bluuebunny/crossref_metadata_2025 huggingface dataset:
Traditional knowledge, attitude and behaviour of indigenous people towards endangered wildlife conservation in Kon Plong District, Vietnam
Authors: Nguyen Thi Thien Huong , Bui Manh Hung , Nienartowicz Andrzej , Dong Thanh Hai , Nguyen Quoc Dung , A Siu , Tran Huu Vy , Smith Lynn
Published: July 2024

Indigenous knowledge, attitudes, and perceptions of local people are very important concepts for wildlife conservation. Endangered wildlife species that live in Kon Plong forests have been under pressure from the communities living around them, including wildlife hunting, trapping, capturing, illegal logging, and encroachment for residential and production land. This study aims to understand the knowledge, attitude, and behaviour of indigenous people towards endangered wildlife in order to protect these species. Some participatory rural appraisal tools were used to discuss the situation and collect information in nine villages of four communes in Kon Plong District from December 2019 to March 2020. The results showed that the levels of knowledge about endangered wildlife among indigenous people in communes were statistically different. People’s knowledge of the law influenced their behaviour. Gender had the greatest influence on the level of knowledge. Most indigenous people had a positive attitude and wanted to protect endangered animals. “Commune” and “culture” were the two factors affecting people’s attitudes. “Commune”, “culture”, and the level of understanding affected the hunting behaviour of people. Negative human impacts have seriously influenced endangered wildlife species. Therefore, it is necessary to develop a long-term conservation strategy and plan, including the establishment of Kon Plong Special-Use Forests, supporting livelihoods for local people, communicating, and raising awareness among local people, and increasing the participation of community organisations.
Advanced control of compressor inlet temperature in supercritical CO2 Brayton cycle
Authors: Wang Rui , Wang Xuan , Tian Hua , Shu Gequn
Published: July 2024

The supercritical CO2 (sCO2) Brayton cycle has gained much interest because of its flexibility, compactness and high efficiency. The sCO2 at the inlet of compressor should work near the critical point to obtain high system efficiency, while the physical properties of sCO2 near the critical point change dramatically, which brings great challenges to the control of the compressor inlet temperature. At present, cooling far from the critical point and adjusting the cooling water flow rate with Proportion- Integration-Differentiation (PID) controller is the commonly used method, but it loses system efficiency and may be out of control sometimes. Therefore, in this study Linear Model Predictive Control (LMPC) and Deep reinforcement learning (DRL) are used to control the compressor inlet temperature and compared with PID. A dynamic model of a recompression sCO2 Brayton cycle is established, and the cooler model is carefully validated against experiment data. The results indicate that both the LMPC and DRL can control the sCO2 temperature near the critical temperature much better than the PID. LMPC works the best because the cold end parameters fluctuate slightly and the cooler model can be regarded as approximately linear, thus LMPC can find almost the global optimal solution. Nevertheless, DRL control exhibits the fastest real-time computation ability and proves good extrapolation ability.
DUAL CONDENSING PRESSURE ORC FOR CRYOGENIC ENERGY STORAGE
Authors: Conlon William M. , Venetos Milton J.
Published: July 2024

A liquid air combined cycle (LACC) is a hybrid energy storage system that uses cryogenic air as a storage medium. Discharge of stored energy involves the pressurization and re-gasification of the stored liquid air, sensible heating of gaseous air, and expansion of the air through a turbine that discharges to atmosphere. During discharge of stored energy, an Organic Rankine Cycle (ORC) operates as a bottoming cycle drawing low-temperature heat from the gas turbine exhaust and using the cryogenic liquid as a heat sink. The quantity of low-grade heat that can be extracted from gas turbine exhaust is constrained by the amount of heat that must be rejected from the ORC. The overall efficiency of the LACC is the net power output divided by the energy inputs, which are the electricity used to cryogenically liquefy air during charging and the fuel consumed by the gas turbine during discharging. Power output can be increased by maximizing the heat input to the ORC, potentially including the water of combustion. To relieve the constraint imposed by the limited availability of cryogenic liquid air and to maximize the heat input and power output, a novel dual condensing pressure cycle is described. The cycle includes both high and intermediate pressure turbines, with one condenser operating at intermediate pressure and the second operating at a low pressure. A fraction of the ORC working fluid is extracted at intermediate pressure and cooled by heating regasifed air. The remainder of the working fluid expands through the intermediate pressure turbine and condenses at low pressure using the cryogenic liquid air as a low temperature heat sink. The low-pressure liquid is pumped to intermediate pressure and used to directly condense the cooled fraction, whereupon the mixture is recuperated and then heated by gas turbine exhaust.
AERODYNAMIC DESIGN AND NUMERICAL ANALYSIS OF A COUNTER-ROTATING CENTRIFUGAL COMPRESSOR
Authors: Brahim ABED Cheikh , LEROUX Arthur
Published: July 2024

