bluuebunny/crossref_metadata_2025 huggingface dataset:
Target gene responses differ when transcription factor levels are acutely decreased by nuclear export versus degradation
Authors: McGehee James , Stathopoulos Angelike
Published: October 2024

Defining the time of action for morphogens requires tools capable of temporally controlled perturbations. To study how the transcription factor Dorsal affects patterning of the Drosophila embryonic dorsal-ventral axis, we used two light-inducible tags that trigger either nuclear export or degradation of Dorsal under blue light. Nuclear export of Dorsal leads to loss of the high-threshold, ventrally expressed target gene snail (sna), while the low-threshold, laterally expressed target gene short-gastrulation (sog) is retained. In contrast, degradation of Dorsal results in retention of sna, loss of sog, and lower nuclear levels compared to when Dorsal is exported from the nucleus. To understand why nuclear export causes loss of sna but degradation does not, we investigated Dorsal kinetics using photobleaching and found that it rapidly re-enters the nucleus even under blue-light conditions favoring export. The associated kinetics of Dorsal being rapidly imported and exported continuously are likely responsible for loss of sna but, alternatively, can support sog. Collectively, our results indicate that this dynamic patterning process is influenced by both Dorsal concentration and nuclear retention.
Loss of STING impairs lactogenic differentiation
Authors: Vickers Ramiah R. , Wyatt Garhett L. , Sanchez Lilia , VanPortfliet Jordyn J. , West A. Phillip , Porter Weston W.
Published: October 2024

Heightened energetic and nutrient demand during lactogenic differentiation of the mammary gland elicits upregulation of various stress responses to support cellular homeostasis. Here, we identify the stimulator of interferon genes (STING) as an immune supporter of the functional development of mouse mammary epithelial cells (MECs). An in vitro model of MEC differentiation revealed that STING is activated in a cGAS-independent manner to produce both type I interferons and proinflammatory cytokines in response to the accumulation of mitochondrial reactive oxygen species. Induction of STING activity was found to be dependent on the breast tumor suppressor gene single-minded 2 (SIM2). Using mouse models of lactation, we discovered that loss of STING activity results in early involution of #3 mammary glands, severely impairing lactational performance. Our data suggest that STING is required for successful functional differentiation of the mammary gland and bestows a differential lactogenic phenotype between #3 mammary glands and the traditionally explored inguinal 4|9 pair. These findings affirm unique development of mammary gland pairs that is essential to consider in future investigations into normal development and breast cancer initiation.
Meiosis as a mechanism for epigenetic reprogramming and cellular rejuvenation
Authors: Berger Frédéric
Published: October 2024

Meiosis is a hallmark of sexual reproduction because it represents the transition from one life cycle to the next and, in animals, meiosis produces gametes. Why meiosis evolved has been debated and most studies have focused on recombination of the parental alleles as the main function of meiosis. However, 40 years ago, Robin Holliday proposed that an essential function of meiosis is to oppose the consequence of successive mitoses that cause cellular aging. Cellular aging results from accumulated defective organelles and proteins and modifications of chromatin in the form of DNA methylation and histone modifications referred to collectively as epigenetic marks. Here, recent findings supporting the hypothesis that meiosis opposes cellular aging are reviewed and placed in the context of the diversity of the life cycles of eukaryotes, including animals, yeast, flowering plants and the bryophyte Marchantia.
Adapting to change: insights from new organisms in cell and developmental biology
Authors: Lemke Steffen , Albright Ashley , Guse Annika
Published: October 2024

We are living in an era of environmental change with undeniable parallels with past mass extinctions. To improve our understanding of planetary health and resilience, we must expand our research beyond traditional lab models. Forecasting the future of biological diversity relies on extrapolation of past trends, which necessitates the study of a wider range of biological systems. The ‘Unconventional and Emerging Experimental Organisms for Cell and Developmental Biology’ meeting, which took place in Dorking, UK, in September 2023, emphasized the importance of this broader approach. Discussions centered on evolutionary innovation, robustness and diversity, underscoring the need for broader taxon sampling and novel experimental models to address current and future challenges.
Erythroblast enucleation at a glance
Authors: Newton Lucas M. , Fowler Velia M. , Humbert Patrick O.
Published: October 2024

