bluuebunny/crossref_metadata_2025 huggingface dataset:
Sub-area design of a reflective metasurface for Bessel beam generation to mitigate the impact of feed occlusion
Authors: Hao Honggang , Zhang Ting , Yin Dan , He Jinfeng
Published: August 2024

This paper introduces a sub-area metasurface designed to mitigate the effects of feed occlusion when generating Bessel beams on reflective metasurfaces. This unit incorporates an anisotropic structure with distinct phase responses tailored for two orthogonal linearly polarized (LP) electromagnetic (EM) waves. The energy loss of the Bessel beam, situated behind the feed source, generated by the outer ring, is minimized through the superposition of the inward traveling waves and strategic partitioning of the array area. Furthermore, the principle of electric field superposition is employed to focus on the inner ring. The simulated results demonstrate that at 9 GHz, the metasurface produces a bifocal effect with focusing efficiencies of 60.1% and 64.3%, in conjunction with a Bessel beam exhibiting a diffraction-free region of 799 mm. For x polarization, the full width at half-maximum (FWHM) of the post-feed Bessel beam is 49.83 mm (1.49λ). In contrast, under y polarization, the FWHM of the Bessel beam with an off-axis angle of 30° is 47.63 mm (1.43λ). The simulated results suggest that the proposed metasurface has promising applications in point-to-multipoint or same-path multi-target wireless power transmission (WPT) systems.
Microscope integrated MHz optical coherence tomography system for neurosurgery: development and clinical in-vivo imaging
Authors: Draxinger Wolfgang , Detrez Nicolas , Strenge Paul , Danicke Veit , Theisen-Kunde Dirk , Schützeck Lion , Spahr-Hess Sonja , Kuppler Patrick , Kren Jessica , Wieser Wolfgang , Mario Bonsanto Matteo , Brinkmann Ralf , Huber Robert
Published: August 2024

Neurosurgical interventions on the brain are impeded by the requirement to keep damages to healthy tissue at a minimum. A new contrast channel enhancing the visual separation of malign tissue should be created. A commercially available surgical microscope was modified with adaptation optics adapting the MHz speed optical coherence tomography (OCT) imaging system developed in our group. This required the design of a scanner optics and beam delivery system overcoming constraints posed by the mechanical and optical parameters of the microscope. High quality volumetric OCT C-scans with dense sample spacing can be acquired in-vivo as part of surgical procedures within seconds and are immediately available for post-processing.
Flexible-queue-management-based bandwidth allocation in higher-speed PONs
Authors: Li Jun , Sun Guanlun , Lu Xiang , Lin Rui , Wosinska Lena
Published: August 2024

Higher-speed passive optical networks (i.e., ITU-T 50G PONs) are envisioned to support various time-sensitive services with diverse quality of service (QoS) requirements (e.g., latency and jitter). To achieve this goal, higher-speed PON introduces multiple queues in each transmission container (T-CONT) so that each queue can carry a type of time-sensitive traffic. However, in the existing dynamic bandwidth allocation (DBA) schemes, the DBA engine in the optical line terminal (OLT) allocates bandwidth to four types of T-CONTs based on their buffer occupancies and priorities without considering queue status (e.g., the amount of data frames in queues) and services’ QoS requirements. To support multiple services belonging to the same T-CONT, the traffic scheduler in each optical network unit (ONU) further assigns the bandwidth of T-CONTs to their associated queues by using priority-based scheduling strategies. In this way, the bandwidth is allocated to queues by the DBA engine and traffic scheduler independently, which cannot guarantee network performance and meet the stringent QoS requirements of time-sensitive services. To solve this problem, we propose a DBA mechanism based on flexible queue management (FQM) to enable direct allocation of bandwidth to the queues under their QoS requirements. The proposed FQM mechanism enables the DBA engine to obtain the arrival time and QoS requirements of data frames in different queues as well as queue status based on the existing report/grant mechanism. By using these parameters, the required bandwidth for each queue in the next polling cycle can be calculated. Then, the DBA engine allocates bandwidth to these queues according to their bandwidth requests and priorities periodically. Simulation results show that the proposed scheme outperforms two benchmarks in the aspects of meeting time-sensitive services’ diverse QoS requirements, even when the traffic load is high.
Accurate reconstruction of terahertz spectral images with enhanced spatial resolution via complex mapping
Authors: Zhu Ting , Chen Hao , Pickwell-MacPherson Emma , Chen Xuequan , Fang Guangyou
Published: August 2024

The wavelength of terahertz waves varies by two orders of magnitude. Long-wavelength terahertz images suffer from low spatial resolution due to the millimeter-level diffraction limit. Conventional resolution-enhancing methods are generally limited by sample types and field of view. To overcome these challenges, we propose a resolution-enhancing algorithm for terahertz spectral imaging. This algorithm leverages the advantage of ultra-broadband complex spectral imaging and determines the mapping relationship between the short- and long-wavelength images through clustering and genetic algorithm optimization. The numerical modality supports nearly all optical configurations and sample types. Transmission and reflection measurements validate the superior performance, demonstrating up to 6-fold resolution improvement. Moreover, the complex spectra can be accurately recovered, enabling precise extraction of broadband complex permittivity and subsequent analysis for sub-diffraction-limit objects.
Effective secrecy throughput optimization for GTLS-based UWOC systems with eavesdropper outage constraint
Authors: Zhou Binna , Wang Ping , Pang Weina , Jiang Hao , Li Ganggang
Published: August 2024

