bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceived stress, sources of stress and coping strategies among undergraduate medical students of Nepal: a cross-sectional study
Authors: Paudel Ujjawal , Parajuli Anima , Shrestha Rashmi , Kumari Shivanee , Adhikari Yadav Saroj , Marahatta Kedar
Published: September 2023

Background: Medical students are subjected to significant stressors impacting their physical and mental health. While some students employ positive coping mechanism, others resort to maladaptive coping measures. This study aims to assess prevalence, severity, and sources of stress, as well as coping strategies among medical students of a non-Western low-income country from South Asia.

Methods: A self-administered questionnaire-based cross-sectional study was carried out. Demographic variables were collected and stress level was assessed using PSS 14 (Perceived Stress Scale 14). The sources of stress were assessed using MSSQ (Medical Student Stressor Questionnaire) and coping strategies were evaluated using the Brief-Coping Orientation to Problems Experienced.

Results: A remarkable response rate of 95% was achieved. Overall, 55% of students were stressed (male 52%, female 60%), the difference among gender was not significant. Initial basic science years students perceived higher levels of stress than later clinical clerkship students. Academic related stressors emerged as leading cause of stress, whereas other variables caused moderate stress. The major stressors were examinations, inadequate time to study, poor marks, extensive amount of learning content, and the need to performing well in the exam. Regarding coping strategies, the study revealed five predominant coping strategies:  active coping, acceptance, planning, self-distraction, and instrumental support. Conversely, the least common coping mechanism was substance use. Conclusions: This study reveals a high prevalence of stress level among the medical students, mainly driven by academic pressure. Stressed students were likely to use maladaptive coping strategies. First year medical students require focused support, and promoting healthier coping measures among all medical students is crucial.. Further studies can be done to evaluate the effects of stress on the academic outcomes of students.
A protocol for a scoping review to identify methods used in clinical practice to assess wound odour
Authors: Gethin Georgina , LeBlanc Kimberly , Ivory John D , McIntosh Caroline , Pastor Damien , Naughten Enda , Hobbs Chloe , McGrath Barry , Cunningham Stephen , Joshi Lokesh , Moloney Suzanne , Probst Sebastian
Published: September 2023

Objective: The objective of this scoping review is to map, from wound assessment tools and other literature, the current methods used to assess wound odour in order to answer the following question:  Which methods of assessment, validated or otherwise, are currently used in wound assessment tools to assess wound odour?

Introduction: Wound assessment includes not only details of the condition of the wound bed but also evaluation of symptoms associated with the wound including that of odour. Odour is cited by clinicians, patients and carers as one of the most distressing wound symptoms. However, there is no consensus on a preferred method to assess odour thus negatively impacting the internal and external validity of many clinical trials and minimising the ability to perform meta-analysis.

Eligibility criteria: Any wound assessment tool or framework that includes assessment of wound odour in any wound aetiology and in any care setting. Any systematic or scoping review that includes assessment of wound odour in any wound aetiology and in any care setting. No limits on date of publication or language will be applied.

Methods: We will employ the Preferred Reporting Items for Systematic Review and Meta-Analyses extension for scoping reviews (PRISMA-ScR) guidelines for this scoping review and base its structure on the framework proposed by Arksey and O’Malley.

Results: A narrative format will summarise extracted data and provide an overview of tools used to assess wound odour. A PRISMA diagram will outline the results of the search strategy. The identified tools will be summarised in table format and stratified according to methods used.

Conclusion: The result of this scoping review will be a list of methods used to assess odour in wounds and will be used to inform a subsequent Delphi study to gain consensus on the preferred method to assess wound odour.
The genome sequence of the star-devouring scaleworm, Acholoe squamosa (Delle Chiaje, 1825)
Authors: Adkins Patrick , Brennan Mitchell , McTierney Sean , Brittain Rachel , Perry Frances ,   Marine Biological Association Genome Acquisition Lab,   Darwin Tree of Life Barcoding collective,   Wellcome Sanger Institute Tree of Life programme,   Wellcome Sanger Institute Scientific Operations: DNA Pipelines collective,   Tree of Life Core Informatics collective,   Darwin Tree of Life Consortium
Published: September 2023

We present a genome assembly from an individual Acholoe squamosa (the star-devouring scaleworm; Annelida; Polychaeta; Phyllodocida; Polynoidae). The genome sequence is 1,481.5 megabases in span. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 15.64 kilobases in length.
Political “Dominance” of J. Biden within the Context of Communicative Manipulation Technologies (Based on the English Language)
Authors: Greydina N.
Published: September 2023

