bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-robust optical microphone with a compact grating interferometric module
Authors: Hu Xinyu , Yue Yan , Cai Chen , Qi Zhi-Mei
Published: July 2023

The high demand for advanced acoustic sensors has prompted optical
microphones to become a current research hotspot; this is especially
the case in light of the performance of existing electroacoustic
microphones having reached the ceiling. In this work, a thermally
stable optical microphone has been developed for sensitive detection
of low-frequency acoustic signals. The microphone was prepared using a
prestressed nickel diaphragm and a compact grating interferometric
module. The adjacent surfaces of the diaphragm and grating form a
short Fabry–Perot cavity, which makes the microphone robust to ambient
temperature fluctuation due to the reduced thermal drift of its
operating point relative to the quadrature point of the
interferometer. The cavity length–operating wavelength relationship of
the microphone operating at the quadrature point was obtained. The
performance of the prepared microphone was tested using various
methods. Experimental results show that the microphone enables stable
operation at the quadrature point over a wide range of temperatures
from 0°C to 60°C with low signal distortion and high sensitivity. The
response of the prepared optical microphone to low-frequency drone
noise was measured and compared with that obtained with a commercial
electret condenser microphone.
Optical phase retrieving employing differentiation of a couple of two-beam π/2 phase-shifted projected interference patterns
Authors: Ramadan W. A. , Wahba H. H. , El-Tawargy A. S.
Published: July 2023

An approach to retrieve the 3D surface map of an estimated (i.e., digitally generated) object by projection of a couple of differentiated two-beam interference patterns is presented. A couple of two-beam interference patterns of a certain spatial frequency, shifted by a phase angle (π/2), are produced. Each one of these patterns is differentiated with respect to the carrier’s phase angle. The four obtained interference patterns are projected onto two estimated objects. Each object’s phase variations are retrieved utilizing the definition of the mathematical differentiation of the intensity distribution of the projected patterns. The inclination of the projected interference pattern on the object’s topography caused a redistribution of the intensity according to Lambert’s “cos” law of illumination. This effect is considered when the object’s phase map is retrieved. The limitations of the presented approach are discussed.
Method for retrieval of aerosol optical depth from multichannel irradiance measurements
Authors: Sztipanov Milos , Li Wei , Dahlback Arne , Stamnes Jakob , Svendby Tove , Stamnes Knut
Published: July 2023

We present, to the best of our knowledge, a new method for retrieval of aerosol optical depth from multichannel irradiance measurements. A radiative transfer model is used to simulate measurements to create the new aerosol optical depth retrieval method. A description of the algorithm, simulations, proof of principle, merits, possible future developments and implementations is provided. As a demonstration, measurements in the New York City area are simulated based on the specific channel configuration of an existing multichannel irradiance instrument. Verification of the method with irradiance measurement data is also provided.
Encaved optical fiber nano-probe exciting whispering gallery mode resonance with focused far off-axis beam
Authors: Kaur Jasleen , Vairagi Kaushal , Minz Rashmi Achla , Enoch Stefan , Mondal Samir K.
Published: July 2023

This paper demonstrates whispering gallery mode (WGM) resonance with the help of an encaved optical nano-probe developed inside an optical fiber tip cavity. The nano-probe generates a tightly focused beam with a spot-size of ∼3 µm. A barium titanate microsphere is placed besides the optical axis inside the cavity. The focused beam remains off-axis of the microresonator and excites the WGM. The off-axis excitation shows unique resonating properties depending on the location of the resonator. A resonant peak with quality factor as high as Q ∼7 × 104 is achieved experimentally. Another design with a shorter cavity length for a bigger resonator is also demonstrated by embedding a bigger microsphere on the cleaved fiber tip surface. The optical probe holds great potential for photonic devices and is ideal for studying morphology-based scattering problems.
X-ray ptychographic and fluorescence microscopy using virtual single-pixel imaging based deconvolution with accurate probe images
Authors: Abe Masaki , Ishiguro Nozomu , Uematsu Hideshi , Takazawa Shuntaro , Kaneko Fusae , Takahashi Yukio
Published: July 2023

Simultaneous measurement of X-ray ptychography and fluorescence microscopy allows high-resolution and high-sensitivity observations of the microstructure and trace-element distribution of a sample. In this paper, we propose a method for improving scanning fluorescence X-ray microscopy (SFXM) images, in which the SFXM image is deconvolved via virtual single-pixel imaging using different probe images for each scanning point obtained by X-ray ptychographic reconstruction. Numerical simulations confirmed that this method can increase the spatial resolution while suppressing artifacts caused by probe imprecision, e.g., probe position errors and wavefront changes. The method also worked well in synchrotron radiation experiments to increase the spatial resolution and was applied to the observation of S element maps of ZnS particles.
Flatness enhancement of multi-wavelength Brillouin-Raman fiber laser with 10 GHz spacing utilizing Raman pump power distribution
Authors: Mamdoohi G. , Soltanian M. R. K. , Légaré F.
Published: July 2023

