bluuebunny/crossref_metadata_2025 huggingface dataset:
Generation of a human iPSC-derived cardiomyocyte/fibroblast engineered heart tissue model
Authors: Cumberland Max J , Euchner Jonas , Azad Amar J , T N Vo Nguyen , Kirchhof Paulus , Holmes Andrew P , Denning Chris , Gehmlich Katja
Published: February 2024

Animal models have proven integral to broadening our understanding of complex cardiac diseases but have been hampered by significant species-dependent differences in cellular physiology. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have shown great promise in the modelling of cardiac diseases despite limitations in functional and structural maturity. 3D stem cell-derived cardiac models represent a step towards mimicking the intricate microenvironment present in the heart as an in vitro model. Incorporation of non-myocyte cell types, such as cardiac fibroblasts, into engineered heart tissue models (EHTs) can help better recapitulate the cell-to-cell and cell-to-matrix interactions present in the human myocardium. Integration of human-induced pluripotent stem cell-derived cardiac fibroblasts (hiPSC-CFs) and hiPSC-CM into EHT models enables the generation of a genetically homogeneous modelling system capable of exploring the abstruse structural and electrophysiological interplay present in cardiac pathophysiology. Furthermore, the construction of more physiologically relevant 3D cardiac models offers great potential in the replacement of animals in heart disease research. Here we describe efficient and reproducible protocols for the differentiation of hiPSC-CMs and hiPSC-CFs and their subsequent assimilation into EHTs. The resultant EHT consists of longitudinally arranged iPSC-CMs, incorporated alongside hiPSC-CFs. EHTs with both hiPSC-CMs and hiPSC-CFs exhibit slower beating frequencies and enhanced contractile force compared to those composed of hiPSC-CMs alone. The modified protocol may help better characterise the interplay between different cell types in the myocardium and their contribution to structural remodelling and cardiac fibrosis.
Models for the retention of duplicate genes and their biological underpinnings
Authors: Assis Raquel , Conant Gavin , Holland Barbara , Liberles David A. , O'Reilly Malgorzata M. , Wilson Amanda E.
Published: February 2024

Gene content in genomes changes through several different processes, with gene duplication being an important contributor to such changes. Gene duplication occurs over a range of scales from individual genes to whole genomes, and the dynamics of this process can be context dependent. Still, there are rules by which genes are retained or lost from genomes after duplication, and probabilistic modeling has enabled characterization of these rules, including their context-dependence. Here, we describe the biology and corresponding mathematical models that are used to understand duplicate gene retention and its contribution to the set of biochemical functions encoded in a genome.
Study of helminth eggs (Ascaris suum) inactivation by anaerobic digestion and electrochemical treatment
Authors: Patil Prajakta Pratap , Mutnuri Srikanth
Published: February 2024

Background The use of insufficiently treated wastewater or Faecal sludge in agriculture raises concerns because of the pathogen content. Helminth eggs (HE) are one of the most crucial pathogens for ensuring public health and safety. Widely used disinfection treatment methods do not guarantee the complete inactivation of helminth eggs. The current study evaluated the effectiveness of anaerobic digestion and electrochemical process on helminth (Ascaris suum) egg inactivation. Methods Lab-scale biochemical methane potential (BMP) assay was conducted by spiking A. suum eggs in a serum bottle. Total solid (TS), volatile solid (VS), pH, biogas production and its composition, and volatile fatty acids (VFA) were analyzed along with A. suum inactivation every third day for the initial 15 days and fifth day for 45 days. In the second set of experiments, a hypochlorite (4700 ppm) solution was generated by electrolysis of aqueous NaCl solution in a membrane-less electrochemical cell. The hypochlorite was diluted (940, 470, 235, and 156ppm) in wastewater, spiked with A. suum eggs and then examined for inactivation at regular intervals. Results The results of the anaerobic digestion treatment documented 98% inactivation of A. suum eggs (0.15 eggs/mL) in 35 days and remained at 0.14 eggs/mL until day 45. Correlation analysis revealed a positive relationship between non-viable eggs and pH and a negative relationship with all the other parameters. Electrochemical treatment achieved 10% inactivation at 940 ppm concentration in 24h. Conclusions This study revealed that the inactivation of A. suum eggs by anaerobic digestion or electrochemical treatment is a combined effect of more than one parameter.
A mixed methods, longitudinal study: characterizing the differences in engagement and perceived learning of medical students in online and in-person team-based learning classes
Authors: Lee Irene Cheng Jie , Wong Peiyan
Published: February 2024

