bluuebunny/crossref_metadata_2025 huggingface dataset:
Indoor air quality at the Arab governmental girls’ schools
Authors: Elsharkawy Mahmoud Fathy , Aljassim Mohammed Tawfiq , Alsaif Abdulmalik Salman , Alsulaiman Sana Abdullah
Published: May 2024

Background A proper and adequate school environment is important for an effective learning process and maintaining the health of the students as they spend most of their time in schools. The physical school environment includes the physical structures; presence of chemicals and biological agents; and the surrounding environment, including air, water, and materials. This study aimed to evaluate the indoor air quality (IAQ) in governmental girls’ schools in the Kingdom of Saudi Arabia (KSA). Methods Seventeen girls’ schools were randomly selected in the Eastern Province of KSA. The indoor levels of PM10 and PM2.5, volatile organic compounds, CO, NO2, and CO2 were measured at different sites inside each school during four months of the year 2020. Results Levels of the six air pollutants were higher inside schools adjacent to roads with moderate traffic activity than schools with low and very low traffic activity. However, the mean level of CO2 inside the selected schools was higher than its outdoor level, suggesting the predominance of an indoor source of CO2. The levels of all measured air pollutants inside governmentally constructed school buildings were higher than those inside the rental type. Conclusion The average levels of air pollutants inside the selected schools were much lower than their air quality guidelines (AQGs), while some CO2 and NO2 levels exceeded their AQGs at some schools.
Corrosion of copper nickel titanium archwire in chlorhexidine, sodium fluoride, and chitosan mouthwashes
Authors: Sufarnap Erliera , Harahap Kholidina Imanda , Adiana Ika Devi , Lim Davin , Lim Chatty , Christy Christy
Published: May 2024

Background Copper (Cu), nickel (Ni), chromium (Cr) ion release, and surface topography change from the orthodontic wire are the initial processes of corrosion that may affect the mechanical properties of the archwire. In this study, we aim to evaluate the effect of CHX, NaF, and chitosan on the corrosion of CuNiTi wire nickel and copper ions released, surface roughness change, and archwire deflection. Methods Ninety samples of CuNiTi Tanzo™ archwires were divided into five groups according to their immersion solution: Artificial Saliva, CHX, NaF, CHX-NaF, and chitosan group. Each group was further divided into three subgroups (n=6) corresponding immersion time, i.e., two, four, and six weeks. The corrosion of the samples was analyzed with an atomic absorption spectrophotometer (AAS), scanning electron microscope (SEM), and universal testing machine (UTM). Results The amount of nickel ion releases was increasing, but the copper ion releases were reduced by the time of observations. The highest nickel ion was released in the CHX-NaF group and the lowest in the chitosan group for six-week immersion. It also corresponded to the surface topography by SEM analysis which showed the most extended cracks and deep pits in the CHX-NaF group and a smoother surface in the chitosan group. Copper ion release showed the highest ion release in the NaF group and the lowest release in the chitosan group. The unloading force of CuNiTi archwire deflection remains the same at week two and week four for all mouthwashes. Conclusion The use of mouthwashes that contained CHX, NaF, and chitosan could further alter the passive layer and cause higher nickel and copper ion release and increased CuNiTi archwire surface structure porosity. But there is no distinction between mouthwashes to release the unloading force within two until four weeks.
Assessment and impact in quality-of-life post radiotherapy in breast cancer patients treated at Acharya Vinoba Bhave Rural Hospital (AVBRH), Sawangi, 2023 - 2024
Authors: Weerarathna Induni Nayodhara , luharia anurag , uke ashish , Mishra Gaurav
Published: May 2024

Introduction The process of breast cancer treatment, especially radiation therapy, frequently alters patients’ lives significantly. It is essential to comprehend how radiation affects breast cancer survivors’ quality of life to improve their overall treatment and well-being. The quality of life among breast cancer patients treated at Acharya Vinoba Bhave Rural Hospital (AVBRH), affiliated with the University Of Datta Meghe Institute Of Higher Education and Research (DMIHER), Sawangi, following radiation therapy is examined in this study during the years 2023–2024. Methods This observational cross-sectional study will be conducted in the Department of Radiotherapy of AVBRH associated with DMIHER, the hospital is situated in the state of Maharashtra, in India, from 2023 to 2024. We will select Breast cancer patients registered in AVBRH at the Radiotherapy department from Jan 2023 to October 2023 and receive treatment in the form of radiotherapy; chemotherapy and radiotherapy. The study will be observational and cross-sectional. This research will take approximately six months. Questionnaires will be distributed on the spot to patients and phone interviews for distant patients will be conducted using an interview checklist. Discussion The study is expected to contribute significantly to the existing body of knowledge by delving into specific challenges and experiences of breast cancer survivors post-radiotherapy, particularly within the context of a rural healthcare setting. By concentrating on this group, the study will contribute to the body of existing knowledge by offering a deeper view of the variables influencing the quality of life in breast cancer survivors. The knowledge gathered from this research will be extremely helpful in understanding the complex effects of radiation therapy on the physical, psychological, and social aspects of survivors’ quality of life.
THE ERUCA SATIVA PSII OPERATING EFFICIENCY UNDER DIFFERENT MONOCHROMATIC LIGHT
Authors: Kulchin Yuriy N. , Kholin Alexander S. , Kozhanov Sergey O. , Subbotin Evgeny P. , Kovalevsky Kirill V. , Subbotina Natalia I. , Gomolsky Andrey S.
Published: May 2024

