Investigation of Strain Effects on Photoelectrochemical Performance of Flexible ZnO Electrodes

In this report, the growth of zinc oxide (ZnO) nanocrystals with various morphologies, nanoflower, nanosheet, and nanorod, on flexible stainless steel (SS) foils to be utilized as photoanodes in photoelectrochemical (PEC) solar cells has been presented. It has been aimed to provide flexibility and adaptability for the next generation systems with the incorporation of SS foils as electrode into PEC cells. Therefore, physical deformation tests have been applied to the prepared ZnO thin film photoanodes. These thin films have been thoroughly characterized before and after straining for better understanding the relationship between the morphology, straining effect and photoelectrochemical efficiency. We observed a notable increase in the maximum incident photon-to-current efficiency (IPCE) and durability of all ZnO photoelectrodes after straining process. The increase in IPCE values by 1.5 and 2.5 folds at 370 nm has been observed for nanoflower and nanorod morphologies, respectively after being strained. The maximum IPCE of 69% has been calculated for the ZnO nanorod structures after straining. Bending of the SS electrodes resulted in the more oriented nanorod arrays compared to its flat counterpart, which improved both the light absorption and also the photo-conversion efficiency drastically. The finite-difference time-domain simulations have also been carried out to examine the optical properties of flat and bent ZnO electrodes. Finally, it has been concluded that SS photoanodes bearing ZnO semiconducting material with nanoflower and nanorod morphologies are very promising candidates for the solar hydrogen generator systems in terms of efficiency, durability, flexibility, and lightness in weight

The Importance of Analytical Chemistry in Therapeutic Drug Monitoring for Personalized Medicine

Personalized therapy (PM) has the potential to adapt treatment with the best response and highest safety to provide better patient care. Key data is drug concentration of biological materials such as plasma and serum.Individual drug therapy means, choice of a drug and its dose regime should fit every individual specifically. Thus efficacy of a drug treatment would improve significantly. When developing an analytical method for (Therapeutic drug monitoring) TDM, it is important to choose a clinically relevant calibration range. This quantitation range should be built around the proposed target concentration, covering majority of samples as seen in the clinic (Ciocan-Cartita et al. 2019).Inter-individual variability in Pharmacokinetic variables may affect the blood concentration of drug so TDM approaches could solve the dosing problem.To achieve individual drug therapy with a reasonably predictive outcome, one must further account for different patterns of drug response among geographically and ethnically distinct populations. Keywords: LC-MS/MS, Therapeutic Drug Monitoring, Lenalidomide, Anastrozole DOI: 10.7176/CMR/12-7-05 Publication date:September 30th 202

Detection of audio covert channels using statistical footprints of hidden messages

We address the problem of detecting the presence of hidden messages in audio. The detector is based on the characteristics of the denoised residuals of the audio file, which may consist of a mixture of speech and music data. A set of generalized moments of the audio signal is measured in terms of objective and perceptual quality measures. The detector discriminates between cover and stego files using a selected subset of features and an SVM classifier. The proposed scheme achieves on the average 88% discrimination performance on individual steganographic algorithms and 98.5% on individual watermarking algorithms. Between 75 and 90% discrimination performance is achieved in universal tests. Correct detection performance for individual embedding algorithms is roughly 90% when the detector can encounter any one in an ensemble of different embedding algorithms

Nanohole-based phase gradient metasurfaces for light manipulation

The commonly accepted approach for metasurface design utilizes nanopillars with varying diameters. In this study, contrary to usual design approach, we propose and design highly efficient, broadband and polarization-independent nanohole all-dielectric metasurfaces operating in the visible spectrum. High focusing efficiency above 70% is achieved between 450 and 700 nm wavelength region with a numerical aperture (NA) value of 0.60. Moreover, focusing efficiency is succeeded higher than 47% with NA = 0.85 for a design wavelength of 532 nm. Nanohole metasurfaces exhibit less chromatic aberration (< 18%) compared to nanopillar based metasurfaces. The nanohole array metasurfaces is investigated under the oblique illumination condition and its performance is found to be satisfactory in a wide range of incidence angles. Furthermore, nanohole and nanopillar metasurfaces are analyzed and their performances are compared for different incidence angles, NAs and operating wavelengths. It is shown that contrary to dielectric pillars commonly deployed in the design of metasurfaces, nanoholes with varying diameters allow phase changes with better performances

