bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral Pulsations of Dissipative Solitons in Ultrafast Fiber Lasers: Period Doubling and Beyond
Authors: Wang Zhiqiang , Coillet Aurélien , Hamdi Saïd , Zhang Zuxing , Grelu Philippe 
Published: February 2023

AbstractPeriod doubling is a universal bifurcation of central importance in all disciplines of nonlinear science, which generally signals the existence of chaotic dynamics in the vicinity of the system parameters. Although observed in diverse ultrafast laser configurations, there is still no consensus on its physical origin. Real‐time spectral characterization techniques have recently allowed revisiting pulsating dynamics, from period‐2 to long‐period pulsations. Following a contextual review, this article presents a variety of bifurcation sequences entailing the spectral pulsations of dissipative solitons. These experiments, using ultrafast fiber lasers operated in both chromatic dispersion regimes, are confronted with numerical simulations to demonstrate that self‐phase modulation represents a general mechanism triggering period‐2 bifurcations. In addition, by ramping up the pump power, original sequences of period‐doubling bifurcations intertwined with more complex bifurcations are presented, where entrainment phenomena are unveiled. These findings provide a more general understanding of the period‐doubling bifurcation in ultrafast laser systems while highlighting their potentially intricate combinations with complex bifurcations, which may be exclusively observable from the spectral domain.
Terahertz Semiconductor Dual‐Comb Sources with Relative Offset Frequency Cancellation
Authors: Li Ziping , Ma Xuhong , Zhou Kang , Liu Binbin , Wang Chenjie , Liao Xiaoyu , Guan Wen , Wu Shumin , Liu Han , Zhang Zhenzhen , Cao J. C. , Li Min , Yan Ming , Zeng Heping , Li Hua 
Published: February 2023

AbstractA dual‐comb source, employing two frequency combs with a slight difference in repetition frequencies, shows unique advantages in high precision spectroscopy, imaging, ranging, communications, and so on. In the terahertz (THz) frequency range, the electrically pumped quantum cascade laser (QCL) offers the possibility of realizing a compact dual‐comb source due to its semiconductor‐based chip‐scale configuration. Although dual‐comb operation of THz QCLs has been experimentally demonstrated, a full stabilization of THz dual‐comb sources is still challenging. Here, a self‐reference method is proposed for a pure THz QCL system. Without using any external locking components, one dual‐comb line is filtered out and it is beaten with the whole dual‐comb signal, which eliminates the common carrier offset frequency noise and reduces the dual‐comb repetition frequency noise. It is demonstrated that the self‐reference technique can significantly improve the long‐term stability of the dual‐comb signal. A record “maxhold” linewidth of 14.8 kHz (60 s) is obtained by implementing the self‐reference technique, while without the self‐reference, the dual‐comb lines show a “maxhold” linewidth of 2 MHz (15 s). The method provides the simplest way to improve the long‐term stability of THz QCL dual‐comb sources, which can be further adopted for various measurements.
Ray Engineering from Chaos to Order in 2D Optical Cavities
Authors: Xu Chenni , Wang Li‐Gang , Sebbah Patrick 
Published: February 2023

AbstractChaos, namely exponential sensitivity to initial conditions, is generally considered a nuisance, inasmuch as it prevents long‐term predictions in physical systems. Here, an easily accessible approach to undo deterministic chaos and tailor ray trajectories in arbitrary 2D optical billiards by introducing spatially varying refractive index therein is presented. A new refractive index landscape is obtained by a conformal mapping, which makes the trajectories of the chaotic billiard fully predictable and the billiard fully integrable. Moreover, trajectory rectification can be pushed a step further by relating chaotic billiards with non‐Euclidean geometries. Two examples are illustrated by projecting billiards built on a sphere as well as the deformed spacetime outside a Schwarzschild black hole, which respectively lead to all periodic orbits and spiraling trajectories remaining away from the boundaries of the transformed 2D billiards/cavities. An implementation of this method is proposed, which enables real‐time control of chaos and can further contribute to a wealth of potential applications in the domain of optical microcavities.
Rare‐Earth‐Ion Doped Bi1.5ZnNb1.5O7 Photochromics: A Fast Self‐Recoverable Optical Storage Medium for Dynamic Anti‐Counterfeiting with High Security
Authors: Li Xuefeng , Lin Hang , Lin Shisheng , Li Peng , Wang Pengfei , Xu Ju , Cheng Yao , Zhang Qiwei , Wang Yuansheng 
Published: February 2023

