode through an antireplica/replica template-assisted procedure. The chemical surface and electrochemical properties of this novel 3D electrode have been studied in a 5 M KOH electrolyte. Microstructural characterization and compositional analysis were studied by SEM, energy-dispersive X-ray spectroscopy, XRD technique, and Kripton adsorption at -198 °C, together with cyclic voltammetry and galvanostatic charge-discharge cycling measurements, Coulombic efficiency, cycle stability, and their leakage current drops, in addition to the self-discharge and electrochromoactive behavior, were performed to fully characterize the 3D nanostructured electrode. Large areal capacitance value of 0.5 F/cm2 and Coulombic efficiency of 97.5% are obtained at a current density of 6.4 mA/cm2 for a voltage window of 1.2 V (between -0.5 and 0.8 V). The 3D nanostructured silver electrode exhibits excellent capacitance retention (95%) during more than 2600 cycles, indicating a good cyclic stability. Additionally, the electrode delivers a high energy density of around 385.87 µWh/cm2 and a power density value of 3.82 µW/cm2 and also displays an electrochromoactive behavior. These experimental results strongly support that this versatile combined fabrication procedure is a suitable strategy for improving the electrochemical performances of 3D nanostructured silver electrodes for applications as micro-supercapacitors or in electrochemical devices.

7.
J Clin Med ; 12(18)2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37762906

RESUMO

BACKGROUND: The 3D-REAL-IR MRI sequence allows for an in vivo visualization of endolymphatic hydrops. Qualitative assessment methods of the severity of vestibular and cochlear hydrops are the most commonly used. METHODS: A quantitative volumetric measurement of vestibular EH in patients with definite unilateral Ménière's disease using the 3D-REAL-IR sequence and the calculation of the endolymphatic ratio (ELR) was intended. RESULTS: Volumetric calculations of the vestibules, vestibular endolymph and vestibular ELR are performed in 96 patients with unilateral Ménière's disease and correlated with classic qualitative grading scales. CONCLUSIONS: Quantitative volumetric measurement of vestibular hydrops using the 3D-REAL-IR sequence is feasible and reproducible in daily clinical practice. Vestibular ELR values exceeding 60% defined radiologically significant vestibular hydrops, while values below 30% defined radiologically non-significant vestibular hydrops.

8.
Micromachines (Basel) ; 14(4)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37421072

RESUMO

Optical characterization of nanoporous alumina-based structures (NPA-bSs), obtained by ALD deposition of a thin conformal SiO2 layer on two alumina nanosupports with different geometrical parameters (pore size and interpore distance), was performed by two noninvasive and nondestructive techniques such as spectroscopic ellipsometry (SE) and photoluminescence (Ph) spectra. SE measurements allow us to estimate the refraction index and extinction coefficient for the studied samples and their dependence with wavelength for the 250-1700 nm interval, showing the effect of sample geometry and cover-layer material (SiO2, TiO2, or Fe2O3), which significantly affect the oscillatory character of both parameters, as well as changes associated with the light incidence angle, which are attributed to surface impurities and inhomogeneity. Photoluminescence curves exhibit a similar shape independently of sample pore-size/porosity, but they seem to affect intensity values. This analysis shows the potential application of these NPA-bSs platforms to nanophotonics, optical sensing, or biosensing.

9.
Int J Mol Sci ; 24(8)2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37108198

RESUMO

Tuning and controlling the magnetic properties of nanomaterials is crucial to implement new and reliable technologies based on magnetic hyperthermia, spintronics, or sensors, among others. Despite variations in the alloy composition as well as the realization of several post material fabrication treatments, magnetic heterostructures as ferromagnetic/antiferromagnetic coupled layers have been widely used to modify or generate unidirectional magnetic anisotropies. In this work, a pure electrochemical approach has been used to fabricate core (FM)/shell (AFM) Ni@(NiO,Ni(OH)2) nanowire arrays, avoiding thermal oxidation procedures incompatible with integrative semiconductor technologies. Besides the morphology and compositional characterization of these core/shell nanowires, their peculiar magnetic properties have been studied by temperature dependent (isothermal) hysteresis loops, thermomagnetic curves and FORC analysis, revealing the existence of two different effects derived from Ni nanowires' surface oxidation over the magnetic performance of the array. First of all, a magnetic hardening of the nanowires along the parallel direction of the applied magnetic field with respect their long axis (easy magnetization axis) has been found. The increase in coercivity, as an effect of surface oxidation, has been observed to be around 17% (43%) at 300 K (50 K). On the other hand, an increasing exchange bias effect on decreasing temperature has been encountered when field cooling (3T) the oxidized Ni@(NiO,Ni(OH)2) nanowires below 100 K along their parallel lengths.