Rotationally tunable polarization-insensitive single and multifocal metasurface

Metasurfaces with superior capabilities to tailor wave fronts of light have become one of the most widely investigated optical elements. Incorporating tunable features into the metasurface design is required. In this study, we have proposed and designed highly efficient rotationally tunable metasurface lens structures inspired by Moire lenses operating at a 532 nm wavelength. The proposed structures consist of two cascaded all-dielectric metasurfaces, which have reverse phase profiles with respect to each other. The metasurfaces are designed with periodically arranged TiO2 nano-rods on a SiO2 substrate in a square lattice. We demonstrated that the focal length changes nonlinearly according to the mutual rotation of metasurfaces from 30 degrees to 150 degrees with a focusing efficiency as high as 55% and a wide focal length variation between 11.4 mu m and 4.2 mu m. Moreover, we have designed and proposed a tunable polarization-insensitive multifunctional focal system. Using the proposed multifunctional focal system, focal planes can be formed in consecutive planes and the number of focal planes can be made single or multiple

Ultrasonography Causes Agitation and Pain Leading to Hemodynamic Disturbance in Neonates: A Prospective Observational Study

Background: Ultrasonography is widely used in neonatological practice and studies investigating the hemodynamic effects of various treatment protocols or clinical situations. On the other hand, pain causes changes in the cardiovascular system; so, in the case of ultrasonography leading to pain in neonates, it may cause hemodynamic alterations. In this prospective study, we evaluate whether ultrasonographic application causes pain and changes in the hemodynamic system. Methods: Newborns undergoing ultrasonographic examination were enrolled in the study. Vital signs, cerebral and mesenteric tissue oxygenation (StO2) levels, and middle cerebral artery (MCA) Doppler measurements were recorded, and NPASS scores were calculated before and after ultrasonography. Results: We enrolled 39 patients in the study. After ultrasonography, Neonatal Pain, Agitation, and Sedation Scale (NPASS) scores were significantly higher (p 2, diastolic and systolic blood pressure; p = 0.03; p p p p = 0.02, p = 0.03, respectively) were altered. Cerebral (p = 0.008) and mesenteric (p = 0.039) StO2 levels were significantly lower in the whole study group, MCA end-diastolic velocity decreased (p = 0.02), and the resistive index (p = 0.03) increased in patients whose NPASS score was >7 after ultrasonography. Conclusions: This study is the first to show that ultrasonography may cause pain in newborn patients, and alters vital signs and hemodynamic parameters. Therefore, precautions should be taken to protect newborn babies from pain during ultrasound applications, as they are already exposed to many noxious stimuli. Furthermore, pain scores should be considered in studies using ultrasonography and evaluating hemodynamic parameters to increase the reliability of the studies

Broadband asymmetric light transmission based on all-dielectric metasurfaces in the visible spectrum

An asymmetric transmission device composed of all dielectric phase gradient metasurfaces on the dielectric substrate in the visible wavelengths is proposed and designed. In order to verify its operation principle and investigate its asymmetric transmission performance, ray and wave analyses are employed together. Specifically, ray tracing and finite-difference time-domain techniques are carried out in the study. The analytical calculations of the designed structure are confirmed with the results of the ray and wave analysis. It is also demonstrated that broadband and high contrast asymmetric transmission occur across nearly the entire visible spectrum from wavelengths of 500-715 nm. Especially, the difference of transmission between forward and backward illuminations in the design wavelength of 532 nm is found to be nearly 90% under TM polarization. In addition, it is indicated that a slight degradation in the asymmetric transmission performance of the structure occurs due to the change of the light polarization. It is shown that the asymmetric transmission has been directly related to the total reflection of the light for only one direction excitation case. The proposed structure can be fabricated with emerging nanofabrication techniques in conformal metasurfaces and can be realized in different wavelength ranges

Accelerating beam generation via all-dielectric metasurfaces

Metamaterials XII (2019: Prague, Czech Republic )All-dielectric metasurfaces are unique component to control optical wavefront with high transmission or reflection coefficient. Recently, accelerating beam, which propagates along curved arbitrary trajectories, has been realized with conventional diffractive optical elements (DOE). However, DOE suffer from low sampling ratio of rapid phase gradients and its diffraction efficiency drops quickly when the wavelength is switched to another wavelength which is different than the designed wavelength. In this study, we show accelerating beam which is generated by highly efficient and polarization insensitive all-dielectric metasurfaces in the visible wavelength. The acceleration beam is numerically generated with the proposed metasurfaces which are composed of TiO2 nanopillars residing on glass substrate using finite difference time-domain computational method. It is shown that this beam has the ability to propagate curved trajectories in air medium. Transmission efficiency of the proposed structure is above 65% and desired arbitrary trajectories have been achieved. Generating highly efficient accelerating beam can be used in photonic applications in optical imaging, spectroscopy, optical micromanipulation and nonlinear optics. © 2019 SPIE