In this work, the effective secrecy throughput (EST) which explicitly captures both the reliability and secrecy features of wiretap channels for an underwater wireless optical communication (UWOC) system has been optimized by considering the generalized transmit laser selection (GTLS) scheme. Specifically, the instantaneous channel state information (CSI) of the main channel and eavesdropper’s channel is assumed to be unavailable at the transmitter, which is more practical for the underwater application. The fading of salinity induced oceanic turbulence channels is described by the Weibull distribution considering angular pointing error. The GTLS scheme is first introduced into the UWOC eavesdropping system to improve the quality of the main channel. Based on these models, the analytical closed-form expression of the EST with a constraint on the maximum allowed secrecy outage probability (SOP) is mathematically derived in terms of Meijer’s G function and Gauss hypergeometric function. Then, an optimization problem with the objective of maximizing the constrained EST of the proposed UWOC system while ensuring wiretap code rate constraints are formulated. To solve this problem, a whale optimization algorithm (WOA) based wiretap code rates optimization method is effectively developed to acquire the maximum constrained EST, which is validated by the exhaustive search (ES) method. Simulation results suggest that the maximum constrained EST of this UWOC system can be significantly improved by the GTLS scheme. Besides, the maximum allowed SOP has a pronounced impact on the maximum constrained EST. The presented results could offer valuable insights into the physical layer security (PLS) performance enhancement of UWOC systems.
Impact of the Ge-Si interfacial barrier on the temperature-dependent performance of PureGaB Ge-on-Si p + n photodiodes
Authors: Marković Lovro , Knežević Tihomir , Nanver Lis K. , Attariabad Asma , Azizur-Rahman Khalifa M. , Mah Jasmine J. , Wang Kang L. , Suligoj Tomislav
Published: August 2024

A temperature-dependent study of the near-infrared (NIR) responsivity of Ge-on-Si photodiodes is presented. The diodes, formed as n-Ge islands within oxide windows on n-Si and capped with Ga and B layers (PureGaB), exhibit low dark current of ∼2 × 10−13 A/µm2 and broadband responsivity. Temperature-dependent measurements reveal an inherent potential barrier at the low-doped n-Ge on the n-Si heterointerface. This leads to a decrease in responsivity with decreasing temperatures for wavelengths above 1100 nm. The Al-migration process along the Ge-Si interface, associated with the sidewall passivation and found to be a means of reducing dark current, increases the barrier height. Irrespective of the barrier height, room-temperature responsivity is fully recovered by applying a reverse bias to lower the interface barrier. In the devices with the highest barrier, the responsivity at 1310 nm increased from 4.8 to 164 mA/W, at 0 V and 18 V reverse bias, respectively. An additional increase in maximum responsivity at 1550 nm is attributed to Al-sidewall passivation leading to a measured responsivity of 126.4 mA/W at 18 V reverse bias.
Modelling and next-value prediction of beam propagation from grating structures using a simplified transformer model
Authors: Lim Yu Dian , Tan Chuan Seng
Published: August 2024

In this study, a simplified transformer model is used to perform next-value prediction on light coupled out from silicon photonics gratings to free space. Finite-difference time-domain (FDTD) simulation is performed to simulate the electric field (E-field) in laser light coupled from gratings with pitches of 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 µm, to free-space. Only E-field distribution from 0.6 µm is used in model training, and the trained transformer model is used to predict the E-field from the rest of the gratings. Prediction of accuracy up to 92.5% is obtained. The time taken for model training is 1908.4 seconds, which is significantly shorter than the conventional three-dimensional FDTD simulation that takes up to several hours. To further reduce the training time, transformer models can be trained with stepped datasets, but with compromised prediction accuracies. In summary, we demonstrated that the transformer model can be used to perform next-value E-field prediction using minimal training data. The developed and trained transformer model can be integrated to the state-of-the-art FDTD software to further expedite the existing FDTD simulation.
Quantitative analysis of the contrast modulation for multilateral shearing interferometers
Authors: Zhong Hui , Li Yanqiu , Liu Ke , Zhang Xiaotian , Han Xiting , Wang Tao
Published: August 2024