A simple high flat amplitude multi-wavelength Brillouin–Raman fibre laser (MBRFL) with 10 GHz spacing and excellent optical signal-to-noise ratio (OSNR) in C-Band spectral region is demonstrated. The laser consists of a linear cavity in which 12 km dispersion compensating fiber (DCF) in addition to 49 cm Bismuth-oxide Erbium doped fiber (Bi-EDF) are employed as a gain medium for amplification. The impact of Raman pump power distribution through changes in coupling ratio on amplitude flatness is carried out by comparing the peak power discrepancy between odd- and even-order Brillouin Stoke lines. This is the main property that allows the efficient controlling of gain propagation between lasing lines that is vital for Stokes flattening initiation and other output spectra characteristics. The attainment of MBRFL with outstanding OSNR necessitates the utilizing of Bi-EDF as a noise suppressor. By utilizing a 50/50 coupler, 354 identical channels together with uniform Brillouin Stokes linewidth within only 0.3-dB maximum power difference between adjacent channels is generated. The average OSNR and Stokes power are 28 dB and -5 dBm respectively when the RPP is set at 1300 mW. To date, this is the highest flatness 10 GHz spacing MBRFL with outstanding OSNR attained in MBRFL that incorporate only a single Raman pump unit.
SHCT: segmented helical computed tomography based on multiple slant source-translation
Authors: Wang Zhisheng , Cui Junning , Liu Yue , Li Shangyu , Li Zongfeng , Wang Shunli
Published: July 2023

Micro-computed tomography (Micro-CT) is inevitably required to inspect long large objects with high resolution. It is well known that helical CT solves the so-called “long object” problem, but it requires that the measured object be strictly located in the lateral field of view (FOV). Therefore, developing a novel scanning method to extend the FOV in both the lateral and axial directions (i.e., the large helical FOV) is necessary. Recently, due to the application of linearly distributed source arrays and the characteristics of easy extension of the FOV and engineering implementation, straight-line scanning systems have attracted much attention. In this paper, we propose a segmented helical computed tomography (SHCT) based on multiple slant source-translation. SHCT can readily extend the helical FOV by adjusting the source slant translation (SST) length, pitch (or elevation of the SST trajectory), and number of scanning circles. In SHCT, each projection view is truncated laterally and axially, but the projection data set within the cylindrical FOV region is complete. To ensure reconstruction efficiency and avoid the lateral truncation, we propose a generalized backprojection-filtration (G-BPF) algorithm for SHCT approximate reconstruction. Experimental results verify the effectiveness of the proposed SHCT methods for imaging large and long objects. As the pitch decreases, the proposed SHCT methods can reconstruct competitive, high-quality volumes.
Optimization of extreme ultra-violet light emitted from the CO2 laser-irradiated tin plasmas using 2D radiation hydrodynamic simulations
Authors: Sunahara Atsushi , Hassanein Ahmed , Tomita Kentaro , Namba Shinichi , Higashiguchi Takeshi
Published: July 2023

We studied Extreme Ultra-Violet (EUV) emission characteristics of the 13.5 nm wavelength from CO2 laser-irradiated pre-formed tin plasmas using 2D radiation hydrodynamic simulations. Our results indicate that when a CO2 laser irradiates pre-formed tin plasma, the heated plasma expands towards the surrounding plasma, steepening the density at the ablation front and lowering the density near the laser axis due to the transverse motion of the plasma. Consequently, the laser absorption fraction decreases, and the contribution to EUV output from the ablation front becomes dominant over that from the low-density plasmas. We estimated that an EUV conversion efficiency of 10% from laser to EUV emission could be achieved with a larger laser spot size, shortened laser pulse width, and longer pre-formed plasma density scale length. Our results offer one optimizing solution to achieve an efficient and powerful EUV light source for the next-generation semiconductors.
Pulse high energy Fe: ZnSe laser pumped by Q-switched Er: YAG laser
Authors: Xu Fei , Pan Qikun , Zhang Yueru , Zhang Ranran , Chen Yi , Yu Deyang , Chen Fei
Published: July 2023

We report a pulse Fe: ZnSe laser pumped by an optical chopper Q-switched Er: YAG laser. By analyzed the spatial and temporal match of the gain and chopper, the maximum energy of the optical chopper Q-switched Er: YAG laser is 31mJ with the pulse width of 165 ns. By employing this Er: YAG laser as pump laser of Fe: ZnSe crystal, the maximum output energy of Fe: ZnSe laser is 10mJ with the pulse width of 80 ns at room temperature, that is the maximum energy of Fe: ZnSe laser at this Q-switched system to the best of our knowledge. We also study the directly Q-switched Fe: ZnSe laser, and the 2.7mJ mid-infrared laser with the pulse width of 200 ns is obtained at 80 K.
Robust Kramers–Kronig holographic imaging with Hilbert–Huang transform
Authors: Chang Xuyang , Shen Cheng , Liu Sitian , Zheng Dezhi , Wang Shuai , Yang Changhuei , Huang Norden E. , Bian Liheng
Published: July 2023

