Magnifying Power Research Articles

Visuelle Beeinträchtigung in der Kontaktlinsenpraxis

Purpose. The aim of this case report is to describe the treatment of myopic eyes with pathological reduced vision. A contact lens and a spectacle lens build a telescope and the associated magnification helps to increase vision acuity. Material and Methods. The myopic not presbyopic eyes (−3.00 D) were overcorrected by −7 D with bitoric, spherical, rigid contact lenses, base curve = 8.00/7.65 mm, back-vertex-power = −10.00/−12.00 D, over-all diameter = 10.4 mm. The refractive compensation with the spectacle lens, back-vertex-power = +6.50 D (corneal-vertex-distance 12.0 mm), front-surface-power = +7.50 D, refractive index = 1.50, over-all diameter = 65 mm, centre thickness = 7.10 mm together with contact lens build a Galilean type telescope with a maximum of magnification power. Results. The magnification power of the telescope was Vs = 1.091, the magnification power of the spectacle lens was Ve = 1.037 and the related total magnification power was Vg = 1.131. The telescope increased the binocular distance vision acuity from 0.40− to 0.63 and the binocular near vision acuity from 0.32+ to 0.40+. Conclusion. The Galilei system described is suitable for improving visual acuity in the case of special visual impairments.

Evaluation of dentin features in teeth after caries removal by three techniques (chemomechanical, mechanical with a smart bur, and air-abrasion): an in vitro study.

Different methods for removing dental carious lesions exist, including conventional rotary caries removal and new advanced technology like polymer-based burs, chemomechanical agents, air abrasion, and laser. This study shows the differences in features of dentin (smear layer, patency of dentinal tubules, surface irregularities, intertubular micro porosities, and exposed dentinal tubules) among different types of caries removal techniques. An in vitro study was done on 60 primary molars with occlusal class I active caries. Teeth were divided into three groups according to a method of caries removal (G1: chemomechanical, G2: mechanical with a smart bur, and G3: air-abrasion). After complete caries excavation, the teeth were examined under a scanning electronic microscope (SEM) with the power of magnification 4,000x and 8,000x to show the morphological dentinal features with SEM microphotographs. Data obtained was analyzed using the SPSS program where Fisher exact, Kruskal-Wallis and multiple Wilcoxon sum rank tests were used. The level of significance is when the p-value is less than 0.05. Generally, SEM showed the highest ratio of score 1 of smear layer presence, surface irregularities, and microporosity in all groups in both magnifications. The patency of tubules showed the highest ratio of score 1 in G1, scores 2 in both G2 and G3 in magnification 4,000x, while 8,000x there was the highest ratio of its score 1 in G1 and G2 while the G3 has score 2 as the highest score. The exposed dentinal tubules showed the highest ratio in G1 in score 3, in G2 in score 2, and in G3 in score 1 in magnification 4,000x, while 8,000x there was the highest ratio of its score 2 in both G1 and G3 while the G3 has highest score 1. The study with magnification 4,000x showed a significant difference (S) among three groups in exposed dentinal tubules with a p-value (0.012), and there was S between chemomechanical and smart, chemomechanical and air-abrasions groups with a p-value (0.041, 0.001 subsequentially). Other dentin features showed non-significant differences (NS) among or between groups in both magnifications (4,000x, 8,000x). All groups were effective in removing caries and can successfully treat young, scared or stressed patients. All methods of caries removal produce clinically parametric changes in the residual dentin.

