bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of AlGaN-based deep UV LED performance by p-AlInGaN/AlInGaN graded superlattice electron blocking layer
Authors: Xu Yuan , Yin Mengshuang , Sang Xien , Wang Fang , Liou Juin J. , Liu Yuhuai
Published: July 2023

In this paper, we significantly improved the internal quantum efficiency and output power of AlGaN-based deep UV (DUV) LEDs by replacing the conventional p-AlGaN electron blocking layer (EBL) with the p-AlInGaN/AlInGaN graded superlattice (SL) EBL. Simulation results show that the introduction of the p-AlInGaN graded SL EBL improved the carrier distribution while having the lower electric field, thus increasing the radiative recombination rate in multiple quantum wells (MQWs). The highest IQE obtained by p-AlInGaN/AlInGaN graded SL EBL is 96.6%, which is 44.9% higher than the conventional p-AlGaN EBL with no efficiency droop. At the same time, the output power is 4.6 times that of the conventional p-AlGaN EBL. It is believed that the proposed p-AlInGaN graded SL EBL will be helpful in the development of high-performance DUV LEDs.
Chlorophyll-based model underpinned by measured inherent optical properties of Jerlov water types
Authors: Hollins Richard C. , Williamson Craig A.
Published: July 2023

An existing chlorophyll-based model has been updated and re-calibrated using measured data describing Jerlov water types, harvested from the World-wide Ocean Optics Database. This study has provided new chlorophyll concentration data, and used them in conjunction with recently published spectra of absorption and scattering coefficients to create an updated parameter set that describes eight of the 10 Jerlov water types. The updated model is consistent with other data, and it interprets the measured characteristics in terms of underlying properties. Techniques for inter-conversion between inherent and apparent optical properties have been further investigated, and the improved precision has uncovered new challenges that have been addressed using empirical techniques.
Shape recovery from fusion of polarization binocular vision and shading
Authors: Tan Zhiying , Kong Weifeng , Ji Yan , Tao Xu , Zhao Jinying , Wang Meiling , Xu Xiaobin
Published: July 2023

The shape from polarization can recover the fine texture of the target
surface. However, the gradient field for shape recovery by
polarization is ambiguous, which is caused by the multi-value of the
azimuth angle. In response to the problem, a method of correcting the
ambiguity by the fusion of polarization binocular vision and shading
information is proposed in this paper. An iterative optimization
algorithm is designed to estimate the direction of the light source,
which provides the basis for the shading method to calculate the depth
map. Additionally. the low-frequency depth map generated by binocular
matching is used to correct the polarization gradient field. The
polarization gradient field of the holes and small zenith angle
regions in the binocular are corrected by the improved shading method.
In the experiment, four different material target objects were used
for shape recovery and compared with other methods. The results of the
fusion method proposed are better in terms of fine texture. At the
camera working distance of  700 mm, the resolving power
performs well and demonstrates that changes in the depth of at least
0.1 mm can be distinguished from that recovery result.
Optical image conversion and encryption based on structured light illumination and a diffractive neural network
Authors: Su Yanfeng , Xu Kang , Rong Wenzhe , Wang Zhihan , Xue Ruijie , Xue Lijuan , Cai Zhijian , Wan Wenqiang
Published: July 2023

In this paper, an optical image encryption method is proposed based on structured light illumination and a diffractive neural network (DNN), which can realize conversion between different images. With the use of the structured phase mask (SPM) in the iterative phase retrieval algorithm, a plaintext image is encoded into a DNN composed of multiple phase-only masks (POMs) and ciphertext. It is worth noting that ciphertext is a visible image such that the conversion of one image to another is achieved, leading to high concealment of the proposed optical image encryption method. In addition, the wavelength of the illuminating light, all Fresnel diffraction distances, the optical parameters of the adopted SPM such as focal length and topological charge number, as well as all POMs in the DNN are all considered as security keys in the decryption process, contributing to a large key space and high level of security. Numerical simulations are performed to demonstrate the feasibility of the proposed method, and simulation results show that it exhibits high feasibility and safety as well as strong robustness.
Intracavity filtering effect in a dual-output linear-cavity all-PM fiber laser mode-locked by NPE
Authors: Peng Siwei , Liu Xuanyi , Fu H. Y. , Li Qian
Published: July 2023

We have demonstrated a stable and low-noise all-polarization-maintaining (PM) ultrafast erbium-doped fiber laser mode-locked via nonlinear polarization evolution (NPE) in a linear cavity with dual outputs. A detailed design strategy is presented. The all-PM configuration enhances the capability of resistance to environmental fluctuations. Self-starting mode-locking is realized by using a non-reciprocal phase shifter. The dual-output structure offers the intracavity filtering effect, where the reflective port serves as a bandpass spectral filter, significantly improving the transmissive-port optical properties. The laser directly generates ultrashort pulses with a pulse duration of 129 fs operating at a fundamental repetition rate of 105.8 MHz. The integrated root-mean-square (RMS) relative intensity noise from 10 Hz to 10 MHz is ∼0.008%, and the integrated RMS timing jitter from 5 kHz to 10 MHz is ∼36fs. Long-term stability is confirmed in 25 h with a RMS power fluctuation of  ∼0.10%. Our high-performance fiber laser is a prospective candidate for low-noise applications.
Nested micro-ring refractive index sensor based on a subwavelength grating waveguide and the Vernier effect
Authors: Shi Xinyu , Chen Ming , Li Renjie , Wang Xiangyang , Han Wenhao , Zhao Wanli , Liu Jinbiao , Teng Chuanxin , Deng Shijie , Cheng Yu , Yuan Libo
Published: July 2023