AbstractConventional inorganic photochromic (PC) anti‐counterfeiting material generally require time‐consuming identification of information or response to changes in display information, resulting in low‐level readout and decoding efficiency. In this study, a new type of inorganic PC self‐bleaching material, i.e., rare‐earth‐ion‐doped Bi1.5ZnNb1.5O7 (BZN) ceramic and corresponding mono‐/bi‐crystalline‐phase glass ceramic (GC) composite, are developed. The as‐prepared materials reveal maximum self‐recovery levels of the PC and the PC modulated upconversion luminescence ≈96.61% and 99.55%, respectively, and the self‐bleaching times are less than 20 min to the naked eyes. Unlike conventional thoughts of electrons’ trapping/detrapping with the aid of conduction band/valence band transportation, a new PC mechanism for ferroelectric oxides, involving the state exchanges between defects and color centers via direct electron transfer, is proposed. The proof‐of‐concept experiments demonstrate the unparalleled potentials offered by the self‐driven‐recovery BZN‐based bi‐crystalline‐phase GC composite for encoding, displaying, and erasing of time‐dependent information. The brought dynamical anti‐counterfeiting based on multimode optical storage favors to achieve complexity and concealment of the encrypted information to meet high‐security standard. This finding offers unique insight for designing integrated stimuli‐responsive and time‐dependent smart devices, particularly advanced anti‐counterfeiting technology.
Electro‐Optically Tunable Low Phase‐Noise Microwave Synthesizer in an Active Lithium Niobate Microdisk
Authors: Gao Renhong , Fu Botao , Yao Ni , Guan Jianglin , Zhang Haisu , Lin Jintian , Li Chuntao , Wang Min , Qiao Lingling , Cheng Ya 
Published: February 2023

AbstractPhotonic‐based low‐phase‐noise microwave generation with real‐time frequency tuning is crucial for a broad spectrum of subjects, including next‐generation wireless communications, radar, metrology, and modern instrumentation. Here, for the first time to the best of the authors’ knowledge, narrow‐bandwidth dual‐wavelength microlasers are generated from nearly‐degenerate polygon modes in a high‐Q active lithium niobate microdisk. The record‐high‐Q (≈107) nearly‐degenerate polygon modes formation with independently controllable resonant wavelengths and free spectral ranges is enabled by the weak perturbation of the microdisks using a tapered fiber. Moreover, because a high spatial overlap factor between the pump and the dual‐wavelength laser modes is achieved, the gain competition between the two lasing modes spatially separated with a π‐phase difference is suppressed, leading to stable dual‐wavelength laser generation with low threshold, and in turn, the low noise microwave source. The stable beating signal confirms the low phase‐noise achieved in the tunable laser. Without the need of external phase stabilizers, the measured microwave signal shows a phase noise of −123 dBc Hz−1 and an electro‐optic tuning efficiency of −1.66 MHz V−1. The linewidth of the microwave signal is measured as 6.87 kHz, which is more than three orders of magnitude narrower than current records based on integrated dual‐lasers.
Light‐Matter Interactions Revealing Load‐Induced Phase Mobility in Elastomers
Authors: Huynh Nha Uyen , Koohbor Behrad , Youssef George 
Published: February 2023

AbstractElastomers with segmental microstructure are a fascinating class of shock‐tolerant and impact‐resistant materials. However, their technological potential remains untapped due to a vague understanding of the molecular contributions to their superior mechanical behavior. Herein, in situ light‐matter interactions, to reveal the extent of microstructural mobility by temporally exploiting molecular processes during creep response, are leveraged. The segmental microstructure comprises aromatic hard domains embedded within an aliphatic soft matrix. High‐resolution digital image correlation reveals the development of strain striations, mild anisotropy, and the mechanisms responsible for domain mobility, where the rate of hard segment mobility is found to be 60% slower than that of the soft segment. Terahertz spectral analyses pinpoint the contributions of interchain hydrogen bonding of the hard segments and their significant conformational changes by observing spectral features at ≈1.2THz and ≈1.67THz. Moreover, the domain mobility is examined using experimental and computational light scattering approaches, uncovering dynamic scattering and elucidating the difference in the complex refractive index of the soft and hard segments. The study unlocks the pathway for quantitative measurements of elusive molecular mobility and conformational changes during mechanical loading and sheds light on the origin of the shock tolerance in some elastomeric polymers with segmental microstructure.
The mystery of the ice cold rose—Microbiome of an Arctic winter frost flower
Authors: Thiele Stefan , Vader Anna , Øvreås Lise 
Published: February 2023