Background The rapid transition to online delivery of medical curriculum has facilitated the continuation of medical education during the COVID-19 pandemic. Whilst active learning approaches, including Team-Based Learning (TBL), are generally more supportive of the learner’s needs during such transition, it remains elusive how different learning environments affect a learner’s motivation, engagement, and perceived learning over a prolonged period. We leveraged on Self-Determination Theory (SDT) and key learners’ characteristics to explore the levels of student’s engagement and perceived learning in two TBL learning environments, online and in-person, over an extended period. We hypothesize that students’ self-reported perceptions of engagement and learning will be lower in online compared to in-person TBL classes. Methods This is a mixed methods study with 49 preclinical graduate medical students completing the same questionnaire twice for each learning environment, online TBL and in-person TBL, over an eight-month period. Quantitative data were collected on learners’ characteristics, basic psychological needs satisfaction, motivation, student’s engagement and perceived learning. The final questionnaire also explored participants’ perception on which learning environment better supported their learning. Results We found that autonomy support, perceived competence and needs satisfaction, and perceived learning were higher in-person than online. Additionally, most learners felt that in-person TBL was better for learning, as the concepts of learning space and the community of practice were mediated by being in-person. Conclusions TBL, being an active instructional method, can maintain students’ engagement because it supports many aspects of SDT constructs and perceived learning. However, online TBL is unable to fully support the students’ needs and perceived learning. Hence, we strongly advocate for any in-person opportunities to be included in a course, as in-person classes best supports students’ engagement and perceived learning.
The genome sequence of the Scarlet Tiger moth, Callimorpha dominula (Linnaeus, 1758)
Authors: Boyes Douglas , Holland Peter W. H. ,   University of Oxford and Wytham Woods Genome Acquisition Lab,   Darwin Tree of Life Barcoding collective,   Wellcome Sanger Institute Tree of Life Management, Samples and Laboratory team,   Wellcome Sanger Institute Scientific Operations: Sequencing Operations,   Wellcome Sanger Institute Tree of Life Core Informatics team,   Tree of Life Core Informatics collective,   Darwin Tree of Life Consortium
Published: February 2024

We present a genome assembly from an individual male Callimorpha dominula (the Scarlet Tiger moth; Arthropoda; Insecta; Lepidoptera; Erebidae). The genome sequence is 658.1 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 15.45 kilobases in length. Gene annotation of this assembly on Ensembl identified 20,234 protein coding genes.
The genome sequence of the Top-horned Hunchback fly, Acrocera orbiculus (Fabricius, 1787)
Authors: Crowley Liam M. , Phillips Neil , Hardy Ed , McAlister Erica ,   University of Oxford and Wytham Woods Genome Acquisition Lab,   Natural History Museum Genome Acquisition Lab,   Darwin Tree of Life Barcoding collective,   Wellcome Sanger Institute Tree of Life Management, Samples and Laboratory team,   Wellcome Sanger Institute Scientific Operations: Sequencing Operations,   Wellcome Sanger Institute Tree of Life Core Informatics team,   Tree of Life Core Informatics collective,   Darwin Tree of Life Consortium
Published: February 2024

We present a genome assembly from an individual female Acrocera orbiculus (the Top-horned Hunchback fly; Arthropoda; Insecta; Diptera; Acroceridae). The genome sequence is 221.0 megabases in span. Most of the assembly is scaffolded into 5 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 18.67 kilobases in length. Gene annotation of this assembly on Ensembl identified 10,439 protein coding genes.
Medical cannabis: Mechanisms of action and therapeutic targets
Authors: Kowalczyk Klaudia , Lasek Patryk , Trąbka Natalia , Binkowska Paulina , Demidowicz Gabriela , Lasota Nina , Smerdzyński Maciej , Łach Katarzyna , Ściurka Kinga , Panuciak Kinga
Published: February 2024

Introduction: In recent years, multiple publications underscored many beneficial properties associated with medical marihuana. Its current applications encompass pain relief, multiple sclerosis, the treatment of anxiety disorders, Dravet syndrome and other. It can potentially extent to the treatment of patients with fibromyalgia or in people with diabetic complications. The expansive potential of medical cannabis in the prevention and treatment of many diseases is seen in its complex and multidirectional mechanisms of action. Medical marihuana has impact on cannabinoid receptors, and it exerts effects through many other molecular targets.
Aim of the study: This review seeks present mechanisms of action of medical marihuana and explore its potential therapeutic targets.
Materials and methods: A comprehensive review of literature available in the PubMed and Google Scholar databases was performed, using the following keywords: "medical marihuana", "medical cannabis", "medical marihuana mechanism of action", "therapeutic targets of medical marihuana", "endocannabinoid system", “medical marihuana in pain treatment”, “medical marihuana amygdala body”, “medical marihuana serotonin receptors”.
Conclusions: Medical marihuana emerges as a promising candidate in the treatment of many diseases and common condition. However, further research is imperative to ascertain the effects of the drug and transform it into an effective medication which maximizes benefits and minimalizes side effects.
Ofertas públicas de adquisición y su efecto sobre la rentabilidad de los mercados accionarios: el caso de Nutresa y sura en Colombia
Authors: Melo-Velandia Luis Fernando , Orozco-Vanegas Camilo Andrés , Parra-Amado Daniel
Published: February 2024