In this paper, a nested micro-ring refractive index sensor based on a
subwavelength grating waveguide and the Vernier effect is proposed. In
this scheme, the nested micro-ring structure is combined with a
subwavelength grating structure to enhance the contact area between
the optical field and the analyte, and the wavelength offset is
doubled through the Vernier effect. The proposed sensor can
effectively increase sensing sensitivity, taking into account the
improvement of the free spectral range. This structure enables the
device to reach a sensitivity of 8030 nm/RIU near
1550 nm wavelength in a deionized water environment, with a
detection limit of 5.659×10−5 RIU and free spectral range of
41.956 nm. The device suggested in this study has a greater
reduced footprint than the conventional micro-ring resonant sensor,
measuring just 35µm×25µm. Due to its high integration, high
sensitivity, and large free spectral range compared to conventional
micro-ring resonant sensors, such structures are of great value in
biosensing and environmental monitoring.
Defect characterization in optical coatings using scattered light
Authors: Loglia Balthazar , Derrick Emma , Ingraham Luke , Fraser Alexandra , Geng Yutong , Sanger-Johnson Grace , Colby Kace , Kontos Antonios
Published: July 2023

Optical coatings play a vital role in sensing technologies. The
development of new coatings that exhibit minimal optical losses
requires a detailed understanding of the development of defects within
them. Current methods of defect characterization involve direct
microscope imaging or x-ray diffraction studies in the case of
crystallites. In this paper, we demonstrate the characterization of
coating defects using light scattering, which can yield information
about their size, location, and index of refraction. The method
requires measuring the scattered power of each individual defect as a
function of angle and comparing the data with theoretical models.
Finally, we argue that this method can be used for the determination
of the defect location within a multi-layer stack.
Ultra-compact dual band imaging spectrometer with freeform prisms
Authors: Ji Yiqun , Han Jizhou , Zhao Shijia , Wang Chinhua
Published: July 2023

Wide spectrum and miniaturization are the main challenges in the imaging spectrometer design. In this paper, we propose an ultra-compact dual band imaging spectrometer (CDBIS) with cemented freeform prisms, which works at both the visible-near-infrared (VNIR) from 400 nm to 1000 nm and the shortwave-infrared (SWIR) from 1000 nm to 1700 nm. The imaging spectrometer is only composed of three cemented prisms, a primary prism and two triangular prisms. And a freeform surface characterized by the Zernike polynomial is introduced in each prism. The CDBIS is dispersed by a diffraction grating, which is designed on the second surface of the primary prism. Based on vector aberration theory (VAT), the relationship among the astigmatism generated by the introduced freeform surfaces, the wavelength, and the field of view is studied. Accordingly, a wideband is realized by introducing the freeform surfaces after the diffraction grating. Furthermore, through optimizing the coefficients of Zernike polynomial terms, residual astigmatism at different wavelengths is well balanced. An imaging spectrometer with a volume of only 100cm3 is obtained, with a spectral resolution of 1.45 nm at VNIR and 2.40 nm at SWIR, respectively. It has a huge potential for broadband space exploration.
New trends in photonic switching and optical networking architectures for data centers and computing systems [Invited]
Authors: Yoo S. J. Ben
Published: July 2023

The rapid increases in data traffic coupled with user preferences are
driving the data center and computing system service providers to
offer energy-efficient, intelligent, flexible, cost-effective,
high-capacity, and low-latency data services without added complexity
to the users. Disaggregated heterogeneous reconfigurable computing
systems realized by photonic switching and interconnects can enhance
throughput and energy efficiency for artificial intelligence/machine
learning (AI/ML) workloads, especially when aided by the
AI/ML-enhanced control plane. Photonic switching and new optical
networking architectures are expected to solve many of these
challenging problems. This paper discusses new trends in photonic
switching and optical network architectures for future data centers
and computing systems summarized as follows: (1) flat
reconfigurable disaggregated computing enabled by high-radix photonic
switching and interconnects in data centers; (2) chiplet-based
computing architectures empowered by embedded photonics toward
heterogeneous reconfigurable computing; (3) nanosecond-scale
photonic switching in data centers and computing systems;
(4) AI/ML in self-driving, application-aware, and
situation-aware data centers; (5) the emergence of flexible
networking for cloud computing, edge computing, and split computing,
as well as flexible networking for 5G/6G RF-optical networks; and
(6) the deployment of embedded co-designed silicon photonics
being considered for future data centers.
Hyperspectral image super-resolution via spectral matching and correction
Authors: Cao Xuheng , Lian Yusheng , Liu Zilong , Wu Jiahui , Zhang Wan , Liu Jianghao
Published: July 2023

