University of Alcalá

High-speed/high-data-rate signal transmission is a fundamental operational requirement for emerging beyond-5G/6G wireless communication applications, such as immersive augmented reality and virtual reality [1] . For the constituent monolithic microwave integrated circuits aimed at the RF transceiver front ends corresponding to these appealing technologies, microstrip-to-microstrip transitions are widely recognized as essential RF components [2] . They perform the role of transmission media necessary to maintain the RF power signal transmission/interconnection among two or more microstrip lines of the circuit modules corresponding to different layers in compact multistack RF systems. They should exhibit wideband/broadband transmission frequency responses with low power insertion loss levels within their operational ranges. To make them compatible with multilayer microwave integrated circuits, microstrip transitions are currently developed in two distinct basic types, namely, via hole transitions and vialess aperture-/slot-line-coupled transitions. Due to their simpler configuration of two microstrip lines that are directly connected through the circuit board layers by means of a via hole, via hole transitions have become popular, and today they are exploited in most RF/microwave multilayer components [3] . However, although they can attain broadband transmission bandwidths (BWs) above dc, their frequency selectivity can be restricted by low-pass-type responses and poor filtering performance [4] .

The extraordinary preservation of Cueva de Los Murciélagos (Albuñol, Spain) provides a unique opportunity to identify the materials and the techniques involved in archery during the Early Neolithic period. Arrows with preserved feathers, tied fibres, adhesive substance, and two probable bowstrings have been studied trough an unprecedented multi-proxy investigation, including microscopy and biomolecular methods, to unravel archery techniques. The study has identified the oldest known sinew bowstrings, the first evidence for the use of olive tree (Olea europaea) and reed (Phragmites sp.) to produce arrow shafts in prehistoric European archery, and the identification of birch bark tar as a coating on the shafts. The results of this study provide insights into ancient craft, technological solutions, and adaptations to local resources in the production of these reed-shafted hardwood tipped arrows and bowstrings. Their deposition in a burial cave sheds new light on the role of these artefacts in a Neolithic farming community.

Literature on Group One organoelement chemistry is dominated by lithium, though sodium and potassium also feature prominently, whereas rubidium and caesium are rarely mentioned. With recent breakthroughs hinting that organoelement compounds of these two heavier metals can perform better than their lighter congeners in particular applications, important advantages could be missed unless complete sets of alkali metals are included in studies. Here, we report the synthesis and characterisation of a complete set of multi‐alkali‐metallated molecular compounds of the 1,3,5‐tris[(4,6‐dimethylpyridin‐2‐yl)aminomethyl]‐2,4,6‐triethylbenzene framework. Made by deprotonating the framework N‐H bonds by a suitable base, the set comprises six THF‐solvated compounds, four of which are homometallic, either containing Li in a trinuclear structure or Na, K, and Rb in hexanuclear structures. Since deprotonation was incomplete with Cs, its homometallic compound is tetranuclear containing two un‐metallated N‐H bonds. A heterobimetallic trilithium‐tricaesium hexanuclear compound was also obtained by using a bimetallic Li‐Cs base for deprotonation. Such alkali‐metallated frameworks are often precursors to other multimetallic frameworks with unique properties across different fields of science.

A density functional theory (DFT) investigation was performed to elucidate the interaction mechanisms between boric acid (BA) and various macrocyclic host molecules. The calculated complexation energies were negative, indicating that these interactions are energetically favorable. Structural analyses revealed the formation of hydrogen bonds, particularly between BA and the hosts β-cyclodextrin (β-CD), pillar[5]arene (P[5]), and pyrogallol[5]arene (P[5]G). Notably, the hydroxyl groups (OH) of BA played a crucial role in establishing intermolecular hydrogen bonds, which significantly enhanced the stability of the BA/β-CD and BA/P[5] complexes, as confirmed by natural bond orbital (NBO) and intermolecular Gradient model based on Hirshfeld partition (IGMH) analyses. Furthermore, the calculated HOMO–LUMO energy gaps for the BA/β-CD, BA/P[5], and BA/P[5]G complexes were found to be larger than those of the individual hosts, indicating a kinetically stable systems. The studied host systems demonstrate potential for enhancing the bioavailability of boric acid and reducing its toxicity through effective host–guest recognition.