Se emplea un estudio de eventos en el que se evalúa si hay impactos significativos en las rentabilidades anormales del mercado accionario colombiano a partir de las ofertas públicas de adquisición (opa) realizadas sobre las empresas Nutresa y sura. Se define el evento como el 17 de enero de 2022, el cual está relacionado con la adjudicación de las primeras opa y el anuncio de una segunda ronda de estos instrumentos; se encuentra evidencia estadística de que dicho evento tuvo un efecto significativo sobre los retornos de las acciones estudiadas. En particular, se puede afirmar que, bajo las diferentes especificaciones estimadas, los retornos fueron estadísticamente distintos durante el evento respecto a aquellos que se hubieran observado en tiempos normales sin la presencia de este.
Recharging Retail: Estimating Consumer Demand Spillovers from Electric Vehicle Charging Stations
Authors: Babar Yash , Burtch Gordon
Published: February 2024

Problem definition: We estimate the impact of electric vehicle (EV) charging stations on volumes of consumer foot traffic received by nearby retail establishments. We also explore the conditions under which any effects manifest. Methodology/results: We use a differences-in-differences design, exploiting the staggered introduction of Tesla Supercharger stations across the United States. We combine data on Supercharger installations with mobile phone–based estimates of retailer foot traffic. We explore heterogeneity in the treatment effect, in terms of EV charger characteristics, visitor characteristics, establishment type, and local physical context. We estimate that establishments experience an average 4% increase in monthly visits following the installation of a Tesla Supercharger. These effects arise primarily for retailers that offer relatively quick services (e.g., fast food) and for those located very near to the charger (within 150 meters). The effects are also more pronounced when the Supercharger is one of the first EV chargers introduced into the local area. Managerial implications: We document evidence of the positive retail demand spillovers arising from EV charging station infrastructure. We also document the conditions under which the benefits manifest. Insights for EV network operators, retailers, and policymakers are included.

Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0519 .
On the Importance of Service Parts When Taking Commonality and Reliability Decisions
Authors: Driessen Joni , Arts Joachim , van Houtum Geert-Jan
Published: February 2024

Competitive Original Equipment Manufacturers (OEMs) do not only sell equipment, but also provide service contracts that ensure proper functioning and uptime of equipment after the sale. This makes OEMs responsible for a large part of an equipment’s life cycle. Therefore, OEMs aim to minimize the total life cycle costs of their equipment, in particular by commonality and reliability level decisions during the design phase. We consider these decisions for one component occurring in a family of systems. The commonality decision is about choosing a common component or dedicated components for the systems. The life cycle costs consist of design and production costs of all components, repair costs, inventory holding costs of service parts, and logistic downtime costs (i.e., downtime costs due to insufficient spare parts inventory). At many OEMs, the design department tends to exclude service parts considerations for the commonality and reliability level decisions. Excluding service parts leads to a simpler decision model, however, this may lead to non–optimal decisions. We compare two approaches for the commonality and reliability decisions: the anticipating approach, which includes inventory holding costs of service parts and logistic downtime costs, and the nonanticipating approach, which excludes these costs. Since the cost function under the anticipating approach is intractable, we first derive a cost function that approximates the actual costs via an asymptotic analysis. Next, we show that the anticipating approach selects the common component more frequently in comparison with the nonanticipating approach. For many problem instances, the nonanticipating approach leads to decisions that have a much higher overall cost than using the anticipating approach. The relative cost difference can become arbitrarily large when the family of systems consists of many systems.

Funding: J. Driessen was funded by the Netherlands Organisation for Scientific Research [Grant 407-12-001].
Pseudo-Ludwig’s angina: spontaneous sublingual haematoma elicited by warfarin
Authors: Orhun Nagihan , Ekin Utku , Sanchez Jessimar , Azzam Moh'd Hazem , Manickam Rajapriya
Published: February 2024

Spontaneous bleeding into the upper airways is a rare and potentially life-threatening complication of chronic anticoagulation. There are scarce cases in the literature demonstrating upper airway haematomas secondary to warfarin use, which is the predominant anticoagulant used by clinicians despite having a complex pharmacokinetic and pharmacodynamic profile. We report a compelling case featuring warfarin-induced sublingual haematoma, managed conservatively through the reversal of anticoagulation using fresh frozen plasma complemented by vigilant monitoring within the Intensive Care Unit (ICU).
Speech services by speech volunteers for children with cleft lip and palate in professional lacking area: Pilot study
Authors:   Department of Otorhinolaryngology, Faculty of Medicine, Khon Kaen University, Khon Kaen Province, Thailand, Prathanee Benjamas , Rattanapitak Ampika ,   Eastern Languages Department, Faculty of Humanities, Chiang Mai University, Chiang Mai Province, Thailand, Sampanthawong Tanyaratch ,   Northern Women’s Development Foundation, YMCA, Chiang Rai Building, Chiang Rai Province, Thailand, Makarabhirom Kalyanee ,   Department of Communication Sciences and Disorders, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Published: February 2024