Counter-rotating turbomachines offer more design and control options than conventional machines. While axial counter-rotating turbomachines have been widely studied, few studies have focused on centrifugal ones. This paper presents a detailed numerical study on the benefits of counter-rotating impellers for centrifugal compressors, specifically the impact of speed ratio on performance gain. The study used 0D/1D models and optimization methods to meet design criteria. The aerodynamic performance of the new designs was compared to a baseline configuration consisting of a centrifugal impeller and a vaned wedge diffuser. The new design features a first impeller with perfect axial inlet and mixed flow or a purely radial blade at the impeller exit, and a parametrically designed counterrotating bladed diffuser with radial or mixed flow inlet and radial outlet. Optimized solutions were determined using validated 0D/1D loss models and analyzed using a 3D CFD solver. The results show that this new configuration can increase efficiency on a wide range compared to the baseline using speed ratio modulation.
Guidelines and optimization criteria of a machine learning-based methodology for mixture design in ORC systems
Authors: Mariani Valerio , Ottaviano Saverio , De Pascale Andrea , Cazzoli Giulio , Branchini Lisa , BianchiValerio Mariani Gian Marco , Ottaviano Saverio , De Pascale Andrea , Cazzoli Giulio , Branchini Lisa , Bianchi Gian Marco
Published: July 2024

orking fluid selection in organic Rankine cycles (ORC) is a critical issue in the system design for specific applications. In most cases, pure fluids are employed as working medium, and the choice among commercial products is fundamentally based on the heat source temperature level, on fluid cost and safety requirements. Mixtures of organic fluids present some interesting features. First of all, zeotropic blends can help reducing the irreversibility associated to the isothermal heat transfer of pure working fluids in the evaporator and in the condenser, with potential improvement of the overall conversion efficiency from heat sources with finite capacity. Moreover, the possibility of using fluids with relatively high global warming potential, blended with low-GWP fluids, allows reducing the equivalent carbon emissions (according to the European F-gas regulation), helping the full transition to cleaner compounds. However, there is a lack of organic mixtures specifically optimized for ORC systems, particularly because different applications require fluids with different properties, and the available solution may not be the optimal for the specific case. Due to the large number of molecules available to be combined, the use of numerical algorithms is mandatory to accomplish the mixture formulation task (type, number and amount of each component). In this work, an optimization tool based on a Bayesian statistical inference methodology is implemented and tested, to define the composition of mixtures of different groups of organic fluids (HFC, HFO, HC). The algorithm adopts a mixed exploration-exploitation searching strategy on a solution domain made by the different pure molecules commonly employed. The tool is programmed to fulfil the maximization of an objective function, built from a set of key physical properties and performance indexes of the mixture. The choice of the properties accounted in the optimization (with relative weight) is discussed, and the algorithm is applied to a case study to demonstrate its capability to define a low-GWP blend replacing HFC 134a, maintaining and possibly enhancing the performance.
Visual Narratives in Health Communication: Evaluating Comics as Tools for Health Literacy by the Indonesian Ministry of Health
Authors: Sabri Sabri , Adiprabowo Vani Dias , Sumarlan Iman , Mohamad Rafidei
Published: July 2024

This study investigates the efficacy of comics as a strategic communication tool for health promotion, utilizing a qualitative analysis of literature and examples from the “Sehat Negeriku” website managed by the Indonesian Ministry of Health. The multifaceted nature of comics, incorporating visual storytelling and character-driven narratives, offers a unique method for conveying complex health messages in an accessible and engaging manner. This research identifies several key advantages of comics in health communication, including increased appeal and interest among diverse demographics, enhanced memory retention through visual cues, emotional engagement that deepens message impact, stimulated creativity and imagination, and the ability to reach a broad audience. Data collection involved a thorough review of existing literature and content analysis of health communication comics, focusing on their structure, content, and reception. The findings highlight how comics, by blending entertainment with educational content, can effectively reduce resistance to health messages, facilitate behavioral change, and contribute to public health knowledge. Furthermore, the study underscores the importance of considering cultural relevance and audience-specific characteristics in comic design to maximize their educational impact. This paper contributes to the understanding of visual communication in public health and supports the integration of comics into broader health promotion strategies.
Analgesic advice for children with special needs who have odontogenic pain
Authors: Gorman Hannah , de Souza Michelle C
Published: July 2024

Many children struggle or refuse to take oral medications. The refusal of medication occurs for many reasons including learned and pre-existing anxiety, sensitivity to tastes and textures and sensory–motor/coordination difficulties (for tablet swallowing). Oral analgesics play a vital role in managing the odontogenic pain of children. This is especially true when they have limited access to appropriate dental care services, are pre-cooperative or lack the ability to be compliant for conventional dental treatment.

CPD/Clinical Relevance:

Practical advice around the facilitation of analgesic administration for odontogenic pain is lacking for parents of children who may not accept conventional preparations.
Addressing inequalities in the perioperative care for older adults
Authors: Thirunavukarasu Giothini S , Partridge Judith S L , Dhesi Jugdeep K
Published: July 2024

Older adults constitute a large proportion of patients undergoing surgery and present with complexity, predisposing them to adverse postoperative outcomes. Inequalities exist in the provision of surgical care across the United Kingdom evidenced by increased waiting times in areas of social deprivation, a disparity in the provision of surgical care across geographic locations as well as a variation in the medical management of comorbidities in surgical patients. Addressing inequalities in the delivery of perioperative care for older adults necessitates a multi-faceted approach. It requires implementation of an evidence-based approach to optimisation of older surgical adults using Comprehensive Geriatric Assessment and optimisation methodology at scale, development of an age-attuned, flexible, transdisciplinary workforce, a restructuring of funding to commission services addressing the needs of the older surgical population and a change in culture and professional and public understanding of the needs of the older surgical patient.
The use of peripheral vasopressors and its implications for hospital medicine
Authors: Kalinoski Michael , Kalinoski Thomas , Pendleton Kathryn
Published: July 2024