Laser–Plasma ion acceleration is acquiring importance on a daily basis due to incipient applicability in certain research fields. However, the energy and divergence control of these brilliant sources can be considered a bottleneck in the development of some applications. In this work, we present the commissioning of a compact proton beamline based on a triplet of quadrupoles dedicated to focus and collect short and energetic pulses, open to the user community. The focused proton beam characterization has been carried out by imaging of scintillation detectors with different particle filters. Experimental results have been compared with numerical simulations performed with Monte Carlo code (MCNP6) and TSTEP that have been used to retrieve the deposited energy, the particle tracking, and the particle distribution in different focal configurations, respectively. Charges of nC ($\sim$$10^{10}$ protons with energies up to 17.25 MeV) have been measured at the focal planes reducing the beam to spot sizes of a few millimetres in RMS (root mean square). The percentage fluctuation of the transported charges values has been studied. Finally, the beam rigidity has been measured by transverse moving of the quadrupoles and subsequent beam centroid shift, allowing to cross correlate the deflected energy with the energy ranges resulting from the filtering process.

In contemporary electrical distribution systems, multiple parallel inverters collaborate to form an advanced power distribution network, which poses stability challenges. Small-signal analysis is a fundamental method for characterizing interactions between system impedances. In three-phase ac systems, stability assessment involves examining the source-to-load impedance ratio in the complex dq plane using the Generalized Nyquist criterion (GNC). In this context, the digital twin (DT) concept is arising as the forefront of energy sector digitization, providing real-time data through high-fidelity models mirroring physical systems. This article presents a stability analysis method employing a DT approach to determine the closed-loop impedance of the physical system and estimate the connected system’s equivalent impedance. Broadband excitation based on pseudorandom binary sequences (PRBS) is applied with Fourier techniques for frequency response extraction. Impedance ratio assessment is performed on an edge-computing platform, delivering real-time stability information. Experimental results are provided for a dual-hybrid converter, one operating as a grid-forming system and the other in grid-following mode. The outcomes demonstrate the feasibility and potential of the proposal as a foundational approach to enhance robustness based on stability indexes.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

Acanthamoeba species are responsible for serious human infections, including Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis (GAE). These pathogens have a simple life cycle consisting of an infective trophozoite stage and a resistant cyst stage, with cysts posing significant treatment challenges due to their resilience against harsh conditions and chemical agents. Current treatments for AK often involve combining diamines, such as propamidine, and biguanides, such as chlorhexidine (CLX), which exhibit limited efficacy and significant toxicity. Thus, the effect of new therapeutic molecules, such as multifunctional systems (e.g., carbosilane dendritic molecules), should be studied as potential alternatives due to their biocidal properties and lower toxicity. This study evaluates various dendritic compounds against trophozoites and cysts of two Acanthamoeba clinical isolates, both alone and in combination with CLX, and assesses their cytotoxicity on HeLa cells. The results indicated that certain dendritic compounds, especially BDSQ024, were effective against both trophozoites and cysts. Additionally, combinations of dendritic molecules and CLX showed enhanced efficacy in eliminating trophozoites and cysts, suggesting potential for synergistic treatments. The study underscores the promise of dendritic molecules in developing more effective and less toxic therapies for Acanthamoeba infections.

Anthropogenic environments such as wastewater treatment plants (WWTPs) and landfills are sources of antimicrobial resistance (AMR). Black-headed gulls (Chroicocephalus ridibundus) frequently use WWTPs and may be vectors for AMR. We used GPS tracking data for 39 gulls for up to 8 months, combined with a shedding curve, to study sources and dispersal distances of AMR in Iberia. The gulls used 21 different WWTPs (684 visits) and three landfills (21 visits). Areas of high risk of AMR dissemination were an average of 25 km from the infection source, with a maximum of 500 km. Solar saltworks and natural waterbodies were particularly exposed to AMR dissemination, followed by agriculture, sports facilities, and tourist beaches. There was important variability between individual gulls in their habitat specialization, and which WWTPs they visited. Studying the spatial movements of gulls after visiting WWTPs and landfills helps pinpoint sensitive locations where pathogen transmission is most likely.