Background. Recently, to control plants development and to better understanding the plants response to various light sources, largely due to advances in industry light-emitting diodes (LEDs), it is necessary to understand the photochemical processes carrying out under impact of different factors. At the number of works authors have established a significant impact of different intensities and light spectrum on the growth and morphometric characteristics of plants. Plants growth and development depends on photochemical activity among many other factors. The range of works were carried out to assess the influence of light intensity and spectrum on the photochemical characteristics of various crops, including rocket. However, the insufficient number of works and the lack of assessment of the photosystem operating efficiency of industrially important crops grown under high light intensities became the rationale for our work.
Purpose. The main purposes of our work was to confirm the significant impact of various light treatments on the photochemical activity of plants and determine the optimal light treatments for the operating efficiency of the PSII photosystem using an industrially important crop.
Materials and methods. To reach work purposes, we measured key parameters of chlorophyll fluorescence and assessed the rocket photosynthetic activity. Plants were cultivated in phytoboxes under LEDs with three monochromatic light spectra (red (R), green (G), blue (B)). Each light spectrum treatment includes six intensities (100, 300, 500, 700, 1000, and 1400 µmol/m-2 s-1). Warm white light with an intensity of 200 µmol/m-2 s-1 was used as the control.
The chlorophyll fluorescence measurements in rocket leaves were conducted on the 28th day after sowing with Hansatech FMS 1+ pulsed fluorimeter in one day at phytoboxes. Fluorescence of actinic light-adapted leaves (Fs) and maximum fluorescence of actinic light-adapted leaves (Fm’) were measured. Statistical analysis was performed using the Microsoft Office Excel (USA).
Results. The results obtained established that the rocket photochemical apparatus responses differently to a stressful state caused by a high irradiation level under the certain spectrum. The operating efficiency of PSII for each monochromatic light treatment and specific intensity varies. Thus, it suggests different plants responses to stress caused by the particular combination of growth conditions. The level of electron transfer has the direct linear correlation with the PPFD increase.
Conclusion. Thus, irradiation intensity in the range from 100 to 500 µmol/m-2 s-1 is the most optimal for the operating efficiency of the PSII photosystem under any light spectra used in our work. The use of monochromatic blue light for rocket is probably undesirable, as it is likely caused protective mechanisms disruption of fluorescence quenching.
Investor-Paid Credit Ratings and Managerial Information Disclosure
Authors: Li Wei
Published: May 2024

Unlike issuer-paid credit rating agencies (CRAs), investor-paid CRAs are compensated by investors for providing rating services. Exploiting the staggered timing of rating initiation by an investor-paid rating agency (the Egan Jones Ratings (EJR)), I document that the coverage by EJR increases rated firm managers’ voluntary disclosure of negative news. Consistent with EJR’s rating coverage deterring managerial bad news hoarding by informing investors of downside risks, I find that the effect of EJR coverage is more pronounced when issuer-paid CRAs tend to assign inflated ratings and when rated firms’ managers have a stronger incentive to conceal bad news. I also document that firms unwind upward earnings management after being covered by EJR. In contrast, coverage by an issuer-paid CRA (Standard & Poor’s) is not associated with changes in managerial information disclosure. I conclude that investor-paid CRAs function as a type of effective information intermediary to discipline firm managers and improve corporate transparency.

This paper was accepted by Brian Bushee, accounting.

Funding: The author acknowledge financial support from the MOE Project of the Key Research Institute of Humanities and Social Science in University [Grants 22JJD790093 and 22JJD790094], the Program for Innovative Research Team of Shanghai University of Finance and Economics, and the 111 Project [Grant B18033].

Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2021.01914 .
Technological Changes and Countries’ Tax Policy Design: Evidence from Anti–Tax Avoidance Rules
Authors: Brühne Alissa I. , Jacob Martin , Schütt Harm H.
Published: May 2024

We investigate the association between technological changes and corporate tax policies in 34 OECD countries between 1996 and 2016. We use a shift-share design to capture the differential exposure of countries to U.S. technological advancements. Our study shows that countries’ antitax avoidance rules are tightened as their exposure to U.S. technological advancements increases. The tightening is particularly concentrated in countries that are larger, more exposed to intangibles, and have higher profit shifting incentives. Our findings have important implications for corporate executives as a country’s anti–tax avoidance rules are associated with foreign technological advancements.

This paper was accepted by Eric So, accounting.

Funding: A. I. Brühne and M. Jacob acknowledge funding by the Deutsche Forschungsgemeinschaft [Project-ID 403041268–TRR 266 Accounting for Transparency].

Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2021.03955 .
CEO Initial Contract Duration and Corporate Acquisitions
Authors: Chen Guoli , Huang Ronghong , Mei Shunji , Tan Kelvin Jui Keng
Published: May 2024

We examine the organizational impact of CEO initial contract duration on corporate acquisitions. We argue that CEOs with shorter initial contract durations are more likely to experience time pressure. Consequently, they are more likely to manage time by engaging in corporate mergers and acquisitions (M&As) to achieve quick growth. In addition, these CEOs are more likely to engage in straightforward deals, acquiring targets that are private, divested, related, small, and using cash payment, because these types of transactions are quicker to complete, carry less risk, and generally come with good performance prospects. Using a sample of firms that underwent new CEO appointments between 1990 and 2017 and detailed employment contract data collected from SEC filings, we find strong support for our hypotheses. In addition, we apply UK corporate governance reform to CEO contract duration as an exogenous shock to show causal evidence of such relations. This study contributes to the literature on CEO contracts, corporate acquisitions, time management and strategic leadership.

Supplemental Material: The online appendix is available at https://doi.org/10.1287/orsc.2022.16493 .
The Dynamic Pickup and Allocation with Fairness Problem
Authors: Neria Gal , Tzur Michal
Published: May 2024

Urban logistic applications that involve pickup and distribution of goods require making routing and allocation decisions with respect to a set of sites. In cases where the supply quantities and the time in which they become available are unknown in advance, these decisions must be determined in real time based on information that arrives gradually. Furthermore, in many applications that satisfy the described setting, fair allocation is desired in addition to system effectiveness. In this paper, we consider the problem of determining a vehicle route that visits two types of sites in any order: pickup points (PPs), from which the vehicle collects supplies, and demand points (DPs), to which these supplies are delivered. The supply quantities offered by each PP are uncertain, and the information on their value arrives gradually over time. We model this problem as a stochastic dynamic routing and resource allocation problem, with the aim of delivering as many goods as possible while obtaining equitable allocations to DPs. We present a Markov decision process formulation for the problem; however, it suffers from the curse of dimensionality. Therefore, we develop a heuristic framework that presents a novel combination of operations research and machine learning and is applicable for many dynamic stochastic combinatorial optimization problems. Specifically, we use a large neighborhood search (LNS) to explore possible decisions combined with a neural network (NN) model that approximates the future value given any state and action. We present a new reinforcement learning method to train the NN when the decision space is too large to enumerate. A numerical experiment with 38 to 180 site instances, based on data from the Berlin Foodbank and randomly generated data sets, confirms that the heuristic obtains solutions that are on average approximately 28.2%, 41.6%, and 57.9% better than three benchmark solutions.

Funding: This research was partially supported by the Israel Science Foundation [Grant 463/15], by the Shlomo Shmeltzer Institute for Smart Transportation at Tel Aviv University, by the Israeli Smart Transportation Research Center (ISTRC), and by the Council for Higher Education in Israel (VATAT).

Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2023.0228 .
International Nurses Day 2024: the economic power of care
Authors: Bueser Tootie
Published: May 2024

Tootie Bueser explores the wider economic contributions of nursing practice to the healthcare system, in line with the theme of this year's International Nurses Day, celebrated on 12 May.
Should all critical care patients with a central venous catheter in situ be screened for central catheter related thrombosis?
Authors: Shepherd Nicholas Martin , Carle Coralie
Published: May 2024

There are many studies on central catheter related thrombosis (CCRT), however, there are significantly fewer studies focusing on the incidence and evolution of CCRT in the adult critical care population. This article reviews data collected from observational studies that have performed bedside duplex ultrasound for surveillance of CCRT and discuss if we should routinely screen for CCRT. The reported CCRT incidence is 17–38%, with most thrombus being detectable on ultrasound within seven days of line placement. Nearly all CCRT are designated as asymptomatic (no associated pulmonary embolism (PE) or deep vein thrombosis (DVT)) and no significant changes in mortality rates amongst patients that develop CCRT were reported. Based on the evidence reviewed, we do not recommend screening routinely for CCRT in the adult critical care population.
Inequities in COVID-19-Related Patient Outcomes by Socio-Demographic Characteristics: A Scoping Review
Authors: Kaufman Michelle R. , Palmer Caroline , Hirner Sarah , Palen Lori-Ann , Asuquo Theresa , Toure Kadidiatou , Hynes Emilie C. , Dixon Julia M. , Reynolds Teri , Cooper Lisa A.
Published: May 2024

Abstract: Socio-demographic inequities in health treatment and outcomes are not new. However, the COVID-19 pandemic presented new opportunities to examine and address biases. This article describes a scoping review of 170 papers published prior to the onset of global vaccinations and treatment (December 2021). We report differentiated COVID-19-related patient outcomes for people with various socio-demographic characteristics, including the need for intubation and ventilation, intensive care unit admission, discharge to hospice care, and mortality. Using the PROGRESS-Plus framework, we determined that the most researched socio-demographic factor was race/ethnicity/culture/language. Members of minoritized racial and ethnic groups tended to have worse COVID-19-related patient outcomes; more research is needed about other categories of social disadvantage, given the scarcity of literature on these factors at the time of the review. It is only by researching and addressing the causes of social disadvantage that we can avoid such injustice in future public health crises.
Predictors of Incident Stroke and Subsequent Mortality Among a Sample of Veterans with Experience of Housing Instability
Authors: Lin Chen , DeRussy Aerin J. , Richman Joshua S. , Montgomery Ann Elizabeth
Published: May 2024