The research is a communicative analysis based on the interpretative model of speech behaviour of the incumbent US President J. Biden, demonstrating the implementation of an attempt of political dominance in the international context of the highest state level. The constructed form of communicative representation finds expression on the verbal and nonverbal levels. Specific communicative moves determined allow us to fully perceive the multidimensionality of the embedded meaning. Both the broad macro-textual and narrow micro-textual levels of political discourse are subjected to communicative analysis. The study of a political domination structure, the threat, interpreted through the means of communicative manipulation, acquires a deep consideration. One of the forms of psychological and tactical violence within the framework of political discourse is a threat. The latter receives a pragmatic implementation, reflecting the ways of manifestation in the context of communicative manipulation means – both of direct and indirect expression. Media materials in text and video formats are being studied. The conducted research introduces a number of clarifying theoretical positions in understanding the theory and practice of communicative manipulation technologies.
A new health-based metaheuristic algorithm: cholesterol algorithm
Authors: Seçkiner Serap Ulusam , Yilkici Yüzügüldü Şeyma
Published: September 2023

This paper seeks to explore the effectiveness of a new health-based metaheuristic algorithm inspired by the cholesterol metabolism of the human body. In the study, the main idea is the focus on the performance of the cholesterol algorithm on unconstrained continuous optimization problems. The performances of the proposed cholesterol algorithm are evaluated based on 23 comparison tests and results were compared with Particle Swarm Optimization, Genetic Algorithm, Grey Wolf Optimization, Whale Optimization Algorithm, Harris Hawks Optimization, Differential Evolution, FireFly Algorithm, Cuckoo Search, Multi-Verse Optimizer, and JAYA algorithms. Results showed that this novel cholesterol algorithm implementation can compete effectively with the best-known solution to test functions.
Supplier's selection of plate material using analytical hierarchy process and additive ratio assessment methods
Authors: Salsabila Ja'iza , Ernawati Dira
Published: September 2023

PT PAL Indonesia (PERSERO) is among the prominent shipyard companies in Indonesia that currently employs a simplistic supplier selection weighting system, prioritizing low prices and material specification conformity. This approach often leads to subjective assessments, making it challenging for the company to identify suitable suppliers from a large pool. Therefore, this study proposed a methodology to enhance supplier selection by incorporating additional criteria based on Dickson's criteria and company policies. The Analytical Hierarchy Process (AHP) and Additive Ratio Assessment (ARAS) methods were utilized for this purpose. The findings indicate that PT Krakatau Steel (A1) emerges as the top-ranked supplier with a Ki value of 0.19, followed by PT Diansakti Sejahtera (A5) in second place with a Ki value of 0.157, and PT Gunawan Dianjaya Steel (A3) in third place with a Ki value of 0.152. PT Jastindo Raya (A4) secures the fourth position with a Ki value of 0.151, while PT Gunung Raja Paksi (A2) takes the fifth and final spot with a Ki value of 0.15. This research helps the company effectively select the best suppliers, particularly in the procurement sector, by employing the AHP-ARAS method and considering Dickson's criteria, thereby addressing existing gaps the company encounters.
Morphometric Analysis of Tectonically Active Bhimtal-Naukuchiatal Lake Basin, Kumaun Himalaya
Authors: Gururani Kalpana , Kotlia Bahadur Singh , Chand Pooja , Kukreti Manmohan , Parashar Deepanshu , Kalkhundiya Arun , Bhatt Pankaj Kumar , Pandey Arvind
Published: September 2023

Bhimtal-Naukuchiatal region, which is an integral part of the Kumaun Lesser Himalaya, is sensitive to natural disasters and has a fragile environment as a result of neotectonic activity along the thrust and secondary thrust/faults. With regard to neotectonic activity, this study aims to comprehend the tectonic instability of the basin. Morphometric analysis is a computable research of landforms that is crucial to understanding how the landscape has evolved in response to nearby tectonic activity. In present exercise we have calculated ten morphometric indices, viz., Valley floor width-height ratio (Vf), Hypsometric Integral (HI), Stream-Length gradient Index (SL), Bifurcation ratio (Rb), Drainage density (Dd), Stream Order (Sµ) and average Sinuosity (S), Relief (H), steepness (Ksn), Chi integral (?) and Asymmetric Factor (AF). The result shows low values of Vf indicate high upliftment rate, more incision and less channel down cutting. Most morphometric results suggest tilted basin, resulting in V-shaped valleys and a distorted and unstable longitudinal profile, which indicate the area is governed by both tectonics and lithology. The field geomorphic features along with the software based calculations suggest that the Bhowali-Bhimtal-Naukuchiatal is tectonically active zone.
Assessment of Trace Element Concentrations in Groundwater Sources of a Rural Village in Kerala, India
Authors: Thaniem Muhammed , Prakash Anupama , Muniasamy Muniyandi , Eeshwar Rangasamy , Sundarabalan Palanisamy
Published: September 2023

Water is an essential part of all living organisms. India is already experiencing the effects of the impending global freshwater crisis in terms of water quantity and quality. The study, which was carried out in a rural village (Villiappally Gramapanchayath) in Kerala, sought to quantify the level of trace elements in the ground water and to determine how they affected the quality of the water suitable for human use. Twenty-two public wells that are used by the residents for their everyday needs are sampled in the pre-monsoon for the analysis. ICP-MS was used to analyse the water samples for the presence of the heavy metals Zn, Pb, Fe, Cd, As, and Al. The acquired value from ICP-MS analysis is compared with BIS standard values of drinking water quality. From the analysed heavy metals, cadmium and iron in some of the wells are exceeding the permissible limit of BIS. HPI of each well is carried out and find out that DW1, DW2 and DW14 is not fit for drinking purpose. By analysing the Metal Index (MI) out of 22 wells, 9 wells are pure in quality and others are slightly to moderately affected. Certain metals in different wells shows slight greater concentration than the permissible limits of BIS. These might be taken into account for a safer drinking water.
Pressure ulcer prevention devices in the management of older patients at risk after hospital discharge: an SNDS study
Authors: Lartigau Marion , Barateau Martine , Rosé Mathieu , Petricã Nicoleta , Salles Nathalie
Published: September 2023