Gross and Histopathological Study of Postscabietic Nodules

Background: Nodular postscabietic scabies refer to the persistent intermittent signs of scabies that are seen in active and post-treatment period that might last for months. The spectrum of clinico-morphological ranges that can be observed with sarcoptic nodules is broad, and most of the entity's criteria can be elicited histopathologically and pathologically. The management of such nodules may be a challenge. They are commonly treated through local application of corticosteroids or injection of corticosteroids to nodules but the response to treatment is less than clent and relapses are very frequent. The objective of this study was to illuminate which of these features prevail and which ones fade in scarred sites which undergo postscabietic nodule development. The time span between August 2021 to May 2022 was allowed to collect samples from patients with (1-60) years old and full of scabies burrows who visit teaching hospitals and private dermatology clinics in Kut, Wasit Province, Iraq. Treat groups were split into 30 females, and 20 males; with persistent itchy nodular lesions of scabies demonstrated clinically and histopathologically. Everity grade scabies was evaluated by the number of lesions and rated it as severity of itching. Long-term treatment with topical glucocorticoids for 14 days in every age. Tissue from the blisters of patient was obtained after medication. The specimens were washed, fixed and cut to 4-5 µm and stained with H&E. The staining allowed us to observe the fragments of tissues under light microscope with different magnification power. We have observed excessive males and the prevalence of SCABies were more in a young adult group in comparison with other age groups. It was found that lesions with wiry projections tended to persist for two weeks to 52 weeks and the number of nodules had varied from one to fourteen lesions. Examination of Histopathological slide showing acanthosis in 80, histolymphocytic infiltration in 76, and eosinophilia in 100 of total cases in the whole period. After the scabitic nodule loop, the body experiences a hypersensitivity reaction. From the three hundred cases examined microscopically, most (80%) of them were found to be characterized by acanthotic epidermis and diffuse dense dermal lymphocytic infiltration. Neutrophilic reaction, epithelioid-granulomatous inflammation and eosinophilia have been diagnosed in 76 % sight upon while 100 % of other nodules have shown eosinophilia.

Multimodal Use of Contact Endoscopy in Neurosurgery: Case Series with Technical Note and Literature Review

BackgroundOriginally adopted for the cytological screening of cervical and uterine cancer, contact endoscopy (CE) is now widely used in several fields of oncological surgery. The CE method, with magnification power up to 150x, was designed to enhance visualization and identify microscopic changes indicative of pre-cancerous and cancerous lesions at early stages. In this pilot study, we evaluated the multimodal applications of CE during different endoscopic intracranial neurosurgical procedures. MethodsTwenty patients with skull base lesions underwent surgery using different minimally invasive endoscopic approaches (endonasal, transorbital, and supraorbital). CE was used to distinguish the pathology from the surrounding healthy tissue by positioning the endoscope either in proximity or directly onto the target tissue. Special attention was given to the visualization of the margins of the lesion to differentiate compression/displacement from infiltration of the normal surrounding tissue. ResultsWith its unprecedented range of magnification, CE could clearly identify the microvascular pattern and cytological architecture of a tissue not detectable by simple white light endoscopy, with no reported damage due to heat transmission or iatrogenic injuries. All the lesions diagnosed as “presumed neoplastic tissue” by CE were confirmed by histopathology. The most promising results were observed in surgeries for meningioma and pituitary adenoma, as these lesions exhibit distinctive microvascular networks. ConclusionCE represents a new and effective technique for the in vivo identification of pathological microvascular and tissue features, allowing preservation of normal tissue during different endoscopic approaches. The use of CE could improve diagnostic accuracy and assist in intraoperative decision-making, becoming a key tool in various applications in neurosurgical field.

Estimation of the shear bond strength and adhesive remnant index of orthodontic adhesives stored in static magnetic field

ABSTRACT Purpose Static magnetic field (SMF) affects the polymerization reaction of orthodontic adhesives. Although their effects on shear bond strength (SBS) and adhesive remnant index (ARI) are not investigated yet, the current research designed to search the impact of storage of the orthodontic composite on SMF on SBS and ARI. Materials and Methods Biofix and Heliosit orthodontic adhesives were employed in this study, beside 60 extracted premolars that were separated into two equal groups according to adhesive type. Each group, furtherly, is divided into three subgroups (10 each) according to the storage field magnetic intensity as Zero, 225 and 1000Gauss. The tensile instron machine was performed to debond the brackets after incubation for 24 h in a dark wet environment at 37C°. ARI was evaluated by stereomicroscope at 20 magnification power. SBS and ARI data were analysed by ANOVA and Kruskal–Wallis tests, respectively. P was set at 0.05. The results SBS of Heliosit adhesive significantly increased with elevation of field intensity at 8.5496, 9.7592 and 11.2129MPas, while Biofix SBS was significantly changed from 9.1547, 11.8294 and 8.7132MPas with Zero, 225 and 1000Gauss field intensity, respectively. ARI showed a non-significant difference at three storage intensities as p = 0.543, 0.377 for Biofix and Heliosit, respectively. Conclusion Storage of Biofix and Heliosit orthodontic adhesives in 225Gauss SMF improves SBS. Furthermore, an increase in SMF intensity up to 1000Gauss improves Heliosit SBS, unlike Biofix which shows significant reduction.