Vasopressor medications for circulatory shock have historically been administered through central venous catheters due to concern for extravasation injury when given peripherally. However, recent studies have demonstrated the safety of peripheral administration of vasopressor medications at lower doses and for a limited duration. Peripheral use of vasopressors is appealing to both patients and providers, as obtaining central access is an invasive procedure associated with the risk of pneumothorax, bleeding, and infection. Furthermore, waiting to initiate these medications until central access is obtained can lead to delays in care. Conversely, valid concerns remain regarding the risk of tissue extravasation associated with peripheral vasopressors, which can be life and limb threatening. We discuss the guidelines and data for optimal dose, duration, intravenous line (IV) size, IV location, and nursing IV site monitoring for peripheral vasopressors. We then explore adverse events associated with peripheral vasopressors. Finally, we describe how this practice change may impact hospital medicine providers.
Clinical reasoning—the essentials for teaching medical students, trainees and non-medical healthcare professionals
Authors: Jay Robert , Davenport Clare , Patel Rakesh
Published: July 2024

Clinical reasoning is fundamental for effective clinical practice. Traditional consultation models for teaching clinical reasoning or conventional approaches for teaching students how to make a diagnosis or management plan that rely on learning through observation only, are increasingly recognised as insufficient. There are also many challenges to supporting learners in developing clinical reasoning over time as well as across different clinical presentations and contexts. These challenges are compounded by the differences in how experts and novices make sense of clinical information, and the different cognitive processes each use when processing and communicating this information using precise medical language. Diagnostic errors may be due to cognitive biases but also, in a majority of cases, due to a lack of clinical knowledge. Therefore, effective educational strategies to develop clinical reasoning include identifying learners’ knowledge gaps, using worked examples to prevent cognitive overload, promoting the use of key features and practising the construction of accurate problem representations. Deliberate reflection on diagnostic justification is also recommended, and overall, contributes to a growing number of evidence-based and theory-driven educational interventions for reducing diagnostic errors and improving patient care.
Squamous cell carcinoma of the ovary arising from a mature cystic teratoma associated with hypercalcaemia
Authors: Montebello Annalisa , Maniscalco Nicoletta , Grech Martina , Cuschieri Andrew , Brockdorff Kristel Marie Von
Published: July 2024

We present a rare case of a 40-year-old nulliparous lady, with no past medical or surgical history, who was diagnosed with metastatic squamous cell carcinoma of the right ovary that originated from a mature cystic ovarian teratoma. Our patient underwent debulking total abdominal hysterectomy, bilateral salpingo-oophorectomy and partial omentectomy followed by postoperative carboplatin and paclitaxel chemotherapy. Rapid disease progression ensued, complicated by severe parathyroid hormone-related protein-induced hypercalcaemia resistant to medical therapy. The patient was treated in a palliative manner and died five months after her diagnosis.
Supporting advanced practice: feedback from a mental health, community and primary care advanced practice support project in South Yorkshire, UK
Authors: Jenkinson Cheryl , Fisher Sarah
Published: July 2024

Background:

Despite the significant input from Heath Education England (HEE), now NHS England (NHSE), there are still significant variations around advanced practice programmes, support and training, particularly in less developed areas such as mental health, community posts and primary care. To help target these areas, and to support the NHS Long Term Plan (2023) to increase the number of advanced clinical practitioners (ACPs), the Faculty of Advanced Practice South Yorkshire recruited three ACP leads from mental health, community, and primary care backgrounds to establish a support project led by one professional lead. These leads were able to utilise their lived experience of completing the ACP MSc programme and working as an ACP to help trainee advanced clinical practitioners (tACPs) navigate their journey. The ACP leads also developed a variety of educational events, which further supported the trainees' needs.

Aim:

This article reports the feedback given via an online questionnaire from trainees that accessed the project, which ended in March 2024. Its aim is to highlight the often-undervalued concept of using clinicians personal experience regarding advanced training and practice, to mentor, support and ultimately retain the future ACP workforce.

Methods:

An email with a link to a questionnaire was sent to 128 tACPs or recently qualified ACPs that had applied for their training via the Faculty of Advanced Practice South Yorkshire. The questionnaire, created in Microsoft Forms, was completed anonymously, and produced both numerical and free-text data. The questionnaire solicited feedback around: the number of contacts they had and how they contacted; the ACP leads; types of support accessed; and the educational events available. Free text answers were analysed by the author (CJ) and a second reviewer (SF) to generate a consensus on themes.

Results:

A total of 64 clinicians responded, of which 43 were tACPs, 10 were ACPs, five had other job titles (community matron, pharmacist, practice nurse) and five did not state what their job title was. Responses suggest that the support accessed from the project was highly beneficial and could not be gained elsewhere. A key factor in the project's success was the ACP leads' lived experience of having previously completed advanced practice training, as well as their ability to tailor learning events to the trainees' needs.