Multilateral shearing interferometers (multi-LSIs) utilize the phase difference information of multiple shear directions with high accuracy and strong noise resistance. However, the interferogram fringe contrast of multi-LSIs can reverse due to the effect of contrast modulation, leading to incorrect measurement result. This issue has lacked comprehensive quantitative research to effectively guide the elimination of its effects. In this work, a quantitative analysis of the contrast modulation is proposed. This paper rigorously derives contrast modulation function, analyzing the effect of aberration and shear ratio on it. It is the first time that a quantitative theoretical model of aberration measurement range and shear ratio has been established, offering guidance in practical application for precise shear ratio adjustment to eliminate modulation effect and extend measurement range. By eliminating modulation effects, phase difference information from multiple directions can be effectively utilized, maximizing the benefits of multi-LSIs. In simulation and experiment, the distribution of fringe contrast reversal bands and the variation of aberration measurement range with shear ratio are consistent with theoretical analysis, which verifies the validity of the proposed approach. This approach aims to address the issue of interferogram fringe contrast inversion caused by modulation in multi-LSIs, providing a theoretical basis and practical guidance for precise measurement.
Characterization of intensity correlation via single-photon detection in quantum key distribution
Authors: Xing Tianyi , Liu Junxuan , Zhang Likang , Wang Min-Yan , Li Yu-Huai , Liu Ruiyin , Peng Qingquan , Wang Dongyang , Wang Yaxuan , Liu Hongwei , Li Wei , Cao Yuan , Huang Anqi
Published: August 2024

One of the most significant vulnerabilities in the source unit of quantum key distribution (QKD) is the correlation between quantum states after modulation, which shall be characterized and evaluated for its practical security performance. In this work, we propose a methodology to characterize the intensity correlation according to the single-photon detection results in the measurement unit without modifying the configuration of the QKD system. In contrast to the previous research that employs extra classical optical detector to measure the correlation, our method can directly analyse the detection data generated during the raw key exchange, enabling to characterize the feature of correlation in real-time system operation. The basic method is applied to a BB84 QKD system and the characterized correlation decreases the secure key rate shown by the security proof. Furthermore, the method is extended and applied to characterize the correlation from the result of Bell-state measurement, which demonstrates its applicability to a running full-scheme MDI QKD system. This study provides an approach for standard certification of a QKD system.
Two-wavelength non-dispersive infrared sensing systems using stacked electrically controllable photonic-crystal band-pass filters
Authors: Awane Yusuke , Inoue Takuya , Noda Susumu
Published: August 2024

We present a scheme of non-dispersive infrared (NDIR) sensing utilizing stacked, two-wavelength electrically controllable bandpass filters that integrate multiple quantum wells (MQWs) and photonic crystals. By appropriately designing the MQWs and photonic crystals, we realize electrically controllable filters that exhibit symmetric, narrow-band transmittance spectra with high transmittance at two target wavenumbers (1035 cm-1 and 1085 cm-1) and demonstrate independent modulation of the transmittance at each target wavenumber when the two filters are stacked. In addition, by using the proposed stacked filters, we construct two-wavelength mechanical-chopper-free NDIR systems with a single detector and demonstrate its ability to robustly measure the gas concentration even when the absolute optical power incident on the detector is varied.
Virtual Fresnel drag in spatiotemporal transformation medium
Authors: Liu Yichao , Deng Ruihang , Sun Fei
Published: August 2024

A moving dielectric medium can modify the propagation of light by adding an extra velocity in the direction of the medium’s motion, a phenomenon commonly referred to as Fresnel drag. However, moving dielectric slabs typically result in boundary reflections and cannot drag light when their refractive index approaches unity. In this study, we use a more intuitive geometrical method to explore the drag effect within the conceptual framework of a virtual moving geometry—a space with impedance matched to the air, thereby precluding the occurrence of boundary reflections. Subsequently, we demonstrate that the virtual moving geometry can be realized by a stationary bianisotropic spatiotemporal transformation medium utilizing transformation optics. This medium incorporates both spatial and temporal degrees of freedom, providing it with enhanced flexibility and functionality for the manipulation of electromagnetic waves, such as arbitrary reflectionless bending (achieving a virtual Fresnel drag effect), nonreciprocal transmission, and the induction of a virtual Doppler effect. Ultimately, we apply the spatiotemporal transformation medium to design a nonreciprocal reflectionless field shifter and a nonreciprocal invisibility cloak. The introduction of a virtual moving geometry to design the spatiotemporal transformation medium can serve as theoretical support for the rapidly evolving field of time-varying metamaterials.
Flexible and transparent ultra-broadband low-profile frequency selective rasorber
Authors: Ma Xia , Guo Chenjiang , Huang Chao , Yuan Yi , Wang Yanni , Huang Xiaojun , Ding Jun , Pang Xiaoyan
Published: August 2024

An ultra-broadband, low-profile, flexible, and transparent frequency selective rasorber (FSR) is designed based on indium tin oxide (ITO) film. The -1 dB transmission band of the resistive sheet and the bandpass FSS are 0.10 - 8.61 GHz and 3.09 - 7.09 GHz, respectively. By integrating the resistive sheet and the bandpass FSS, a transmission band ranging 1.95 - 6.27 GHz with |S21| larger than -3 dB is achieved, alongside an absorption band ranging 7.34 - 10.83 GHz with absorptance larger than 0.8. Additionally, the FSR presented in this paper is designed by single-layer bandpass FSS and adopts coplanar coupling to realize an ultrabroad transmission band. Its ultra-broadband absorption and transmission performance are verified through experiments and the working principles are analyzed through an equivalent circuit model (ECM). The proposed FSR possesses unique advantages integrating ultrabroad band, optical transparency, flexibility, low profile, and light weight. The proposed FSR exhibits the potential to reduce the out-of-band radar cross-section (RCS), with its optical transparency showing promise for window applications.
High-precision high-stability acousto-optic pulse picking driver with a direct digital synthesis technique
Authors: Zhang Yunwei , Wang Shang , Fan Yuyuan , Liu Junliang , Qin Zengguang , Zhao Zhigang , Liu Zhaojun
Published: August 2024