Holography based on Kramers–Kronig relations (KKR) is a promising technique due to its high-space-bandwidth product. However, the absence of an iterative process limits its noise robustness, primarily stemming from the lack of a regularization constraint. This Letter reports a generalized framework aimed at enhancing the noise robustness of KKR holography. Our proposal involves employing the Hilbert–Huang transform to connect the real and imaginary parts of an analytic function. The real part is initially processed by bidimensional empirical mode decomposition into a series of intrinsic mode functions (IMFs) and a residual term. They are then selected to remove the noise and bias terms. Finally, the imaginary part can be obtained using the Hilbert transform. In this way, we efficiently suppress the noise in the synthetic complex function, facilitating high-fidelity wavefront reconstruction using ∼20% of the exposure time required by existing methods. Our work is expected to expand the applications of KKR holography, particularly in low phototoxicity biological imaging and other related scenarios.
Reconfigurable all-optical bistability/tristability in dual injection-locked Fabry–Perot laser diodes
Authors: Banović Mladen Ž. , Atanasijević Petar A. , Krstić Marko M. , Mihailović Peđa M. , Crnjanski Jasna V. , Petričević Slobodan J. , Gvozdić Dejan M.
Published: July 2023

In this Letter, we present a detailed theoretical and experimental investigation of optical bistability and tristability in dual injection-locked Fabry–Perot laser diodes. The proposed device can be reconfigured between the bistable and tristable regimes, simply by adjusting the power level of the injected control optical signal. The tristability presented in the experiment is achieved for relatively low optical input powers between 1.03 and 1.25 mW, with the output signal ratio of up to 7 dB between stable states. Such a device is a potential candidate for designing trits, a bit analogy in ternary computational logic.
Luminescent solar concentrator efficiency versus edge solar cell coverage
Authors: Lu Xi , Zhou Jingjian , Jash Madhuri , Sychugov Ilya
Published: July 2023

This Letter introduces an analytical approach to estimate the waveguiding efficiency of large-area luminescent solar concentrators (LSCs), where the edges are covered by a varied number of mirrors and solar cells. The model provides physically relevant description in the whole range of optical (absorption, scattering) and geometrical (size) parameters of rectangular LSCs. A 19 × 19 cm2 silicon quantum dot-based LSC has been fabricated to verify the theory. Within an experimental error, the predicted waveguiding efficiency matched well the measured one. A critical LSC size, beyond which a part of the device turns inactive, has been determined as N/α for N attached solar cells (one or two) and LSC material absorption coefficient α. This model provides a straightforward waveguiding analysis tool for large-area LSCs with different structural parameters relevant for both high concentration ratio and glazing applications.
Phase retrieval for arbitrary complex-valued objects using structured illumination
Authors: Kuzmenko Alexander , Butok Oleksandr
Published: July 2023

A method to solve of the phase retrieval problem in the non-convex formulation has been proposed for complex-valued objects with the support constraint. It has been shown that two coded diffraction patterns (CDPs) obtained in the same Fresnel or Fraunhofer diffraction plane by masking the object with two, direct and inverse, random binary amplitude masks are sufficient to reconstruct an arbitrary complex-valued object with an accuracy to the global phase. The general solution of the problem was found as the sum of two mutually phase-consistent partial solutions obtained by applying the modified error-reduction or hybrid input-output algorithm to each of two “mask+CDP” pairs. The results of model experiments confirmed the possibility of noise-resistant and high-accuracy retrieval of complex-valued objects of various types with the oversampling ratio σ ≥ 2 making use of a small number of iterations. The method is applicable to coherent radiation of any kind.
Low-noise short-wavelength pumped frequency down-conversion for Quantum Frequency Converters
Authors: Geus Jan , Elsen Florian , Nyga Sebastian , Stolk Arian , van der Enden Kian , van Zwet Erwin , Haefner Constantin , Hanson Ronald , Jungbluth Bernd
Published: July 2023

In this paper, we present a novel single stage quantum frequency conversion (QFC) scheme based on an enhancement cavity, which allows for high conversion efficiencies with record low noise levels, 100 times smaller than in previous systems and close to the thermal background. Our approach represents a significant improvement over traditional QFC methods that rely on periodically poled waveguide crystals, which typically produce high levels of noise with input wavelengths in the visible spectrum.
One of the key challenges in QFC is the generation of noise photons - photons that are not part of the desired output state. Those noise photons are one of the major limitations of today’s quantum network experiments. It has been widely believed that single stage QFC of qubit photons in the visible range would result in too many noise photons in the telecom band, because of SPDC induced by the short wavelength driver laser. However, using the enhancement cavity design, we are able to overcome this challenge and demonstrate high-fidelity QFC from the visible to telecom band.
Our results have important implications for the development of practical QFC devices for a range of applications, including quantum communication and quantum networks, where low noise levels are critical.
Multi-channel measurements of C. elegans’ largest Lyapunov exponents using optical diffraction
Authors: Magnes Jenny , Zanetti Raffaella , Zhang Susannah , Canavan Katherine
Published: July 2023

Dynamic diffraction (DOD) is a form of microscopy that allows the dynamic tracking of changing shapes in a 1D time series. DOD is capable of capturing the locomotion of a nematode while swimming freely in a 3D space, allowing the locomotion of the worm to more closely mimic natural behavior than in some other laboratory environments. More importantly, we are able to see markers of chaos as DOD covers dynamics on multiple length scales. This work introduces a multichannel method to measure the dynamic complexity of microscopic organisms. We show that parameters associated with chaos, such as the largest Lyapunov exponent (LLE), the mean frequency, mutual information (MI), and the embedding dimension, are independent of the specific point sampled in the diffraction pattern, thus demonstrating experimentally the consistency of our dynamic parameters sampled at various locations (channels) in the associated optical far-field pattern.
Terahertz multi-band absorber and dual-bandwidth polarization converter based on VO2 and graphene
Authors: Jia Yang , Wang Guan , Zhang Xin , Li Yachen , Miao Feng , Gao Yachen
Published: July 2023