Conclusion:

Meeting the demands of ACP training in areas where the role is less established remains an ongoing challenge. It seems some of these challenges relate to the lack of practical support being provided by employers or higher education institutions, such as lived experience of completing the task of ACP training. Support projects, like the one discussed in this article, appear aptly placed to help fulfil these needs and begs the question ‘why aren't there more?’, especially when advanced practitioners are fundamental to the future healthcare workforce.
A mixed-method review of the efficacy of a virtual fracture clinic: an 8-year follow up
Authors: McDonough Andrew , Lyle Victoria , Angus Michelle , Heaslip Sarah , Noblet Tim
Published: July 2024

Background:

Virtual fracture clinics are well established methods of managing trauma patients safely and effectively. While they have been widely adopted, there is a lack of research on their longer-term implementation and success.

Aims:

This paper aimed to review factors that may influence the success of a virtual fracture clinic.

Methods:

Business analytics were used to calculate clinic discharge and return rates, as well as the reasons for them. Qualitative analysis was used to look at patient satisfaction with virtual consultations; data were extracted from two differing time points via telephone interviews.

Results:

The mean discharge rate across the 2014–2021 period was 28%. The largest discharge rate was seen in 2014 (43%) and the lowest was seen in 2021 (28%). Return rates to the emergency department at the two different time points were 2% and 0.9% respectively. Patient satisfaction was rated as ‘good’ or higher in all parameters at both time points.

Discussion:

This article describes the long-term success of a virtual fracture clinic. Results demonstrate excellent patient satisfaction coupled with the lowest return rates in the published literature. Discharge rates started extremely high and have declined with time. The factors for these results are discussed along with ideas for further prospective research.
OPTIMIZING PREOPERATIVE HAEMOGLOBIN MONITORING AND TRANSFUSION PRACTICES IN SHOULDER ARTHROPLASTY SURGERY: A COST-EFFECTIVE ANALYSIS OF PREOPERATIVE ADMISSIONS IN THE NATIONAL HEALTH SERVICE
Authors: Arvidsson A. M. , Ibrahim I. K. , Vannet N.
Published: July 2024

Shoulder replacement surgery is a well-established orthopaedic procedure designed to significantly enhance patients’ quality of life. However, the prevailing preoperative admission practices within our tertiary shoulder surgery unit involve a two-stage group and save testing process, necessitating an admission on the evening before surgery. This protocol may unnecessarily prolong hospital stays without yielding substantial clinical benefits.

The principal aim of our study is to assess the necessity of conducting two preoperative group and save blood tests and to evaluate the requirement for blood transfusions in shoulder arthroplasty surgeries. A secondary objective is to reduce hospital stay durations and the associated admission costs for patients undergoing shoulder arthroplasty. We conducted a retrospective observational study covering the period from 1st January 2023 to 31st August 2023, collecting data from shoulder arthroplasty procedures across three hospitals within the Aneurin Bevan University Health Board.

Our analysis included 21 total shoulder replacement cases and 13 reverse shoulder replacement cases. Notably, none of the patients required postoperative blood transfusions. The mean haemoglobin drop observed was 14 g/L for total shoulder replacements and 15 g/L for reverse shoulder replacements. The mean elective admission duration was 2.4 nights for total shoulder replacements and 2 nights for reverse shoulder replacements. Our data indicated that hospital stays were extended by one night primarily due to the preoperative group and save blood tests.

In light of these findings, we propose a more streamlined admission process for elective shoulder replacement surgery, eliminating the need for the evening-before-surgery group and save testing. Hospital admissions in these units incur a cost of approximately £500 per night, while the group and save blood tests cost around £30 each. This revised admission procedure is expected to optimise the use of healthcare resources and improve patient satisfaction without compromising clinical care.
Tackling obesity in Indonesia: current problems and future directions
Authors: Tahapary Dicky Levenus
Published: July 2024

[No abstract available]
Contentious public finance: how entanglement shapes the costs of resisting elitist budgetary preferences
Authors: Novak Mikayla
Published: July 2024

Entangled political economy views societal phenomena as featuring substantial interaction between economic and political entities, but questions have been raised about the conceptual properties of entanglement. The political economist Randall Holcombe has raised questions concerning the economic influences affecting uneven patterns of entanglement between entities. Drawing upon his own transaction costs-based framework of political stratification, Holcombe suggests that political elites incur relatively low transaction costs associated with bargaining over policies, whereas non-elites incur relatively high costs. This suggests that elites actively participate in policy design and implementation and can outmaneuver the non-elite public to externalize the costs of political decisions, yielding noticeable clustering effects within entangled network structures. This article seeks to build upon Holcombe’s insights, as well as the transaction cost politics of Charlotte Twight, illustrating how groups engaging in political processes attempt to manipulate transaction costs to secure favorable outcomes. Transaction cost manipulation by elites to secure advantages is commonly studied, but less so is how non-elitists succeed in adjusting the transaction costs of political exchanges to help prevent fiscal exploitation by elitists. The public finance case of Colorado’s Taxpayer’s Bill of Rights is used to illustrate how dynamic entanglements between elites and non-elites delivered institutional change better aligning with non-elite fiscal preferences.
Archival Care at Arsip Jazz Indonesia
Authors: Stuparitz Otto
Published: July 2024