Fusing a low-spatial-resolution hyperspectral image (LR-HSI) and a high-spatial-resolution RGB image (HR-RGB) is an important technique for HR-HSI obtainment. In this paper, we propose a dual-illuminance fusion-based super-resolution method consisting of spectral matching and correction. In the spectral matching stage, an LR-HSI patch is first searched for each HR-RGB pixel; with the minimum color difference as a constraint, the matching spectrum is constructed by linear mixing the spectrum in the HSI patch. In the spectral correlation stage, we establish a polynomial model to correct the matched spectrum with the aid of the HR-RGBs illuminated by two illuminances, and the target spectrum is obtained. All pixels in the HR-RGB are traversed by the spectral matching and correction process, and the target HR-HSI is eventually reconstructed. The effectiveness of our method is evaluated on three public datasets and our real-world dataset. Experimental results demonstrate the effectiveness of our method compared with eight fusion methods.
Ranging disambiguation of LiDAR using chirped amplitude-modulated phase-shift method
Authors: Zhang Zheyuan , Shirahata Takuma , Chen Ruiyan , Yamashita Shinji , Set Sze Yun
Published: July 2023

Ranging ambiguity is the major challenge in most LiDAR techniques with amplitude modulation, which limits the performance of range detection due to the tradeoff between the ranging precision and the unambiguous range. Here we propose a novel disambiguation method using a laser with chirped amplitude modulation (sweeping modulation frequency), which can in theory infinitely expand the unambiguous range and completely solve the ranging ambiguation problem. The usage of the earlier proposed Chirped Amplitude-Modulated Phase-Shift (CAMPS) technique enables us to detect the phase-shift of chirped signals with high precision. Incorporating this technique with the proposed disambiguation method, the absolute distance well beyond the conventional unambiguous range can easily be found with merely <1% frequency sweep range. When certain conditions are met, the Non-Mechanical Spectrally Scanned LiDAR (NMSL) system employing the CAMPS method and the Dispersion-Tuned Swept Laser (DTSL) can also realize disambiguation in non-mechanical line-scanning measurement.
Rapid single-photon color imaging of moving objects
Authors: Yao Dan , Connolly Peter W. R. , Sykes Arran J. , Shah Yash D. , Accarino Claudio , Grant James , Cumming David R. S. , Buller Gerald S. , McLaughlin Stephen , Altmann Yoann
Published: July 2023

This paper outlines an experimental demonstration of a Bayesian image reconstruction approach to achieve rapid single-photon color imaging of moving objects. The capacity to extract the color of objects is important in a variety of target identification and computer vision applications. Nonetheless, it remains challenging to achieve high-speed color imaging of moving objects in low-photon flux environments. The low-photon regime presents particular challenges for efficient spectral separation and identification, while unsupervised image reconstruction algorithms are often slow and computationally expensive. In this paper, we address both of these difficulties using a combination of hardware and computational solutions. We demonstrate color imaging using a Single-Photon Avalanche Diode (SPAD) detector array for rapid, low-light-level data acquisition, with an integrated color filter array (CFA) for efficient spectral unmixing. High-speed image reconstruction is achieved using a bespoke Bayesian algorithm to produce high-fidelity color videos. The analysis is conducted first on simulated data allowing different pixel formats and photon flux scenarios to be investigated. Experiments are then performed using a plasmonic metasurface-based CFA, integrated with a 64 × 64 pixel format SPAD array. Passive imaging is conducted using white-light illumination of multi-colored, moving targets. Intensity information is recorded in a series of 2D photon-counting SPAD frames, from which accurate color information is extracted using the fast Bayesian method introduced herein. The per-frame reconstruction rate proves to be hundreds of times faster than the previous computational method. Furthermore, this approach yields additional information in the form of uncertainty measures, which can be used to assist with imaging system optimization and decision-making in real-world applications. The techniques demonstrated point the way towards rapid video-rate single-photon color imaging. The developed Bayesian algorithm, along with more advanced SPAD technology and utilization of time-correlated single-photon counting (TCSPC) will permit live 3D, color videography in extremely low-photon flux environments.
Fabrication of waveguide directional couplers using 2-photon lithography
Authors: Flynn Christopher , Cao Haimu , Applegate Brian E. , Tkaczyk Tomasz S.
Published: July 2023

Advances in 2-photon lithography have enabled in-lab production of sub-micron resolution and millimeter scale 3D optical components. The potential complex geometries are well suited to rapid prototyping and production of waveguide structures, interconnects, and waveguide directional couplers, furthering future development and miniaturization of waveguide-based imaging technologies. System alignment is inherent to the 2-photon process, obviating the need for manual assembly and allowing precise micron scale waveguide geometries not possible in traditional fused fiber coupler fabrication. Here we present the use of 2-photon lithography for direct printing of multi-mode waveguide couplers with air cladding and single mode waveguide couplers with uncured liquid photoresin cladding. Experimental results show reproducible coupling which can be modified by selected design parameters.
Harmonics elimination in phase-shifting fringe projection profilometry by use of a non-filtering algorithm in frequency domain
Authors: Lin Shuai , Zhu Huijie , Guo Hongwei
Published: July 2023