A method for maintaining a fixed phase relationship between the driving signal of acousto-optic modulator (AOM) and the original mode-locked seed laser is proposed and realized, which stabilizes the amplitude of diffracted signal output from the AOM for subsequent amplification. A field-programmable gate array (FPGA), combined with external summing amplifiers, is used to directly synthesize high-timing-precision driving signals that are synchronized with the seed laser pulses, and the accuracy of signal timing control reaches 160 ps. Using this driver, the standard deviation of the diffracted signal output from the AOM is significantly decreased from 0.52% to 0.18%. This pulse-picking solution also includes a control system that can flexibly control the frequency, gating width, etc., of the driving signal, which makes it more convenient for subsequent laser amplification and makes it suitable for a variety of mode-locked lasers.
Ultra-thin DLC diaphragm-based optical fiber sensor achieving a highly sensitive and broadband acoustic response
Authors: Wu Zhicheng , Zhang Zhetao , Sun Zhengnan , Ai Zhijun , Guo Yiran , Zhu Qingzhe , Zhao Ke , Xiao Hanyan , Zhang Qiaogen
Published: August 2024

In the design of an extrinsic Fabry–Perot interferometer (EFPI) acoustic sensor, broadband response and high-sensitivity sensing are usually conflicting and need to be carefully balanced. Here, we present a novel, to the best of our knowledge, optical fiber acoustic sensor based on an ultra-thin diamond-like carbon (DLC) film, fabricated using the plasma-enhanced chemical vapor deposition method, and transferred by a surface-energy-assisted method. The sensor exhibits a broadband response ranging from 200 Hz to 100 kHz, maintains an average sensitivity of 457.3 mV/Pa within the range of 6 to 30 kHz, and can detect weak acoustic signals down to 3.23 µPa/Hz1/2@16.19 kHz. The combination of an ultra-thin DLC film with a relatively high Young’s modulus and internal stresses results in a trade-off between high sensitivity and a broadband response. This performance demonstrates that our sensor is among the most advanced in the EFPI acoustic sensor family, with significant potential for applications such as photoacoustic spectroscopy, defect diagnosis, and bio-imaging.
Dual frequency comb UV spectroscopy with one million resolved comb lines
Authors: Vodopyanov Konstantin , Muraviev Andrey , Konnov Dmitrii , Vasilyev Sergey
Published: August 2024

We have demonstrated high resolution dual comb spectroscopy in two wide UV bands: 325-342 nm and 372-410 nm based on high harmonic generation of a low-noise 2.35-μm Cr:ZnS dual comb laser system (the 7th and the 6th harmonics respectively). The bands consist of ~550,000 spectrally resolved comb modes for the 7th harmonics, and ~1,000,000 modes for the 6th harmonics with 80 MHz mode separation.
Modeling local decoherence of a spin ensemble using a generalized Holstein–Primakoff mapping to a bosonic mode
Authors: Kolmer Forbes Andrew , Daniel Blocher Philip , Deutsch Ivan H.
Published: August 2024

We show how the decoherence that occurs in an entangling atomic spin–light interface can be simply modeled as the dynamics of a bosonic mode. Although one seeks to control the collective spin of the atomic system in the permutationally invariant (symmetric) subspace, diffuse scattering and optical pumping are local, making an exact description of the many-body state intractable. To overcome this issue we develop a generalized Holstein–Primakoff approximation for collective states which is valid when decoherence is uniform across a large atomic ensemble. In different applications the dynamics is conveniently treated as a Wigner function evolving according to a thermalizing diffusion equation, or by a Fokker–Planck equation for a bosonic mode decaying in a zero-temperature reservoir. We use our formalism to study the combined effect of Hamiltonian evolution, local and collective decoherence, and measurement backaction in preparing nonclassical spin states for application in quantum metrology.
Diatom abundance in the polar oceans is predicted by genome size
Authors: Roberts Wade R. , Siepielski Adam M. , Alverson Andrew J.
Published: August 2024