Comparison of Reading Speed in Low Vision Patients Using Different Types of Low Vision Devices Having Same Magnification Power

Comparison of Reading Speed in Low Vision Patients Using Different Types of Low Vision Devices Having Same Magnification Power

Commentary: Leap forward in presbyopia management - Correcting beyond spectacles.

Commentary: Leap forward in presbyopia management - Correcting beyond spectacles.

Star cluster formation and survival in the first galaxies

ABSTRACT Using radiation-hydrodynamic cosmological simulations, we present a detailed (0.1 pc resolution), physically motivated portrait of a typical-mass dwarf galaxy before the epoch of reionization, resolving the formation, and evolution of star clusters into individual 10 M⊙ star particles. In the rest-frame ultraviolet, the galaxy has an irregular morphology with no bulge or disc, dominated by light emitted from numerous, compact, and gravitationally-bound star clusters. This is especially interesting in light of recent James Webb Space Telescope observations that − aided by the magnifying power of gravitational lenses – have imaged, at parsec-scale resolution, individual young star clusters forming in similar galaxies at z> 6. Because of their low metallicities and high temperatures, star-forming gas clouds in this galaxy have densities ∼100 times higher than typical giant molecular clouds; hence, their expected star formation efficiencies (SFEs) are high enough (around 10 − 70 per cent) to produce a sizeable population of potential globular cluster progenitors, but typically smaller (a few 100 − 2 ×104M⊙, half-mass radii of up to 3 pc) and of lower metallicities (10−3.5– 10−2.5 Z⊙). The initial mass function of the star-forming clouds is log-normal, whereas the bound star cluster mass function is a power-law with a slope that depends mainly on SFE but also on the temporal proximity to a major starburst. We find slopes between −0.5 and −2.5 depending on the assumed sub-grid SFE. Star formation is self-regulated on galactic scales; however, the multimodal metallicity distribution of the star clusters and the fraction of stars locked into surviving bound star clusters depends on SFE.

Effect of three different preparation designs on the marginal adaptation of indirect overlay restoration fabricated from lithium disilicate ceramic material: An in-vitro comparative study

ObjectivesMarginal adaptation is considered one of the key factors influencing the success of indirect restorations. This study aimed to estimate the marginal fit of lithium disilicate overlays with three distinct preparation designs before and after cementation. MethodsThirty maxillary first premolars were divided into the hollow chamfer design (HCD11HCD: Hollow Chamfer Design.) group,butt-joint design (BJD22BJD: Butt-Joint Design.) group, and conventional occlusal box design (COD33COD: Conventional Occlusal Design.) group (n = 10 each). The samples were scanned using an intra-oral scanner, and overlays were fabricated using computer-assisted design and milled on a computer-assisted machine. The finished restorations were luted using a self-adhesive resin RelyX Ultimate. The marginal gap was assessed using a digital microscope with 230X magnification power. Statistical analysis was conducted using analysis of varianceandposthoc(Bonferroni correction) tests, assuming a significance level of 5%. ResultsThe HCD and BJD groups recorded significantly lower marginal gap, (11.39 ± 0.72, 16.29 ± 0.75) and (11.59 ± 0.75, 16.93 ± 0.65) respectively, than the COD group (24.57 ± 1.18, 34.45 ± 1.09) both pre- and post-cementation. ConclusionThis study demonstrated that modification of tooth preparation plays a significant role in the marginal adaptation of the lithium disilicate overlays. The gap was smaller with the HCD and BJD than with the COD, with a statistically significant difference.