Assuntos
Nanoporos , Nanofios , Nanofios/química , Óxido de Alumínio , Níquel/química , Nanotecnologia/métodos
10.
Front Public Health ; 10: 985430, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36544789

RESUMO

Understanding the role of space in infectious diseases' dynamics in urban contexts is key to developing effective mitigation strategies. Urbanism, a discipline that both studies and acts upon the city, commonly uses drawings to analyze spatial patterns and their variables. This paper revisits drawings as analytical and integrative tools for interdisciplinary research. We introduce the use of drawings in two interdisciplinary projects conducted in the field of global public health: first, a study about the heterogeneous burden of tuberculosis and COVID-19 in Lima, Peru, and second, a study about urban malaria in Jimma, Ethiopia. In both cases, drawings such as maps, plans, and sections were used to analyze spatial factors present in the urban context at different scales: from the scale of the territory, the city, and the district, to the neighborhood and the household. We discuss the methodological approaches taken in both cases, considering the nature of the diseases being investigated as well as the natural and social context in which the studies took place. We contend that the use of drawings helps to reimagine space in public health research by adding a multidimensional perspective to spatial variables and contexts. The processes and products of drawing can help to (a) identify systemic relations within the spatial context, (b) facilitate integration of quantitative and qualitative data, and (c) guide the formulation of policy recommendations, informing public and urban health planning.


Assuntos
COVID-19 , Doenças Transmissíveis , Estados Unidos , Humanos , Saúde Global , Pesquisa Interdisciplinar , COVID-19/epidemiologia , Cidades
11.
Eur Respir Rev ; 31(165)2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-35896272

RESUMO

INTRODUCTION: People with tuberculosis experience long-term health effects beyond cure, including chronic respiratory diseases. We investigated whether tuberculosis is a risk factor for subsequent lung cancer. METHODS: We searched PubMed, Scopus, Cochrane, Latin American and Caribbean Health Sciences Literature and the Scientific Electronic Library Online for cohort and case-control studies providing effect estimates for the association between tuberculosis and subsequent lung cancer. We pooled estimates through random-effects meta-analysis. The study was registered in PROSPERO (CDR42020178362). RESULTS: Out of 6240 records, we included 29 cohort and 44 case-control studies. Pooled estimates adjusted for age and smoking (assessed quantitatively) were hazard ratio (HR) 1.51 (95% CI 1.30-1.76, I2=81%; five studies) and OR 1.74 (95% CI 1.42-2.13, I2=59%; 19 studies). The occurrence of lung cancer was increased for 2 years after tuberculosis diagnosis (HR 5.01, 95% CI 3.64-6.89; two studies), but decreased thereafter. Most studies were retrospective, had moderate to high risk of bias, and did not control for passive smoking, environmental exposure and socioeconomic status. Heterogeneity was high. CONCLUSION: We document an association between tuberculosis and lung cancer occurrence, particularly in, but not limited to, the first 2 years after tuberculosis diagnosis. Some cancer cases may have been present at the time of tuberculosis diagnosis and therefore causality cannot be ascertained. Prospective studies controlling for key confounding factors are needed to identify which tuberculosis patients are at the highest risk, as well as cost-effective approaches to mitigate such risk.


Assuntos
Neoplasias Pulmonares , Tuberculose , Exposição Ambiental , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/epidemiologia , Estudos Prospectivos , Estudos Retrospectivos
12.
Eur Arch Otorhinolaryngol ; 279(12): 5591-5600, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35578137