A principal goal in ecology is to identify the determinants of species abundances in nature. Body size has emerged as a fundamental and repeatable predictor of abundance, with smaller organisms occurring in greater numbers than larger ones. A biogeographic component, known as Bergmann’s rule, describes the preponderance, across taxonomic groups, of larger-bodied organisms in colder areas. Although undeniably important, the extent to which body size is the key trait underlying these patterns is unclear. We explored these questions in diatoms, unicellular algae of global importance for their roles in carbon fixation and energy flow through marine food webs. Using a phylogenomic dataset from a single lineage with worldwide distribution, we found that body size (cell volume) was strongly correlated with genome size, which varied by 50-fold across species and was driven by differences in the amount of repetitive DNA. However, directional models identified temperature and genome size, not cell size, as having the greatest influence on maximum population growth rate. A global metabarcoding dataset further identified genome size as a strong predictor of species abundance in the ocean, but only in colder regions at high and low latitudes where diatoms with large genomes dominated, a pattern consistent with Bergmann’s rule. Although species abundances are shaped by myriad interacting abiotic and biotic factors, genome size alone was a remarkably strong predictor of abundance. Taken together, these results highlight the cascading cellular and ecological consequences of macroevolutionary changes in an emergent trait, genome size, one of the most fundamental and irreducible properties of an organism.
Bacteria face trade-offs in the decomposition of complex biopolymers
Authors: Guseva Ksenia , Mohrlok Moritz , Alteio Lauren , Schmidt Hannes , Pollak Shaul , Kaiser Christina
Published: August 2024

Although depolymerization of complex carbohydrates is a growth-limiting bottleneck for microbial decomposers, we still lack understanding about how the production of different types of extracellular enzymes affect individual microbes and in turn the performance of whole decomposer communities. In this work we use a theoretical model to evaluate the potential trade-offs faced by microorganisms in biopolymer decomposition which arise due to the varied biochemistry of different depolymerizing enzyme classes. We specifically consider two broad classes of depolymerizing extracellular enzymes, which are widespread across microbial taxa: exo-enzymes that cleave small units from the ends of polymer chains and endo-enzymes that act at random positions generating degradation products of varied sizes. Our results demonstrate a fundamental trade-off in the production of these enzymes, which is independent of system’s complexity and which appears solely from the intrinsically different temporal depolymerization dynamics. As a consequence, specialists that produce either exo- or only endo-enzymes limit their growth to high or low substrate conditions, respectively. Conversely, generalists that produce both enzymes in an optimal ratio expand their niche and benefit from the synergy between the two enzymes. Finally, our results show that, in spatially-explicit environments, consortia composed of endo- and exo-specialists can only exist under oligotrophic conditions. In summary, our analysis demonstrates that the (evolutionary or ecological) selection of a depolymerization pathway will affect microbial fitness under low or high substrate conditions, with impacts on the ecological dynamics of microbial communities. It provides a possible explanation why many polysaccharide degraders in nature show the genetic potential to produce both of these enzyme classes.
Adapting the informed push model to the last mile of the contraceptive supply chain in South Kivu in the Democratic Republic of Congo
Authors: LaNasa Katherine H. , Yalaza Michel , Hitayezu Felix , Roijmans Frank
Published: August 2024

In the Democratic Republic of Congo (DRC), contraceptive security is one of the largest barriers to improving access to family planning. This article presents findings from a pilot study that adapted an informed push distribution model to the last mile of the contraceptive supply chain, between the health zone pharmacy and health facilities, in the eastern region of DRC. The intervention consisted of three changes in the supply chain: organization of more efficient transportation routes, in-depth involvement of the community in supply chain management and bundling of contraceptives with other essential medications for efficient delivery. The intervention was implemented from October 2017 to October 2018 in the Katana health zone of the South Kivu province. Although there was not a statistically significant difference in availability of contraceptives during the pilot study period, there were sharp declines in the mean length of stockouts at health facilities and the monthly transportation costs of delivering contraceptives. Overall, the pilot study demonstrated it is feasible to adapt the IPM to a new location with complex geographical, political and socioeconomical influences. Future studies will be required to evaluate whether the adapted informed push model is more effective than the existing pull supply chain system for contraceptives in the DRC.
The use of rapid diagnostic tests for chronic Chagas disease: An expert meeting report
Authors: Perez Freddy , Vermeij Debbie , Salvatella Roberto , Castellanos Luis Gerardo , de Sousa Andrea Silvestre
Published: August 2024

Chagas disease, caused by Trypanosoma cruzi, affects millions of people globally and is associated with significant underdiagnosis and undertreatment. Current diagnostic algorithms face challenges in remote regions. We aimed to review the potential of rapid diagnostic tests (RDTs) for screening or diagnosing chronic Chagas disease in endemic areas. An expert panel representing scientific and academic institutions from the Americas convened with the aim of discussing the use of RDTs. The study employed the nominal group technique, gathering insights from diverse experts during a 3-day meeting. Panel discussions covered RDT application, research protocols, and regulatory mechanisms. The results indicate that RDTs play a crucial role in surveillance and screening, although limitations in sensitivity and specificity exist. The expert group recommends standardized protocols, emphasizes the importance of cost-effectiveness assessments, and highlights the need to consider geographic validation. Despite these challenges, RDTs present a promising avenue for improving Chagas disease diagnosis in resource-limited settings. Future research and a collaborative approach are deemed essential for effective implementation.
A new protocol for multispecies bacterial infections in zebrafish and their monitoring through automated image analysis
Authors: Schmitz Désirée A. , Wechsler Tobias , Li Hongwei Bran , Menze Bjoern H. , Kümmerli Rolf
Published: August 2024