AbstractUnder very cold conditions, delicate ice‐crystal structures called frost flowers emerge on the surface of newly formed sea ice. These understudied, ephemeral structures include saline brine, organic material, inorganic nutrients, and bacterial and archaeal communities in their brine channels. Hitherto, only a few frost flowers have been studied during spring and these have been reported to be dominated by Rhizobia or members of the SAR11 clade. Here we report on the microbiome of frost flowers sampled during the winter and polar night in the Barents Sea. There was a distinct difference in community profile between the extracted DNA and RNA, but both were dominated by members of the SAR11 clade (78% relative abundance and 41.5% relative activity). The data further suggested the abundance and activity of Cand. Nitrosopumilus, Nitrospinia, and Nitrosomonas. Combined with the inference of marker genes based on the 16S rRNA gene data, this indicates that sulfur and nitrogen cycling are likely the major metabolism in these ephemeral structures.
The Impact of the COVID‐19 Pandemic on Care Partners of People with Parkinson's Disease
Authors: Speelberg Daniël H.B. , Hulshoff Max J. , Book Elaine , Dahodwala Nabila , Korell Monica , Tanner Caroline M. , Marras Connie 
Published: February 2023

AbstractBackgroundSince the onset of the coronavirus disease 2019 pandemic, the caregiving routine for care partners of people with Parkinson's disease (PwPD) changed substantially.ObjectivesTo understand the nature and severity of burden in care partners of PwPD during the ongoing pandemic. We also sought to describe care partners' perceived change in burden and factors associated with increased burden.MethodsCross‐sectional online questionnaire‐based study among care partners of PwPD, registered in the Fox Insight study. The questionnaire consisted of the Modified Caregiver Strain Index, whether an aspect of strain had changed over the course of the pandemic and additional pandemic‐specific infection and lifestyle‐related items.ResultsTwo hundred seventy‐three non‐paid primary care partners responded to the questionnaire, 73% female with a median age at enrollment of 64 years, 56% reporting a household income greater than 75,000 USD per year, and 61% retired. An increase in burden compared to before the pandemic was prevalent, ranging from 33% to 63% for individual items. Emotional strain increased most frequently (63%). Decreases in burden were uncommon; work adjustments (7%) and time demands (6%) decreased most frequently. PD‐related factors and care partner roles in personal care of the PwPD were the factors that were associated with strain in multivariable analysis, whereas social and pandemic‐related factors were not.ConclusionIn this affluent and mostly retired cohort, increases in emotional strain during the pandemic were prevalent. Despite this, caregiving roles in personal care and severity of symptoms in the PwPD were more strongly associated with strain than social and pandemic‐related factors.
Oxidative Stress Mediated by N6‐Methyladenosine Methylation Contributes to High‐Fat Diet Induced Male Reproductive Dysfunction
Authors: Sun Jingyi , Li Mujiao , Xiong Yuting , Zhai Lingling , Zhao Jian 
Published: February 2023

ObjectiveTo determine the mechanism of oxidative stress mediated by N6‐methyladenosine (m6A) methylation contributing to high fat diet‐induced reproductive dysfunction.ResultsIn vivo, compared with those in the Control group, the sperm count and sperm motility decrease significantly; the testosterone, luteinizing hormone levels, hyaluronidase, acrosomal enzyme levels, and total antioxidant capacity decrease significantly; malondialdehyde increases significantly in the DIO and DIO‐R groups. The expression of nuclear factor erythroid 2‐related factor 2 (Nrf2), superoxide dismutase 1 (SOD1), and NAD(P)H quinone dehydrogenase 1 (NQO1) decreases significantly in the DIO and DIO‐R groups; m6A levels in testis tissue in the DIO and DIO‐R groups increase; the enrichment of m6A‐modified Nrf2 mRNA in testis in the DIO group and DIO‐R group increases significantly. Also the m6A regulatory proteins increase significantly in the DIO group and DIO‐R group. In vitro, compared to palmitic acid treated cells, the reactive oxygen species (ROS) level significantly decreases in STM2457, S‐Adenosylhomocysteine treated cells and YTHDC2, YTHDF2 gene silence cells; however, Nrf2 expression increases in all treated cells. In addition, m6A expression decreases.ConclusionsOxidative stress mediates by methylation of m6A may contribute to high fat diet‐induced male reproductive dysfunction.
Preventive Effect of Indian Gooseberry (Phyllanthus emblica L.) Fruit Extract on Cognitive Decline in High‐Fat Diet (HFD)‐Fed Rats
Authors: Chen Ying‐Yin , Chen Sheng‐Yi , Lin Jer‐An , Yen Gow‐Chin 
Published: February 2023