In phase-shifting fringe projection profilometry, fringe harmonics caused by device nonlinearities as well as other factors may badly ruin the measurement results. Generally, the used phase-shifting algorithm enables restraint of effects of harmonics below a certain order depending on the number of phase shifts. When reducing the number of phase shifts for efficiency, high order harmonics will affect the phase-measuring results because of aliasing caused by insufficient sampling rate. To overcome this issue, this paper suggests a non-filtering technique operating in frequency domain, that enables improvement of measurement accuracy by eliminating effects of high order harmonics. With this technique, the phase-shifting algorithm is restated as a process of retrieving the fundamental complex fringes from the phase-shifted fringe patterns. Implementing a Fourier transform to this calculated complex fringe pattern, the actual fundamental signals and the aliased harmonics have their own lobes with separated peaks in the frequency domain. We reconstruct each order of the aliased harmonics by exploiting their relations with the fundamental signals and then estimate their magnitudes by using the spectral peaks. Instead of directly filtering the fringe spectrum, we subtract spectra of the harmonics from Fourier transform of the just calculated complex fringes, so that the Fourier spectrum of the fundamental fringes without harmonics is recovered through an iterative operation. Further, the phase map is measured accurately. Simulation and experimental results confirm that this proposed method can significantly suppress effects of fringe harmonics. Meanwhile, by taking advantage of non-filtering, it effectively preserves the edges and details of the measured surfaces from being blurred.
Visibly transparent multifunctional camouflage coating with efficient thermal management
Authors: Chamoli Sandeep Kumar , Li Wei
Published: July 2023

Camouflage technology has attracted growing interest in many thermal applications. In particular, high-temperature infrared (IR) camouflage is crucial to the effective concealment of high-temperature objects but remains a challenging issue, as the thermal radiation of an object is proportional to the fourth power of temperature. Here, we proposed a coating to demonstrate high-temperature IR camouflage with efficient thermal management. This coating is a combination of hyperbolic metamaterial (HMM), gradient epsilon near zero (G-ENZ) material, and polymer. HMM makes the coating transparent in the visible range (300–700 nm) and highly reflective in the IR region, so it can serve as a thermal camouflage in the IR. G-ENZ and polymer support BE mode (at higher angles ∼50° to 90° in the 11–14 µm atmospheric window) and vibrational absorption band (in 5–8 µm non-atmospheric for all angles), respectively. So it is possible to achieve efficient thermal management through radiative cooling. We calculate the temperature of the object's surface, considering the emissivity characteristics of the coating for different heating temperatures. A combination of silica aerogel and coating can significantly reduce the surface temperature from 2000 K to 750 K. The proposed coating can also be used in the visible transparent radiative cooling due to high transmission in the visible, high reflection in the near-IR (NIR), and highly directional emissivity in the atmospheric window at higher angles, and can therefore potentially be used as a smart window in buildings and vehicles. Finally, we discuss one more potential future application of such a multifunctional coating in water condensation and purification.
Advanced active polymer probe for near-field optics
Authors: Chen Hongshi , Jiang Quanbo , Issa Ali , Li Borui , Ge Dandan , Jradi Safi , Lalevee Jacques , Marguet Sylvie , Deturche Regis , Couteau Christophe , Plain Jerome , Bachelot Renaud
Published: July 2023

We report on a novel, to the best of our knowledge, active probe for scanning near-field optical microscopy (SNOM). A fluorescent nanosphere, acting as the secondary source, is grafted in an electrostatic manner at the apex of a polymer tip integrated into the extremity of an optical fiber. Thanks to the high photostability and sensitivity of the secondary source, the near-field interaction with a gold nanocube is investigated. It is shown that the spatial resolution is well defined by the size of the fluorescent nanosphere. The polarization-dependent near-field images, which are consistent with the simulation, are ascribed to the local excitation rate enhancement. Meanwhile, measurement of the distance-dependent fluorescence lifetime of the nanosphere provides strong evidence that the local density of states is modified so that extra information on nano-emitters can be extracted during near-field scanning. This advanced active probe can thus potentially broaden the range of applications to include nanoscale thermal imaging, biochemical sensors, and the manipulation of nanoparticles.
Extreme ultraviolet broadband imaging spectrometer using dispersion-matched zone plates
Authors: Mostafa Yahia , Bouza Zoi , Byers James , Babenko Ievgeniia , Ubachs Wim , Versolato Oscar O. , Bayraktar Muharrem
Published: July 2023

We present simultaneous 1D imaging and broadband spectroscopy of a laser-produced plasma (LPP) source of extreme ultraviolet light, using a tapered zone plate that is matched to the dispersion of a transmission grating. We describe the design and fabrication of the zone plates in the 5–80 nm wavelength regime with designed spatial resolution of ∼10 µm and spectral resolution of ∼0.8 nm. Subsequently, we benchmark the imaging spectrometer with a solid tin target LPP. Plane wave propagation simulations qualitatively match the experimental results and confirm the device performance.
Field recovery via simplified carrier-assisted differential detection with interleaved subcarrier loading scheme at low CSPR condition
Authors: He Long , Yuan Yangsheng , Cai Yangjian , Li Jianghao
Published: July 2023