Application of physical vapor deposition technology for practical utilization of nano-size copper oxide for lead uptake from solution: kinetics, equilibrium, and recycling studies

For the first time, copper oxide-coated glass beads (CuO-GBs) were fabricated using physical vapor deposition (PVD) technology for sequestrating Pb2+ ions from solution is addressed. Compared to other coating procedures, PVD offered high-stability uniform CuO nano-layers attached with 3.0-mm glass beads. Heating of copper oxide-coated glass beads after deposition was rather necessary to achieve the best stability of the nano-adsorbent. Detection of nano-size copper oxide on the beads was made by FTIR (intense peak at 655cm-1 for CuO bond stretching) and XRF (Cu peak at 8.0keV). Scanning electron micrographs taken at high magnification power indicated the presence of CuO in nano-range deposited over glass beads. The maximum deposited amount of CuO on the beads was 1.1% and accomplished at the following operational conditions: internal pressure 10-5mmHg, Ar flow rate 8.0mL/min, voltage 84V, pre-sputtering time 20s, total sputtering time 10.0min, and post-heating temperature 150°C for 3h. A univariate analysis indicated that the optimum Pb2+ uptake by CuO-GBs from solution was achieved at pH 7.0-8.0, 7 beads/50mL, 120-min contact time, and 15-mg/L initial concentration. Kinetic data for Pb2+ uptake was best presented by a pseudo-second-order model with a relative prediction error of 3.2 and 5.1% for GBs and CuO-GBs, respectively. On the other hand, Pb2+ equilibrium isotherms at 25°C were fairly presented by the Langmuir model, and the predicted saturation values were 5.48 and 15.69mg/g for GBs and CuO-GBs, respectively. CuO and CuO-GBs had similar Pb2+ saturation values (~ 16mg/g), although the latter demonstrated 4 times faster kinetic, thanks to fixation CuO on glass beads. Moreover, the chemical stability of copper oxide-coated glass beads was tested under different conditions. Recycling of copper oxide-coated glass beads was also investigated, and 90% of the surface was recovered using 0.01-M HNO3.

Geometric parameters sensitivity evaluation based on projection trajectories for X-ray cone-beam computed laminography.

X-ray cone-beam computed laminography (CL) is widely used for large flat objects that computed tomography (CT) cannot investigate. The rotation angle of axis tilt makes geometric correction of CL system more complicated and has more uncertain factors. Therefore, it is necessary to evaluate sensitivity of the geometric parameters of CL system in advance. This study aims to objectively and comprehensively evaluate sensitivity of CL geometric parameters based on the projection trajectory. This study proposes the Minimum Deviation Unit (MDU) to evaluate sensitivity of CL geometric parameters. First, the projection trajectory formulas are derived according to the spatial relationship of CL system geometric parameters. Next, the MDU of the geometric parameters is obtained based on the projection trajectories and used as the evaluation index to measure the sensitivity of parameters. Then, the influence of the rotation angle of the axis tilt and magnification on the MDU of the parameters is analyzed. At low magnification, three susceptible parameters (η, u0, v0) with MDU less than 1 (° or mm) must be calibrated accurately to avoid geometric artifacts. The sensitivity of CL parameters increases as the magnification increases, and all parameters become highly sensitive when the magnification power is greater than 10. The results of this study have important guiding significance for the subsequent further parameter calibration.

The Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS)