A terahertz metamaterial with multiple functions is proposed based on patterned graphene, concentric gold rings and gold columns, and vanadium dioxide (VO2). By adjusting the temperature of VO2, it can be in metal state or insulator state, correspondingly the metamaterial can work as a dual-bandwidth polarization converter or an multi-bandwidth absorber. When the metamaterial acts as a polarization converter, by adjusting the Fermi level of graphene, the converter can realize simultaneously x-polarized wave to y-polarized wave polarization conversion (CPC) and line-to-circular (LTC) polarization conversion (PC). In addition, by adjusting the Fermi level of graphene, the operating frequency and operating efficiency of the absorber and polarization converter can be dynamically tuned. By studying the electric field distribution and the surface current of the metamaterial, the physical mechanism of efficient absorption and dual-bandwidth polarization is explored. Moreover, the proposed multifunctional metamaterial is highly robust to incidence angle. It has potential applications in communication, spectroscopy, sensors, and physical detection.
Electrically pumped optomechanical beam GaN-LED accelerometer based on the quantum-confined Stark effect
Authors: Zhu Gangyi , Ji Xin , Zhang Zhenfu , Yan Xingcan , Yang Ying , Qin Feifei , Li Xin , Wu Jiagui , Sun Xiaojuan , Yang Junbo , Wang Yongjin
Published: July 2023

Micro-nano optomechanical accelerometers are widely used in automobile, aerospace, and other industrial applications. Here, we fabricate mechanical sensing components based on an electrically pumped GaN light-emitting diode (LED) with a beam structure. The relationship between the blueshift of the electroluminescence (EL) spectra and the deformation of the GaN beam structure based on the quantum-confined Stark effect (QCSE) of the InGaN quantum well (QW) structure is studied by introducing an extra mass block. Under the equivalent acceleration condition, in addition to the elastic deformation of GaN-LED, a direct relationship exists between the LED’s spectral shift and the acceleration’s magnitude. The extra mass block (gravitational force: 7.55×10−11  N) induced blueshift of the EL spectra is obtained and shows driven current dependency. A polymer sphere (PS; gravitational force: 3.427×10−12  N) is placed at the center of the beam GaN-LED, and a blueshift of 0.061 nm is observed in the EL spectrum under the injection current of 0.5 mA. The maximum sensitivity of the acceleration is measured to be 0.02  m/s2, and the maximum measurable acceleration is calculated to be 1.8×106  m/s2. It indicates the simultaneous realization of high sensitivity and a broad acceleration measurement range. This work is significant for several applications, including light force measurement and inertial navigation systems with high integration ability.
Development of Accurate Long-lead COVID-19 Forecast
Authors: Yang Wan , Shaman Jeffrey
Published: July 2023

Coronavirus disease 2019 (COVID-19) will likely remain a major public health burden; accurate forecast of COVID-19 epidemic outcomes several months into the future is needed to support more proactive planning. Here, we propose strategies to address three major forecast challenges, i.e., error growth, the emergence of new variants, and infection seasonality. Using these strategies in combination we generate retrospective predictions of COVID-19 cases and deaths 6 months in the future for 10 representative US states. Tallied over >25,000 retrospective predictions through September 2022, the forecast approach using all three strategies consistently outperformed a baseline forecast approach without these strategies across different variant waves and locations, for all forecast targets. Overall, probabilistic forecast accuracy improved by 64% and 38% and point prediction accuracy by 133% and 87% for cases and deaths, respectively. Real-time 6-month lead predictions made in early October 2022 suggested large attack rates in most states but a lower burden of deaths than previous waves during October 2022 –March 2023; these predictions are in general accurate compared to reported data. The superior skill of the forecast methods developed here demonstrate means for generating more accurate long-lead forecast of COVID-19 and possibly other infectious diseases.
Self-paced online learning to improve knowledge competencies for hypertension among medical students in Uganda: A pre-post study
Authors: Edward Anbrasi , Kalyesubula Robert , Pariyo George , Kyazze Andrew Peter , Hu Xiao , Appel Lawrence J. , Matsushita Kunihiro
Published: July 2023