RESUMO

PURPOSE: Current studies show that frequency tuning modification is a good marker for the detection of endolymphatic hydrops (EH) employing magnetic resonance imaging (MRI) in patients with Ménière's disease (MD). The purpose of the present study is to analyze the auditory and vestibular function with audiometric and vestibular-evoked myogenic potentials (VEMP) responses, respectively, in both the affected and unaffected ears of patients with unilateral MD using MRI as diagnostic support for the degree of EH. METHODS: We retrospectively reviewed the medical records of 76 consecutive patients with unilateral definite MD (age 55 (28-75); 39 women, 37 men). MRI was used through intravenous gadolinium administration, audiometry, and VEMPs. Functional tests were performed up to a week after the MRI. All were followed up one year after imaging utilizing clinical, auditory, and vestibular testing to rule out bilateral involvement. RESULTS: In the unaffected ear, the mean pure-tone average is normal even in cases with hydrops and, for a similar severity of hydrops is significantly lower than in the affected ear. Significant differences for the amplitude of the response at 0.5 kHz, at 1 kHz between the affected and unaffected ears were found to be lower in the affected ears. The relative amplitude ratio (1 Kz-0.5 kHz) was significantly lower in the affected ear and in the case of the oVEMP response depends on the degree of EH. The response in the unaffected ear was not modified by the presence or the degree of hydrops. CONCLUSION: In the unaffected ear, hydrops is not associated with hearing deterioration. For a similar degree of hydrops, hearing loss is significantly greater in the affected ear. The endolymphatic hydrops in the vestibule induces a frequency bias in the VEMP response only in the affected ear and not in the unaffected ear. Because of these findings we consider that hydrops does not represent an active disorder in the unaffected ear.


Assuntos
Hidropisia Endolinfática , Doença de Meniere , Potenciais Evocados Miogênicos Vestibulares , Masculino , Humanos , Feminino , Pessoa de Meia-Idade , Doença de Meniere/complicações , Doença de Meniere/diagnóstico , Estudos Retrospectivos , Hidropisia Endolinfática/diagnóstico , Hidropisia Endolinfática/diagnóstico por imagem , Potenciais Evocados Miogênicos Vestibulares/fisiologia , Imageamento por Ressonância Magnética/métodos , Edema
13.
Audiol Res ; 12(2): 202-211, 2022 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-35447743

RESUMO

BACKGROUND: Although diagnostic criteria have been established for superior canal dehiscence syndrome, cases in which the diagnosis is not easy are frequent. On those occasions, some tests such as vibration-induced nystagmus or vestibular-evoked myogenic potentials can offer invaluable help due to their high sensitivity and specificity. METHODS: We studied 30 patients showing superior canal dehiscence or "near-dehiscence" in a CT scan. Skull vibration-induced nystagmus and high frequency ocular vestibular-evoked myogenic potentials are performed in each patient. The aim of the study is to determine how useful both tests are for detection of superior canal dehiscence or near-dehiscence. RESULTS: Of the 60 temporal bones studied, no dehiscence was the result in 22, near-dehiscence in 17 and a definite finding in 21. In 10/30 patients, there was no SVIN (Skull vibration induced nystagmus) during otoneurological testing, while in 6/30, induced nystagmus was mainly horizontal, and in 14/30 there was vertical up-beating. All patients had a positive oVEMP (Ocular vestibular evoked myiogenic potentials) at 0.5 kHz in both ears and the HFoVEMP (High frequency ocular vestibular evoked myiogenic potentials) response was positive in 25/60 (41.6%) of the ears studied and in 19/30 of the patients evaluated (in 6 it was positive in both ears). Up-beat SVIN will point to a SCD (Superior Canal Dehiscence) mainly when HFoVEMP are present, and when this is negative there is a high probability that it is not a SCD. CONCLUSIONS: When SVIN and HFoVEMP results are added (or combined), they not only improve the possibilities of detecting SCD, but also the affected side.

14.
Transbound Emerg Dis ; 69(3): 1108-1117, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-33711193

RESUMO

Air and surfaces of swine farms are the two alternative samples to obtain information about the health status of the herd. The aim of this study was to assess air and surface sampling for the detection of porcine circovirus type 2 (PCV2) in vaccinated and unvaccinated fattening farms, studying the relationship between the viral load in these samples with the viremia at herd level. Three swine fattening batches (one unvaccinated; two vaccinated) were monitored at 10, 12, 14, 16 and 18 weeks old; at each stage, blood, air and different surfaces were sampled and analysed by qPCR. In all herds, PCV2 was detected in all types of samples. Whenever viremia was detected, PCV2 was also detected in air and surface samples, even in those cases with a low estimated prevalence (1.6%); moreover, in two out of the three herds, PCV2 was detected in air and surface samples earlier than in the blood of the sampled population. In addition, a good correlation between the viremia of pig population and the PCV2 load in air and surface samples was found in both cases (τ = 0.672 and 0.746, respectively; p <0.05). These results show that air and surface samples could be useful tools to monitor PCV2 infection, being suitable for detecting the virus in cases of low prevalence and even before pigs develop viremia; therefore, these sampling techniques would speed up the implementation of the required measures to prevent productive and economic losses due to PCV2 infection.