Abstract: Homelessness is associated with poor health outcomes and early development of cardiovascular disease. This study investigated the correlates of incident stroke and its association with mortality among Veterans experiencing housing instability. Using a national sample of Veterans (n=565,608) with incident housing instability between 2014–2018, we compared characteristics of Veterans who did and did not experience incident stroke and conducted logistic regressions to assess two outcomes: incident stroke and mortality. Almost four percent experienced a first stroke and were more frequently male, older than 55 years, Black, and non-Hispanic. A higher rate of mortality was observed among those with a first stroke compared with those with no stroke (17.6% vs. 10.8%), although the difference was not statistically significant. Incident stroke was associated with triple the odds of death among unstably-housed Veterans compared with those who did not have an incident stroke. Implications include the need to screen and monitor for stroke risk among Veterans with experience of housing instability, particularly for those who are older.
The Effect of Patient-Physician Concordance on Perinatal Care: The Family Physicians' Perspective
Authors: Barreto Tyler W. , Taylor Melina K. , Goldstein Jessica Taylor , Walters Grace , Eden Aimee R.
Published: May 2024

Abstract: Demographic concordance between patients and clinicians has been associated with better outcomes. The current perinatal care workforce is not adequately diverse to allow for patient-clinician concordance. In this mixed-methods study, we aimed to understand family physicians' perception of the impact of patient-clinician concordance on perinatal care. The predominantly (91%) non-Hispanic White sample of 1,505 family physicians (FPs) perceived gender and language concordance to affect perinatal care more than racial or ethnic concordance. Religious concordance is not perceived to greatly affect perinatal care. Nearly half (721) of the respondents chose to leave a free-text comment on the impact of concordance on perinatal care. Four categories emerged (patients, physicians, the patient-physician relationship, and potential ways to mitigate the impact of discordance). Based on the perceptions of FPs experienced in perinatal care, intentionally supporting continuity of care between patients and clinicians may help to mitigate the negative impact of discordance on perinatal outcomes.
Attitudes towards Telemedicine among Pregnant People and Parents of Toddlers in an Urban Safety-net Setting
Authors: Bachiller Karla , Devera Jean L. , Zapata Lesly P. , Zimmerman Margaux , Hall Taylor A. , Casey Sharon M. , Pierre-Joseph Natalie , Perkins Rebecca B.
Published: May 2024

Abstract: Objective. To understand attitudes towards telemedicine and to further elucidate benefits, disadvantages, and visit preferences in a largely minority, urban safety-net setting. Methods. Between 2020 and 2021, pregnant people, and parents of children younger than two years old were recruited from outpatient clinics. Interviews were conducted via phone, recorded, transcribed, and translated. Data were analyzed using content analysis. Results. Seventy-four (74) individuals participated including 42 pregnant people and 32 parents. Most participants cited advantages to telemedicine including safety, convenience, improved access, and less disruption of work schedules, and wished to continue to have the telemedicine option available after the pandemic. Conclusions. Patients seeking care in safety-net settings, many of whom are working parents, noted that telemedicine improves access to care by providing an efficient and accessible option that overcomes barriers related to transportation and work schedules. Their experiences highlight the importance of continuing to offer telemedicine services.
Women's Preventive Services Utilization in Illinois in the Aftermath of the ACA and the COVID-19 Pandemic
Authors: Handler Arden , Pham Trang Ngoc Doam , Rankin Kristin
Published: May 2024

Abstract: This study explores the association between health system changes over the last decade and women's preventive care utilization in Illinois. A cross-sectional analysis using Illinois Behavioral Risk Factor Surveillance System (BRFSS) data from 2012–2020 among women aged 21–75 (n=21,258) examined well-woman visit (WWV) receipt and breast and cervical cancer screening overall and over several time periods. There was an increase in the prevalence of receiving a WWV for Illinois women overall from 2012–2020. However, the overall adjusted prevalence difference was only significant for the 2020 versus 2015–2019 comparison and not for 2015–2019 versus 2012–2014. The COVID-19 pandemic was not associated with a decrease in the prevalence of mammogram use but was manifest for cervical cancer screening, particularly for Black women. Finally, those reporting having a WWV in the past year had a significantly higher prevalence of being up to date with screening compared with those not reporting a WWV.
How We Found Consensus on Pediatric Decision-Making and Why It Matters
Authors: Salter Erica K. , Ross Lainie Friedman , Hester D. Micah
Published: May 2024