Objective:

Our aim was to measure the effectiveness of home healthcare pressure ulcer (PU) prevention devices (PUPDs) for at-risk patients after hospital discharge in France.

Method:

We conducted a retrospective analysis of PU-associated hospitalisations based on the French medico-administrative database (Système National des Données de Santé, SNDS), which covers the entire French population. All adults >70 years of age, hospitalised from 1 July to 31 December 2015, and equipped with a medical bed at home, were included. Follow-up was for a maximum of 18 months. Propensity score matching allowed the comparison of PUPD equipped and non-equipped groups (No-PUPD), considering sociodemographic characteristics and other factors.

Results:

The study included 43,078 patients. Of this population, 54% were PUPD patients and 46% No-PUPD. After matching, PUPD patients had significantly fewer PUs than No-PUPD patients (5.5% versus 8.9%, respectively; p<0.001). The adoption of PUPD reduced by 39% the risk of a PU in hospital. Patients equipped within the first 30 days at home after hospitalisation had fewer PUs than those equipped later (4.8% versus 5.9%, respectively). The estimated PUPD use costs represented 1% of total healthcare expenditure per patient during the study period.

Conclusion:

The study results demonstrated the effectiveness of the adoption of mattress toppers or prevention mattresses in reducing PU occurrence in patients aged >70 years of age. A short delay in PUPD delivery appeared to have a real impact in the medical setting. Future research on a larger population might provide more evidence on the appropriate support and timeframe to choose based on risk assessment.
Treatment of fungal infection on left ventricle assist device driveline exit site: a case report and systematic review
Authors: Brandão Sara Michelly Gonçalves , Biseli Bruno , Ayub-Ferreira Silvia Moreira , Strabelli Tânia Mara Varejão , Bocchi Edimar Alcides
Published: September 2023

Objective:

The use of ventricular assist devices (VAD) is increasing; however, diagnosis and management of device complications, such as the driveline exit site (DES) being the portal of entry for fungal infection, is not well known.

Method:

A systematic review involving searching PubMed (2005 to July 2020) was conducted. The case of a 43-year-old female patient who had a left VAD (LVAD) (HeartMate 3, Abbott, US) is also reported.

Results:

The patient was successfully treated with ketoconazole cream and oral fluconazole for likely superficial DES fungal infections. We included 36 studies that met our inclusion criteria; however, only one was included in our review. In the literature, five cases of DES fungal infection were reported, with Candida being the only fungal pathogen.

Conclusion:

LVAD fungal infections are uncommon but can be responsible for high mortality rates, require a prolonged period of treatment, and can present a huge problem when surgical alternatives are not available. However, Candida species are most common. Fungal infections can only produce clear discharge, and so the classic definition of driveline infection based on purulent secretion can vary. Negative skin culture does not exclude the diagnosis of infection of the DES, and so empirical diagnosis may only be clinically based.
Nutritional management of equine gastric ulcers
Authors: Witherow Briony
Published: September 2023

Over the last 10 years there has been increasing awareness and subsequently recorded cases of equine gastric ulcer syndrome and with this comes an increased interest in appropriate nutrition and feed management. This review presents a systematic approach to assessing the ration of a horse at risk of or diagnosed with equine gastric ulcer syndrome and demonstrates the ample evidence upon which to base nutritional recommendations for horses with equine squamous gastric disease, and to a lesser extent, equine glandular gastric disease, with an emphasis on forage. Careful selection and management of the forage ration should be the first step in designing a suitable ration, followed by selection of an appropriately low starch and sugar (less than 2 g per kg body weight per day and 1 g per kg body weight per meal) complementary feed.
Equestrianism's social license to operate: assumptions, reality and the future
Authors: Williams Jane M.
Published: September 2023

Horse sports and equestrian activities are high risk to the horses and people undertaking them. Societal views on using animals for human entertainment are changing and there is increased debate on how animal welfare is safeguarded. Traditional management systems that reduce opportunities for expression of normal behaviour and high levels of disease and injury in horses interacting with humans have increased public scrutiny on the use of horses by humans, resulting in equestrianism's social license to operate being questioned. A social license to operate is a virtual license from society to engage in an activity – without this, the future of equestrianism is under threat. This review explores what constitutes a social license to operate and considers how stakeholders in the equestrian sector could work together to generate an effective social license to operate to ensure horses have a good life in all aspects of their relationship with humans.
Experiences and perceptions of evidence use among senior health service decision makers in Ireland: a qualitative study
Authors: Calnan Susan , McHugh Sheena
Published: September 2023

Background:

To support evidence-informed decision making in a health service context, there is a need to better understand the contextual challenges regarding evidence use.