The zebrafish Danio rerio has become a popular model host to explore disease pathology caused by infectious agents. A main advantage is its transparency at an early age, which enables live imaging of infection dynamics. While multispecies infections are common in patients, the zebrafish model is rarely used to study them, although the model would be ideal for investigating pathogen-pathogen and pathogen-host interactions. This may be due to the absence of an established multispecies infection protocol for a defined organ and the lack of suitable image analysis pipelines for automated image processing. To address these issues, we developed a protocol for establishing and tracking single and multispecies bacterial infections in the inner ear structure (otic vesicle) of the zebrafish by imaging. Subsequently, we generated an image analysis pipeline that involved deep learning for the automated segmentation of the otic vesicle, and scripts for quantifying pathogen frequencies through fluorescence intensity measures. We used Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae, three of the difficult-to-treat ESKAPE pathogens, to show that our infection protocol and image analysis pipeline work both for single pathogens and pairwise pathogen combinations. Thus, our protocols provide a comprehensive toolbox for studying single and multispecies infections in real-time in zebrafish.
Identification of unmet palliative care needs of nursing home residents: A scoping review protocol
Authors: Crowley Patrice , Saab Mohamad M. , Cornally Nicola , Ronan Isabel , Tabirca Sabin , Murphy David
Published: August 2024

Introduction

Nursing home residents often have life limiting illnesses in combination with multiple comorbidities, cognitive deficits, and frailty. Due to these complex characteristics, a high proportion of nursing home residents require palliative care. However, many do not receive palliative care relative to this need resulting in unmet care needs. To the best of our knowledge, there have been no literature reviews to synthesise the evidence on how nursing home staff identify unmet palliative care needs and to determine what guidelines, policies, and frameworks on identifying unmet palliative care needs of nursing home residents are available.

Aim

The aim of this scoping review is to map and summarise the evidence on identifying unmet palliative care needs of residents in nursing homes.

Methods

This scoping review will be guided by the JBI Manual for Evidence Synthesis. The search will be conducted in CINAHL, MEDLINE, Embase, Web of Science, APA PsycINFO, and APA PsycArticles. A search of grey literature will also be conducted in databases such as CareSearch, Trip, GuidelineCentral, ClinicalTrials.gov, and the National Institute for Health and Care and Excellence website. The search strategy will be developed in conjunction with an academic librarian. Piloting of the screening process will be conducted to ensure agreement among the team on the eligibility criteria. Covidence software will be used to facilitate deduplication, screening, and blind reviewing. Four reviewers will conduct title and abstract screening. Six reviewers will conduct full text screening. Any conflicts will be resolved by a reviewer not involved in the conflict. One reviewer will conduct data extraction using pre-established data extraction tables. Results will be synthesised, and a narrative synthesis will be used to illustrate the findings of this review. Data will be presented visually using tables, figures, and word clouds, as appropriate.
Patients’ experiences with musculoskeletal spinal pain: A qualitative systematic review protocol
Authors: El Chamaa Alaa , Kowalski Katie , Parikh Pulak , Rushton Alison
Published: August 2024

Background

Musculoskeletal (MSK) spinal pain encapsulates various conditions including lumbar (low back), cervical (neck), and thoracic pain that significantly impact individual and global health. While clinical aspects of spinal pain have been well-studied, understanding patients’ personal narratives and lived experiences remains essential for enhancing patient-centered care, improving treatment adherence, and informing healthcare policies. It provides deep insights into the impacts of spinal pain, guiding more effective and empathetic treatment approaches. This systematic review aims to synthesize qualitative evidence on patients’ experiences with MSK spinal pain, providing insight into the challenges faced, coping strategies, daily life impacts, and healthcare interactions. The objective of this review is to synthesize the qualitative evidence regarding the lived experiences of patients with MSK spinal pain.

Methods

This systematic review will use a meta-aggregation approach to synthesize data from qualitative studies, that will be identified through a comprehensive search of electronic databases and supplemented by grey literature searches. Two independent reviewers will screen, identify, and extract data from eligible studies. In cases of disagreement, conflicts will be resolved by consulting a third reviewer. These same reviewers will then use the Joanna Briggs Institute (JBI) qualitative quality assessment tool to evaluate the methodological quality of the identified studies, with the derived scores informing the synthesis process, that will involve extracting each study’s findings along with their supporting illustrations, then grouped into categories based on similarity in meaning. These categories will then be aggregated to form synthesized findings.

Implications

Synthesized findings on patients’ lived experiences with MSK spinal pain including key themes, patterns, and insights will be presented. By emphasizing patient narratives, the results of the review can contribute to the optimization of outcomes, and to enhance patient-provider relations and improve quality of care in MSK spinal health.
Surgeon- and hospital-level variation in wait times for scheduled non-urgent surgery in Ontario, Canada: A cross-sectional population-based study
Authors: de Jager Pieter , Aleman Dionne , Baxter Nancy , Bell Chaim , Bodur Merve , Calzavara Andrew , Campbell Robert , Carter Michael , Emerson Scott , Gagliardi Anna , Irish Jonathan , Martin Danielle , Lee Samantha , SaxeBraithwaite Marcy , Seyedi Pardis , Takata Julie , Yang Suting , Zanchetta Claudia , Urbach David R.
Published: August 2024

Background

Canadian health systems fare poorly in providing timely access to elective surgical care, which is crucial for quality, trust, and satisfaction.