The growing burden of hypertension (HT) is projected to reach 1.56 billion globally by 2025 and is an increasing public health concern, even for low- and middle-income countries (LMIC) like Uganda, where the prevalence of HT is 31.5%. The objective of this study was to test the effectiveness of a freely available HT online course on knowledge competencies for medical students in Uganda. The online course was developed by a multidisciplinary team at Johns Hopkins University to address HT control in resource-constrained healthcare settings. Students in the 3rd, 4th, and 5th years of medical school were randomly selected to participate in the online course. Pre and post knowledge tests were administered using an online survey system. Of the 201 invited students, 121 (60.2%) completed the study. Significant improvements in mean knowledge scores were evident following the online course completion for Module 1, Fundamentals of HT (21.9±2.5 to 23.7±2.5, p<0.001), and Module 2, Basics of HT Management (14.9±3.3 to 18.5±4.3, p<0.001). No statistically significant differences were evident by gender or school year. Students who took a shorter duration to complete the course had significantly higher mean score improvement between pre- and post-test (mean score improvement 7.0 if <4 weeks, 3.6 if 4–8 weeks, and 3.7 if >8 weeks, p<0.003). Students recognized information on blood pressure measurement (32.2%) and HT management (22.3%) as the most important concept addressed in the course. A self-paced online course, complementing medical school training, improved knowledge on HT burden and management in Uganda.
The age profile of respiratory syncytial virus burden in preschool children of low- and middle-income countries: A semi-parametric, meta-regression approach
Authors: Antillón Marina , Li Xiao , Willem Lander , Bilcke Joke ,   RESCEU investigators, Jit Mark , Beutels Philippe
Published: July 2023

Background

Respiratory syncytial virus (RSV) infections are among the primary causes of death for children under 5 years of age worldwide. A notable challenge with many of the upcoming prophylactic interventions against RSV is their short duration of protection, making the age profile of key interest to the design of prevention strategies.

Methods and findings

We leverage the RSV data collected on cases, hospitalizations, and deaths in a systematic review in combination with flexible generalized additive mixed models (GAMMs) to characterize the age burden of RSV incidence, hospitalization, and hospital-based case fatality rate (hCFR). Due to the flexible nature of GAMMs, we estimate the peak, median, and mean incidence of infection to inform discussions on the ideal “window of protection” of prophylactic interventions. In a secondary analysis, we reestimate the burden of RSV in all low- and middle-income countries. The peak age of community-based incidence is 4.8 months, and the mean and median age of infection is 18.9 and 14.7 months, respectively. Estimating the age profile using the incidence coming from hospital-based studies yields a slightly younger age profile, in which the peak age of infection is 2.6 months and the mean and median age of infection are 15.8 and 11.6 months, respectively. More severe outcomes, such as hospitalization and in-hospital death have a younger age profile. Children under 6 months of age constitute 10% of the population under 5 years of age but bear 20% to 29% of cases, 28% to 39% of hospitalizations, and 38% to 50% of deaths.

On an average year, we estimate 28.23 to 31.34 million cases of RSV, between 2.95 to 3.35 million hospitalizations, and 16,835 to 19,909 in-hospital deaths in low, lower- and upper middle-income countries. In addition, we estimate 17,254 to 23,875 deaths in the community, for a total of 34,114 to 46,485 deaths. Globally, evidence shows that community-based incidence may differ by World Bank Income Group, but not hospital-based incidence, probability of hospitalization, or the probability of in-hospital death (p ≤ 0.01, p = 1, p = 0.86, 0.63, respectively). Our study is limited mainly due to the sparsity of the data, especially for low-income countries (LICs). The lack of information for some populations makes detecting heterogeneity between income groups difficult, and differences in access to care may impact the reported burden.

Conclusions

We have demonstrated an approach to synthesize information on RSV outcomes in a statistically principled manner, and we estimate that the age profile of RSV burden depends on whether information on incidence is collected in hospitals or in the community. Our results suggest that the ideal prophylactic strategy may require multiple products to avert the risk among preschool children.
Scanning iron response regulator binding sites using Dap-seq in the Brucella genome
Authors: Zhang Huan , Sun Tianhao , Cao Xudong , Wang Yifan , Ma Zhongchen , Wang Yueli , Yang Ningning , Xu Mingguo , Deng Xiaoyu , Li Honghuan , Wang Benben , Yi Jihai , Wang Zhen , Zhang Qian , Chen Chuangfu
Published: July 2023

Iron is an essential element required for all organisms. Iron response regulator (Irr) is a crucial transcriptional regulator and can affect the growth and iron uptake of Brucella. The growth rate of Brucella melitensis M5-90 irr mutant was significantly lower than that of B. melitensis M5-90 under normal or iron-sufficient conditions, however, the growth rate of the B. melitensis M5-90 irr mutant was significantly higher than that of B. melitensis M5-90 under iron-limited conditions. In addition, irr mutation significantly reduced iron uptake under iron-limited conditions. Previous studies suggested that the Irr protein has multiple target genes in the Brucella genome that are involved in iron metabolism. Therefore, in the present study, a Dap-seq approach was used to investigate the other iron metabolism genes that are also regulated by the Irr protein in Brucella. A total of seven genes were identified as target genes for Irr in this study and the expression levels of these seven genes was identified using qRT-PCR. The electrophoretic mobility shift assay confirmed that six out of the seven genes, namely rirA (BME_RS13665), membrane protein (BME_RS01725), hypothetical protein (BME_RS09560), ftrA (BME_RS14525), cation-transporting P-type ATPase (zntA) (BME_RS10660), and 2Fe-2S binding protein (BME_RS13655), interact with the Irr protein. Furthermore, the iron utilization and growth assay experiments confirmed that rirA was involve in iron metabolism and growth of Brucella. In summary, our results identified six genes regulated by the Irr protein that may participate in iron metabolism, and the rirA was identified as a regulon of Irr and it also plays a role in iron metabolism of Brucella. Collectively, these results provide valuable insights for the exploration of Brucella iron metabolism.
Gamified assessment of cognitive performance during moderate hypoxia
Authors: Keeler Jason M. , Tourula Erica , Hite M. Jo , Listman Jennifer B. , Heeger David J. , Port Nicholas L. , Schlader Zachary J.
Published: July 2023

Introduction

There is a need for rapid and objective assessment tools to identify people at risk of impaired cognitive function during hypoxia.