Abstracts: Drawing on ethnographic fieldwork and analysis of musical media, this article focuses on the archival record of Chinese-Javanese jazz producer Harry Lim maintained in the collections of Arsip Jazz Indonesia (Indonesia Jazz Archive). I examine Lim’s history as a transnational migrant in the 1940s American music business and connect his history to social values shaped by the grassroots archivists. I use archival care, the idea that archiving should be practiced with more attention to the people and communities that produced and value materials, to interpret these practices as a form of reparative cultural work. Berdasarkan penelitian etnografis dan analisis media musik, artikel ini berfokus pada berbagai arsip dan dokumentasi mengenai Harry Lim, seorang produser jazz Tionghoa-Jawa, yang tersimpan dalam koleksi Arsip Jazz Indonesia atau Indonesia Jazz Archive. Saya mengkaji sejarah Lim sebagai seorang migran transnasional dalam bisnis musik Amerika dekade 1940-an, serta menghubungkan sejarahnya dengan nilai-nilai sosial yang dibentuk oleh para pengarsip akar rumput. Saya menggunakan konsep mengurus arsip para (archival care), gagasan bahwa pengarsipan harus dilakukan dengan lebih memperhatikan orang-orang dan komunitas yang menghasilkan dan menilai materi dalam perwalian kearsipan, untuk menafsirkan temuan saya sebagai bentuk karya budaya reparatif.
Label-free Raman imaging of saturated and unsaturated fatty acid uptake, storage, and return toward baseline levels in macrophages
Authors: Hobro Alison J. , Sugiyama Takeshi , Pavillon Nicolas , Umakoshi Takayuki , Verma Prabhat , Smith Nicholas
Published: July 2024

Lipids play many important roles in the body including cell signaling and energy storage. The presence of excessive lipids, or disruption of normal lipid metabolic processes in the cell, has been linked to lifestyle diseases such as atherosclerosis and obesity. Where the affected cells are part of the innate immune system such dysregulation of lipids has also been implicated in impaired immune responses to infection. Therefore, understanding how macrophages are affected by the presence of fatty acids in their local environment is an important step in understanding lifestyle disease development. Using Raman spectroscopic imaging we studied the uptake of several concentrations of palmitic, stearic, oleic and linoleic acid in live macrophage cells. Macrophages readily take up these lipids, which can be observed by Raman imaging at the edge of the cytoplasm close to the cell membrane, with the exact distribution dependent on the nature of the fatty acid (unsaturated/saturated) and the exposure concentration. At the highest concentrations, all fatty acids appear to be toxic to the macrophage cells after 24 hours of exposure. By comparing the Raman intensities of the pure fatty acids and ratiometric imaging of the intensities within the macrophage cells we were able to determine that the toxicity of a fatty acid is not due directly to the amount of fatty acid present in the macrophage, rather the nature of the fatty acid is important. This demonstrates the power of high-resolution ratiometric Raman imaging for bioanalysis. In addition, we monitored macrophage cells after removing fatty acids from the surrounding environment, observing a reduction in fatty acid content of the cells over the following 48 hours, showing that even heavily lipid-laden macrophages can process these excess lipids once fatty acids are removed from the environment.
Lamellar Columns Photonic Crystal Mirror with High Reflectivity for Extreme-Ultraviolet Radiation
Authors: Wang Chih-Chung , Lee Chao-Te , Li Jia-Han
Published: July 2024

For the applications in the extreme ultraviolet (EUV) region, early research [1] revealed that the suitable design of multilayer mirrors with a wavelength of 5 to 50 nm can increase the reflectivity. Li et al. have done related research on Mo/Si multilayer films and proposed vacuum voids mixing in the Si layer can be used to increase the reflectivity for EUV radiation [2]. It is found that the higher proportion of vacuum voids, the higher reflectivity can be obtained from 73.43% for no vacuum voids to 83.24% for full vacuum voids. According to [2], the reflectivity can be effectively improved by vacuum mixing Si layers in 40 pairs of Mo/Si multilayer films. Mo has a larger extinction coefficient than Si in the 13.5 nm wavelength region, so Mo is designed as an absorber to localize into the low-intensity standing wave field. By using a Si layer mixed into the vacuum, the high-intensity regions will have a smaller extinction coefficient, i.e. the imaginary part of the refractive index. The reflectance can be improved by mixing the Si layer in vacuum is because it has more difference between the real parts of the refractive index of the Si layer and the Mo layer; thereby, the interference effect is enhanced. For the multilayer columnar structure mixed into the vacuum layer [3], there are also related researches on the applications in the visible light region. It is not yet found to use similar kinds of structures in extreme ultraviolet light region. In this paper, we propose a hybrid Mo/Si multilayer cylinder-film in control of the constructive interference in multilayer films to enhance reflectivity of EUV radiation.
Animation of dielectric metasurface 3D hologram
Authors: Onozawa Tamaki , Beppu Junpei , Yamaguchi Masakazu , Takahashi Shunsuke , Ikezawa Satoshi , Iwami Kentaro
Published: July 2024