ScopeMethylglyoxal (MG)‐derived advanced glycation end products (AGEs) directly bind to the receptor for advanced glycation end products (RAGE), subsequently exacerbating obesity and obesity‐induced cognitive decline. Indian gooseberry (Phyllanthus emblica L.) fruit has antiobesity properties. However, the underlying mechanism by which Indian gooseberry fruit prevents obesity‐induced cognitive decline remains unclear.Methods and resultsThis study aims to investigate the preventive effect of a water extract of Indian gooseberry fruit (WEIG) and its bioactive compound gallic acid (GA) on the obesity‐induced cognitive decline through MG suppression and gut microbiota modulation in high‐fat diet (HFD)‐fed rats. Trapping MG, WEIG, and GA significantly ameliorate fat accumulation in adipose tissue and learning and memory deficits. Mechanistically, WEIG and GA administration effectively reduces brain MG and AGE levels and subsequently reduces insulin resistance, inflammatory cytokines, MDA production, and Alzheimer's disease‐related proteins, but increases both antioxidant enzyme activities and anti‐inflammatory cytokine with inhibiting RAGE, MAPK, and NF‐κB levels in HFD‐fed rats. Additionally, WEIG and GA supplementation increases the relative abundances of Bacteroidetes, Gammaproteobacteria, and Parasutterella, which negatively correlate with MG, inflammatory cytokine, and Alzheimer's disease‐related protein expressions.ConclusionThis novel finding provides a possible mechanism by which WEIG prevents obesity‐induced cognitive decline through the gut‐brain axis.
Technical note: TERMA scaling as an effective heterogeneity correction model for convolution‐based external‐beam photon dose calculations
Authors: Laakkonen Linda , Fan Zheyong , Harju Ari 
Published: February 2023

AbstractBackgroundIn highly heterogeneous medium, such as one with lung tissue or air cavities, the dose in the low‐density region or after it, as calculated by the conventional methods based on convolution with an energy‐spreading kernel, is usually overestimated in comparison with measurements or more accurate predictions.PurposeTo correct the overestimation, we propose a method of scaling the total energy released per mass (TERMA).MethodsThe scaling depends on both the density distribution and the effective beam size in the lateral direction.ResultsThe corrected convolution method achieved a significantly improved accuracy in both the lung‐like tissue and the water‐like region after air, compared to the uncorrected method. The TERMA correction only adds about 10% to the overall computational cost.ConclusionsDue to the improvement in accuracy and the preservation of computational efficiency, the proposed dose calculation method will be valuable for inverse treatment planning.
Surface‐GCN: Learning interaction experience for organ segmentation in 3D medical images
Authors: Tian Fengrui , Tian Zhiqiang , Chen Zhang , Zhang Dong , Du Shaoyi 
Published: February 2023