Aims and objectives:

To examine experiences of evidence use and perceived barriers, facilitators and recommended strategies to increase research use among senior decision makers in the national health service in Ireland.

Methods:

We conducted semi-structured interviews with decision makers in Ireland’s national health service (n= 17) from August 2021 to January 2022. Criterion sampling was used (division in the organisation and grade of position), and interviews were analysed using thematic analysis. Barriers and facilitators were mapped according to multiple-level categories (individual, organisational, research, social, economic, political) identified in the literature.

Findings:

Health service decision makers described a blended and often reactive approach to using evidence; the type and source of evidence used depended on the issue at hand. Barriers and facilitators to research use manifested at multiple levels, including the individual (time); organisational (culture, access to research, resources, skills); research (relevance, quality); and social, economic and political levels (external links with universities, funding, political will). Strategies recommended by participants to enhance evidence-informed decision making included synthesising key messages from the research, strengthening links with universities, and fostering more embedded research.

Discussion and conclusion:

Evidence use in health service contexts is a dynamic process with multiple drivers. This study underlines the need for a multilevel approach to support research use in health services, including strategies targeted at less tangible elements such as the organisational culture regarding research.
Introduction: Characters in/as Connection
Authors: Grenouilleau-Loescher Rebecca , Haklin Kathryn A.
Published: September 2023

Abstract: This introduction to the special issue "Connecting Characters in Modern and Contemporary French-language Fiction" offers a critical context for studying character networks and interdependency. Through the lens of Glissant's concept of "Relation" and in dialogue with Jagoda's notion of "network aesthetics," the issue examines what connects characters in fictional works, how these links shape narrative meaning within and across texts, and how character interdependency reflects diverse social, political, and historical contexts. From the nineteenth-century novel to the multi-perspectival fictions of today, the issue attests to a shift in our critical understanding of characters, from a focus on individual centrality to movement within community.
Mise(ère)-en-scène : Transposition and the Child in Hugo's and Ly's Les misérables
Authors: Sweat Amber Patrice
Published: September 2023

Abstract: This article explores the relationship between Victor Hugo's novel and Ladj Ly's film, both titled Les misérables , focusing on their shared themes of marginality and societal injustice in the banlieues of Paris. This article further examines how the film transposes Hugo's work, highlighting the continuity of misery and social hierarchies in the banlieue across generations. The article also delves into the representation of children in both works, revealing how they are both victimized by and implicated in systems of violence and prejudice. Lastly, it discusses Ly's use of filmmaking techniques to challenge power dynamics and provide marginalized communities with agency and visibility, both on-screen and in lived experiences.
« Nos solitudes à partager » : Personnages-voix , êtres en relation dans les romans de Laurent Mauvignier
Authors: Deleuze Laëtitia
Published: September 2023

Abstract: Lire les romans de Laurent Mauvignier, c'est plonger dans un espace de personnages-voix , des vies bouleversées et déconnectées par un événement dramatique qui les replie en haute solitude. La blessure signe la rupture du langage entre les personnages, qui cherchent à mettre en mots le manque de l'autre. Pourtant, les voix intérieures sont souvent adressées et aspirent à un lien, même fantasmé. L'écriture puissante creuse au plus près des expériences psychiques et sensorielles. Depuis l'isolement des personnages, la fiction et le réseau étoilé des voix recréent une connexion, et tissent des "solitudes à partager" (Glissant): une relation qui se transforme en devenir.
Deep reinforcement learning for proactive spectrum defragmentation in elastic optical networks
Authors: Etezadi Ehsan , Natalino Carlos , Diaz Renzo , Lindgren Anders , Melin Stefan , Wosinska Lena , Monti Paolo , Furdek Marija
Published: September 2023

The immense growth of Internet traffic calls for advanced techniques to enable the dynamic operation of optical networks, efficient use of spectral resources, and automation. In this paper, we investigate the proactive spectrum defragmentation (SD) problem in elastic optical networks and propose a novel deep reinforcement learning-based framework DeepDefrag to increase spectral usage efficiency. Unlike the conventional, often threshold-based heuristic algorithms that address a subset of the defragmentation-related tasks and have limited automation capabilities, DeepDefrag jointly addresses the three main aspects of the SD process: determining when to perform defragmentation, which connections to reconfigure, and which part of the spectrum to reallocate them to. By considering service attributes, the spectrum occupancy state expressed by several different fragmentation metrics, and the reconfiguration cost, DeepDefrag is able to consistently select appropriate reconfiguration actions over the network lifetime and adapt to changing conditions. Extensive simulation results reveal superior performance of the proposed scheme over a scenario with exhaustive defragmentation and a well-known benchmark heuristic from the literature, achieving lower blocking probability at a smaller defragmentation overhead.
Evolution properties of a complex coherent square Gaussian–Schell-model beam in a uniaxial crystal orthogonal to the optical axis
Authors: Zhou Jun , Li Huguang , Zhou Jianyang
Published: September 2023