Erythroid enucleation, the penultimate step in mammalian erythroid terminal differentiation, is a unique cellular process by which red blood cells (erythrocytes) remove their nucleus and accompanying nuclear material. This complex, multi-stage event begins with chromatin compaction and cell cycle arrest and ends with generation of two daughter cells: a pyrenocyte, which contains the expelled nucleus, and an anucleate reticulocyte, which matures into an erythrocyte. Although enucleation has been compared to asymmetric cell division (ACD), many mechanistic hallmarks of ACD appear to be absent. Instead, enucleation appears to rely on mechanisms borrowed from cell migration, endosomal trafficking and apoptosis, as well as unique cellular interactions within the microenvironment. In this Cell Science at a Glance article and the accompanying poster, we summarise current insights into the morphological features and genetic drivers regulating the key intracellular events that culminate in erythroid enucleation and engulfment of pyrenocytes by macrophages within the bone marrow microenvironment.
Gut microbiota are involved in leptin-induced thermoregulation in the Mongolian gerbil (Meriones unguiculatus)
Authors: Tang Liqiu , Lv Jinzhen , Zhang Xueying , Wang Chen-Zhu , Wang Dehua
Published: October 2024

Leptin is a hormone that is secreted by adipocytes and may promote energy expenditure by increasing thermogenesis. Our previous studies have shown that thermo-transient receptor potentials (thermo-TRPs) and gut microbiota are associated with thermoregulation in Mongolian gerbils, which are characterized by relative high serum leptin concentrations. Here, we tested whether leptin can stimulate non-shivering thermogenesis (NST) in Mongolian gerbils, and whether thermo-TRPs and gut microbiota are involved in leptin-induced thermogenesis. First, gerbils were given acute leptin treatment (ALT) with different doses. Results showed that ALT significantly increased the body temperature of gerbils and changed the composition of gut microbiota. Moreover, ALT groups showed a trend towards increased expression of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT). Then, we investigated the effect of chronic leptin treatment (CLT) on gerbils. Surprisingly, CLT did not affect gerbils' food intake and body mass, but it significantly increased the body temperature at the end. Further, CLT did not affect the expression of thermogenic markers in BAT, white adipose tissue (WAT) or skeletal muscle. However, CLT increased the expression of leptin receptors and TRPV2 in the small intestine and affected the composition of gut microbiota. Together, our data suggest leptin may increase body temperature by regulating gut microbiota. In conclusion, serum hyperleptin in Mongolian gerbils is beneficial for adapting to cold environments, and TRPV2 and gut microbiota are involved.
Elevated Plasma IL-6 Coincides with Activation of STAT3 in PBMC After Acute Resistance Exercise
Authors: TSAI SHUN-HSI , CHENG HAO-CHIEN , LITTLE JONATHAN P. , ISLAM HASHIM , LIU HUNG-WEN
Published: October 2024

Introduction

Changes in plasma concentrations of anti-inflammatory cytokines, such as interleukin-6 (IL-6) and IL-10, after acute resistance exercise (RE) have been widely explored. Whether observed changes in plasma cytokine concentration correspond to the activation of anti-inflammatory signaling pathways in immune cells after acute RE is unknown. This study aimed to determine if changes in plasma cytokines after acute RE resulted in the activation of anti-inflammatory signaling pathways in peripheral blood mononuclear cells (PBMC).

Methods

Healthy young males (N = 16; age = 23.5 ± 2.7 yr; BMI = 22.4 ± 1.7 kg·m−2) participated in a single session of whole-body RE (4 sets of 4 different exercises at 70% 1-repetition maximum with the last set to failure) and a sedentary control (CON) condition in a randomized crossover design. Blood samples were collected at several time points before and after the exercise bout.

Results

Higher plasma IL-6, IL-10, and IL-1 RA concentrations were observed after RE compared with CON. Phosphorylation of STAT3 and protein expression of SOCS3 in PBMC were increased in RE compared with CON. The elevation of plasma IL-6, but not IL-10, coincided with the activation of STAT3 signaling in PBMC.