Methods

We conducted a cross-sectional analysis of surgical wait times for adults receiving non-urgent cataract surgery, knee arthroplasty, hip arthroplasty, gallbladder surgery, and non-cancer uterine surgery in Ontario, Canada, between 2013 and 2019. We obtained data from the Wait Times Information System (WTIS) database. Inter- and intra-hospital and surgeon variations in wait time were described graphically with caterpillar plots. We used non-nested 3-level hierarchical random effects models to estimate variation partition coefficients, quantifying the proportion of wait time variance attributable to surgeons and hospitals.

Results

A total of 942,605 procedures at 107 healthcare facilities, conducted by 1,834 surgeons, were included in the analysis. We observed significant intra- and inter-provider variations in wait times across all five surgical procedures. Inter-facility median wait time varied between six-fold for gallbladder surgery and 15-fold for knee arthroplasty. Inter-surgeon variation was more pronounced, ranging from a 17-fold median wait time difference for cataract surgery to a 216-fold difference for non-cancer uterine surgery. The proportion of variation in wait times attributable to facilities ranged from 6.2% for gallbladder surgery to 23.0% for cataract surgery. In comparison, surgeon-related variation ranged from 16.0% for non-cancer uterine surgery to 28.0% for cataract surgery.

Implications

There is extreme variability in surgical wait times for five common, high-volume, non-urgent surgical procedures. Strategies to address surgical wait times must address the variation between service providers through better coordination of supply and demand. Approaches such as single-entry models could improve surgical system performance.
Access to an outdoor open pack promotes estrus activity in dairy cows
Authors: Smid Anne-Marieke C. , Burnett Tracy A. , Madureira Augusto M. L. , McLellan Kathryn J. , Wegner Claire S. , von Keyserlingk Marina A. G. , Weary Daniel M.
Published: August 2024

Dairy cows have a partial preference to access an outdoor deep-bedded pack, but the effects of continuous access to an outdoor area on estrous behaviors has not been studied. Our objective was to investigate if access to an outdoor open deep-bedded pack improves the expression of estrus behaviors. We enrolled 60 lactating Holstein cows directly after calving and followed them each for 12 weeks. Cows were housed in a single freestall pen holding 36 cows at a time, with a dynamic group composition. Half of the cows were randomly assigned to the OUTDOOR treatment; these cows had access to an outdoor open pack via an automated selection gate. INDOOR cows were housed together with OUTDOOR cows but were not allowed outdoor access. All cows were fitted with an automated activity monitor (AAM) 21 ± 3 d before expected calving date. Estrous behaviors (i.e., standing to be mounted and mounting behaviors) were continuously monitored using video, and the intensity of mounting (i.e., the number of standing to be mounted and other mounting behaviors per hour) was calculated per estrus event per cow. Temperature and humidity were monitored by data loggers indoors, and these data were used to calculate the Temperature Humidity Index (THI). Following an alert from the AAM, cows were checked to detect the presence of a dominant preovulatory follicle and an absence of a mature corpus luteum (CL) by rectal ultrasonography following milking, as well as 7 d thereafter to confirm ovulation by the presence of a new CL. A total of 94 estrus events were used in the final analysis. INDOOR cows tended to have a lower mounting intensity with increasing indoor THI, but no such effect was noted for OUTDOOR cows. The total number of cows in estrus positively influenced mounting intensity. OUTDOOR cows had a longer duration of estrus, as measured by the automated monitors, compared with INDOOR cows (12.4 ± 0.7 h versus 9.9 ± 0.8 h). Estrus event number and the total number of cows in estrus were both positively associated with estrus duration. These results indicate that access to an outdoor pack tended to increase mounting behavior for freestall housed dairy cows, especially during periods of elevated THI. We conclude that providing dairy cows access to an outdoor area can help with estrus detection and may thus help improve the reproductive programs on dairy farms.
The impact of China’s digital inclusive financial development gap on the optimization of rural consumption structure
Authors: Yi Shuaihang , Qi Ying , Ya Yongxiang , Shi Jiaying , Cui Yiniu
Published: August 2024