Background: Cleft lip and cleft palate are the most common birth defects. Children with cleft lip with or without cleft palate (CP±L) face a vary of challenges, depending on the type and severity of the cleft including speech difficulty, dental problems, feeding difficulty, ear infections and hearing loss. Articulation error is the most common residual defect in children with cleft palate with or without cleft lip. Objective: To compare the numbers of pre- and post- articulation errors after using the Model of Speech Therapy by Volunteers (STV) for children with CP±L. Materials and methods: 9 children, aged range 6; 4-14; 2 years old, were included in this study and completely participated in the study. Pre- and post-articulation tests by Myanmar Articulation, Resonation, Nasal Emission and Nasal Turbulence Test were assessed at Mahamuni Monastery, and Thiriyadana Guha Pone Htoon Shan Monastery, Tachileik, Myanmar. STV is composed of a 3-day speech camp (1st month), 3 times 1-day site visits for complicated cases (2nd, 6th, and 10th months) and 3 times of 1-day follow-up speech camps (4th, 8th, and 12th months), Phonological approaches, traditional strategies, and specific techniques for speech correction in children with CP±L were taught to speech volunteers (SVs) and caregivers. Homework was assigned to SVs and caregivers. SVs provided a session of 45-minute speech correction every week. Caregivers practiced 5 sessions of 30 minutes in speech exercises /weeks at home. Results: STV revealed significant reductions in the numbers of articulation errors including articulation screening test [median difference: MD=6 (95% confident interval: CI=5.2-9.2)], and Myanmar articulation standard test at both word and sentence levels; [MD=8 (95% CI=6.5-10.8) and MD=5 (95% CI=4.2-8.3), respectively]. Conclusion: STV significantly decreased a number of articulation errors in children with CP±L of Myanmar, a professional lacking area, and could be applied in any area that has a similar situation. The result was a primary study, the further research should enroll more participants for generalization.
A vignette study analysing factors influencing attributions of responsibility to victims and perpetrators of intimate partner violence against women
Authors: Leon Carmen M. , Aizpurua Eva
Published: February 2024

Evidence shows that blaming attitudes towards victims of intimate partner violence against women (IPVAW) are widespread, creating a social climate that condones this form of violence. The aim of the current study is to analyse the potential impact of multiple factors surrounding the scenario and some personal and attitudinal characteristics of the respondents on the responsibility attributed to victims and perpetrators of IPVAW. To achieve this, a factorial survey design in which each respondent (N = 1,007; 51.1% women) received a unique vignette describing a hypothetical case of IPVAW was implemented in an online survey conducted in Spain. We found that most respondents (78.9%) indicated that the victim was not at all responsible for her own victimisation, whereas 73.7 per cent indicated that the perpetrator was very responsible for his own behaviour. Our results also show the prominent role that attitudes, as opposed to many characteristics of the abuse, play in evaluations of victim blame (that is, sexist beliefs and acceptability of IPVAW). Our findings reveal some persistence of victim-blaming attitudes despite years of public awareness and education efforts in Spain.
Difference of carrier dynamics in a semiconductor saturable absorber mirror with and without B+ ion-implantation
Authors: Wang Meng , You Si-Qi , Cheng Yu-Nuo , Liu Qing-Yu , Wang Yong-Gang , Chen Jun-Ru , Sun Yang , Lin Nan , Huang Ting , Ma Xiao-Yu
Published: February 2024

Three samples whose growth temperatures were 450°C, 500°C, and 560°C for SESAM1, SESAM2, and SESAM3, respectively, were tested by femto-second time-resolved transient absorption spectroscopy. The results indicate that the carrier dynamics of excited state absorption were dominant, and the lifetimes of carriers trapped by defect levels were about tens of pico-seconds. To further study the influence of carrier dynamics and recovery time of samples by ion-implantation, B+ ions of 80 and 130 KeV were implanted into the samples with dose of 1014/cm2. The modified samples showed a dominance of ultra-fast carrier dynamics of ground-state bleaching and direct recombination, which lasted for hundreds of femto-seconds, over excited state absorption. Additionally, carrier fast trapping was observed to be competitive with the excited state absorption process. After ion-implantation, the carrier dynamics of carrier trapping were enhanced, which contributed to forming an ultra-short laser, while the carrier dynamics of absorption of the excited state were suppressed. The conclusion that defect levels were partially eliminated by B+ ion-implantation can be drawn.
Plasmonic nano-bowls for monitoring intra-membrane changes in liposomes, and DNA-based nanocarriers in suspension
Authors: Das Sathi , Tinguely Jean-Claude , Obuobi Sybil Akua Okyerewa , Škalko-Basnet Nataša , Saxena Kanchan , Ahluwalia Balpreet Singh , Mehta Dalip Singh
Published: February 2024