ABSTRACT: This article describes the process engaged by 17 expert scholars in the development of a set of six consensus recommendations about the normative foundations of pediatric decision-making. The process began with a robust pre-reading assignment, followed by three days of in-person symposium discussions that resulted in a publication in Pediatrics entitled “Pediatric Decision-Making: Consensus Recommendations” (Salter et al. 2023). This article next compares the six recommendations to existing statements about pediatric decision-making (specifically those developed by the American Academy of Pediatrics), highlighting similarities and differences. Finally, the article discusses the value of finding consensus in the field of pediatric bioethics.
Predictive ultrafast laser-induced formation of MoOx using machine learning algorithms
Authors: Cano-Lara M. , Espinal-Jimenez A. , Camacho-López S. , Garcia-Granada A. A. , Rostro-Gonzalez H.
Published: May 2024

This research introduces an innovative methodology leveraging machine
learning algorithms to predict the outcomes of experimental and
numerical tests with femtosecond (fs) laser pulses on 500-nm-thick
molybdenum films. The machine learning process encompasses several
phases, including data acquisition, pre-processing, and prediction.
This framework effectively simulates the interaction between fs laser
pulses and the surface of molybdenum thin films, enabling precise
control over the creation of MoO
x
phases. The exceptional precision of
fs laser pulses in generating molybdenum oxides at localized
micrometer scales is a significant advantage. In this study, we
explored and evaluated 13 different machine learning methods for
predicting oxide formation results. Our numerical results indicate
that the extra trees (ET) and gradient boosting (GB) algorithms
provide the best performance in terms of mean squared error, mean
absolute error, and R-squared values: 48.44, 3.72, and 1.0 for ET and
32.25, 3.72, and 1.0 for GB. Conversely, support vector regression
(SVR) and histogram gradient boosting (HGB) performed the worst, with
SVR yielding values of 712.48, 15.27, and 0.163 and HGB yielding
values of 434.29, 16.37, and 0.548. One of the most significant
aspects of this research is that training these algorithms did not
require hyperparameter optimization, and the training and validation
process only needed 54 experimental samples. To validate this, we used
a technique known as leave-one-out cross-validation, which is a robust
validation method when the available data is limited. With this
research, we aim to demonstrate the capability of machine learning
algorithms in applications where data is limited due to the high cost
of real experimentation, as is often the case in the field
of optics.
Adaptive compound control of laser beam jitter in deep-space optical communication systems
Authors: Su Yunhao , Han Junfeng , Wang Xuan , Ma Caiwen , Wu Jianming
Published: May 2024

In deep-space optical communication systems, precise pointing and aiming of the laser beam is essential to ensure the stability of the laser link. In this paper, an adaptive compound control system based on adaptive feedforward and Proportional-Integral-Differentiation (PID) feedback is proposed. The feedforward controller is stabilized using Youla-Kucera (YK) parameterization. In the YK parameterized structure, the free parameter Q(z) consists of an adaptive filter. The proposed method constitutes an adaptive feedforward control algorithm through the adaptive filter Q(z). The problem of suppressing laser jitter is transformed into a problem of minimizing a sensitivity function containing the adaptive filter. The stability of the compound control system is ensured by configuring the individual parameters of the YK parameterized feedforward controller and the PID controller, and the adaptive regulation of the controller is realized on the premise of system stability. To verify the effectiveness of the compound control system, we established an experimental platform for laser beam stabilization control. We experimentally compare the effectiveness of the proposed control method with the classical method. The experimental results show that the method proposed in this paper can effectively suppress the complex laser beam jitter consisting of narrow-band sinusoidal and broad-band continuous vibrations.
Iterative algorithm computational spectrometer based on a single-hidden-layer neural network
Authors: Zheng Yuanhao , Liao Haojie , Yang Lin , Chen Yao
Published: May 2024

Computational spectrometers have great application prospects in hyperspectral detection, and fast and high-precision in situ measurement is an important development trend. The computational spectrometer based on iterative algorithms has low requirements for computational resources and is easy to achieve hardware integration and in situ measurement. However, iterative algorithms are difficult to achieve high reconstruction accuracy due to the ill-posed nature of problems. Neural networks have powerful learning capabilities and can achieve high-precision spectral reconstruction. However, solely relying on neural network algorithms for reconstruction requires higher storage space and computing power from hardware devices, which makes it difficult to integrate large-scale neural network models into embedded systems. We propose using neural networks to alleviate the effect of the problem ill-posedness on the reconstruction results of iterative algorithms, so as to improve the reconstruction accuracy of the iterative algorithm computational spectrometers. First, spectral reconstruction was performed with iterative algorithms using a public spectral dataset. Then, a single-hidden-layer neural network was trained to establish a fitting relationship between the iterative algorithm spectral reconstruction results and the original spectrum. Finally, simulation and experimental results show that the proposed application of neural networks to alleviate the ill-posed problem of the iterative algorithm spectral reconstruction can effectively improve the reconstruction accuracy of iterative algorithm computational spectrometers with low computational resources. The research results may have good potential in achieving fast and high-precision in situ measurements of computational spectrometers.
Subwavelength and broadband on-chip mode splitting with shifted junctions
Authors: Haines Jack , Naik Pooja Uday , Ji Kunhao , Vitali Valerio , Franz Yohan , Petropoulos Periklis , Guasoni Massimiliano
Published: May 2024

