Search

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. [ABSTRACT FROM AUTHOR]

Neurodynamic exercise is a specific type of exercise used as a neural treatment that focuses on restoring altered homeostasis in the neuroimmune system by mobilising the nervous system and other structures. A prospective, randomized clinical trial was performed to evaluate the effect of neurodynamic exercises on disability and neck pain in elderly women over four weeks. Participants were randomized into two groups: a neurodynamic (NM) group (n = 28) and a non-specific exercise (NSE) group (n = 28). Inclusion criteria were women over 65 years of age who subjectively admitted to having mechanical neck pain for more than six months. Results showed that specific neurodynamic exercises can improve pain and disability in older women with chronic mechanical neck pain. Improvements were observed in all variables (p < 0.05). Significant between-group differences in favour of the NM group were only found for neck pressure pain thresholds and both tibialis anterior muscles. Larger effect sizes were obtained in favour of the NM group, especially for pain, disability, neck extension and inclination and pressure pain thresholds. Neurodynamic exercises have been shown to be more clinically relevant in disability and neck pain in older women. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Geometrical, chemical, optical and ionic transport changes associated with ALD of TiO2-coating on the porous structure of two nanoporous alumina membranes (NPAMs), which were obtained by the two-step aluminum anodization method but with different pore size and porosity, are presented. Chemical and morphological changes were determined by analyzing XPS spectra and SEM images, showing practically total coverage of the NPAMs surface and leading to a reduction in the geometrical parameters of both samples, while SAED and high resolution TEM measurements allowed us to determine the crystalline structure and thickness of the TiO2-coating, with the latter confirmed by depth-profile XPS analysis. Spectroscopic ellipsometry measurements were also carried out in order to detect changes in characteristic optical parameters (refractive index, n, and extinction coefficient, k), due to the TiO2-coating of NPAMs. Considering the common application of NPAMs in solute/ion diffusion processes, the effect of the TiO2-coverage on electrochemical parameters was analyzed by measuring the concentration potential with a typical model electrolyte (KCl solutions), leading to an increase of the electropositive character for both kinds of samples. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study aimed to determine the immediate and short-term effects of a single upper cervical high-velocity, low-amplitude (HVLA) manipulation on standing postural control and cervical mobility in chronic nonspecific neck pain (CNSNP). A double-blinded, randomized placebo-controlled trial was performed. Forty-four patients with CNSNP were allocated to the experimental group (n = 22) or control group (n = 22). All participants were assessed before and immediately after the intervention, with a follow-up on the 7th and 15th days. In each evaluation, we assessed global and specific stabilometric parameters to analyze standing postural balance and performed the cervical flexion-rotation test (CFRT) to analyze upper cervical mobility. We obtained statistically significant differences, with a large effect size, in the limited cervical rotation and global stabilometric parameters. Upper cervical HVLA manipulation produced an improvement in the global stabilometric parameters, significantly decreasing the mean values of velocity, surface, path length, and pressure in all assessments (p < 0.001; ƞ 2 p = 0.323–0.856), as well as significantly decreasing the surface length ratio (L/S) on the 7th (−0.219 1/mm; p = 0.008; 95% confidence interval (CI): 0.042–0.395) and 15th days (−0.447 1/mm; p < 0.001; 95% CI: 0.265–0.629). Limited cervical rotation values increased significantly immediately after manipulation (7.409°; p < 0.001; 95% CI: 6.131–8.687) and were maintained during follow-up (p < 0.001). These results show that a single upper cervical HVLA manipulation produces an improvement in standing postural control and increases the rotational range of motion (ROM) in the upper cervical spine in patients with CNSNP. [ABSTRACT FROM AUTHOR]

Optical changes associated with the surface coating of different metal oxides and nanolayers by the ALD technique of a nanoporous alumina structure (NPAS) obtained by the two-step anodization method were analyzed. The NPASs were coated with: (i) a single layer (SiO2 or TiO2), and (ii) a double layer of SiO2 plus Al2O3 or aluminum doped ZnO (AZO) to estimate the effect of surface layer coverage material, geometrical parameters (pore-size/porosity), and number of layers on light transmission/reflection. Chemical surface characterization of the different NPASs was carried out by analyzing XPS spectra, which allowed us to obtain an estimation of the coating layer homogeneity. Transmittance and spectroscopic ellipsometry measurements were analyzed in order to detect changes in characteristic optical parameters such as band gap, refractive index, and extinction coefficients associated with the material and the characteristics of the single or double coating layers. [ABSTRACT FROM AUTHOR]

In this work, the entire manufacturing process of electrostatic supercapacitors using the atomic layer deposition (ALD) technique combined with the employment of nanoporous anodic alumina templates as starting substrates is reported. The structure of a usual electrostatic capacitor, which comprises a top conductor electrode/the insulating dielectric layer/and bottom conductor electrode (C/D/C), has been reduced to nanoscale size by depositing layer by layer the required materials over patterned nanoporous anodic alumina membranes (NAAMs) by employing the ALD technique. A thin layer of aluminum-doped zinc oxide, with 3 nm in thickness, is used as both the top and bottom electrodes' material. Two dielectric materials were tested; on the one hand, a triple-layer made by a successive combination of 3 nm each layers of silicon dioxide/titanium dioxide/silicon dioxide and on the other hand, a simple layer of alumina, both with 9 nm in total thickness. The electrical properties of these capacitors are studied, such as the impedance and capacitance dependences on the AC frequency regime (up to 10 MHz) or capacitance (180 nF/cm2) on the DC regime. High breakdown voltage values of 60 V along with low leakage currents (0.4 μA/cm2) are also measured from DC charge/discharge RC circuits to determine the main features of the capacitors behavior integrated in a real circuit. [ABSTRACT FROM AUTHOR]