Assuntos
Infecções por Circoviridae , Circovirus , Doenças dos Suínos , Vacinas Virais , Animais , Anticorpos Antivirais , Infecções por Circoviridae/epidemiologia , Infecções por Circoviridae/prevenção & controle , Infecções por Circoviridae/veterinária , Fazendas , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/prevenção & controle , Viremia/veterinária
15.
Nanomaterials (Basel) ; 11(12)2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34947752

RESUMO

Geometrically modulated magnetic nanowires are a simple yet efficient strategy to modify the magnetic domain wall propagation since a simple diameter modulation can achieve its pinning during the nanowire magnetization reversal. However, in dense systems of parallel nanowires, the stray fields arising at the diameter interface can interfere with the domain wall propagation in the neighboring nanowires. Therefore, the magnetic behavior of diameter-modulated nanowire arrays can be quite complex and depending on both short and long-range interaction fields, as well as the nanowire geometric dimensions. We applied the first-order reversal curve (FORC) method to bi-segmented Ni nanowire arrays varying the wide segment (45-65 nm diameter, 2.5-10.0 µm length). The FORC results indicate a magnetic behavior modification depending on its length/diameter aspect ratio. The distributions either exhibit a strong extension along the coercivity axis or a main distribution finishing by a fork feature, whereas the extension greatly reduces in amplitude. With the help of micromagnetic simulations, we propose that a low aspect ratio stabilizes pinned domain walls at the diameter modulation during the magnetization reversal. In this case, long-range axial interaction fields nucleate a domain wall at the nanowire extremities, while short-range ones could induce a nucleation at the diameter interface. However, regardless of the wide segment aspect ratio, the magnetization reversal is governed by the local radial stray fields of the modulation near null magnetization. Our findings demonstrate the capacity of distinguishing between complex magnetic behaviors involving convoluted interaction fields.

16.
Life (Basel) ; 11(12)2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34947872

RESUMO

Currently available anti-viral drugs may be useful in reducing the viral load but are not providing the necessary physiological effects to reduce the SARS-CoV-2 complications efficiently. Treatments that provide better clinical outcomes are urgently needed. Vitamin C (ascorbic acid, AA) is an essential nutrient with many biological roles that have been proven to play an important part in immune function; it serves as an antioxidant, an anti-viral, and exerts anti-thrombotic effects among many other physiological benefits. Research has proven that AA at pharmacological doses can be beneficial to patients with acute respiratory distress syndrome (ARDS) and other respiratory illnesses, including sepsis. In addition, High-Dose Intravenous Vitamin C (HDIVC) has proven to be effective in patients with different viral diseases, such as influenza, chikungunya, Zika, and dengue. Moreover, HDIVC has been demonstrated to be very safe. Regarding COVID-19, vitamin C can suppress the cytokine storm, reduce thrombotic complications, and diminish alveolar and vascular damage, among other benefits. Due to these reasons, the use of HDIVC should be seriously considered in complicated COVID-19 patients. In this article, we will emphasize vitamin C's multiple roles in the most prominent pathophysiological processes presented by the COVID-19 disease.

17.
Nanomaterials (Basel) ; 11(11)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34835841

RESUMO

Magnetic nanomaterials are of great interest due to their potential use in data storage, biotechnology, or spintronic based devices, among others. The control of magnetism at such scale entails complexing the nanostructures by tuning their composition, shape, sizes, or even several of these properties at the same time, in order to search for new phenomena or optimize their performance. An interesting pathway to affect the dynamics of the magnetization reversal in ferromagnetic nanostructures is to introduce geometrical modulations to act as nucleation or pinning centers for the magnetic domain walls. Considering the case of 3D magnetic nanowires, the modulation of the diameter across their length can produce such effect as long as the segment diameter transition is sharp enough. In this work, diameter modulated Fe67Co33 ferromagnetic nanowires have been grown into the prepatterned diameter modulated nanopores of anodized Al2O3 membranes. Their morphological and compositional characterization was carried out by electron-based microscopy, while their magnetic behavior has been measured on both the nanowire array as well as for individual bisegmented nanowires after being released from the alumina template. The magnetic hysteresis loops, together with the evaluation of First Order Reversal Curve diagrams, point out that the magnetization reversal of the bisegmented FeCo nanowires is carried out in two steps. These two stages are interpreted by micromagnetic modeling, where a shell of the wide segment reverses its magnetization first, followed by the reversal of its core together with the narrow segment of the nanowire at once.