We design and fabricate a sub-wavelength on-chip mode splitter based on the implementation of a shifted junction between a single-mode waveguide and a multimode waveguide. A proper choice of the device parameters enables to split the input beam into a combination of different guided modes of the multimode waveguide, minimizing radiation and reflection losses that amount to ∼ 0.4 dB in our experiments. Because the splitting mechanism does not rely on phase-matching, we achieve broadband operation that could exceed 200 nm bandwidth (<0.5 dB splitting variation). This approach ensures temporal and phase synchronization among the output modes, with applications spanning from the emergent multimode photonics platform to traditional single-mode photonics operations.
Generation of subnatural-linewidth orbital angular momentum entangled biphotons using a single driving laser in hot atoms
Authors: Ma Jiaheng , Wang Chengyuan , Li Bingbing , Chen Yun , Yang Ye , Wang Jinwen , Yang Xin , Qiu Shuwei , Gao Hong , Li Fuli
Published: May 2024

Orbital angular momentum (OAM) entangled photon pairs with narrow bandwidths play a crucial role in the interaction of light and quantum states of matter. In this article, we demonstrate an approach for generating OAM entangled photon pairs with a narrow bandwidth by using a single driving beam in a 85Rb atomic vapor cell. This single driving beam is able to simultaneously couple two atomic transitions and directly generate OAM entangled biphotons by leveraging the OAM conservation law through the spontaneous four-wave mixing (SFWM) process. The photon pairs exhibit a maximum cross-correlation function value of 27.7 and a linewidth of 4 MHz. The OAM entanglement is confirmed through quantum state tomography, revealing a fidelity of 95.7% and a concurrence of 0.926 when compared to the maximally entangled state. Our scheme is notably simpler than previously proposed schemes and represents the first demonstration of generating subnatural-linewidth entangled photon pairs in hot atomic systems.
Integration of O-band quantum dot lasers with AlGaN/GaN waveguides
Authors: O’Brien Megan , Maraviglia Nicola , Uzun Ali , Arafat Yeasir , Zubialevich Vitaly , Genc Muhammet , Li Zhi , Roycroft Brendan , O’Callaghan James , Parbrook Peter J. , Corbett Brian
Published: May 2024

We integrate edge-emitting etched-facet InAs/GaAs quantum dot (QD) lasers to an AlGaN/GaN-on-sapphire waveguide platform via micro-transfer printing. The lasers are placed into a trench etched into the sapphire substrate so as to transversely align the waveguides. The AlGaN/GaN waveguide structure is designed to allow for tolerant alignment of the active lasing mode to the passive waveguide mode. 4 μm wide waveguides show a TE propagation loss of 4.5 dB/cm. For a QD laser with a 1.2 mm long cavity and 3.5 μm wide ridge waveguide, 2.3 mW was measured at 80 mA under continuous wave conditions from the end of a 0.64 cm long 4 μm wide waveguide with an estimated coupling efficiency of >20 %. The measured coupled output power is 1.5 mW at 70°C and 100 mA. To our knowledge, this is the first demonstration of the heterogeneous integration of a GaAs lasing device to a GaN-based PIC by any means. The results show real promise for GaN to be a suitable platform for integrated photonics applications requiring O-band operation.
Mid-infrared tunable filter based on a femtosecond-written silica volume Bragg grating
Authors: Talbot Lauris , Per Siems Malte , Richter Daniel , David Nicolas , Blais-Ouellette Sébastien , Nolte Stefan , Bernier Martin
Published: May 2024

A silica volume Bragg grating (VBG) is used to filter the light of a mid-infrared (mid-IR) supercontinuum laser. The VBG with a 7 µm period was inscribed with 800 nm pulses with a 100 fs duration and the phase-mask technique over a glass thickness of 3 mm. Despite silica’s absorption, the VBG allows obtaining a narrowband light source tunable from 2.9 to 4.2 µm with a full width at half maximum (FWHM) of 29 nm. This demonstrates the great potential of using femtosecond-written VBGs as highly tunable, yet selective, spectral filters in the mid-IR.
Microcavity induced by a few-layer GaSe crystal on a silicon photonic crystal waveguide for efficient optical frequency conversion
Authors: Chen Xiaoqing , Zhang Yanyan , Ji Yingke , Zhang Yu , Wang Jianguo , Wu Xianghu , Zhao Chenyang , Fang Liang , Jiang Biqiang , Zhao Jianlin , Gan Xuetao
Published: May 2024

We demonstrate the post-induction of high-quality microcavities on a silicon photonic crystal (PC) waveguide by integrating a few-layer GaSe crystal, which promises efficient on-chip optical frequency conversions. The integration of GaSe shifts the dispersion bands of the PC waveguide mode into the bandgap, resulting in localized modes confined by the bare PC waveguides. Thanks to the small contrast of refractive index at the boundaries of the microcavity, it is reliable to obtain quality factors exceeding 104. With the enhanced light–GaSe interaction by the microcavity modes and GaSe’s high second-order nonlinearity, remarkable second-harmonic generation (SHG) and sum-frequency generation (SFG) are achieved with continuous-wave (CW) lasers.
2 × 2 MIMO dual spiral octagonal prism liquid DRA with snake-shaped DGS for OAM multiplexing
Authors: Zhang Gaoji , Wang Zhe , Yu Zhong , Nie Haitao , Chen Xue , Zhang Haotian
Published: May 2024