In this Letter, we propose a simplified carrier-assisted differential detection (CADD) receiver with interleaved subcarrier loading scheme to further reduce the system hardware complexity while preserving the capability of field recovery of double sideband (DSB) complex-valued signals at the low carrier to signal power ratio (CSPR) condition. The numerical results show that the simplified CADD receiver requires less gap subcarriers to achieve a bit-error-rate (BER) below the 7% hard-decision forward error correction (HD-FEC) limit of 3.8 × 10−3 as compared with a conventional CADD receiver. Despite the robustness to the time delay fluctuation decreases, which can be avoided using time-independent components in place of time delay line, more than a 3.2-dB optical signal-to-noise ratio (OSNR) gain can be obtained regardless of CSPR.
Miniature GaN optoelectronic temperature sensor
Authors: Wang Binju , Fu Kang , Fu Jianwei , Ye Ziqi , Shi Fan , Yan Jiabin , Wang Yongjin
Published: July 2023

The combination of plastic optical fiber (POF) with monolithically integrated transmitter and receiver is becoming increasingly attractive for the development of miniature optoelectronic sensing systems. Here, we propose a temperature sensing system by integrating a GaN optoelectronic chip with a POF and aluminum (Al) reflector. Owing to the overlap between electroluminescence and responsivity spectra of multiple quantum well (MQW) diodes, both the transmitter and the receiver having identical MQW structures are monolithically integrated on a tiny GaN chip by using the same fabrication process flow. Environmental temperature change leads to thermal deformation in the Al reflector, which reflects the transmitted light back with a light pulse. The reflected light is coupled into the guided POF again and sensed by the on-chip receiver. Finally, the temperature information is read out as electrical signals. When the ambient temperature changes from 20.1°C to 100°C, the optically induced electrical signal decreases from −3.04 µA to −3.13 µA. The results suggest that the monolithically integrated GaN device offers a promising option for optoelectronic temperature sensing systems.
Spiking ruby revisited: self-induced periodic spiking oscillations leading to chaotic state in a Cr:Al2O3 laser with cw 532-nm pumping
Authors: Otsuka Kenju , Sudo Seiichi
Published: July 2023

This paper reexamines a 60-year-old mystery of spiking behavior in ruby lasers with a cw 532-nm pump, paying special attention to mode matching between the pump and lasing beam within a ruby crystal placed in a semi-confocal laser cavity. Periodic spiking oscillations were observed in a limited pump power regime, where spikes obeying the generic asymmetric hyperbolic function appeared at a repetition rate around 50 kHz and with a 130-150ns width and 0.1-0.6μJ energy depending on the pump power. The physics of the spiking behavior based on Kleinman’s mechanical approach and a plausible interpretation for the periodic spiking oscillation in terms of self-induced mode matching between the pump and laser beams through the self-induced Kerr-lens effect are addressed. The statistical nature inherent to spiking and the associated self-organized critical behavior in quasi-periodic spiking oscillations as well as chaotic states occurring outside the periodic spiking regime are also explored from a nonlinear dynamics point of view.
Attenuation hotspots in neurotropic human astroviruses
Authors: Ali Hashim , Lulla Aleksei , Nicholson Alex S. , Hankinson Jacqueline , Wignall-Fleming Elizabeth B. , O’Connor Rhian L. , Vu Diem-Lan , Graham Stephen C. , Deane Janet E. , Guix Susana , Lulla Valeria
Published: July 2023

During the last decade, the detection of neurotropic astroviruses has increased dramatically. The MLB genogroup of astroviruses represents a genetically distinct group of zoonotic astroviruses associated with gastroenteritis and severe neurological complications in young children, the immunocompromised, and the elderly. Using different virus evolution approaches, we identified dispensable regions in the 3′ end of the capsid-coding region responsible for attenuation of MLB astroviruses in susceptible cell lines. To create recombinant viruses with identified deletions, MLB reverse genetics (RG) and replicon systems were developed. Recombinant truncated MLB viruses resulted in imbalanced RNA synthesis and strong attenuation in iPSC-derived neuronal cultures confirming the location of neurotropism determinants. This approach can be used for the development of vaccine candidates using attenuated astroviruses that infect humans, livestock animals, and poultry.
Influence of the vessel wall geometry on the wall-induced migration of red blood cells
Authors: Zhang Ying , Fai Thomas G.
Published: July 2023

The geometry of the blood vessel wall plays a regulatory role on the motion of red blood cells (RBCs). The overall topography of the vessel wall depends on many features, among which the endothelial lining of the endothelial surface layer (ESL) is an important one. The endothelial lining of vessel walls presents a large surface area for exchanging materials between blood and tissues. The ESL plays a critical role in regulating vascular permeability, hindering leukocyte adhesion as well as inhibiting coagulation during inflammation. Changes in the ESL structure are believed to cause vascular hyperpermeability and entrap immune cells during sepsis, which could significantly alter the vessel wall geometry and disturb interactions between RBCs and the vessel wall, including the wall-induced migration of RBCs and the thickening of a cell-free layer. To investigate the influence of the vessel wall geometry particularly changed by the ESL under various pathological conditions, such as sepsis, on the motion of RBCs, we developed two models to represent the ESL using the immersed boundary method in two dimensions. In particular, we used simulations to study how the lift force and drag force on a RBC near the vessel wall vary with different wall thickness, spatial variation, and permeability associated with changes in the vessel wall geometry. We find that the spatial variation of the wall has a significant effect on the wall-induced migration of the RBC for a high permeability, and that the wall-induced migration is significantly inhibited as the vessel diameter is increased.
Prevalence and risk factors of schistosomiasis and hookworm infection in seasonal transmission settings in northern Côte d’Ivoire: A cross-sectional study
Authors: Kouadio Jules N. , Giovanoli Evack Jennifer , Sékré Jean-Baptiste K. , Achi Louise Y. , Ouattara Mamadou , Hattendorf Jan , Balmer Oliver , Bonfoh Bassirou , Zinsstag Jakob , Utzinger Jürg , N’Goran Eliézer K.
Published: July 2023

Background

Schistosomiasis and hookworm infection remain public health problems in large parts of sub-Saharan Africa. The epidemiology of schistosomiasis and hookworm was studied in seasonal transmission settings in the northern part of Côte d’Ivoire.