Programmable nanoscale carriers, such as liposomes and DNA, are readily being explored for personalized medicine or disease prediction and diagnostics. The characterization of these nanocarriers is limited and challenging due to their complex chemical composition. Here, we demonstrate the utilization of surface-enhanced Raman spectroscopy (SERS), which provides a unique molecular fingerprint of the analytes while reducing the detection limit. In this paper, we utilize a silver coated nano-bowl shaped polydimethylsiloxane (PDMS) SERS substrate. The utilization of nano-bowl surface topology enabled the passive trapping of particles by reducing mobility, which results in reproducible SERS signal enhancement. The biological nanoparticles’ dwell time in the nano-trap was in the order of minutes, thus allowing SERS spectra to remain in their natural aqueous medium without the need for drying. First, the geometry of the nano-traps was designed considering nanosized bioparticles of 50-150 nm diameter. Further, the systematic investigation of maximum SERS activity was performed using rhodamine 6 G as a probe molecule. The potential of the optimized SERS nano-bowl is shown through distinct spectral features following surface- (polyethylene glycol) and bilayer- (cholesterol) modification of empty liposomes of around 140 nm diameter. Apart from liposomes, the characterization of the highly crosslinked DNA specimens of only 60 nm in diameter was performed. The modification of DNA gel by liposome coating exhibited unique signatures for nitrogenous bases, sugar, and phosphate groups. Further, the unique sensitivity of the proposed SERS substrate displayed distinct spectral signatures for DNA micelles and drug-loaded DNA micelles, carrying valuable information to monitor drug release. In conclusion, the findings of the spectral signatures of a wide range of molecular complexes and chemical morphology of intra-membranes in their natural state highlight the possibilities of using SERS as a sensitive and instantaneous characterization alternative.
Polarized representation for depolarization-dominant materials
Authors: Jarecki Quinn , Kupinski Meredith
Published: February 2024

The light-matter interactions which occur in common indoor environments are strongly depolarizing, but the relatively small polarization attributes can be informative. This information is used in applications such as physics-based rendering and shape-from-polarization. Look-up table polarized bidirectional reflectance distribution functions (pBRDFs) for indoor materials are available, but closed-form representations are advantageous for their ease of use in both forward and inverse problems. First-surface Fresnel reflection, diffuse partial polarization, and ideal depolarization are popular terms used in closed-form pBRDF representations. The relative contributions of these terms are highly dependent on material, albedo/wavelength, and scattering geometry. Complicating matters further, current pBRDF representations incoherently combine Mueller matrices (MM) for Fresnel and polarized diffuse terms which couples into depolarization. In this work, a pBRDF representation is introduced where first-surface Fresnel reflection and diffuse polarization are coherently combined using Jones calculus to avoid affecting depolarization. The first-surface and diffuse reflection terms are combined using an analytic function which takes as input the scattering geometry as well as geometry-independent material parameters. Agreement with wide-field-of-view polarimetric measurements is demonstrated using the new pBRDF which has only six physically meaningful parameters: the scalar-valued depolarization parameter and average reflectance which are geometry-dependent and four geometry-independent material constants. In general, depolarization is described by nine parameters but a triply-degenerate (TD) model simplifies depolarization to a single parameter. To test this pBRDF representation, the material constants for a red 3D printed sphere are assumed and the geometry-dependent depolarization parameter is estimated from linear Stokes images. The geometry-averaged error of the depolarization parameter is 4.2% at 662 nm (high albedo) and 11.7% at 451 nm (low albedo). The error is inversely proportional to albedo and depolarization, so the TD-MM model is considered appropriate for depolarization-dominant materials. The robustness of the pBRDF representation is also demonstrated by comparing measured and extrapolated Mueller images of a Stanford bunny of the same red 3D printing material. The comparison is performed by using Mueller calculus to simulate polarimetric measurements based on the measured and extrapolated data.
Characterization of optical fibers doped with nanoparticles for distributed displacement sensing
Authors: Silveira Mariana , Díaz Camilo , Avellar Letícia , Blanc Wilfried , Marques Carlos , Leal-Junior Arnaldo
Published: February 2024

High-scattering optical fibers have emerged as a key component in distributed sensing systems, primarily due to their capacity to enhance signal-to-noise ratio. This paper presents an experimental characterization of optical fibers doped with oxide nanoparticles for displacement sensing. They were manufactured using the phase-separation technique and different doping compounds, including calcium, strontium, lanthanum and magnesium. The Rayleigh backscattering (RBS) signatures in time and frequency domains were acquired using an Optical Backscatter Reflectometer (OBR). The maximum representative length, backscattering gain and strain sensitivity were evaluated. The results indicate that the fiber co-doped with magnesium and erbium chlorides offered the best compromise between strain sensitivity (0.96 pm/μϵ) and maximum length (17 m). For conditions of single and multiple perturbations, strain saturation was reached at ≥7000 μm and <1500 μm, respectively. In addition, the results reveal that, under a condition of variable temperature (30-60 °C), the sensor response becomes significantly nonlinear over length, requiring a technique for temperature cross-sensitivity mitigation that accounts for nonlinearities in sensitivity and hysteresis.
High resolution and large measurement range voltage sensing based on an optoelectronic oscillator utilizing an unbalanced Mach–Zehnder interferometer
Authors: Wu Beilei , Chen Hong , Wang Muguang , Yin Bin , Ma Jiuyang , Zhao Xiaotong , Xiao Shiying , Cai Shiyi , Yan Fengping
Published: February 2024