In this paper, we proposed a 2 × 2 multiple-input multiple-output (MIMO) dual spiral octagonal prism liquid dielectric resonator antenna (DRA) with snake-shaped defective ground structure (DGS) for space multiplexing of orbital angular momentum (OAM). The DRA element adopts an inner and outer nested dual spiral structure filled with 0.035 g/ml of brine outside and a cylinder filled with distilled water inside. The proposed MIMO antenna can generate resonance at 1.78–3.02 GHz and 4.01–7.73 GHz (S11≤−10 dB). The isolation among ports is below −20 dB at 2.6 GHz and below −40 dB at 5.1 GHz, which can effectively isolate the l = ±1 and l = ±3 modes’ OAM waves through the snake-shaped DGS. The proposed MIMO antenna improves spectral efficiency by OAM spatial multiplexing with l = ±1 and l = ±3 modes’ OAM, which improves the data transmission efficiency. The proposed MIMO antenna provides a novel, to the best of our knowledge, solution for wireless communications to improve spectral efficiency.
Orbital Hall diffraction and its application for vortex measurement
Authors: Zhao Lu , Chen Yiting , Zhang Jianwei
Published: May 2024

We observe significant orbital angular momentum (OAM)-helicity-dependent centroid shifts in the Fraunhofer patterns for the far-field diffraction of optical vortex beams passing through a thin single wire, thus suggesting the orbital Hall effect (OHE) of light in diffraction. Based on the OHE with a thin cross wire, we further experimentally develop a compact and robust alignment-free method to measure the OAM states of light. These findings indicate that not only does the OHE of light offer insights into vortex diffraction with broken rotational symmetry, it may also provide a reliable and efficient way to simplify the vortex measurement for waves of different natures.
Photonic stepped-frequency radar with 150-m unambiguous detection and centimeter range resolution
Authors: Zhang Ziqian , Liu Yang , Magi Eric , Eggleton Benjamin J.
Published: May 2024

Photonic stepped-frequency radars based on optical frequency-shifting modulation have shown attractive properties such as wide bandwidth, centimeter range resolution, inherent frequency-time linearity with low spectrum spurs, and reduced system complexity. However, existing approaches typically exhibit meter- or centimeter-level radar range ambiguity, inversely proportional to the frequency step, due to the large frequency shift determined by acousto-optic or electro-optic (EO) modulators. Here, we overcome this limitation by injecting a narrowband, stepped-frequency signal into an optical frequency-shifting fiber cavity to achieve, for the first time, to our knowledge, a broadband photonic stepped-frequency radar with 150-m unambiguous detection and centimeter range resolution, surpassing the reported photonic- and electronic-based counterparts. The demonstrated approach effectively resolves the trade-off between ambiguity range and shifting frequency while maintaining the signal quality and bandwidth, bringing its practicality into reach for outdoor applications.
Microbe transmission from pet shop to lab-reared zebrafish reveals a pathogenic birnavirus
Authors: Rice Marlen C. , Janik Andrew J. , Elde Nels C. , Gagnon James A. , Balla Keir M.
Published: May 2024

Zebrafish are popular research organisms selected for laboratory use due in part to widespread availability from the pet trade. Many contemporary colonies of laboratory zebrafish are maintained in aquaculture facilities that monitor and aim to curb infections that can negatively affect colony health and confound experiments. The impact of laboratory control on the microbial constituents associated with zebrafish in research environments compared to the pet trade are unclear. Diseases of unknown causes are common in both environments. We conducted a metatranscriptomic survey to broadly compare the zebrafish-associated microbes in pet trade and laboratory environments. We detected many microbes in animals from the pet trade that were not found in laboratory animals. Cohousing experiments revealed several transmissible microbes including a newly described non-enveloped, double-stranded RNA virus in the Birnaviridae family we name Rocky Mountain birnavirus (RMBV). Infections were detected in asymptomatic animals from the pet trade, but when transmitted to laboratory animals RMBV was associated with pronounced antiviral responses and hemorrhagic disease. These experiments highlight the pet trade as a distinct source of diverse microbes that associate with zebrafish and establish a paradigm for the discovery of newly described pathogenic viruses and other infectious microbes that can be developed for study in the laboratory.
Structure and activity of the septal peptidoglycan hydrolysis machinery crucial for bacterial cell division
Authors: Chen Yatian , Gu Jiayue , Yang Biao , Yang Lili , Pang Jie , Luo Qinghua , Li Yirong , Li Danyang , Deng Zixin , Dong Changjiang , Dong Haohao , Zhang Zhengyu
Published: May 2024