Purpose To evaluate the effect of a physical therapy program on vaginal length and diameter, pelvic floor strength, and quality of life among gynecological cancer survivors suffering from late-effect vaginal stenosis. Methods Thirty-four women who were previously diagnosed with gynecological cancer and experiencing vaginal stenosis, at least 12 months post-oncological treatment, were enrolled. The intervention program consisted of ten weeks of individualized weekly sessions, each lasting 50 min, involving perineal massage, progressive vaginal dilation, and pelvic floor exercises. Pre- and post-treatment evaluations included assessments of pelvic floor muscle strength through digital palpation, measurements of vaginal length and diameter using a silicone vaginal dilator, and classification of stenosis according to the Common Terminology Criteria for Adverse Events (CTCAE v5.0). Health-related quality of life was assessed using the FACT-G and FACT-Cx questionnaires. Results Twenty-one women completed the physical therapy program. There was a significant increase in vaginal length (p < 0.001), vaginal diameter (p < 0.001) and improvement in pelvic floor muscle strength (p < 0.001), with a large effect size (r = 0.81), a medium effect size (r = -0.77) and a medium effect size (r = -0.78), respectively. This resulted in resolution of vaginal stenosis in 14 participants (66.7%) following intervention. Mean scores for FACT-Cx and FACIT-G, encompassing total scores and physical, social, and functional well-being domains, increased significantly after the treatment. Conclusion The proposed physical therapy program demonstrated positive effects on vaginal stenosis, pelvic floor muscle strength and health-related quality of life in gynecological cancer survivors.

Industrias cómo la textil, construcción, empaquetamiento, automotriz y aviación, han sacado provecho de las características mecánicas y ambientales que brindan las fibras naturales. En este sentido, se ha explorado la caracterización mecánica de la fibra de mocora y su compatibilidad cómo material compuesto, considerando que esta fibra endémica del Ecuador tiene aplicaciones estructurales de manera artesanal. A este respecto, esta investigación busca caracterizar dicha fibra por medio de microscopia electrónica de barrido, utilizando un voltaje de aceleración de 15 kV y 20 kV y magnificación de 500x y 1.6Kx. De igual manera, se realizan pruebas mecánicas con normas ASTM-D 5034 para la fibra trenzada y ASTM D 2256-02 para el material compuesto mediante una máquina de prueba universal. Las propiedades térmicas son determinadas mediante análisis de termogravimetría, desarrolladas utilizando una temperatura inicial de 40 ℃ hasta alcanzar una temperatura límite de 600 ℃ con un escalón de 15℃ por minuto. Las pruebas de adherencia a resina poliéster insaturada se dan mediante una solución de resina con 20% estireno, 0,03% de peróxido de etil metil cetona y 12% de naftaleno de cobalto. Por medio de estos métodos, se encontró que la fibra presenta una distribución longitudinal con cuerpos aglomerados y tubulares sin concentradores de esfuerzos. Dentro de las características más destacables se encuentra el porcentaje de elasticidad, una propiedad importante en aplicaciones mecánicas. De igual manera, se halló una buena resistencia a la degradación por altas temperaturas, aunque también presentó falencias en la adherencia adecuada a la resina. La caracterización de este estudio permite demostrar que la fibra de mocora tiene ventajas sobre otras fibras de uso estructural y comparativamente se encuentra cercana al desempeño de la fibra de coco, lo que permite concluir que tiene un potencial importante de aplicación a la industria que busca materiales resistentes, dando soporte a la caracterización de fibras emergentes ecuatorianas para una industria competitiva y económicamente circular.

Background Peritonitis is a frequent complication of PD that can lead to technique discontinuation and increase morbidity and mortality. It is caused mainly by gram-positive bacteria (up to 70%); however, gram-negative organisms usually have relatively poor outcomes. Among gram-negative bacteria, Acinetobacter is rare, especially Acinetobacter ursingii. Case report We report the third case of PD peritonitis caused by Acinetobacter ursingii, treated with directed intraperitoneal antibiotics with good clinical response and favorable outcome. Conclusion Although Acinetobacter ursingii is rare, it is potentially harmful because of its challenging identification and antibiotic resistance with therapeutic consequences, requiring at least two antibiotics and careful follow up. Keeping in mind that it is ubiquitous, careful technique, training/retraining seems highly recommended.