The analytical formulas for spectral density, degree of coherence, and effective beam widths of complex coherent square Gaussian–Schell-model (GSM) beams in a uniaxial crystal orthogonal to the optical axis are derived. Based on these analytical formulas, the evolution properties are investigated by a set of numerical examples. It is demonstrated that the complex coherent square GSM beams spread at different rates in the directions parallel and orthogonal to the optical axis due to the anisotropic crystal, but the self-shift effect of the light field is almost unaffected by the fact that the uniaxial crystal is anisotropic. The effect of anisotropy of the uniaxial crystal on the effective width of the beam in the x direction and that in the y direction is completely opposite. The results provide a way for the modulation of the complex coherent square GSM beams and enrich the propagation theory of uniaxial crystal.
Ultrawide tunable terahertz phase shifter based on a double-layer liquid crystal–dielectric grating
Authors: Jiang Songlin , Fan Fei , Ji Yunyun , Zhao Huijun , Cheng Jierong , Wang Xianghui , Chang Shengjiang
Published: September 2023

The ultrawide tunable terahertz (THz) phase shifter has always been in high demand by THz applications, especially in terms of broadband transmission and phase modulation. In this paper, we design and fabricate a composite device that combines a double-layer liquid crystal (LC) with a double-sided etched grating metasurface. By introducing the natural anisotropy of LC based on the artificial anisotropy of the metasurface, the anisotropy of the device is significantly enhanced, and this anisotropy can be dynamically modulated by an external field. When the LC molecules rotate in the x−y plane, the experimental results show that the phase difference can vary between −83∘ and 277° at 0.52 THz with a large phase-shift modulation depth of 360° (i.e., 2π). The same phase-shift modulation depth can be obtained when the LC molecules rotate in the x−z plane, in which the phase difference can vary between 207° and 567° at 1.14 THz. Our proposed composite device shows an ultrawide phase shift regulation and an ultra-large phase-shift modulation depth in the THz regime, which may provide a new strategy for various THz phase and polarization devices.
Damage, waveguide, and electrical properties in (La, Sr)(Al, Ta)O3 single crystal irradiated with carbon ions
Authors: Qiao Mei , Wang Tiejun , Liu Yong , Liu Tao , Wang Zhenxing , Cui Wanling , Wang Xiaoxin , Li Xin , Xu Shicai
Published: September 2023

The (La, Sr)(Al, Ta)O3 crystal was irradiated via 20.0 MeV C ion with fluence of 1.0×1015ions/cm2. The Rutherford backscattering (RBS)/channeling spectra, the hardness and elastic modulus as continuous functions of the depth, and X-ray diffraction (XRD) are used to analyze the irradiation damage, hardness, and structural changes in the near-surface area of samples. Prism coupling and end-face coupling methods were used to study the changes of optical waveguide properties under different annealing conditions. Considering the potential applications of low-loss waveguide structure in photoelectric sensors, electrical properties of (La, Sr)(Al, Ta)O3 samples were studied as an important detection indicator of sensors.
Butterfly-shaped and dromion-like optical similaritons in an asymmetric twin-core fiber amplifier
Authors: Raju Thokala Soloman , Myakalwar Ashwin Kumar
Published: September 2023

Butterfly-shaped and dromion-like optical waves in a tapered graded-index waveguide (GRIN) with an external source are reported for the first time, to our knowledge. More pertinently, we obtain these waves both analytically and numerically in a generalized nonlinear Schrödinger equation (GNLSE), which describes self-similar wave propagation in GRIN with variable group-velocity dispersion (GVD), nonlinearity, gain, and source. The proposed GNLSE appertains to the study of similariton propagation through asymmetric twin-core fiber amplifiers. Dromion-like structures, which have generally been investigated in the (2+1) or higher dimensional systems, are reported in the (1+1) dimensional GNLSE with an external source. Herein, we introduce the concept of soliton management when the variable group-velocity dispersion and Kerr nonlinearity functions are suggested. For example, when the GVD parameter is perturbed, we observe the emergence of vibration of dromion-like structures. Then the dromion-like structure is transformed into oscillation by the modulation instability of the modified coefficient of the Gaussian GVD function, exhibiting interference based on two dromion-like structures. Additionally, the phenomenon of unbreakable PT symmetry of these nonlinear waves has been demonstrated for three explicit examples.
Remote terahertz wireless power transfer with self-resonating spoof plasmonic structures
Authors: Cheng Shu-Ling , Wu Hong-Wei , Sun Wen-Jun , Zhou Nong , Peng Cheng-Yao , Sheng Zong-Qiang , Zhang Wen-Bing
Published: September 2023