Three-dimensional (3D) metasurface holograms that enable natural 3D viewing with less fatigue are expected to be applied to 3D displays[1], AR/VR devices, and so on. In this study, we achieved a 3D holographic animation that can be observed with the naked eye without using a lens[2] as shown in Figure 1, by fabricating an array of large-area metasurface holograms. A movie that consists of 8 frames was successfully reproduced with a maximum speed of 2.8 fps.
Wavelength Independent Coupling Length Variation analysis using Silicon on Insulator based Rectangular Waveguide for Coupler/Splitter Application
Authors: Vardhan Shalini , Singh Ritu Raj
Published: July 2024

Silicon on Insulator (SoI) technology poised to revolutionalize photonic world in terms of device compactness and operational speed. Many of the photonic active and passive devices uses waveguides in their geometry to couple optical power. Devices which uses coupler as their part of geometry are ring resonator, race track resonator, coupler and splitter itself [1]–[3]. As optical power transfers from one waveguide to other waveguides, therefore, coupling length (Lc) is an important parameter which requires precise calculation. To validate coupling length variation, rigourous simulation is performed using Finite Element Method (FEM) based Comsol Multiphysics software at 1550 nm operational wavelength.
Low temperature annealing for vanadium dioxide in photonic integrated circuits
Authors: Du Yuxin , Sun Kai , Zheng Zihang , de Groot Cornelis H. , Fang Xu
Published: July 2024

We show at the annealing temperature of vanadium dioxide (VO2) fabricated using atomic layer deposition can be suppressed to 300 °C, significantly improving the compatibility of VO2 with photonic integrated circuits.
Grating Diffraction Select Radial Mode at the Inner Active Cladding of Hybrid-Cavity Microlaser
Authors: Chen Jinghan , Abazi Adrian , Eich Alexander , Tomishige Yoshitaka , Takeda Harunobu , Mikami Yuya , Tate Naoya , Oki Yuji , Schuck Carsten , Yoshioka Hiroaki
Published: July 2024

Miniaturized, tunable, on-chip lasers are crucial to developing photonic integrated circuits (PICs). Microrings, a common integrable laser, often exhibit multi-mode propagation that leads to unstable lasing. Researchers have integrated azimuthal gratings onto microrings to improve performance to realize single-mode lasing [1]. However, microring lasers with active semiconductor cores face challenges related to design flexibility and the need for precision in fabrication. We introduce a hybrid-cavity grating-integrated lasers, incorporating a Si3N4 microring and active polymeric cladding. This design simplifies fabrication and provides flexible gain choices for diverse wavelength lasing. The issue is the complexity of the mode due to the broad distribution of the active cladding. We demonstrate the generation and selection of radial modes from the grating diffraction at the inner active cladding. And the radial mode is partly coupled with whispering gallery modes (WGMs) propagating in the microring.
Beam Steering with Integrated Optical Phased Array using DNN
Authors: Nakai Makoto , Takai Isamu
Published: July 2024

Integrated optical-phased-array (OPA) has drawn significant attention due to the potential use in wide range of applications, such as LiDAR (Light Detection and Ranging) and free space communication. Beam emitted from OPA is electronically steerable by controlling the phase of light entering the antenna array [1]. During the fabrication process, the device dimension and waveguide sidewall roughness apt to change within the OPA circuit. This shifts the phase of light entering each antenna, resulting in a phase error. To prevent the distortion of the emitted beam, a look-up table of phase modulation voltage (PM-voltage) is prepared for each beam angle. Another factor which distorts beam is the change of chip temperature, which shifts the refractive index. In an environment which temperature changes rapidly, a look-up table for each angle and temperature will be required, resulting in a massive amount of calibration work. In this work, deep neural network (DNN) is used to predict the PM-voltage which controls the phase modulators to form a desired far field pattern (FFP).
Thermal conductivity measurement of transparent thin film by photothermal heating with continuous wave laser
Authors: Tanjaya Nicholaus K. , Ishii Satoshi
Published: July 2024

Optical methods using lasers to extract thermal conductivities including frequency-domain thermoreflectance, time-domain thermoreflectance, and laser flash methods require either pulse lasers or frequency modulated lasers to heat samples. In contrast, we recently developed a thermal conductivity measurement scheme based on quantitative phase microscope (QPM) where a heating laser can be a continuous (CW) laser. The use of CW laser simplifies the optical system. Additionally, our method has an advantage to extract thermal conductivity and thermo-optic coefficient (TOC) simultaneously. In terms of the fitting model of our method, so far it was limited only for transparent substrate. In the current work, we experimentally show that with the modified fitting model, our system can measure the thermal conductivity and TOC of a transparent film on a transparent substrate. A measurement result for an indium gallium zinc oxide (IGZO) thin film deposited on a glass substrate is presented as an example.
Nanocavity induced by atomically thin transition metal dichalcogenide in photonic crystal waveguide
Authors: Fong C.F. , Yamashita D. , Fang N. , Fujii S. , Chang Y.-R. , Taniguchi T. , Watanabe K. , Kato Y. K.
Published: July 2024