Purpose

To test the hypotheses that performance on gamified cognitive tests examining the cognitive domains of executive function (Gridshot), working memory (Capacity) and spatial tracking (Multitracker) will be reduced during normobaric exposure to moderate normobaric hypoxia.

Methods

Following three consecutive days of practice, twenty-one healthy adults (27 ± 5 y, 9 females) completed five 1-min rounds of the tablet-based games Gridshot, Capacity, and Multitracker (Statespace Labs, Inc.) at Baseline and 60 and 90 min after exposure to 14.0 ± 0.2% (hypoxia) and 20.6 ± 0.3% (normoxia) oxygen. Both conditions were completed on the same day and were administered in a single-blind, block randomized manner. Arterial oxyhemoglobin saturation was estimated via forehead pulse oximetry (SpO2). Data were analyzed using ANCOVA with a covariate of Baseline.

Results

Compared to normoxia (98 ± 1%), SpO2 was lower (p < 0.001) at 60 (91 ± 3%) and 90 (91 ± 2%) min of hypoxia. No condition x time interaction effects were identified for any gamified cognitive tests (p ≥ 0.32). A main effect of condition was identified for Capacity (p = 0.05) and Multitracker (p = 0.04), but not Gridshot (p = 0.33). Post hoc analyses of the composite scores for both Capacity (p = 0.11) and Multitracker (p = 0.73) demonstrated no difference between conditions.

Conclusion

Performance on gamified cognitive tests was not consistently affected by acute normobaric moderate hypoxic exposure.
Prescription patterns of granulocyte colony–stimulating factors in patients with breast cancer: A real-world study
Authors: Hsu Shu-Wei , Chiang Shao-Chin , Hsu Jason C. , Ko Yu
Published: July 2023

Background and objectives

Myelosuppressive chemotherapy is effective for breast cancer but carries a potential risk of febrile neutropenia (FN). Clinical practice guidelines have recommended prophylaxis with granulocyte colony-stimulating factor (G-CSF) to reduce the incidence of FN in patients receiving chemotherapy. We aimed to examine the use of G-CSFs for primary prophylaxis for FN and to see whether it follows the guidelines. In addition, we examined the changes in the use of long-acting and short-acting G-CSFs in patients with breast cancer over the past ten years.

Methods

This was a retrospective observational real-world study. The data were obtained from the clinical research database of three hospitals affiliated with Taipei Medical University. Patients with breast cancer who initiated their first chemotherapy regimen between January 1, 2011, and December 31, 2020, were identified by the ICD codes and their use of filgrastim or pegfilgrastim was identified by the Anatomical Therapeutic Chemical codes. Whether and how G-CSF was prescribed during the study patients’ first chemotherapy regimen was examined, and the annual change in the total number of short- and long-acting G-CSFs prescribed to the study patients from 2011 to 2020 was analyzed.

Results

Among the 2,444 patients who were prescribed at least one of the examined 15 breast cancer chemotherapy drugs, 1,414 did not use any G-CSFs during their first chemotherapy regimen while 145 used G-CSFs for primary prophylaxis and 185 for treatment. Among the patients receiving high FN risk regimens, only 8.6% used G-CSF for primary prophylaxis. The average (± SD) number of days for short-acting G-CSF use was 2.3 (± 1.5) days with a median of 2 days. In addition, it was found that there was a significant reduction in long-acting G-CSF use (p = 0.03) whereas the changes in short-acting G-CSF use over time were not significant (p = 0.50).

Conclusions

Our study results show that G-CSFs are used for primary prophylaxis in a small percentage of patients with breast cancer and the duration of short-acting G-CSF use is relatively short. Considering the significant clinical and economic impact of FN, it is hoped that the prescription patterns of G-CSFs observed can provide an important reference for future clinical practice and reimbursement policy.
The geographical pension gap: Understanding the causes of inequality in China’s pension funds
Authors: Zhang Songbiao , Wang Xining , Li Huajin , Wang Huilin
Published: July 2023