Aims. We present the Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) selected from MUSE and HST observations of 17 lensing clusters. The sample consists of 603 continuum-faint (−23 < MUV < −14) lensed Lyman-α emitters (producing 959 images) with secure spectroscopic redshifts between 2.9 and 6.7. Combining the power of cluster magnification with 3D spectroscopic observations, we were able to reveal the resolved morphological properties of 268 Lyman-α emitters. Methods. We used a forward-modeling approach to model both Lyman-α and rest-frame UV continuum emission profiles in the source plane and measure spatial extent, ellipticity, and spatial offsets between UV and Lyman-α emission. Results. We find a significant correlation between UV continuum and Lyman-α spatial extent. Our characterization of the Lyman-α halos indicates that the halo size is linked to the physical properties of the host galaxy (SFR, Lyman-α equivalent width, Lyman-α line FWHM). We find that 48% of Lyman-α halos are best fit by an elliptical emission distribution with a median axis ratio of q = 0.48. We observe that 60% of galaxies detected both in UV and Lyman-α emission show a significant spatial offset (ΔLyα − UV). We measure a median offset of ΔLyα − UV = 0.58 ± 0.14 kpc for the entire sample. By comparing the spatial offset values with the size of the UV component, we show that 40% of the offsets could be due to star-forming sub-structures in the UV component, while the larger offsets (60%) are more likely due to greater-distance processes such as scattering effects inside the circumgalactic medium or emission from faint satellites or merging galaxies. Comparisons with a zoom-in radiative hydrodynamics simulation of a typical Lyman-α emitting galaxy show a very good agreement with LLAMAS galaxies and indicate that bright star-formation clumps and satellite galaxies could produce a similar spatial offset distribution.

3D 4K exoscope in snore surgery simulation: pre-clinical experience.

The application of 3D exoscopic technology is spreading worldwide, in several surgical scenarios. In this study, we present the first-time use of the exoscopic system (VITOM® and Versacrane™) in a cadaver simulation of transoral Snore Surgery. All participants (n = 14) were asked to perform 2 exercises that simulate tasks required in Snore Surgery, they were then administered a questionnaire assessing their evaluation of the applied exoscopic technology. Participants were divided into groups according to age and experience. Mean zooming and focusing time was higher in young surgeons than in seniors, and similar results were obtained for mean procedural times. The responses to the questionnaire showed that in the vast majority (86%), the exoscopic technology was well rated. The exoscope can be considered a useful tool, thanks to its magnifying power and high-definition images, as well as for its indirect ability to enhance staff involvement in the procedure and for educational purposes.

Characteristic dermoscopic signs of Melasma among patients attending dermatology-teaching centre in Sulaymaniyah city

Background and objectives: Melasma is a common acquired pigmentary disorder which mainly involves sun exposed areas and characterized by the presence of single or multiple hyperpigmented patches distributed symmetrically over face and extending up to neck. Dermoscopy is a noninvasive technique has been tapped recently in various hyperpigmentary conditions like melasma. This research aims to determine the characteristic dermoscopic signs of melasma. Methods: A descriptive study of 100 patients with melasma were conducted over a period of 4 months, these patients were diagnosed clinically and digital images obtained first then dermoscopy examination done for different sites of face by: dermoscope device of 20X power of magnification, and Many digital images of dermoscopy findings obtained thorough attachment of the dermoscopic device to a smart phone. Results: Females constitute 79% of our patients while 21% were males. On dermoscopic examination: 69% of cases had pseudoreticular network sign, 41% had arcuate and annular sign, 21% had globules sign, 32% had sparing of perifollicular region sign and 51% had telangieactasia sign. The presence of telengiectasia in male patients was statistically significant 80.95%, Malar distribution was the most common pattern observed in 68%, more than one pattern was present in a number of patients. Conclusions: This study showed that the pseudoreticular network sign is the most common deromatoscopic signs among our patients. Telangiectasia is very common finding in our patients precisely in males.

Evaluation of Microleakage Using Dye-penetration Method in Three Different Composite Resin Core Build-up Materials: An In Vitro Study