A voltage sensor with high resolution and large measurement range based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The key component in the cavity to select the oscillating signal is a finite impulse response (FIR)-microwave photonic filter (MPF) which consists of a sinusoidal broadband optical signal, an unbalanced Mach–Zehnder interferometer (MZI), a section of dispersion compensating fiber, and a photodetector. The center frequency of the FIR-MPF is mainly determined by the free spectral range (FSR) of the FIR-MPF. In the lower arm of the MZI, a cylindrical piezoelectric ceramic (PZT) wrapped with a section of optical fiber acts as voltage sensing head. Due to the inverse piezoelectric effect of PZT, the variation of the voltage will cause radial deformation of the cylindrical PZT and then lead to the change of the FSR of the MZI, determining the shift of center frequency of FIR-MPF as well as the frequency of the oscillating signal of the OEO. Thus, by monitoring the shift of the oscillation frequency of the OEO using an electric spectrum analyzer or a digital signal processor, a high-speed interrogation and high-resolution voltage measurement can be realized. Additionally, in the proposed scheme, an infinite impulse response (IIR)-MPF consisting of a fiber ring resonator is cascaded with the FIR-MPF to ensure the single-mode oscillation of the OEO. The experimental results show that a total range of 1700 V voltage sensing from – 200 V to 1500 V is accomplished with the voltage sensitivity of 0.25 GHz/100 V and the resolution of 0.3 V. By adjusting the proportion of the length of single mode fiber between two branches of MZI, the impact of temperature can be greatly reduced. The proposed sensor offers advantages such as a large measurement range, high resolution, high-speed interrogation, and stability to temperature disturbances, making it highly suitable for sensing applications in smart grids.
Over 3.8 W, 3.4 µm picosecond mid-infrared parametric conversion based on a simplified one-to-many scheme
Authors: Zhao Junqing , Chen Yewang , Ouyang Deqin , Liu Minqiu , Li Chunbo , Wu Xu , Xiong Xianwei , Mo Liqiang , Wang Meng , Liu Xing , Lv Qitao , Ruan Shuangchen
Published: February 2024

In this paper, we demonstrate a simplified one-to-many scheme for efficient mid-infrared (MIR) parametric conversion. Such a scheme is based on a continuous wave (CW) single longitudinal mode master oscillator power-amplifier (MOPA) fiber system as the signal source and a picosecond pulsed MOPA fiber system, exhibiting multiple longitudinal modes, as the pump source. The signal and pump beams are combined and co-coupled into a piece of 50-mm long 5% MgO-doped PPLN crystal for the parametric conversion. As high as ∼3.82 W average power at a central idler wavelength of ∼3.4 µm is achieved when the launched pump and signal powers are ∼41.73 and ∼11.45 W, respectively. Above some threshold value, the delivered idler power shows a roll-over effect against the signal power and saturation-like effect against the pump power. Consequently, the highest conversion efficiency is observed at such a threshold pump power. To the best of our knowledge, our result represents the highest average power produced from any single-pass parametric conversion source with >3 µm idler wavelength feeding with a CW signal. Moreover, our proposed scheme can simplify the design of parametric conversion system significantly and meanwhile make the system more robust in applications. This is attributed to two main aspects. Firstly, the scheme’s one-to-many feature can reduce wavelength sensitivity remarkably in the realization of quasi-phase-matching. Secondly, for moderate power requirement it does not always require a high peak power synchronized pulsed signal source; a CW one can be an alternative, thereby making the system free from complex time synchronization and the related time jitter.
High-power polarization-maintaining LP11-mode fiber laser based on long-period fiber grating for precise welding
Authors: Zhu Qixin , Shi Jianhong , Hu Huixuan , Wu Jie , Wang Zhiyuan , Xing Yinbing , Li Jinyan , Yan Dapeng , Li Cheng
Published: February 2024

An LP11-mode output all-fiber laser was presented, utilizing long-period fiber gratings (LPFGs) and polarization-maintaining optical fiber (PMF). The LPFG was designed and fabricated, achieving a 90.56% efficiency in LP01 to LP11 mode conversion. Furthermore, the transmission stability of LP11-mode in the PMF was also explored, with the spatial mode overlap ratio exceeding 0.95. Ultimately, the high-power polarization-maintaining (PM) fiber laser, capable of the LP11 mode output, was constructed, with the output power of 600 W and the beam quality M2 of 2.84. During the process of welding a thick Al-plate, the LP11 fiber laser exhibits a notable 1.88 times greater depth of fusion compared to the commercial single-mode fiber laser, when operating at the laser welding head speed of 100 mm/s. For applications demanding non-circular symmetric high-order modes, this research holds substantial potential for widespread adoption within the field of industrial processing.
Improving fourth harmonic generation performance by elevating the operation temperature of ADP crystal
Authors: Liu Guowei , Wang Zhengping , Yu Pingzhang , Ren Hongkai , Sun Xun , Xu Xinguang
Published: February 2024