The sustainability of social pension insurance is of great significance in guaranteeing the essential life of the elderly and promoting social stability. Based on the provincial panel data from 2012 to 2020, this study uses non-spatial measurement methods, ArcGIS visualization research methods, and geographic detectors to study the regional differences in China’s pension fund balances and the underlying influencing factors. Compared with the traditional way of establishing regression equations to explore the correlation of influencing factors, geographic detectors can quantify the strength of each influencing factor and detect the interaction of different influencing factors. This study found that: First, the growth rate of China’s overall pension fund balances has been declining yearly, with the fastest decline in northeast China, the middle in the Western and Central regions of China, and the slowest decline in Eastern China. Second, the spatial distribution of pension fund balances shows agglomeration characteristics, with high-value areas mainly distributed in Eastern China and low-value regions distributed primarily in Western and Northeastern China. Third, the overall Theil index for pension fund balances is trending down, but the Theil index for the Eastern region is on the rise. Fourth, seven factors, including the working-age population, the population aged 65 and above, and regional GDP, are the main factors that lead to regional differences in the balance of urban and rural residential insurance funds. Finally, the superimposed effects of each element are reflected in double-factor enhancement or non-linear enhancement relation.
NRF2 activators inhibit influenza A virus replication by interfering with nucleo-cytoplasmic export of viral RNPs in an NRF2-independent manner
Authors: Waqas Fakhar H. , Shehata Mahmoud , Elgaher Walid A. M. , Lacour Antoine , Kurmasheva Naziia , Begnini Fabio , Kiib Anders E. , Dahlmann Julia , Chen Chutao , Pavlou Andreas , Poulsen Thomas B. , Merkert Sylvia , Martin Ulrich , Olmer Ruth , Olagnier David , Hirsch Anna K. H. , Pleschka Stephan , Pessler Frank
Published: July 2023

In addition to antioxidative and anti-inflammatory properties, activators of the cytoprotective nuclear factor erythroid-2-like-2 (NRF2) signaling pathway have antiviral effects, but the underlying antiviral mechanisms are incompletely understood. We evaluated the ability of the NRF2 activators 4-octyl itaconate (4OI), bardoxolone methyl (BARD), sulforaphane (SFN), and the inhibitor of exportin-1 (XPO1)-mediated nuclear export selinexor (SEL) to interfere with influenza virus A/Puerto Rico/8/1934 (H1N1) infection of human cells. All compounds reduced viral titers in supernatants from A549 cells and vascular endothelial cells in the order of efficacy SEL>4OI>BARD = SFN, which correlated with their ability to prevent nucleo-cytoplasmic export of viral nucleoprotein and the host cell protein p53. In contrast, intracellular levels of viral HA mRNA and nucleocapsid protein (NP) were unaffected. Knocking down mRNA encoding KEAP1 (the main inhibitor of NRF2) or inactivating theNFE2L2gene (which encodes NRF2) revealed that physiologic NRF2 signaling restricts IAV replication. However, the antiviral effect of all compounds was NRF2-independent. Instead, XPO1 knock-down greatly reduced viral titers, and incubation of Calu3 cells with an alkynated 4OI probe demonstrated formation of a covalent complex with XPO1. Ligand–target modelling predicted covalent binding of all three NRF2 activators and SEL to the active site of XPO1 involving the critical Cys528. SEL and 4OI manifested the highest binding energies, whereby the 4-octyl tail of 4OI interacted extensively with the hydrophobic groove of XPO1, which binds nuclear export sequences on cargo proteins. Conversely, SEL as well as the three NRF2 activators were predicted to covalently bind the functionally critical Cys151 in KEAP1. Blocking XPO1-mediated nuclear export may, thus, constitute a “noncanonical” mechanism of anti-influenza activity of electrophilic NRF2 activators that can interact with similar cysteine environments at the active sites of XPO1 and KEAP1. Considering the importance of XPO1 function to a variety of pathogenic viruses, compounds that are optimized to inhibit both targets may constitute an important class of broadly active host-directed treatments that embody anti-inflammatory, cytoprotective, and antiviral properties.
Competition among variants is predictable and contributes to the antigenic variation dynamics of African trypanosomes
Authors: Escrivani Douglas O. , Scheidt Viktor , Tinti Michele , Faria Joana , Horn David
Published: July 2023

Several persistent pathogens employ antigenic variation to continually evade mammalian host adaptive immune responses. African trypanosomes use variant surface glycoproteins (VSGs) for this purpose, transcribing one telomeric VSG expression-site at a time, and exploiting a reservoir of (sub)telomeric VSG templates to switch the active VSG. It has been known for over fifty years that new VSGs emerge in a predictable order in Trypanosoma brucei, and differential activation frequencies are now known to contribute to the hierarchy. Switching of approximately 0.01% of dividing cells to many new VSGs, in the absence of post-switching competition, suggests that VSGs are deployed in a highly profligate manner, however. Here, we report that switched trypanosomes do indeed compete, in a highly predictable manner that is dependent upon the activated VSG. We induced VSG gene recombination and switching in in vitro culture using CRISPR-Cas9 nuclease to target the active VSG. VSG dynamics, that were independent of host immune selection, were subsequently assessed using RNA-seq. Although trypanosomes activated VSGs from repressed expression-sites at relatively higher frequencies, the population of cells that activated minichromosomal VSGs subsequently displayed a competitive advantage and came to dominate. Furthermore, the advantage appeared to be more pronounced for longer VSGs. Differential growth of switched clones was also associated with wider differences, affecting transcripts involved in nucleolar function, translation, and energy metabolism. We conclude that antigenic variants compete, and that the population of cells that activates minichromosome derived VSGs displays a competitive advantage. Thus, competition among variants impacts antigenic variation dynamics in African trypanosomes and likely prolongs immune evasion with a limited set of antigens.
Characteristics of the economic phenomenon of happiness and related aspects among the self-employed population in Lithuania
Authors: Tauraitė Viktorija , Aleksandravičienė Akvilė
Published: July 2023