Aim of the current research is to establish and assess the microleakage in bulk-fill composite, nanohybrid ormocer-based resins, and nanofilled composite resin core build-up materials employing the dye-penetration technique. Sixty human mandibular first premolar teeth with a solitary root canal without dental caries were chosen for this research. Each specimen was subjected to decoronation of 2 mm from the cementoenamel junction (CEJ), following which the root canal treatment procedure was rendered complete. A space for the post was made for all the 60 samples. Following positioning of the post, specimens were allocated into one of the following three investigational groups (20 specimens in every group) on the basis of the core build-up materials used as group I: bulk-fill composites, group II: nanohybrid ormocer-based resins, and group III: nanofilled resin composites. Direct composite was used for core build-up and subjected to light-curing. Following this, the specimens were immersed in 1% methylene blue solution for 24 hours interval. Each section was evaluated for dye diffusion employing a stereomicroscope with software at a magnifying power of 40× and surface contact between dentin and base of the material was evaluated under scanning electron microscope. Nanohybrid ormocer-based composites exhibited the least microleakage at 1.12 ± 0.14, in pursuit by nanofilled composite resins at 1.79 ± 0.09, and finally the bulk-fill composites at 2.85 ± 0.11, amid the investigational groups studied. A statistically significant difference amid the three dissimilar cores buildup substances was found upon analysis of variance. Despite the study limitations, this research came to a conclusion that each of the three investigated core build-up substances exhibited microleakage. However, amid the three, nanohybrid ormocer-based composites depicted the lowest amount of microleakage in pursuit by the nanofilled resins and the bulk-fill composites. Core build-up is an important requirement as the remaining tooth substance following root canal treatment reduces and needs reinforcement with core build-up to sustain the tooth structure and provide resistance. A vital mandate for enduring efficiency of the restoration in the mouth is high-quality adhesive bond of these agents to cavity walls with diminished microleakage.

Synthesis of Nano-Pomegranate Peel via Sol-Gel Method and Screen Characterization

Nano peel solution was prepared using Sol-gel technology at a temperature of (80) Celsius. A number of tests were performed to describe the properties and structure of Nano material, including scanning probe microscopy (SPM), which showed the symmetric cumulative distribution of the solution Nanoparticles and the average grain size equal to 64.5 nm and the identical distribution of the Nanoparticles with a diameter of 37.75 nanometers, with a measurement area ranging between (1531.23-1558.19) nanometers. Nano-solution analyzed with a scanning electron microscope (SEM), Inspect type (S50), with a magnification power up to X2000, where dense flakes of Nano particles with a diameter of (50 ± 10) nanometers were observed. The antibacterial activity of Nano-solution by using gram- positive bacteria St. aurous and gram-negative E. coli show the inhibition diameter of (St. aurous) was 27 mm and 25 mm in (E. coli).

Dynamical properties ofz∼4.5 dusty star-forming galaxies and their connection with local early-type galaxies

ABSTRACTThere is a large consensus that gas in high-z galaxies is highly turbulent, because of a combination of stellar feedback processes and gravitational instabilities driven by mergers and gas accretion. In this paper, we present the analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at 4 ≲ z ≲ 5. Taking advantage of the magnifying power of strong gravitational lensing, we quantified their kinematic and dynamical properties from ALMA observations of their [C ii] emission line. We combined the dynamical measurements obtained for these galaxies with those obtained from previous studies to build the largest sample of z ∼ 4.5 galaxies with high-quality data and sub-kpc spatial resolutions, so far. We found that all galaxies in the sample are dynamically cold, with rotation-to-random motion ratios, V/σ, between 7 and 15. The relation between their velocity dispersions and their star formation rates indicates that stellar feedback is sufficient to sustain the turbulence within these galaxies and no further mechanisms are needed. In addition, we performed a rotation curve decomposition to infer the relative contribution of the baryonic (gas, stars) and dark matter components to the total gravitational potentials. This analysis allowed us to compare the structural properties of the studied DSFGs with those of their descendants, the local early type galaxies. In particular, we found that five out of six galaxies of the sample show the dynamical signature of a bulge, indicating that the spheroidal component is already in place at z ∼ 4.5.

ID: 3522946 EC-V (ENDOCYTOSCOPIC VASCULAR) CLASSIFICATION IS USEFUL FOR NOT ONLY QUALITATIVE DIAGNOSIS BUT ALSO PATHOLOGICAL DIAGNOSIS

Endocytoscopy (EC) is a kind of contact type endoscope that allows in vivo, real-time cellular observation with 520-times magnification, launched since 2019. Thus far, narrow-band imaging (NBI) could make it possible to analyze the surface microvessels of colorectal lesions for differentiating neoplasms from non-neoplasms and for predicting the histopathological diagnosis. EC combined with NBI (EC-NBI) enables in vivo observation of blood vessels in more detail compared to conventional magnification power. The aim of this study was to validate the evidence whether the observation of surface microvessels using EC-NBI was useful in predicting the histopathology of colorectal lesions.