In current inertial confinement fusion (ICF) facilities, potassium dihydrogen phosphate (KH2PO4, KDP) type crystals are the only nonlinear optical (NLO) materials that can satisfy the aperture requirement of the ICF laser driver. Ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystal is a typical isomer of KDP crystal, with a large nonlinear optical coefficient, high ultraviolet transmittance, and large growth sizes, which is an important deep ultraviolet (UV) NLO material. In this paper, we investigated the effect of ADP temperature on its fourth-harmonic-generation (FHG) performance. When the temperature of the ADP crystal was elevated to 48.9 °C, the 90° phase-matched FHG of the 1064 nm laser was realized. Compared with the 79° phase-matched FHG at room temperature (23.0 °C), the output energy at 266 nm, conversion efficiency, angular acceptance, and laser-induced damage threshold (LIDT) increased 113%, 71%, 623%, 19.6%, respectively. It shows that elevating ADP temperature is an efficient method to improve its deep UV frequency conversion properties, which may also be available to other NLO crystals. This discovery provides a very valuable technology for the future development of UV, deep UV lasers in ICF facilities.
Direct generation of multicolor Bessel beams from a Pr3+: WPFG fiber laser
Authors: Yoneda Yuto , Srinivasa Rao A. , Fujimoto Yasushi , Miyamoto Katsuhiko , Omatsu Takashige
Published: February 2024

Multicolor visible high-order Bessel (Bessel-vortex) beams which have a helical wavefront and a long confocal length have garnered significant interest for applications in materials processing and biomedical technologies. In this paper, we demonstrate the direct generation of multicolor (523, 605 and 637 nm) Bessel-vortex beams from a Pr3+-doped water-proof fluoro-aluminate glass (Pr3+: WPFG) fiber laser with an intracavity lens which induces chromatic and spherical aberration. The handedness of the generated Bessel-vortex beam is selectively controlled through lateral displacement of the intra-cavity lens.
Hybrid spherical array for combined volumetric optoacoustic and B-mode ultrasound imaging
Authors: Lin Hsiao-Chun Amy , Deán-Ben Xosé Luís , Ozbek Ali , Shao Yi-Hsuan , Lafci Berkan , Razansky Daniel
Published: February 2024

Optoacoustic (OA) imaging has achieved tremendous progress with state-of-the-art systems providing excellent functional and molecular contrast, centimeter scale penetration into living tissues, and ultrafast imaging performance, making it highly suitable for handheld imaging in the clinics. OA can greatly benefit from efficient integration with ultrasound (US) imaging, which remains the routine method in bedside clinical diagnostics. However, such integration has not been straightforward since the two modalities typically involve different image acquisition strategies. Here, we present a new, to our knowledge, hybrid optoacoustic ultrasound (OPUS) imaging approach employing a spherical array with dedicated segments for each modality to enable volumetric OA imaging merged with conventional B-mode US. The system performance is subsequently showcased in healthy human subjects. The new OPUS approach hence represents an important step toward establishing OA in point-of-care diagnostic settings.
Self-injection-locked optical parametric oscillator based on microcombs
Authors: Lei Fuchuan , Sun Yi , Helgason Óskar B. , Ye Zhichao , Gao Yan , Karlsson Magnus , Andrekson Peter A. , Torres-Company Victor
Published: February 2024

Narrow-linewidth yet tunable laser oscillators are one of the most
important tools for precision metrology, optical atomic clocks,
sensing, and quantum computing. Commonly used tunable coherent
oscillators are based on stimulated emission or stimulated Brillouin
scattering; as a result, the operating wavelength band is limited by
the gain media. Based on nonlinear optical gain, optical parametric
oscillators (OPOs) enable coherent signal generation within the whole
transparency window of the medium used. However, the demonstration of
OPO-based Hertz-level linewidth and tunable oscillators has remained
elusive. Here, we present a tunable coherent oscillator based on a
multimode coherent OPO in a high-Q microresonator, i.e., a
microcomb. Single-mode coherent oscillation is realized through
self-injection locking (SIL) of one selected comb line. We achieve
coarse tuning up to 20 nm and an intrinsic linewidth down to
sub-Hertz level, which is three orders of magnitude lower than the
pump. Furthermore, we demonstrate that this scheme results in the
repetition rate stabilization of the microcomb. These results open
exciting possibilities for generating tunable coherent radiation where
stimulated emission materials are difficult to obtain, and the
stabilization of microcomb sources beyond the limits imposed by the
thermorefractive noise in the cavity.
Generating synthetic population for simulating the spatiotemporal dynamics of epidemics
Authors: Zhu Kemin , Yin Ling , Liu Kang , Liu Junli , Shi Yepeng , Li Xuan , Zou Hongyang , Du Huibin
Published: February 2024

