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Epitaxial GaN nanostructures are developed, and the influence of the AlN buffer layer (temperature modulation) on material characteristics and optoelectronic device application is assessed. The AlN buffer layer was grown on a Si (111) substrate at varying temperatures (770–830 °C), followed by GaN growth using plasma-assisted molecular beam epitaxy. The investigation revealed that the comparatively lower temperature AlN buffer layer was responsible for stress and lattice strain relaxation and was realized as the GaN nano-obelisk structures. Contrarily, the increased temperature of the AlN growth led to the formation of GaN nanopyramidal and nanowax/wane structures. These grown GaN/AlN/Si heterostructures were utilized to develop photodetectors in a metal–semiconductor–metal geometry format. The performance of these fabricated optoelectronic devices was examined under ultraviolet illumination (UVA), where the GaN nano-obelisks-based device attained the highest responsivity of 118 AW−1. Under UVA (325 nm) illumination, the designed device exhibited a high detectivity of 1 × 1010 Jones, noise equivalent power of 1 × 10−12 WHz−1/2, and external quantum efficiency of 45,000%. The analysis revealed that the quality of the AlN buffer layer significantly improved the optoelectronic performance of the device.

Through an interdisciplinary study of the work of Jesuit Athanasius Kircher (1602–1680), the authors investigate the relationship between the cultural policies of the Roman Curia, the Jesuit order, religious diversity, and the aesthetic–spatial configuration of Rome during the early modern age. This paper shares in-depth observations of the recovery of ancient culture and its reworking in a post-reformist Christian age through architectural and spatial elements adopted to endorse the continuity of the ancient past and the Catholic reformistic universalistic aspirations. In this context, Kircher worked to decipher hieroglyphics on obelisks of the Imperial age but from Egyptian times. These defined a specific topography of space as a visual convergence of points: an urban geography of sacral and historical–political value and a connection with the memories of the Roman Empire and the most ancient religions of the ancient times.

The seismic assessment of rocking masonry structures is a complex task, due to the high sensitivity of the behavior to the characteristics of the input motion. The paper compares the results offered by different models and the reliability of widely used intensity measures. A displacement-based approach based on an incremental limit analysis of rigid blocks is proposed for the performance-based assessment of rocking masonry structures, such as: rocky structures (archeological remains, obelisks, columns, trilithons), arch-piers systems (e.g. triumphal arches, belfries), out-of-plane mechanisms of walls (standing out walls, façades in buildings or churches etc.) or artistic assets prone to overturn (pinnacles, statues etc.). The method is compatible with the format of the PERPETUATE performance-based assessment method for cultural heritage assets

In 12 BCE, Augustus undertook the responsibility for the calendar, which had gradually fallen out of alignment with the true dates of solstices and equinoxes. Augustus’ calendar reform, entailing the introduction of a leap day every four years, coincided with the erection of a grand meridian in the Campus Martius, known in Latin as Horologium Augusti. This device utilized the obelisk of Psamtik II (6° century BCE) as its gnomon that casted its shadow upon a travertine floor inscribed with bronze reference marks. Despite the discovery of the obelisk in 18th century and partial excavation of the floor in 1980, comprehending its geometric intricacies, regarding both dimensions and positioning, remained a challenge due to the complexities of conducting precise geomatic measurements in subterranean environments. Consequently, uncertainties persisted regarding its operational mechanics, particularly regarding whether the marks denoted days or ecliptic degrees. This study presents accurate measurements and statistically rigorous analyses that enable a precise repositioning of the meridian and a careful reconstruction of its geometry. The results suggest that the marks likely denoted specific days of the year, as recalled by Pliny the Elder. This provides support to the hypothesis that the monument functioned as an empirical validation of Augustus’ calendrical reform. In addition, the great accuracy achieved in positioning represents a fundamental aid in the desirable scenario to continue excavations of the meridian.

This paper presents a detailed study of a sunk-relief scene from the Temple of Khonsu at Karnak. This scene has not yet been presented in a detailed publication although references have been made to it in several publications. This study revealed the ambiguity of two main elements of the scene actioned in Karnak temples in the reign of Herihor; the first is the lost dedicated obelisk of Herihor and the second is evidence of a new cult of king Amenhotep I and its dating according to his figuration in the scene as \"Imn-htp n bnrt\".