Photonic crystal (PhC) cavities can be formed by depositing materials onto PhC waveguides post-fabrication to modulate the local refractive index. Previous studies suggested that ultrahigh Q-factor PhC cavities could be formed with a small local refractive index modulation of ~0.1% [1, 2]. However, experimental attempts to create such cavities by depositing poly(methyl methacrylate) (PMMA) onto GaAs PhC waveguides were unable to achieve ultrahigh Q cavities because of the thick polymer layer [3]. Another approach of placing nanowires along the PhC waveguide to induce the formation of nanocavities have also been reported [4, 5]. Alternatively, 2D materials with their atomically thin nature represent a novel platform to realize the small refractive index modulation to induce high Q nanocavity in a PhC waveguide. In this work, we report the observation of high Q-factor nanocavities formed by placing atomically thin transition metal dichalcogenide (TMDC) flakes onto PhC waveguides.
Nanoparticle Film Based Mechanoplasmonic Sensors for Wearable Strain Applications of Human-Motion Monitoring
Authors: Matsui Hiroaki , Momose Akira , Yoda Hidehiko , Fujita Aki
Published: July 2024

Recently, electronic devices with stretchable features have received much attention because of the huge promises of strain sensors for human motion monitoring. Flexible strain sensors can monitor large mechanical deformations exceeding commercial electric strain sensors. Similarity, the mechanical method is known as one of external field control of SPRs, which provides an alternative while promising approach for mechanoplasmonic devices.
Transverse spin angular momentum of space-time surface plasmon polaritons
Authors: Kubo A. , Ichiji N. , Oue D. , Yessenov M. , Schepler K. L. , Abouraddy A. F.
Published: July 2024

Spatially structured electromagnetic fields such as evanescent waves and surface plasmon polaritons (SPPs) possess transverse spin angular momentum (t-SAM) in the direction perpendicular to the axis of propagation [1]. Moreover, when the SPP has a two-dimensionally structured profile at the confined interface, the t-SAM possesses both the in-plane (t-SAM∥) and the out-of-plane (t-SAM⊥) components, indicating that the SPP can have a three-dimensional arrangement of spin textures and thus a finite surface area on the Poincaré polarization vector sphere.
Design and Characterization of High Aspect Ratio, Double Insulator Plasmonic Nanostructures for Gas Sensing Applications
Authors: Balois-Oguchi Maria Vanessa , Chu Cheng-Hung , Yamaguchi Takeshi , Tanaka Takuo
Published: July 2024

Optical gas sensors for detecting and monitoring harmful gases is of great interest in medicine, industry and environment sectors [1,2]. With the rapid miniaturization of technology, there is an increasing demand to develop more compact, robust and sensitive gas sensors. To address this demand, plasmonic nanostructures of various designs have been implemented to detect gas molecules through techniques such as surface-enhanced infrared absorption. Our group has developed a plasmonic metamaterial infrared absorber that utilizes vertical metal-insulator-metal channel-type (c-MIM) nanostructures [3], wherein the resonance frequency of the c-MIM couples with the vibration of the target molecule to produce Fano resonance. Using this c-MIM, our group previously demonstrated the detection of butane and carbon di-oxide gases. However, there were two main concerns: (1) can the molecule access the hotspots in the deeper parts of the c-MIM, and (2) can we improve the stability of the channel structure. We address these concerns through the use of a double insulator plasmonic nanostructure, that combines SiO2 and air to engineer the position and intensity of the electromagnetic field generated at the gap between the two Au vertical walls. The c-MIM is supported by a Si grating for increased stability. In this work, we study the geometrical impact of our proposed design on frequency selectivity, electromagnetic field distribution and absorption tunability experimentally and through numerical simulations [4].
Infrared Plasmonic Metasurfaces with Double Resonances for SEIRA Platforms
Authors: Dang Tang , Ma Shuting , Yang Jiaqi , Tabata Hitoshi , Matsui Hiroaki
Published: July 2024

Recent progress in the design and manufacturing of metal nanostructures has opened up new possibilities for generating and controlling localized electromagnetic fields and adjustable spectral resonances. Notably, the recent introduction of multispectral plasmonic nanoantennas has demonstrated significant potential for various spectroscopic applications, such as on-chip plasmon sensing of multiple analytes, as well as simultaneous detection of fluorescence and Raman signals in both the visible and infrared (IR) spectral domains. Surface-enhanced infrared absorptions (SEIRAs) can identify molecules of different chemical nature by matching the plasmonic resonances with the molecular-vibrational peaks. However, the metasurfaces with a single resonance show a narrow resonance peak, which cannot detect excitation wavelengths for a wide range of molecular vibrations. Therefore, it is required to simultaneously measure different molecular vibrations. Our presentation introduces IR metasurfaces with dual resonances consisting of two different sizes, enabling comprehensive measurements of molecular vibrations beyond conventional SEIRA devices with single resonance.
Surface Phonon Resonances in Circular Cavities on the Surface of Bioactive Hydroxyapatite for Biosensing Platforms
Authors: Ma Shuting , Dang Tang , Yoda Hidehiko , Sato Yoshita , Tabata Hitoshi , Matsui Hiroaki
Published: July 2024