The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive bacteria. The hydrolysis of septal PG (sPG) is a crucial step of bacterial cell division, facilitated by FtsEX through an amidase activation system. In this study, we present the cryo-EM structures of Escherichia coli FtsEX and FtsEX-EnvC in the ATP-bound state at resolutions of 3.05 Å and 3.11 Å, respectively. Our PG degradation assays in E. coli reveal that the ATP-bound conformation of FtsEX activates sPG hydrolysis of EnvC-AmiB, whereas EnvC-AmiB alone exhibits autoinhibition. Structural analyses indicate that ATP binding induces conformational changes in FtsEX-EnvC, leading to significant differences from the apo state. Furthermore, PG degradation assays of AmiB mutants confirm that the regulation of AmiB by FtsEX-EnvC is achieved through the interaction between EnvC-AmiB. These findings not only provide structural insight into the mechanism of sPG hydrolysis and bacterial cell division, but also have implications for the development of novel therapeutics targeting drug-resistant bacteria.
Understanding glioblastoma at the single-cell level: Recent advances and future challenges
Authors: Yabo Yahaya A , Heiland Dieter Henrik
Published: May 2024

Glioblastoma, the most aggressive and prevalent form of primary brain tumor, is characterized by rapid growth, diffuse infiltration, and resistance to therapies. Intrinsic heterogeneity and cellular plasticity contribute to its rapid progression under therapy; therefore, there is a need to fully understand these tumors at a single-cell level. Over the past decade, single-cell transcriptomics has enabled the molecular characterization of individual cells within glioblastomas, providing previously unattainable insights into the genetic and molecular features that drive tumorigenesis, disease progression, and therapy resistance. However, despite advances in single-cell technologies, challenges such as high costs, complex data analysis and interpretation, and difficulties in translating findings into clinical practice persist. As single-cell technologies are developed further, more insights into the cellular and molecular heterogeneity of glioblastomas are expected, which will help guide the development of personalized and effective therapies, thereby improving prognosis and quality of life for patients.
The evolution of environmentally mediated social interactions and posthumous spite under isolation by distance
Authors: Mullon Charles , Peña Jorge , Lehmann Laurent
Published: May 2024

Many social interactions happen indirectly via modifications of the environment, e.g. through the secretion of functional compounds or the depletion of renewable resources. Here, we derive the selection gradient on a quantitative trait affecting dynamical environmental variables that feed back on reproduction and survival in a finite patch-structured population subject to isolation by distance. Our analysis shows that the selection gradient depends on how a focal individual influences the fitness of all future individuals in the population through modifications of the environmental variables they experience, weighted by the neutral relatedness between recipients and the focal. The evolutionarily relevant trait-driven environmental modifications are formalized as the extended phenotypic effects of an individual, quantifying how a trait change in an individual in the present affects the environmental variables in all patches at all future times. When the trait affects reproduction and survival through a payoff function, the selection gradient can be expressed in terms of extended phenotypic effects weighted by scaled relatedness. We show how to compute extended phenotypic effects, relatedness, and scaled relatedness using Fourier analysis, which allow us to investigate a broad class of environmentally mediated social interactions in a tractable way. We use our approach to study the evolution of a trait controlling the costly production of some lasting commons (e.g. a common-pool resource or a toxic compound) that can diffuse in space and persist in time. We show that indiscriminate posthumous spite readily evolves in this scenario. More generally, whether selection favours environmentally mediated altruism or spite is determined by the spatial correlation between an individual’s lineage and the commons originating from its patch. The sign of this correlation depends on interactions between dispersal patterns and the commons’ renewal dynamics. More broadly, we suggest that selection can favour a wide range of social behaviours when these have carry-over effects in space and time.
Paramutation at the maize pl1 locus is associated with RdDM activity at distal tandem repeats
Authors: Deans Natalie C. , Talbot Joy-El R. B. , Li Mowei , Sáez-González Cristian , Hövel Iris , Heavens Darren , Stam Maike , Hollick Jay B.
Published: May 2024

Exceptions to Mendelian inheritance often highlight novel chromosomal behaviors. The maize Pl1-Rhoades allele conferring plant pigmentation can display inheritance patterns deviating from Mendelian expectations in a behavior known as paramutation. However, the chromosome features mediating such exceptions remain unknown. Here we show that small RNA production reflecting RNA polymerase IV function within a distal downstream set of five tandem repeats is coincident with meiotically-heritable repression of the Pl1-Rhoades transcription unit. A related pl1 haplotype with three, but not one with two, repeat units also displays the trans-homolog silencing typifying paramutations. 4C interactions, CHD3a-dependent small RNA profiles, nuclease sensitivity, and polyadenylated RNA levels highlight a repeat subregion having regulatory potential. Our comparative and mutant analyses show that transcriptional repression of Pl1-Rhoades correlates with 24-nucleotide RNA production and cytosine methylation at this subregion indicating the action of a specific DNA-dependent RNA polymerase complex. These findings support a working model in which pl1 paramutation depends on trans-chromosomal RNA-directed DNA methylation operating at a discrete cis-linked and copy-number-dependent transcriptional regulatory element.