Recent Progress in Far-Field Optical Metalenses

In this chapter, a review of the recent advances in optical metalenses is presented, with special emphasis in their experimental implementation. First, the Huygens’ principle applied to ultrathin engineered metamaterials is introduced for the purpose of giving curvature to the wavefront of free-space wave fields. Primary designs based on metallic nanoslits and holey screens occasionally with variant width are first examined. Holographic plasmonic lenses are also explored offering a promising route to realize nanophotonic components. More recent metasurfaces based on nano-antenna resonators, either plasmonic or high-index dielectric, are analyzed in detail. Furthermore, 2D material lenses in the scale of a few nanometers enabling the thinnest lenses to date are here considered. Finally, dynamically reconfigurable focusing devices are reported for creating a scenario with new functionalities

SCGG: A Deep Structure-Conditioned Graph Generative Model

Deep learning-based graph generation approaches have remarkable capacities for graph data modeling, allowing them to solve a wide range of real-world problems. Making these methods able to consider different conditions during the generation procedure even increases their effectiveness by empowering them to generate new graph samples that meet the desired criteria. This paper presents a conditional deep graph generation method called SCGG that considers a particular type of structural conditions. Specifically, our proposed SCGG model takes an initial subgraph and autoregressively generates new nodes and their corresponding edges on top of the given conditioning substructure. The architecture of SCGG consists of a graph representation learning network and an autoregressive generative model, which is trained end-to-end. Using this model, we can address graph completion, a rampant and inherently difficult problem of recovering missing nodes and their associated edges of partially observed graphs. Experimental results on both synthetic and real-world datasets demonstrate the superiority of our method compared with state-of-the-art baselines

Efficiency of rotating phase masks in the resolution

The redistribution of light energy in the receiving plane of the diffraction pattern by means of concurrent suppression of side-lobes and the amplification of the central disc by applying rotating phase masks at the exit pupil has been investigated. The magnitude of the suppression of side-lobes depends on the degree of the phase mask at the edge zones of the pupil. The mask is applied to achieve the side-lobe suppression on one side of the PSF. By applying a rotated mask, side-lobe suppression will occur on the other side of the PSF. The resolution of the object or signal under the optimum masking conditions is analysed by employing the standard characteristic parameters of the diffraction

Ultrathin high-index metasurfaces for shaping focused beams

The volume size of a converging wave, which plays a relevant role in image resolution, is governed by the wavelength of the radiation and the numerical aperture (NA) of the wavefront. We designed an ultrathin (λ/8 width) curved metasurface that is able to transform a focused field into a high-NA optical architecture, thus boosting the transverse and (mainly) on-axis resolution. The elements of the metasurface are metal-insulator subwavelength gratings exhibiting extreme anisotropy with ultrahigh index of refraction for TM polarization. Our results can be applied to nanolithography and optical microscopy.Spanish Ministry of Economy and Competitiveness (MEC) (TEC2013-50416-EXP)

Study of the GSM with frequency of 950 MHz on the memory of male mice

Background and aims: The increasing use of productive machines with electromagnetic waves of different frequency and severity has led to perform many studies about the possible impact of the waves on the health of living creatures. The aim of this study was to investigate memory function and reminding in mice, exposed to microwave radiation with a frequency of 950 MHz (GSM signal). Methods: In this experimental study, 120 male mices were divided into 10 groups of 12 animals in each group. The exposed 9 groups were under microwave radiation at the power densities of 0.02, 1.3 and 8.6 mW/ cm2 and the time intervals of 2, 4 and 6 hours and one group was considered as control. The analysis of mice’s memory was done with the passive avoidance trial test and by measuring the frequency of animals entering the dark compartment of shuttle box and their entrance latency time in 6, 12, 24, 48 h, 1 and 2 weeks after the last learning stage. Results: The results showed no significant changes among the latency time of animals in entrance to the dark side of compartment, but the frequency of entrance showed significant difference among the exposure groups with the potent of 0, 0.02, 1.3 and 8.6 mW/cm2. Conclusion: Memory function and analysis of animals exposed to mobile radiation show a decrease depending on exposure time and power. The increasing frequency of animal in entrance to the dark field with the memory of electrical shock should be a sign of animal memory impairment with the exposure to the microwave mobile radiation

Comparison of Online Sexual Activity Among Iranian Individuals With and Without Substance Use Disorder: A Case-Control Study

The most important practical concerns in addiction medicine are the non-substance addiction and related addictive behaviors among individuals with substance use disorder. On the other hand, technological advances, and easy access have increased the frequency of online sexual activities (OSAs) as one of these behaviors. This study aimed to compare the prevalence of OSAs, based on the Internet Sex Screening Test (ISST) scores, among 60 patients with substance use disorder referred to Iran Psychiatric Hospital and 60 non-dependent individuals. The results showed significant negative correlations between the ISST scores and age, age at the onset of substance use, and substance use duration. There was a significant difference between the ISST scores of the case and control groups (P = 0.001). Patients who start using substances at an early age and have a great duration of substance use are more likely to engage in other addictive behaviors such as OSAs. Therefore, it is critical to consider OSAs and other addictive behaviors in patients with substance use disorder to provide better care for this vulnerable community

Obesity Accelerates Leukocyte Telomere Length Shortening in Apparently Healthy Adults: A Meta-Analysis

Background: Shorter telomere length is associated with numerous comorbidities. Several studies have investigated the role of obesity in telomere shortening. In the current systematic review and meta-analysis, we summarized the results of studies that evaluated the association between obesity and telomere length. Methods: A systematic search from Scopus, PubMed, Embase, and ProQuest electronic databases up to 19 March 2021 without language restriction was performed and after data extraction and screening, 19 manuscripts were eligible to be included in the final meta-synthesis. Results: The highest category of telomere length was associated with an approximate 0.75 kg/m2 reduction in body mass index (BMI; WMD = −0.75 kg/m2; CI = −1.19, −0.31; p < 0.001; I2 = 99.4%). Moreover, overweight/obese individuals had 0.036 kbp shorter telomere length compared with non-overweight/obese adults (WMD = −0.036; CI = −0.05, −0.02; p = 0.030; I2 = 100%). According to the results of subgroupings, continent, age, and sample size could be possible sources of heterogeneity. Conclusion: From the results, it was clear that obesity was associated with shorter telomere length. Because of the observational design of included studies, the causality inference of results should be done with caution; thus, further longitudinal studies are warranted for better inference of causal association