Agent-based models have gained traction in exploring the intricate processes governing the spread of infectious diseases, particularly due to their proficiency in capturing nonlinear interaction dynamics. The fidelity of agent-based models in replicating real-world epidemic scenarios hinges on the accurate portrayal of both population-wide and individual-level interactions. In situations where comprehensive population data are lacking, synthetic populations serve as a vital input to agent-based models, approximating real-world demographic structures. While some current population synthesizers consider the structural relationships among agents from the same household, there remains room for refinement in this domain, which could potentially introduce biases in subsequent disease transmission simulations. In response, this study unveils a novel methodology for generating synthetic populations tailored for infectious disease transmission simulations. By integrating insights from microsample-derived household structures, we employ a heuristic combinatorial optimizer to recalibrate these structures, subsequently yielding synthetic populations that faithfully represent agent structural relationships. Implementing this technique, we successfully generated a spatially-explicit synthetic population encompassing over 17 million agents for Shenzhen, China. The findings affirm the method’s efficacy in delineating the inherent statistical structural relationship patterns, aligning well with demographic benchmarks at both city and subzone tiers. Moreover, when assessed against a stochastic agent-based Susceptible-Exposed-Infectious-Recovered model, our results pinpointed that variations in population synthesizers can notably alter epidemic projections, influencing both the peak incidence rate and its onset.
StressME: Unified computing framework of Escherichia coli metabolism, gene expression, and stress responses
Authors: Zhao Jiao , Chen Ke , Palsson Bernhard O. , Yang Laurence
Published: February 2024

Generalist microbes have adapted to a multitude of environmental stresses through their integrated stress response system. Individual stress responses have been quantified by E. coli metabolism and expression (ME) models under thermal, oxidative and acid stress, respectively. However, the systematic quantification of cross-stress & cross-talk among these stress responses remains lacking. Here, we present StressME: the unified stress response model of E. coli combining thermal (FoldME), oxidative (OxidizeME) and acid (AcidifyME) stress responses. StressME is the most up to date ME model for E. coli and it reproduces all published single-stress ME models. Additionally, it includes refined rate constants to improve prediction accuracy for wild-type and stress-evolved strains. StressME revealed certain optimal proteome allocation strategies associated with cross-stress and cross-talk responses. These stress-optimal proteomes were shaped by trade-offs between protective vs. metabolic enzymes; cytoplasmic vs. periplasmic chaperones; and expression of stress-specific proteins. As StressME is tuned to compute metabolic and gene expression responses under mild acid, oxidative, and thermal stresses, it is useful for engineering and health applications. The modular design of our open-source package also facilitates model expansion (e.g., to new stress mechanisms) by the computational biology community.
magpie: A power evaluation method for differential RNA methylation analysis in N6-methyladenosine sequencing
Authors: Guo Zhenxing , Duan Daoyu , Tang Wen , Zhu Julia , Bush William S. , Zhang Liangliang , Zhu Xiaofeng , Jin Fulai , Feng Hao
Published: February 2024

Recently, novel biotechnologies to quantify RNA modifications became an increasingly popular choice for researchers who study epitranscriptome. When studying RNA methylations such as N6-methyladenosine (m6A), researchers need to make several decisions in its experimental design, especially the sample size and a proper statistical power. Due to the complexity and high-throughput nature of m6A sequencing measurements, methods for power calculation and study design are still currently unavailable. In this work, we propose a statistical power assessment tool, magpie, for power calculation and experimental design for epitranscriptome studies using m6A sequencing data. Our simulation-based power assessment tool will borrow information from real pilot data, and inspect various influential factors including sample size, sequencing depth, effect size, and basal expression ranges. We integrate two modules in magpie: (i) a flexible and realistic simulator module to synthesize m6A sequencing data based on real data; and (ii) a power assessment module to examine a set of comprehensive evaluation metrics.
A scoping review of the residual barriers to skilled birth attendance in Ghana: A conceptual framework and a fish bone analysis
Authors: Abredu Juliet , Dwumfour Catherine K. , Alipitio Boo , Alordey Mawusi , Dzomeku Veronica Millicent , Witter Sophie
Published: February 2024

The achievement of the Sustainable Development Goals (SDGs) targets 3.1, 3.2 and 3.3.1 is strongly dependent on the effective utilization of skilled birth services. Despite advancements made in Skilled Birth Attendance (SBA) in Ghana, there are still instances of unassisted childbirths taking place. The aim of this study was to explore the residual barriers of SBA such as community- and health system-related factors affecting SBA in Ghana and to identify strategies for addressing them. An electronic search was done using PubMed, Popline, Science direct, BioMed Central, Scopus and Google scholar for peer reviewed articles as well as grey articles from other relevant sources, published between 200 and 2022 on community- and health system related factors influencing SBA in Ghana. Out of the 89 articles retrieved for full screening, a total of 52 peer-reviewed articles and 1 grey article were selected for the final review. The study revealed that cultural practices (community factors), low quality of service delivery due to the inappropriate behaviors, lack of competency of skilled birth attendants (SBAs) as well as the inefficient distribution of SBAs contribute to ineffective uptake of SBA (health system factors). Also, indirect costs are associated with the utilization of skilled delivery care even with the existence of ‘free’ delivery care policy under the national health insurance (policy factor). For Ghana to achieve the SDGs above and improve SBA, it is essential to enhance the quality of skilled delivery care by addressing the attitude and competencies of skilled birth professionals, while plans are put in place to expand and develop the Community-based Health Planning and Services (CHPS) strategy to help address the access barriers to SBA. More so, the ‘free’ delivery care policy should absorb all the costs associated with skilled delivery for pregnant women as it is intended for.