AbstractBackgroundAccurate segmentation of organs has a great significance for clinical diagnosis, but it is still hard work due to the obscure imaging boundaries caused by tissue adhesion on medical images. Based on the image continuity in medical image volumes, segmentation on these slices could be inferred from adjacent slices with a clear organ boundary. Radiologists can delineate a clear organ boundary by observing adjacent slices.PurposeInspired by the radiologists' delineating procedure, we design an organ segmentation model based on boundary information of adjacent slices and a human–machine interactive learning strategy to introduce clinical experience.MethodsWe propose an interactive organ segmentation method for medical image volume based on Graph Convolution Network (GCN) called Surface‐GCN. First, we propose a Surface Feature Extraction Network (SFE‐Net) to capture surface features of a target organ, and supervise it by a Mini‐batch Adaptive Surface Matching (MBASM) module. Then, to predict organ boundaries precisely, we design an automatic segmentation module based on a Surface Convolution Unit (SCU), which propagates information on organ surfaces to refine the generated boundaries. In addition, an interactive segmentation module is proposed to learn radiologists' experience of interactive corrections on organ surfaces to reduce interaction clicks.ResultsWe evaluate the proposed method on one prostate MR image dataset and two abdominal multi‐organ CT datasets. The experimental results show that our method outperforms other state‐of‐the‐art methods. For prostate segmentation, the proposed method conducts a DSC score of 94.49% on PROMISE12 test dataset. For abdominal multi‐organ segmentation, the proposed method achieves DSC scores of 95, 91, 95, and 88% for the left kidney, gallbladder, spleen, and esophagus, respectively. For interactive segmentation, the proposed method reduces 5–10 interaction clicks to reach the same accuracy.ConclusionsTo overcome the medical organ segmentation challenge, we propose a Graph Convolutional Network called Surface‐GCN by imitating radiologist interactions and learning clinical experience. On single and multiple organ segmentation tasks, the proposed method could obtain more accurate segmentation boundaries compared with other state‐of‐the‐art methods.
Expectations of patients awaiting lung transplantation: A qualitative study
Authors: Mestres‐Soler Olga , Gómez‐Ibáñez Rebeca , Zuriguel‐Pérez Esperanza , Escobar‐Fornieles Roser , Aguayo‐González Mariela , Leyva‐Moral Juan Manuel , Watson Carolina E. 
Published: February 2023

AbstractAimThe main aim of the present study is to examine the expectations and feelings of people awaiting lung transplantation.BackgroundThe assessment of the benefits of lung transplant should consider, among other things, the subjective perceptions of patients about the procedure, especially in relation to the context and to their values, goals and expectations. This is an issue that has not been studied in depth, especially in Spain.DesignExploratory qualitative study.MethodsData were collected through semi‐structured interviews during the period of being on the waiting list for transplantation. Thematic analysis of the data was supported by the Atlas.ti software.ResultsThe study population comprised 16 patients awaiting lung transplant, a number sufficient to reach data saturation. Four categories were identified to describe patients' feelings and expectations: (1) reasons for undergoing the transplant, (2) expectations about life post‐transplant, (3) emotional state, and (4) relationship with the healthcare team.ConclusionsPatients have high expectations of lung transplantation. They see it as offering them a second chance at life, although the future creates uncertainty. The healthcare professionals are identified as key actors, providing essential support and information throughout the various stages of the process. Future research should explore recipients' experiences of lung transplant at later stages.Relevance to clinical practiceIt is important to adapt care through all the lung transplant process, which is accompanied by intense and complex emotions since the beginning. Thus, providing social and psychological support from the beginning may contribute to their health status, helping them deal with all the emotions and feelings experienced, and find balance between expectations and reality.Patient or public contributionSixteen patients awaiting lung transplant were interviewed. Interview transcripts were returned to participants to check for accuracy with their experiences.
The novelty role of polyamide elastomer in the determination of crosslink density and the formation of crosslink network of EPDM vulcanizates
Authors: Hao Yupeng , Kadlcak Jakub , Xu Jiayong , Wu Di , Liu Guangyong 
Published: February 2023

AbstractThe effect of polyamide elastomer (PAE) on the crosslink network of ethylene propylene diene monomer (EPDM) was systematically investigated by using equilibrium swelling method and rheological experiment. The swelling systems of the EPDM‐PAE vulcanizates were discussed by classification way. The results showed that PAE was involved in the construction of the crosslink network and decreases the chemical crosslink density and the total crosslink degree of EPDM vulcanizate. By linearly fitting the relationship between chemical crosslink density and total crosslink degree, the physical crosslink degrees of EPDM, EPDM‐PAE and PAE were estimated as 9.135, 2.934, and 0.820 dNm, respectively. The physical crosslink degree of EPDM vulcanizates was mainly contributed by the entanglement of rubber macromolecular chains. By contrast, the interaction of the inter‐macromolecular chains of EPDM‐PAE and the physical crosslink of PAE itself contributed less to the physical crosslink degree of EPDM vulcanizates. With the increase of aging time under 150°C, the roles of PAE in continuously promoting the crosslink reaction and leading to the degradation of crosslink network resulted in various changes in crosslink density and mechanical properties. It could be expected from this study that the construction of the crosslink network of EPDM‐PAE composite was unique, which provided a novel perspective on the microscopic crosslink structures and macroscopic properties of EPDM‐PAE based products.