In this paper, we use a pair of self-resonating subwavelength spoof plasmonic structures to achieve remote non-radiative terahertz wireless power transfer, while nearly without affecting the electromagnetic environment of free space around the structure. The resonating frequency and quality factor of the magnetic dipole mode supported by the spoof plasmonic structures can be freely tuned by tailoring the geometric structure. By putting the weak source and detector into the self-resonating structures, we can find that the effective non-radiative terahertz power transferring distance can reach several hundred times the radius of the structures. Finally, we also demonstrate the efficient wireless power transfer capability for the multi-target receiving system. These results may provide a novel approach to the design of non-radiative terahertz wireless power transfer and communications.
High-speed 4 × 4 silicon photonic plasma dispersive switch, operating at the 2 µm waveband
Authors: Wang Jiawei , Sia Jia Xu Brian , Li Xiang , Guo Xin , Wang Wanjun , Qiao Zhongliang , Littlejohns Callum G. , Liu Chongyang , Reed Graham T. , Rusli  , Wang Hong
Published: September 2023

The escalating need for expansive data bandwidth, and the resulting capacity constraints of the single mode fiber (SMF) have positioned the 2-μm waveband as a prospective window for emerging applications in optical communication. This has initiated an ecosystem of silicon photonic components in the region driven by CMOS compatibility, low cost, high efficiency and potential for large-scale integration. In this study, we demonstrate a plasma dispersive 4 × 4 photonic switch operating at the 2-μm waveband with the highest switching speed. The demonstrated switch operates across a 45-nm bandwidth, with 10-90% rise and 90-10% fall time of 1.78 ns and 3.02 ns respectively. In a 4 × 4 implementation, crosstalk below -15 dB and power consumption lower than 19.15 mW across all 16 optical paths are indicated. This result brings high-speed optical switching to the portfolio of devices at the promising waveband.
Demonstration of a highly efficient topological vertical coupler
Authors: Okada Sho , Kagami Hibiki , Nishiyama Nobuhiko , Hu Xiao , Amemiya Tomohiro
Published: September 2023

A defect structure is proposed for enhancing the coupling efficiency of vertically incident circularly polarized light in a topological waveguide. In the topological edge-state waveguide based on triangle lattices of hexagons consisting of six nanoholes respecting C6v symmetry in a silicon optical circuit, the vertical coupling rate is improved by removing the nanoholes from one hexagonal cell near the line. The coupling efficiency was evaluated with and without the defect structure. The introduced defect structure operates suitably for focused beams of left- and right-handed circularly polarized light, enhancing the optical communication wavelength bandwidth by up to 10 dB.
Multi-objective fractional-order particle swarm optimization algorithms for data processing of multi-wavelength pyrometer
Authors: Liang Mei , Wang Yongsheng , Wang Changhui
Published: September 2023

This paper focuses the algorithm of the true temperature inversion for high-temperature targets with unknown emissivity by transforming multi-spectral true temperature inversion into multi-objective minimum optimization. Two improved fractional-order particle swarm optimizations (IFOPSO), high-order nonlinear time-varying inertia weight (Hntiw) IFOPSO and global-local best values (Glbest) IFOPSO, are proposed to obtain the true temperature by solving the multi-objective minimum optimization. Combining the inherent advantages of fractional-order calculus to jump out of the local extreme value, the Hntiw IFOPSO algorithm is proposed by replacing the linear time-varying inertia weights with nonlinear functions related to the total number of iterations and the current number of iterations. The Glbest IFOPSO algorithm is designed by using the global local optimal inertia weight and acceleration constant to update the particle velocity and position values, which improves the multi-objective optimization ability and the accuracy of the true temperature inversion. The effectiveness of the proposed methods is verified by the simulation with typical spectral emissivity models and the measured data from rocket tail flame.
Optical closure in highly absorptive coastal waters: significance of inelastic scattering processes
Authors: Mukherjee Soham , Hedley John D. , Fichot Cédric G. , Laliberté Julien , Bélanger Simon
Published: September 2023

In hydrological optics, “optical closure” means consistency between the apparent optical properties (AOPs) determined from radiometric measurements and those derived from radiative transfer modelling based on concurrently measured inherent optical properties (IOPs) and boundary conditions (sea and sky states). Good optical closure not only provides confidence in the data quality but also informs on the adequacy of the radiative transfer parameterization. Achieving optical closure in highly absorptive coastal waters is challenging due to the low signal-to-noise ratio of radiometric measurements and uncertainties in the measurements of IOPs, namely the spectral absorption and backscattering coefficients. Here, we present an optical closure assessment using a comprehensive set of in situ IOPs acquired in highly absorptive coastal waters optically dominated by chromophoric dissolved organic matter (CDOM). The spectral remote sensing reflectance, Rrs(λ), was modeled using the software HydroLight (HL) with measured IOPs and observed boundary conditions. Corresponding in-water in situ Rrs(λ) was derived from radiometric measurements made with a Compact Optical Profiling System (C-OPS; Biospherical). The assessment revealed that the inclusion of inelastic scattering processes in the model, specifically sun-induced CDOM fluorescence (fDOM) and sun-induced chlorophyll fluorescence (SICF) from Chlorophyll-a ([chl]), significantly improved the optical closure and led to good agreement between measured and modeled Rrs (i.e., for 440 ≤ λ ≤ 710 nm with no inelastic processes: R2=0.90, slope=0.64; with inelastic processes: R2=0.96, slope=0.90). The analysis also indicated that fDOM and SICF contributed a substantial fraction of the green-red wavelength Rrs in these waters. Specifically, fDOM contributed ∼18% of the modeled Rrs in the green region and SICF accounted for ∼20% of the modeled Rrs in the red region. Overall, this study points out the importance of accounting for fDOM in remote sensing applications in CDOM-dominated waters.
Strong coupling of excitons and electric/magnetic toroidal dipole modes in perovskite metasurfaces
Authors: Gao Chenggui , You Shaojun , Zhang Ying , Zhou Chaobiao , Xie Quan
Published: September 2023