In this study we present the fabrication of multilayer microneedles with circular obelisk and beveled-circular obelisk geometries, which have potential applications in implantable drug delivery devices. Micro-milling was adopted as an environmental-friendly and cost-effective way to fabricate primary metal microneedle masters. Polylactic acid (PLA) microneedles with sharp tips were then obtained by micromolding followed by oxygen plasma etching and used for preparing polydimethylsiloxane (PDMS) microneedle molds. A spray deposition process was employed for microneedle fabrication to facilitate the formation of multilayer microneedles while helping in maintenance of drug stability. Multilayer microneedles were successfully formed by sequential spraying of poly(lactic-co-glycolic acid) (PLGA) and polyvinylpyrrolidone (PVP) solutions into the mold. The fabricated PLGA-PVP multilayer microneedles penetrated the pig cadaver skin without breakage and released dyes in the skin at different rates, which reveals the potential for implantable microneedles enabling controlled release. Mechanical testing demonstrated that the obelisk-shaped microneedles were mechanically stronger than a pyramid-shaped microneedle and suggested that strong adhesion between PLGA and PVP layers was achieved as well. Structural stability and functionality of a model drug, horseradish peroxidase (HRP), upon spray deposition was examined using circular dichroism (CD) spectroscopy and enzyme activity assay. HRP retained its secondary structure and activity in PVP, whereas HRP in PLGA showed structural changes and reduced activity. Combination of micro-milling and spray deposition would be an attractive way of fabricating drug-containing polymer microneedles with various geometries while reducing prototyping time and process-induced drug instability.

Ancient Egyptian obelisks have been carved thousands of years ago and survived many earthquakes and wind storms. This study examines the aerodynamic characteristics and the response of two of the tallest and slenderest ancient Egyptian obelisks to boundary layer winds using a two-phase methodology. The firstphase involved preparing computational fluid dynamics (CFD) models for the twoobelisks with different angles of projection to wind. The variations in the windpressure coefficient and the forces on the obelisks have been studied for differentprojection angles, different reference velocities and along the height of eachobelisk. Within the second phase structural analysis was performed subjecting eachobelisk to a wind load under different angles of loading. The results show that whensubject to boundary layer winds, the pressure coefficient on the surface and thestresses within the obelisks vary significantly with the angle of attack and dimensions of the obelisk. Highlights: • This study examines the aerodynamic characteristics and the response of two of the tallest and slenderest ancient Egyptian obelisks to boundary layer winds through CFD modeling followed by structural analysis. • The variations in the wind pressure coefficient, the forces and stress have been studied for variations in angles of projection, velocities and along the height for each obelisk. • The pressure coefficient and the stresses within obelisks vary significantly with the angle of attack and dimensions of the obelisk.

Xenolithic structures are considered to be natural defects in the igneous rocks that highly affect their physicochemical and mechanical properties. They are foreign rock fragments trapped in the magma or lava during the cooling process. They are totally unrelated to the igneous rocks, as they compose from different types of rock pieces that enclosed in the monumental granites during their emplacement. This paper aims to study and characterize the xenolith fragment trapped in the studied granitic obelisk. The analytical study was carried out using different techniques such as polarizing microscope, x-ray diffraction, scanning electron microscope, EDS elemental analysis and BET surface area. The results clarified that the studied xenolith fragment is classified as biotite schist xenolith. In addition, it was observed that the xenolith fragment not only affects the aesthetic appearance of the studied granitic obelisk but also it represents a serious weakness point in its structure.

This study reveals remarkable diversity in plant-associated subviral RNA populations, identifying 13 novel viroid-like RNAs alongside 16 known viroids. Notable discoveries include new hammerhead ribozyme-containing species-level ex-circRNAs from Cape gooseberry and grapevine, a symmetric twister ribozyme ex-circRNA in peach, and, surprisingly, ambi-like circular RNAs with RNA-dependent RNA polymerases. These findings significantly expand our understanding of the complexity and evolutionary diversity of plant-associated subviral RNAs.