A general avalanche tester that utilizes an unclamped inductive switching (UIS) test is essential for measuring the maximum energy that a power device can withstand before failure. This procedure is critical for evaluating the reliability and robustness of power devices. Avalanche testers typically require high-precision hollow inductors with broad adjustable ranges and fine increments to accommodate the varying test conditions of different devices. However, this often results in large, heavy, and expensive inductor modules. In this study, we propose and experimentally demonstrate a novel method for testing avalanche tolerance based on avalanche energy equivalence. This method employs the magnetic core inductance as an alternative to the traditionally used bulky air-core inductance in avalanche testers, producing results comparable to those obtained from conventional UIS tests. To verify the equivalence of the avalanche energy, we designed a UIS experimental platform that includes a 1.3 mH magnetic core inductor connected in series with an adjustable air-core inductor. This configuration enables the evaluation of the maximum avalanche current consistency and degree of core inductor attenuation during the UIS test for two commercial P-channel and N-channel power MOSFET devices. The experimental results indicate that the difference between the avalanche energy and maximum avalanche current in the UIS test under both inductor conditions is approximately 1 %. Consequently, the magnetic core inductor can replace the air-core inductor. The method proposed in this study offers a promising direction for optimizing avalanche testers to meet the demands of modern devices for miniaturization and high efficiency, thereby reducing material consumption, production costs, and transportation expenses. This enhances product market competitiveness and holds practical value in engineering applications.

Mesomediterranean vegetation with abundant evergreen broadleaved trees and shrubs is dominant along the coast of northern Greece. Well-dated palynological records are available from the inland submediterranean zone, where evergreen broadleaved trees and shrubs are absent or rare, but less is known about the vegetation history of the coastal area. For instance, it is unclear when and why evergreen broadleaved vegetation expanded during the Holocene. Here we present a new record from a mesomediterranean site, Limni Volvi, near the coast of the Aegean Sea. To understand Holocene vegetation history, we combined palynology, microscopic charcoal analysis and biogeochemical proxies (Ti, Ca, RABD 655–680max ). At the start of the Holocene, open steppe vegetation and high fire activity prevailed around Limni Volvi. Afforestation by deciduous trees was likely delayed compared to sites further inland, due to the lack of moisture at the start of the Holocene, but vegetation composition was generally similar (i.e. submediterranean), with barely any evergreen broadleaved element. Around 8150 cal. BP (6200 cal. BC) trees and shrubs declined in the open woodlands or parklands, and the landscape returned to steppe conditions at 8000 cal. BP (6050 cal. BC), likely because of drier and colder conditions during the “8.2 ka event.” Around the same time, cultural indicators suggest the start of Neolithic agriculture in the region. The present-day mesomediterranean vegetation with evergreen oaks only began to develop after 6000–5000 cal. BP (4050–3050 cal. BC), likely in response to increasing winter temperatures and reduced frost occurrence, further advantaged by human impact during the past 3600 years.

In this paper, we apply the method of Lagrangian descriptors as an indicator to study the chaotic and regular behaviors of trajectories in the phase space of the classical double pendulum system. To successfully quantify the degree of chaos with this tool, we first derive Hamilton’s equations of motion for the problem in nondimensional form and demonstrate how they can be expressed compactly using matrix algebra. Once the dynamical equations are obtained, we conduct a parametric study based on the system’s total energy and other key parameters such as the lengths and masses of the pendulums, as well as gravity, to determine the extent of the chaotic and regular regions in the phase space. Our numerical results reveal that, for a given mass ratio, the maximum chaotic fraction of phase space trajectories is attained when the pendulums have equal lengths. Furthermore, we characterize how chaos grows and decays within the system in terms of the model parameters, and explore the hypothesis that the chaotic fraction follows an exponential law over different energy regimes.

AI techniques for cybersecurity are advancing, but AI-based classifiers are suspectable of adversarial attacks. It is challenging to quantify the efforts required of an adversary to manipulate a system and quantify this resilience such that different systems can be compared using standard metrics. The study intends to quantify the actions required when an attacker abuses an AI-based system and propose a model to assess the attacker’s cybersecurity resilience. The study proposes an Egyptian Vulture Optimized Adaptive Elman Recurrent Neural Networks (EVO-AERNN) model to assess cybersecurity resilience and compare it with machine learning and deep learning-based classifiers. It illustrates the potential of using adversary-aware feature sampling to build more robust classifiers and use an optimized algorithm to maintain inherent resilience. The proposed model is achieved with an accuracy of 0.995, an F1 score of 0.9932, a precision of 0.9921, a recall (before an attack) of 0.987, a recall (after an attack) of 0.632, and a severity score of 0.363. The proposed model is further validated with a secondary dataset. This study paves the way for a more comprehensive knowledge of adversarial attack scenarios on network systems and offers valuable insights, inspiring further research on advancing cybersecurity studies.