Effective manipulation of the interactions between light and matter is crucial for the advancement of various high-performance optoelectronic devices. It is noted that the toroidal dipole resonance refers to an electromagnetic excitation that exists beyond the conventional understanding of electric and magnetic multipoles, which shows great potential for enhancing light-matter interactions. In this work, we investigate the strong coupling properties of electric toroidal dipole (ETD) and magnetic toroidal dipole (MTD) with excitons in (PEA)2PbI4 perovskite metasurfaces. The nanostructure consists of two identical nanobars on a SiO2 substrate, which support ETD and MTD responses. The strong coupling between ETD/MTD modes and perovskite excitons is achieved when adjusting oscillator strength f0, which can be charactered by the clearly anti-crossing behavior appeared in the transmission spectra. The Rabi splitting can be readily tuned by controlling f0. When f0 increases to 1.0, their Rabi splitting values reach as high as 371 meV and 300 meV, respectively. The proposed strong coupling between excitons and ETD/MTDs paves the way for large-scale, low-cost integrated polaritonic devices operating at room temperature.
Liquid-crystal-based visible-light integrated optical phased arrays and application to underwater communications
Authors: Notaros Milica , DeSantis Daniel M. , Raval Manan , Notaros Jelena
Published: September 2023

In this Letter, we present the first, to the best of our knowledge, liquid-crystal-based integrated optical phased arrays (OPAs) that enable visible-light beam forming and steering. A cascaded OPA architecture is developed and experimentally shown to emit a beam in the far field at a 632.8-nm wavelength with a power full width at half maximum of 0.4°×1.6° and 7.2° beam-steering range within ±3.4 V. Furthermore, we show the first visible-light integrated-OPA-based free-space-optical-communications transmitter and use it to demonstrate the first integrated-OPA-based underwater-wireless-optical-communications link. We experimentally demonstrate a 1-Gbps on–off-keying link through water and an electronically-switchable point-to-multipoint link with channel selectivity greater than 19 dB through a water-filled tank.
Wavelength sensitivity reconfigurable SPR photodetector with a blazed grating profile
Authors: Lu Guofeng , Wen Quan , Li Dongling , Yuan Xingquan , Liu Junhong , Yu Hailin
Published: September 2023

Surface plasmonic detectors based on one-dimensional half-wavelength gratings have attracted attention due to their wavelength- or polarization-specific photodetection. Although the effect of a grating period and a grating depth on the photoelectric conversion of 1D half-wavelength grating-based surface plasmon resonance (SPR) detectors has been discussed thoroughly in recent years, the effect of different grating profiles on device performance is still limited to the rectangular shape. In this article, we proposed a wavelength sensitivity reconfigurable photodetector enhanced by SPR with a blazed grating profile. The gold layer was fabricated on a silicon-based blazed grating to form a Schottky barrier and act as an SPR coupler. By measuring the photocurrent in the range of −58° to −48°of an incident angle, the peak shifts of a photocurrent signal waveform are found to depend on the wavelength over 800–1000 nm.
Epsilon-near-zero gratings for polarization selectivity
Authors: Qin Jin , He Hainan , Xu Changqing , Luo Jie , Lai Yun
Published: September 2023

Zero-index materials have emerged as a topic of significant scientific interest in recent years. In this Letter, we investigate the electromagnetic properties of epsilon-near-zero (ENZ) gratings composed of materials with near-zero effective permittivity. Our study reveals that ENZ gratings exhibit a unique polarization selectivity that is opposite to that observed in perfect conductor gratings. Furthermore, we demonstrate that hybrid gratings combining perfect conductors and ENZ materials can block omnidirectional electromagnetic waves of any polarization. In addition, we propose a practical design of the ENZ and hybrid gratings based on dielectric ENZ MMs, exhibiting excellent polarization selectivity and blocking effect. Our research presents a promising approach for the flexible manipulation of polarizations using ENZ gratings.
Thermal dissipation enhancement in flip-chip bonded uni-traveling carrier photodiodes
Authors: Bai Junwu , Shen Yang , Yao Peng , Chen Dekang , Konkol Matthew , Guo Bingtian , Guo Xiangwen , Carey Victoria , Campbell Joe C. , Prather Dennis
Published: September 2023