This paper presents an analysis of the characteristics of the economic phenomenon of happiness and its aspects in the self-employed population in Lithuania. This mixed empirical study uses statistical data, correlational analyzes, and the X^2 criterion. The research data are collected using the methods of questionnaire survey, time diary, and semi-structured expert interview. The concept of happiness is defined based on the results of empirical analysis, which also demonstrate that in 2019 self-employed persons in Lithuania were happy and satisfied with their work and personal life. The research results also reveal that there is a statistically significant relationship between the employed population seeking to balance work and personal life and the level of happiness.
Phenomena of precarity among young graduates – Hungarian case study
Authors: Fónai Mihály , R. Fedor Anita
Published: July 2023

ABSTRACT. In our study we analyse the risk factors of precarity among young graduates. We aim to explore the characteristics that can turn young graduates towards precarity. The position of young graduates is better on the labor market than that of job seekers with lower qualification. Nevertheless, there are some risk factors that can also affect young graduates, such as the uncertainty on the labor market, and the chance and danger of falling into precarity. In this paper, different interpretations of and approaches to precarity are validated as a theoretical framework, taking into account the main theories dealing with the concept of precarity and with precarity as a class. We focus on young graduates as a group at risk of precarity, and thus also analyse the theories dealing with their situation. Our empirical investigation tests the claims of the main theories. For this purpose, we conduct a secondary analysis of the 2018 database of the Graduate Tracking System based on the responses of 15 102 recent graduates. Studies show that the risk of precariousness in Hungary is mainly shaped by the level of education and the post-graduation job. However, since no similar empirical analysis has been conducted for the country, our study is exploratory in nature, which gives it both its value in terms of novelty and its limitations.
Remote workplaces as a determinant of working conditions in education during COVID-19
Authors: Davidavićiene Vida , Rymaniak Janusz , Lis Katarzyna
Published: July 2023

ABSTRACT. The lockdown resulting from the COVID-19 epidemic forced employees of various vocational and social groups into working from home. The article presents the results of the research on the organisation of remote workstations in the education sector conducted in scope of an international remote work project. Unlike the dominant research topic in the literature (well-being, WLB), our research focuses on a newer endeavor: analysis from a workplace design perspective. Statistical methods such as structure indices and correlations were used in the research. The results presented concern the organizational level of the surveyed positions and the impact of external factors on employee preferences in scope of being sent away, including position financing, position time, and organizational efficiency. The study showed a specific profile of remote work of education employees. The results also indicate employees' expectations regarding the financing of physical space and household equipment by employers, as well as the legal regulations of the right to disconnect (R2D). These are the preconditions for the strategic, permanent use of remote work as a tool for organization and management because when working remotely, new forms of the educational function must be developed
From overtourism to no-tourism – costs and benefits of extreme volume of tourism traffic as perceived by inhabitants of two Polish destinations
Authors: Żemła Michał , R. Szromek Adam
Published: July 2023

Overtourism might be one of the most characteristic trends and phenomena of tourism in the 2010s. However, after a rapid transformation caused by overtourism, an even faster and more unexpected change appeared in 2020: due to the COVID-19 pandemic, tourism temporarily disappeared from cities and other destinations worldwide. These two opposite and extreme phenomena were so close in time that they can be compared and their perception by different tourism stakeholders can be analyzed. Host communities were often major victims of overtourism, which led to the development of anti-tourism attitudes in many destinations. However, many inhabitants were also severely affected by the recent decline in tourism, as plenty of them depended economically on tourist arrivals and tourism revenues. This research is conducted for two of the most important destinations in Poland: Kraków and Białka Tatrzańska. The study aims to compare how the transformations to and from overtourism are perceived by inhabitants of these two typical and important tourism destinations. The results show that the impact of tourism was not perceived as crucial by the residents of either destination and that this remains true for both overtourism and no-tourism. However, the economic importance of tourism was strongly emphasized. Additionally, the indicated impact of tourism on their lives and their destination was much stronger for the residents of Białka Tatrzańska than those of Kraków.
The effect of Russian unfriendly-country list and import ban: Gravity framework test
Authors: Krivko Mikhail , Kontsevaya Stanislava , Smutka Luboš
Published: July 2023

Abstract. Since 2021, Russia has maintained a list of unfriendly countries. This list and the import ban list introduced in 2014 are some of the main economic sanctions Russia uses to influence trading partners. This paper attempts to quantify the effect of putting a trading partner on the list of unfriendly countries compared to the Russian import ban. The study uses the data on trade flows between Russia and its trading partners from the UN COMTRADE database for select agri-food products. Employing a gravity framework, we argue that countries added to the unfriendly list in 2022 often had already lost a significant part of exports due to the 2014 Russian import ban introduction. Thus, such countries did not experience significant change compared to the effects of the Russian import ban. Based on this conclusion, Russia has a limited capacity to apply such retaliatory measures to Western countries regarding agri-food trade. Our results also demonstrate that the presence of the import ban drives export flows of the studied products, while the GDP of the trading partner also plays an important role, albeit with a lower magnitude.
Keywords: international trade, Russian import ban, unfriendliness, gravity model.
JEL Classification: C01, C23, F14, Q1, J10, J11