Dielectric Nonlocal Metasurfaces for Fully Solid-State Ultrathin Optical Systems

Most optical systems involve a combination of lenses separated by free-space regions where light acquires the required angle-dependent phase delay for a certain functionality. Very recently, flat-optics structures have been proposed to compress these large free-space volumes and miniaturize the overall optical system. However, these early designs can only replace free-space volumes of limited length, or operate in a very narrow angular range, or require a high-index background. These issues raise questions about the applicability of these devices in practical scenarios. Here, we first derive a fundamental trade-off between the length of compressed free space and the operating angular range, which explains some of the limitations of earlier designs, and we then propose a solution to relax this trade-off using nonlocal metasurface structures composed of suitably coupled resonant layers. This strategy, inspired by coupled-resonator-based band-pass filters, allows replacing free-space volumes of arbitrary length over wide angular ranges, and with very high transmittance. Finally, we theoretically demonstrate, for the first time, the potential of combining local and nonlocal metasurfaces to realize compact, fully solid-state, planar structures for focusing, imaging, and magnification, in which the focal length of the lens (and hence its magnifying power) does not dictate the actual distance at which focusing is achieved. Our findings are expected to extend the reach of the field of metasurfaces and open new unexplored opportunities.

Systematic search for lensed X-ray sources in the CLASH fields

Aims. We exploit the high angular resolution of Chandra to search for unresolved X-ray emission from lensed sources in the field of view of 11 CLASH clusters, whose critical lines and amplification maps were previously obtained with accurate strong-lensing models. We consider a solid angle in the lens plane corresponding to a magnification μ > 1.5, which amounts to a total of ∼100 arcmin2, of which only 10% corresponds to μ > 10. Our main goal is to assess the efficiency of massive clusters as cosmic telescopes to explore the faint end of the X-ray extragalactic source population. Methods. The main obstacle to this study is the overwhelming diffuse X-ray emission from the intracluster medium that encompasses the region with the strongest magnification power. To overcome this aspect, we first searched for X-ray emission from strongly lensed sources that were previously identified in the optical and then performed an untargeted detection of lensed X-ray sources. Results. We detect X-ray emission in either in the soft (0.5−2 keV) or hard (2−7 keV) band in only 9 out of 849 lensed or background optical sources. The stacked emission of the sources without detection does not reveal any signal in any band. Based on the untargeted detection in the soft, hard, and total band images, we find 66 additional X-ray sources without spectroscopic confirmation that are consistent with being lensed (background) sources. Assuming an average redshift distribution consistent with the Chandra Deep Field South survey (CDFS), we estimate their magnification, and after accounting for completeness and sky coverage, measure the soft- and hard-band number counts of lensed X-ray sources for the first time. The results are consistent with current modeling of the population distribution of active galactic nuclei (AGN). The distribution of delensed fluxes of the sources identified in moderately deep CLASH fields reaches a flux limit of ∼10−16 and ∼10−15 erg s−1 cm−2 in the soft and hard bands, respectively, therefore approximately 1.5 orders of magnitude above the flux limit of the CDFS. Conclusions. We conclude that in order to match the depth of the CDFS in exploiting massive clusters as cosmic telescopes, the required number of cluster fields is about two orders of magnitude larger than is offered by the 20 year Chandra archive. At the same time, the discovery of strongly lensed sources close to the critical lines remains an attractive if rare occurrence because the source density in the X-ray sky is low. A significant step forward in this field will be made when future X-ray facilities an angular resolution of ∼1 arcsec and a large effective area will allow the serendipitous discovery of rare, strongly lensed high-z X-ray sources. This will enable studying faint AGN activity in the early Universe and measuring gravitational time delays in the X-ray variability of multiply imaged AGN.