Surface phonon resonance (SPhR) is a phenomenon that occurs when the collective oscillations of atomic lattice are excited by external incident fields from the mid-infrared (MIR) range at the surface of a polar dielectric [1]. SPhR-related phenomenon in the IR range is connected to surface-enhanced infrared absorption (SEIRA) toward spectroscopic measurements through the coupling between the molecular vibrations and SPhRs, leading to biosensing devices with label-free molecular recognition for monitoring biological interactions [2]. The SPhRs of some classical phononic materials such as SiC, h-BN, MoO3, and Al2O3 have higher Q-factors than those of plasmonic materials, however, the sensing of these materials is limited to the target molecules. In contrast, this research focused on a well-known bioactive material, hydroxyapatite (HAp), which actively interacts with the surrounding liquid environment resulting in the change of surface status. The environment-sensitive nature of surface phonons makes it possible to function as active optical probes, defining as “active SEIRA”. In this work, Au microhole arrays were formed on HAp substrates to produce SPhRs confined in circular cavities. SPhRs in the holes with different sizes were examined by IR-ellipsometry under s- and p-polarization light at changing incident angles. The final purpose is to create HAp as a novel biosensing platform based on active-SEIRA for detecting the chemical change of host surface dependent on environment (pH) and examining the affinity to polypeptides.
Femtosecond laser ablation of dielectrics: experimental strategies for probing dynamics and controlling performance
Authors: Garcia-Lechuga Mario , Siegel Jan , Solis Javier , Sanner Nicolas , Utéza Olivier , Grojo David
Published: July 2024

Femtosecond lasers are widely used in the processing of dielectric materials, with applications ranging from microelectronics and photonic device manufacturing to glass processing. Furthermore, the extreme nonlinear and thermodynamic conditions experienced by the material during femtosecond laser processing make it an area of great interest from a fundamental perspective. However, these lead to complex problems with interplay between various processes. In this work, we present different experimental approaches that allow for a better understanding of the fundamentals involved in modifying the dielectric surface, as well as the resulting consequences on machining performance.
Machine Learning Application for High – Precision auto Focusing in Laser Processing on Curved Surface
Authors: Nguyen Thi Phuong Anh , Dinh Viet Hoang , Cao Xuan Binh
Published: July 2024

The use of the laser technology in production has several limitations, particularly when fabricating on curved surfaces. Thus, we suggested a new method that combines an autofocusing methodology with machine learning algorithm that precisely assess the focus status during laser processing on curved surface.
High Speed Glucose Detection Infrared Spectroscopy System Based on Quantum Cascade Laser
Authors: Chen Junyi , Furukawa Hiromitsu
Published: July 2024

The global prevalence of diabetes has risen dramatically, with the number of affected individuals increasing from 108 million in 1980 to 537 million in 2021 [1]. Un-fortunately, there is currently no known cure for diabetes, making early detection through blood glucose testing necessary. Therefore, the development of accurate, rapid, simple, and real-time methods for measuring blood glucose levels is of utmost importance in diagnosing diabetes. Traditional invasive techniques for measuring blood glucose involve the uncomfortable and inconvenient process of pricking a finger to obtain a blood sample [2]. Infrared spectroscopy has emerged as a promising noncontact method for detecting glucose concentrations. Mid-infrared spectroscopy demonstrates a strong and broad absorption pattern that serves as a fingerprint absorption for glucose. Consequently, there has been significant interest in exploring the application of these spectroscopic methods [3].
Laser Parameters for Square-Hole Drilling with Femtosecond Polarized Beam
Authors: Watanabe Wataru , Yoshina Kosuke , Ebata Keiji , Kikuta Hisao
Published: July 2024

Micro-hole drilling with femtosecond lasers enable micro-fabrication with minimal thermal effects, has attracted much attention. The polarization state of a laser beam has a strong influence on the process in almost any kind of laser material processing [4,5].
Computer-generated Holography for Double-sided Image Reproduction
Authors: Suda Ryutaro , Nishizaki Yohei , Naruse Makoto , Horisaki Ryoichi
Published: July 2024

Computer-generated holography (CGH) is a technique to calculate interference patterns that reproduce arbitrary optical fields. Various CGH applications have been proposed, such as next-generation displays1-3). In this study, we present CGH for double-sided image reproduction with a single hologram toward omnidirectional displays for virtual/augmented reality4).
Looking through a dynamic scatterer
Authors: Chandra Sourav , Sarkar Tushar , Kumar Raj , Das Bhargab , Singh Rakesh Kumar
Published: July 2024

Ability to see through a dynamic scatterer is an exciting topic of current research. Here, we demonstrate an experimental technique accomplished by Hanbury Brown-Twiss (HBT) approach to see through a dynamic scatterer.
Privacy-Preserving Human Behavior Estimation with Sparse Sensor Measurements
Authors: Isogawa Mariko
Published: July 2024

Most conventional methods for person behavior estimation acquire information that can easily identify the person, such as images that include information on the face and clothing or acoustic information that includes voice, speech content, musical instrument playing sound, etc. Instead, we have been tack-ling proposed methods that do not acquire them towards privacy-preserving human behavior estimation. Specifically, we have been working on 3D human pose estimation with binary images [1], laser reflection [2], acoustic signals [3], and human mesh estimation with event data [4], making it possible to estimate human behavior in various situations while protecting personal information. In this talk, I will introduce our recent work on these topics.