Methodology

In August 2018, a cross-sectional study was conducted. Urine and stool samples were collected from 742 individuals aged 6–96 years in 16 localities from four departments in northern Côte d’Ivoire. Urine samples were examined by a filtration method for quantification of Schistosoma haematobium eggs. Stool samples were subjected to duplicate Kato-Katz thick smears and eggs of Schistosoma mansoni and soil-transmitted helminths (STHs) were counted. Additionally, a questionnaire was administered to determine demographic characteristics and to identify risk factors of schistosomiasis and STHs. Malacologic surveys were carried out at water points that are contacted by humans and animals.

Principal findings

The prevalence of schistosomiasis was very low. Only two cases of S. mansoni were found (0.3%, 95% confidence interval [CI]: 0.1–1.0%). The distribution of S. haematobium was focal, with cases found only in two departments; Ferkessédougou (5.4%, 95% CI: 2.5–9.9%) and Ouangolodougou (2.7%, 95% CI: 0.9–6.3%). Hookworm was the only STH species observed with a prevalence of 1.5% (95% CI: 0.8–2.8%). A higher risk of S. haematobium infection was observed in males compared to females, but the difference was not statistically significant (2.3% versus 1.3%, odds ratio [OR]: 1.5, 95% CI: 0.8–2.7). Participants aged 16–20 years showed the highest prevalence of S. haematobium. A total of 111 human- and animal-water contact points were identified at 47 water sources. Three potential intermediate host snails of schistosomes were collected; namely, Bulinus forskalii (n = 761), Bulinus truncatus (n = 205), and Biomphalaria pfeifferi (n = 1). Yet, only one specimen of Bu. truncatus was found to be shedding schistosome cercariae.

Conclusions/Significance

This study confirms very low transmission of schistosomiasis and hookworm in northern Côte d’Ivoire. The establishment and rigorous implementation of integrated surveillance-response systems could lead to the elimination of schistosomiasis and hookworm in this part of Côte d’Ivoire.
Nepalese version of Douleur Neuropathique 4 (DN4) questionnaire for detection of neuropathic pain signs and symptoms: Translation and psychometric properties
Authors: Shakya Bigen Man , Shrestha Anil , Poudyal Amod Kumar , Shrestha Ninadini , Acharya Binita , Gurung Renu , Shakya Sujata
Published: July 2023

Objective

This study aimed to translate the DN4 questionnaire into Nepalese version and assess its psychometric properties: diagnostic accuracy, internal consistency, and test-retest reliability.

Methods

An observational study was conducted in a tertiary level teaching hospital of Kathmandu, Nepal. We included 166 patients with chronic pain visiting a pain clinic over a period of one year. The Nepalese version of the DN4 questionnaire was used for detecting signs and symptoms of neuropathic pain. The English version of the questionnaire was translated into Nepali in accordance with the standard guideline with the help of linguistic experts. The patients who met the inclusion criteria were examined and interviewed twice in an interval of two weeks. The association between the index test and the reference test was analyzed using Chi-square test. Diagnostic accuracy was assessed using sensitivity, specificity, Youden’s index, and positive and negative predictive values. We calculated internal consistency using Cronbach’s alpha (∝), and test-retest reliability using Cohen’s kappa and Intra-class correlation coefficient (ICC).

Results

The study showed a significant association between the result of DN4 questionnaire and the gold standard (physician’s diagnosis) (p<0.001). The sensitivity and specificity values for the DN4 questionnaire were 75% and 95.3% respectively. Similarly, positive and negative predictive values were 93.8% and 80.4% respectively. Our study showed adequate internal consistency (∝ = 0.710) and a good test-retest reliability (kappa = 0.872, ICC = 0.877).

Conclusions

The Nepalese version of DN4 questionnaire is a valid and reliable tool for the identification of signs and symptoms of neuropathic pain. This can be used for screening neuropathic pain signs and symptoms in clinical as well as research settings.
Family health partners in regional network structures (NEST): A non-randomized controlled trial among parents of chronically ill and disabled children
Authors: Nickel Stefan , Helmreich Isabella , Broll Jan , Lüdecke Daniel
Published: July 2023

Background

The overarching project goal is to evaluate the effectiveness of a cross-sectoral and cross-service provider offering professional support for families with chronically ill and disabled children: so-called Family Health Partners (in German: ‘Familien-Gesundheits-Partner’ or FGP). This needs-oriented service, which is anchored in regional networks, aims to provide ‘holistic’ support for families with children in need of care.