The thermal properties of modified uni-traveling carrier (MUTC) photodiode flip-chip bonded to AlN and diamond are simulated. The thermal impedance of InGaAs is the primary source of internal heating. An n-down epitaxial structure is designed to improve thermal dissipation. Compared to the conventional p-down configuration, the n-down MUTCs bonded to diamond, or AlN submounts achieved 145% and 110% improvement in dissipated power density at thermal failure, respectively. The improved thermal characteristics presage higher RF output power before thermal failure.
Terahertz Bessel metalens with an extended non-diffractive length and a high efficiency
Authors: Miao Jiahao , Zhou Zhanxuan , Liu Yi , Lin Cong , Zhu Xincheng , Sun Zhuoran , Yu Xiaomei
Published: September 2023

In this paper, we propose a reflective terahertz (THz) Bessel metalens that utilizes polarization-insensitive sub-wavelength metal resonator–dielectric–metal structures. The Bessel metalens is configured with the superposition of hyperboloidal and conical phase profiles, resulting in a high-efficiency and long non-diffractive length Bessel beam. Our experimental results demonstrate that the proposed Bessel metalens has a focusing efficiency of 72.1% and a non-diffractive length of 239λ. This device has promising aspects in the fields of THz imaging systems and other miniaturized and integrated scenes that require non-diffractive Bessel beams.
Xenon-plasma focused ion beam processing of photonic microstructures with GaAs-based quantum dots
Authors: Jaworski Maciej , Chudzyńska Aleksandra , Mrowiński Paweł , Prażmowska-Czajka Joanna , Kijaszek Wojciech , Große Jan , Rodt Sven , Reitzenstein Stephan , Sęk Grzegorz
Published: September 2023

So far, successful focused ion beam (FIB) based fabrication of photonic structures with quantum dots (QDs) has been limited to cases with above 1 µm thick cap, usually in a form of a distributed Bragg reflector of a vertical cavity, which simultaneously protects the active region from the destructive influence of the ion beam. Here, we propose optimized xenon-plasma FIB (Xe-PFIB) technology as a fast and cost-efficient solution alternative to the commonly used combination of electron beam lithography and etching. We demonstrate a 3D processing of GaAs-based photonic microstructures with InGaAs QDs emitting close to the telecom O-band for cylindrical mesas with different cap thicknesses (50-650 nm) obtained by using two approaches: (i) Xe-PFIB for both reducing the cap thickness as well as the in-plane microstructure size, and (ii) wet chemical etching for cap layer removal and subsequent Xe-PFIB for the in-plane milling. The latter appeared more efficient when judging by photoluminescence intensity. Utilizing an additional protecting layer of platinum or carbon was also tested. Eventually, we for the first time show successful FIB-based fabrication of photonic microstructures with bright emission from single QDs capped with only 200 nm layer, which indicates the prospects of this technology for processing of efficient QD-based single-photon sources for quantum communication.
Modeling of a fiber Fabry-Pérot sensor in the broken PT-symmetric region
Authors: Iftikhar Faiza , Ahmad Raja , Cheema Imran
Published: September 2023

Parity-time (PT)-symmetric optical sensors operating around exceptional points have recently gained much attraction due to their improved sensitivity for measuring small perturbations. Previously, most of the PT-symmetric sensors have been based on detecting the mode splitting that arises due to the perturbation-induced change in coupling strength between two sub-cavities of the PT-symmetric system. Here, we present a model of a fiber Fabry-Pérot linear cavities sensor tailored to operate in the broken parity-time symmetric region. We propose, what we believe to be, a new sensing metric based on the mode’s linewidth change as a function of perturbation-induced loss changes in one of the cavities. The coupling strength between the two sub-cavities remains unchanged in our proposed sensor. We derive a mathematical expression that describes a square root dependence of the full-width-half-maximum change as a function of the refractive index change-induced loss, which is introduced via a tapered fiber in one of the fiber cavities. The proposed fiber Fabry-Pérot refractive index sensor has a maximum sensitivity of 2.26 × 107 GHz/RIU and the lowest detection limit of 10−9 RIU, widely outperforming comparable cavity sensors subject to the same refractive index change, gain, and loss settings.
Uncovering specific mechanisms across cell types in dynamical models
Authors: Hauber Adrian L. , Rosenblatt Marcus , Timmer Jens
Published: September 2023

Ordinary differential equations are frequently employed for mathematical modeling of biological systems. The identification of mechanisms that are specific to certain cell types is crucial for building useful models and to gain insights into the underlying biological processes. Regularization techniques have been proposed and applied to identify mechanisms specific to two cell types, e.g., healthy and cancer cells, including the LASSO (least absolute shrinkage and selection operator). However, when analyzing more than two cell types, these approaches are not consistent, and require the selection of a reference cell type, which can affect the results. To make the regularization approach applicable to identifying cell-type specific mechanisms in any number of cell types, we propose to incorporate the clustered LASSO into the framework of ordinary differential equation modeling by penalizing the pairwise differences of the logarithmized fold-change parameters encoding a specific mechanism in different cell types. The symmetry introduced by this approach renders the results independent of the reference cell type. We discuss the necessary adaptations of state-of-the-art numerical optimization techniques and the process of model selection for this method. We assess the performance with realistic biological models and synthetic data, and demonstrate that it outperforms existing approaches. Finally, we also exemplify its application to published biological models including experimental data, and link the results to independent biological measurements.