Implementing the rural revitalization strategy is crucial for ensuring and enhancing the livelihoods of the vast rural population. The upgrading of rural consumption reflects the gradual realization of rural residents’ pursuit of a better life, and the rapid development of digital inclusive finance provides strong support for this. Based on the Digital Inclusive Finance Index released by Peking University and panel data from 30 provinces across the country, this study examines the role of digital inclusive finance in optimizing rural consumption structure through the mediation effect model and analyzes its spatial spillover effects using the spatial Durbin model. The research shows that narrowing the development gap in digital inclusive finance is crucial for upgrading the rural consumption structure, which helps to promote rural residents’ transition to higher-level consumption. Through the analysis of the spatial Durbin model, this study finds spatial spillover effects in this process, meaning that financial development in a particular region promotes local development but inhibits development in neighboring areas. Among various dimensions, the impact of breadth of coverage is the most significant. This trend of financial development affects consumption structure by increasing agricultural productivity and rural residents’ operational income, particularly highlighting its impact on operational income. However, there are significant differences between the eastern and central-western regions in optimizing rural consumption structure, with the eastern region benefiting more while the effects in the central-western region are limited and sometimes even negative. Therefore, regional characteristics should be fully considered in policy formulation to narrow the development gap in digital inclusive finance and achieve high-quality and sustainable development.
Adherence to antiretroviral therapy among cisgender gay, bisexual and other men who have sex with men in Brazil: Evaluating the role of HIV-related stigma dimensions
Authors: Matos Victor C. , Torres Thiago S. , Luz Paula M.
Published: August 2024

Background

In Brazil, ~35% of people living with HIV (PLHIV) have poor adherence to antiretroviral therapy (ART). HIV-related stigma is associated with worst continuum of care outcomes, however evidence from Brazil is scarce. We explored pathways between HIV-related stigma dimensions and ART adherence among Brazilian cisgender gay, bisexual and other men who have sex with men (MSM) living with HIV.

Methods

A sample of MSM ≥18 years was recruited online between February/March 2020 through advertisements on Hornet, a location-based dating app. Validated scales were used to assess ART adherence and HIV-related stigma. Indirect and direct pathways between HIV-related stigma dimensions and ART adherence were estimated using structural equation models while considering socio-demographic and substance use related variables. Models were estimated using mean- and variance-adjusted weighted least squares, and goodness of fit indices were calculated.

Findings

Among 1,719 MSM living with HIV who reported starting ART, 70% were adherent. There was evidence of indirect effects of concerns about public attitudes (standardized coefficient (SC) = -0.095, 95% confidence interval (95%CI) = -0.172 - -0.017) and personalized HIV-stigma (SC = -0.022, 95%CI = -0.043 - -0.001) on ART adherence mediated through negative self-image. Personalized HIV stigma and concerns about public attitudes were both positively associated with negative self-image (SC = 0.129, 95%CI = 0.066–0.193; SC = 0.549, 95%CI = 0.494–0.603), and concerns about public attitudes was associated with HIV disclosure concerns (SC = 0.522, 95%CI = 0.463–0.581). However, the direct paths from personalized HIV stigma and concerns about public attitudes to ART adherence were not significant.

Interpretation

Our research underscores the critical need for multifaceted interventions to eliminate HIV-related stigma at both individual and societal levels. At the individual level, psychotherapeutic interventions to improve self-image might helpful. Additionally, public policy should aim to dismantle structural stigma with awareness campaigns on various media channels, integration of anti-stigma curriculum into schools, and training for professionals.
Predicting tropospheric nitrogen dioxide column density in South African municipalities using socio-environmental variables and Multiscale Geographically Weighted Regression
Authors: Hlatshwayo Sphamandla N. , Tesfamichael Solomon G. , Kganyago Mahlatse
Published: August 2024

Atmospheric nitrogen dioxide (NO2) pollution is a major health and social challenge in South African induced mainly by fossil fuel combustions for power generation, transportation and domestic biomass burning for indoor activities. The pollution level is moderated by various environmental and social factors, yet previous studies made use of limited factors or focussed on only industrialised regions ignoring the contributions in large parts of the country. There is a need to assess how socio-environmenral factors, which inherently exhibit variations across space, influence the pollution levels in South Africa. This study therefore aimed to predict annual tropospheric NO2 column density using socio-environmental variables that are widely proven in the literature as sources and sinks of pollution. The environmental variables used to predict NO2 included remotely sensed Enhanced Vegetation Index (EVI), Land Surface Temperature and Aerosol Optical Depth (AOD) while the social data, which were obtained from national household surveys, included energy sources data, settlement patterns, gender and age statistics aggregated at municipality scale. The prediction was accomplished by applying the Multiscale Geographically Weighted Regression that fine-tunes the spatial scale of each variable when building geographically localised relationships. The model returned an overall R2 of 0.92, indicating good predicting performance and the significance of the socio-environmental variables in estimating NO2 in South Africa. From the environmental variables, AOD had the most influence in increasing NO2 pollution while vegetation represented by EVI had the opposite effect of reducing the pollution level. Among the social variables, household electricity and wood usage had the most significant contributions to pollution. Communal residential arrangements significantly reduced NO2, while informal settlements showed the opposite effect. The female proportion was the most important demographic variable in reducing NO2. Age groups had mixed effects on NO2 pollution, with the mid-age group (20–29) being the most important contributor to NO2 emission. The findings of the current study provide evidence that NO2 pollution is explained by socio-economic variables that vary widely across space. This can be achieved reliably using the MGWR approach that produces strong models suited to each locality.