Methods

We are carrying out a non-randomized controlled trial with four points of measurement (t0-t3 in 18 months), beginning in January 2022. Both intervention and control group include 102 families. Primary outcome measure is the quality of life, secondary outcomes are resilience factors and associated measures as well as the access to care. Multilevel regression models will be used to analyze the longitudinal data.

Discussion

The strength of this study is that it looks at the health and resilience of all family members involved by examining how a FGP can influence the entire family system with regard to increasing quality of life, resilience and self-efficacy. The network structures of FGP also open up better to previously unknown regional supply offers. There are, however, a number of limitations (e.g. type of outcomes, sample size).

Trial registration

This study was first registered on the German Clinical Trials Register before enrolment of participants started (ID: DRKS00027465, 4 January 2022). In order to promote its dissemination, it was also retrospectively registered on ClinicalTrials.gov (ID: NCT05418205, 14 June 2022).
Hepatitis B status and associated factors among participants screened for simulated HIV vaccine efficacy trials in Kenya and Uganda
Authors: Mayanja Yunia , Rida Wasima , Kimani Joshua , Ssetala Ali , Mpendo Juliet , Nanvubya Annet , Mutua Gaudensia , Anzala Omu , Price Matt A.
Published: July 2023

Introduction

Hepatitis B (HBV) prevalence remains high in Sub Saharan Africa and among some key populations such as those with continued exposure through sexual contact. We assessed the HBV status among potential participants who were screened for simulated HIV vaccine efficacy trials in Kenya and Uganda.

Methods

We conducted a cross sectional analysis of data collected from individuals who were screened in Kenya (Nairobi) and Uganda (Entebbe and Kampala). The studies followed hypothetical procedures of an HIV vaccine efficacy trial and aimed to enroll HIV negative key and vulnerable populations at elevated risk of HIV acquisition. HBV status was the main outcome categorized using Hepatitis B surface antigen (HBsAg) and total Hepatitis B core antibody (HBcAb). Baseline characteristics potentially associated with never being infected were analyzed using logistic regression.

Results

We screened 1,366 participants with mean age (SD) 28.7 (7.3) years. Overall, 46.6% were from Entebbe, 50.7% had secondary or higher level of education, 76.4% had informal high-risk jobs and 56.3% were male. Kampala had only female participants contributing 60.6% of females screened. Of the screened participants, 94.7% and 3.4% were negative and positive for HBsAg respectively. The prevalence on HBV infection was 3.9% among males and 2.8% among females while prevalence by site was: Entebbe (4.9%); Kampala (4.1%) and Nairobi (0.3%). The highest HBV prevalence was found among participants aged 25-29-years (5.2%), those with primary level education (4.5%), and those in informal low risk jobs (6.5%). Considering 1265 participants with complete data on HBsAg and HBcAb-Total, HBV status was never infected (67.9%), past infection (28.5%), chronic infection (3.2%) and acute infection (0.5%). Of 859 who were never infected, 685 (79.7%) were tested for anti-HBs titers of whom 60 (8.8%) had titers >10IU/L (immune due to vaccination). The odds of never being HBV infected were lower among older individuals 25–29 years (AOR 0.51; 95%CI 0.36–0.71) and ≥30 years (AOR 0.35; 95% CI 0.25–0.49). The odds were higher among participants with informal high-risk jobs from Kampala (AOR 2.21; 95% CI 1.41–3.47) and Nairobi (AOR 2.61; 95% CI 1.72–4.00) compared to those from Entebbe.

Conclusion

HBV prevalence and immunity due to vaccination were low among HIV negative individuals who are eligible for HIV vaccine trials and prevalence varies by age, education level and main occupation. Younger individuals and those recruited from existing cohorts/ clinics have a higher likelihood of having no prior HBV infection. HIV prevention intervention trials are a platform to identify individuals that need HBV vaccination.
Maternal saliva visfatin level in term and preterm labor: A case control study
Authors: Nasri Khadijeh , Mehrabi Mona , Bayani Mojtaba , Almasi-Hashiani Amir
Published: July 2023

Visfatin, a colony-enhancing factor (pre-B-cell), is an inflammatory biomarker that is secreted from a different number of cells and appears to have some proinflammatory or immune-regulating effects. The aim of this study was to compare maternal saliva visfatin levels in women with preterm and term delivery. In This case-control study, women in labor before 37 weeks of gestation were the case group (n = 40) and women in labor after 37 weeks of gestation were in control group (n = 40). The saliva of the participants was sampled and maternal saliva visfatin level was measured by ELISA test. In this study, 80 pregnant women were studied in case and control groups. The mean age of case and control group was 29.1±6.9 and 30.55±5.3 years, respectively. The results revealed that the mean maternal saliva visfatin level in the preterm group (4.75±2.2) is significantly (p = 0.001) lower than that in term birth group (6.7±3.1). The results of adjusted logistic regression revealed that after adjusting for GDM, preeclampsia, pre pregnancy BMI and weight gain, the mean of maternal saliva visfatin level in the preterm group is significantly lower than that in the term group (p = 0.026). Considering that during the term pregnancy visfatin levels increase and visfatin may play a role in initiating labor, in our study due to the high visfatin level in case group although the level of maternal saliva visfatin was lower than the control group but high levels of visfatin in the case group can represent the role of visfatin in initiating labor and due to this issue can be use the role of this adipokine for early diagnosis of preterm delivery can be used to prevent, treat and improve the prognosis of this disease. Also, this study is the first study to compare the maternal saliva visfatin level between SGA and AGA group and there is no difference between these groups.
Patient education interventions for adolescent and young adult kidney transplant recipients- a scoping review
Authors: Corr Michael , McKeaveney Clare , Wurm Fina , Courtney Aisling , Noble Helen
Published: July 2023