18.
Nanomaterials (Basel) ; 11(9)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34578598

RESUMO

Nowadays, numerous works regarding nanowires or nanotubes are being published, studying different combinations of materials or geometries with single or multiple layers. However, works, where both nanotube and nanowires are forming complex structures, are scarcer due to the underlying difficulties that their fabrication and characterization entail. Among the specific applications for these nanostructures that can be used in sensing or high-density magnetic data storage devices, there are the fields of photonics or spintronics. To achieve further improvements in these research fields, a complete understanding of the magnetic properties exhibited by these nanostructures is needed, including their magnetization reversal processes and control of the magnetic domain walls. In order to gain a deeper insight into this topic, complex systems are being fabricated by altering their dimensions or composition. In this work, a successful process flow for the additive fabrication of core/shell nanowires arrays is developed. The core/shell nanostructures fabricated here consist of a magnetic nanowire nucleus (Fe56Co44), grown by electrodeposition and coated by a non-magnetic SiO2 layer coaxially surrounded by a magnetic Fe3O4 nanotubular coating both fabricated by means of the Atomic Layer Deposition (ALD) technique. Moreover, the magnetization reversal processes of these coaxial nanostructures and the magnetostatic interactions between the two magnetic components are investigated by means of standard magnetometry and First Order Reversal Curve methodology. From this study, a two-step magnetization reversal of the core/shell bimagnetic nanostructure is inferred, which is also corroborated by the hysteresis loops of individual core/shell nanostructures measured by Kerr effect-based magnetometer.

19.
Materials (Basel) ; 14(17)2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34501141

RESUMO

Changes associated to atomic layer deposition (ALD) of SiO2 from 3-aminopropyl triethoxysilane (APTES) and O3, on a nanoporous alumina structure, obtained by two-step electrochemical anodization in oxalic acid electrolyte (Ox sample) are analysed. A reduction of 16% in pore size for the Ox sample, used as support, was determined by SEM analysis after its coverage by a SiO2 layer (Ox+SiO2 sample), independently of APTES or O3 modification (Ox+SiO2/APTES and Ox+SiO2/APTES/O3 samples). Chemical surface modification was determined by X-ray photoelectron spectroscopy (XPS) technique during the different stages of the ALD process, and differences induced at the surface level on the Ox nanoporous alumina substrate seem to affect interfacial effects of both samples when they are in contact with an electrolyte solution according to electrochemical impedance spectroscopy (EIS) measurements, or their refraction index as determined by spectroscopic ellipsometry (SE) technique. However, no substantial differences in properties related to the nanoporous structure of anodic alumina (photoluminescent (PL) character or geometrical parameters) were observed between Ox+SiO2/APTES and Ox+SiO2/APTES/O3 samples.

20.
Front Surg ; 8: 673847, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34136529

RESUMO

Background: Endolymphatic hydrops (EH) is the histopathological hallmark of Ménière's disease (MD) and has been found by in vivo magnetic resonance imaging (MRI) in patients with several inner ear syndromes without definite MD criteria. The incidence and relevance of this finding is under debate. Purpose: The purpose of the study is to evaluate the prevalence and characteristics of EH and audiovestibular test results in groups of patients with fluctuating audiovestibular symptoms not fulfilling the actual criteria for definite MD and compare them with a similar group of patients with definite MD and a group of patients with recent idiopathic sudden neurosensory hearing loss (ISSNHL). Material and Methods: 170 patients were included, 83 with definite MD, 38 with fluctuating sensorineural hearing loss, 34 with recurrent vertigo, and 15 with ISSNHL. The clinical variables, audiovestibular tests, and EH were evaluated and compared. Logistic proportional hazard models were used to obtain the odds ratio for hydrops development, including a multivariable adjusted model for potential confounders. Results: No statistical differences between groups were found regarding disease duration, episodes, Tumarkin spells, migraine, vascular risk factors, or vestibular tests; only hearing loss showed differences. Regarding EH, we found significant differences between groups, with odds ratio (OR) for EH presence in definite MD group vs. all other patients of 11.43 (4.5-29.02; p < 0.001). If the ISSNHL group was used as reference, OR was 55.2 (11.9-253.9; p < 0.001) for the definite MD group, 9.9 (2.1-38.9; p = 0.003) for the recurrent vertigo group, and 5.1 (1.2-21.7; p = 0.03) for the group with fluctuating sensorineural hearing loss. Conclusion: The percentage of patients with EH varies between groups. It is minimal in the ISSNHL group and increases in groups with increasing fluctuating audiovestibular symptoms, with a rate of severe EH similar to the known rate of progression to definite MD in those groups, suggesting that presence of EH by MRI could be related to the risk of progression to definite MD. Thus, EH imaging in these patients is recommended.

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