Background

Adolescence and young adulthood are high risk periods for kidney transplant recipients. The reasons for this are complex; but are predominantly thought to be due to poor adherence to immunosuppressive medications. Patient education can help support young recipients to reduce their risk of behaviour-related transplant loss. The aim of this review was to understand what is known about education interventions targeted at adolescent and young adult kidney transplant recipients.

Methods

Systematic scoping review methodology was utilised. Six online databases were searched for suitable articles. Articles were selected for full text review following title and abstract screening. Articles deemed eligible to be included in the review had data extracted, which were qualitatively analysed using thematic analysis. Findings were validated through a consultation exercise with both young recipients and healthcare professionals.

Results

29 studies were eligible for inclusion in the review. There was a high level of heterogeneity in the content, mode, design, and measurement of efficacy of interventions in the selected studies. Traditional face-to-face education and transition clinics were the most common educational interventions. Using technology to enhance patient education was also a major theme identified. Few studies reported using educational theory or involving patients in intervention design.

Discussion

Four key research gaps were identified. 1.) Lack of educational theory in intervention design 2.) Lack of patient/ stakeholder involvement 3.) Identifying best way to measure efficacy 4.) identifying novel future research questions within already well established paediatric and educational frameworks. Addressing these gaps in future research will help inform best-practice in this vulnerable population.
Expectations of fulfilling the grandparent role in the context of maintaining professional activity. Analysis of an international survey
Authors: Kwiatkowska-Ciotucha Dorota , Załuska Urszula , Grześkowiak Alicja , Peternek Piotr
Published: July 2023

This article aims to assess the expectations of fulfilling the role of grandparents in the context of maintaining professional activity. In the study, data from an international survey conducted using a proprietary questionnaire (the CAWI method) among representatives from 7 European countries was used. The main objective was to find possible differences in the perception of the grandmother’s and grandfather’s roles depending on the characteristics of the respondent. The survey was conducted in May 2022, and the total research sample was 3,008 people. The analysis focused on the respondents’ answers to eight statements on taking care of grandchildren and work-related decisions. The study employed exploratory factor analysis and non-parametric tests (Mann-Whitney U test and Kruskal-Wallis test) to check for differences in assessments according to the respondent characteristics. Statistically significant differences were found between the answers of respondents who differ in age, gender, and place of residence. Factor analysis made it possible to identify two factors: the first one may be named ‘long-term support’ and the second factor may be labelled ‘temporary - emergency care’; this provided a basis for synthesising the analysed statements.
Institutional quality and economic growth in the non-EU post-Soviet countries: Does energy abundance matter?
Authors: Gasimov Ilkin , Jabiyev Farid , Asgarzade Gadir
Published: July 2023

ABSTRACT. After regaining independence, most of the post-Soviet countries encountered socio-economic difficulties during the transition period. These challenges were also accompanied by low institutional quality. Some of the post-Soviet countries, such as Russia, Turkmenistan, Kazakhstan and Azerbaijan, can be categorized as energy-rich, while the remaining countries are non-rich in terms of energy. Thereby, the aim of this study is twofold: first, to analyze the impact of institutional quality on economic growth in the case of non-EU post-Soviet countries, and second, to determine whether there is any difference in the link of institutional quality and economic growth between the energy-rich and non-rich sample countries. Two-Stage Least Squares reveal a U-shaped association between institutional environment and economic growth. Furthermore, the results suggest that this impact is lower in the energy-rich countries compared with their non-rich counterparts. With regards to the control variables, the findings indicate a positive and statistically significant impact of openness on economic growth. Finally, there is a negative association between the remaining control variables, such as inflation, population growth rate and the dependent variable.
Determinants of working capital management in small and medium enterprises: Evidence from Central and Eastern Europe
Authors: Czerwonka Leszek , Jaworski Jacek
Published: July 2023

The main purpose of the paper is to identify the determinants of working capital management in the SME sector at the company, industry and country levels. The research is based on the statistical analysis of the financial data of 8,516 SMEs from Bulgaria, the Czech Republic, Hungary, Poland, Romania, and Slovakia in the years 2012-2020. The influence of firm-specific factors on variables describing working capital management has been identified: company size exerts a positive impact, while company growth, tangibility, leverage, and cash flow have a negative effect. In terms of the influence of industry-specific factors, the average values characterising working capital management in a given industry have a positive impact. Finally, regarding country-specific factors, the positive effects of the GDP growth and unemployment level have also been confirmed. The study contributes to the literature by providing strong evidence of (i) firms in an industry using similar working capital management policies and (ii) industry-specific factors being more influential than country-specific (mainly macroeconomic) determinants of working capital management. In this regard, the study highlights new industry- and country-specific factors and also confirms the influence of previously known determinants at the firm level.