Conclusions

These results highlight a potential mechanism by which RE may exert anti-inflammatory actions in circulating immune cells.
Modulators of Energy Expenditure Accuracy in Adults with Overweight or Obesity: E-MECHANIC Secondary Analyses
Authors: MATTHEWS RACHEL , HÖCHSMANN CHRISTOPH , ERICKSON MELISSA L. , DORLING JAMES L. , SPIELMANN GUILLAUME , JOHANNSEN NEIL M. , CHURCH TIMOTHY S. , MARTIN CORBY K.
Published: October 2024

Purpose

American College of Sports Medicine (ACSM) metabolic equations are used to estimate energy expenditure (EE) of physical activity and prescribe aerobic exercise to meet EE requirements. Limited evidence supports their accuracy in sedentary adults with overweight or obesity during controlled exercise interventions. The purpose of this study was to compare EE estimated by the ACSM walking equation versus EE measured by indirect calorimetry during a 24-wk aerobic exercise intervention, and identify potential modulators for their accuracy.

Methods

Data from the exercising groups (8 or 20 kcal·kg body weight−1·wk−1) of the E-MECHANIC study were utilized in this ancillary analysis (N = 103). Every 2 wk for the initial 8 wk and monthly thereafter, EE was measured via indirect calorimetry during absolute (2 mph, 0% grade) and relative (65%–85% peak oxygen uptake (V̇O2peak)) workload exercise. Resting metabolic rate, V̇O2peak, and body composition were assessed at baseline and follow-up. An EE offset factor (EOF) was calculated to express measured EE as a percentage of the estimated EE at each workload (EOF < 100% represents an overestimation of ACSM estimated EE).

Results

The accuracy of the equation decreased with increasing exercise workload (0.44%, 9.2%, and 20.3% overestimation at absolute, relative, and maximal workloads, respectively, at baseline) and overestimation of EE was greater after the exercise intervention. Furthermore, race, sex, age, fat mass, and V̇O2peak were identified as modulators for equation accuracy. Greater overestimation of EE was observed in Black compared with White females, particularly at lower exercise workloads.

Conclusions

These findings support future efforts to improve the accuracy of metabolic equations, especially in diverse populations. Researchers should account for exercise efficiency adaptations when using metabolic equations to prescribe exercise precisely.
Δυνατότητες βιολογικής καλλιέργειας και αξιοποίησης του αυτοφυούς είδους Helichrysum amorginum στη νήσο Αμοργό
Authors: Σταυρόπουλος Γεώργιος
Published: October 2024

Η αειφόρος αξιοποίηση της σπάνιας ελληνικής χλωρίδας αποτελεί μία σύγχρονη πρόκληση που δύναται να εισφέρει αφενός στην προστασία του φυτικού πλούτου της χώρας και αφετέρου στην ενίσχυση της οικονομικής ανάπτυξης τοπικών κοινοτήτων. Τα ενδημικά φυτά της Ελλάδος αποτελούν μία επί τω πλείστω ανεξερεύνητη πηγή φυτογενετικών πόρων και ελέω κλιματικής αλλαγής μπορούν να καταστούν πολύτιμα στην προσπάθεια για ενίσχυση του πρωτογενούς τομέα παρέχοντας τη δυνατότητα νέων εφαρμογών σε διάφορους βιομηχανικούς κλάδους. Ενώ έχει αναπτυχθεί ερευνητική δραστηριότητα γύρω από τη μελέτη του φυτοχημικού προφίλ αρκετών ενδημικών φυτικών ειδών της χώρας μας, είναι εξαιρετικά σπάνια στη βιβλιογραφία αναφορά για μελέτη εισαγωγής σε καλλιέργεια ενδημικών φυτών σε συνθήκες αγρού. Το Helichrysum amorginum Boiss. & Orph είναι ένα από τα 1.435 επισήμως καταγεγραμμένα ενδημικά φυτικά είδη και υποείδη της χώρας μας χαρακτηρισμένο ως “περιορισμένου γεωγραφικού εύρους” της νησιωτικής περιοχής των Κυκλάδων. Η παρούσα διατριβή πραγματεύτηκε τη μελέτη διάφορων πτυχών του πολλαπλασιασμού, της βιολογικής καλλιέργειας στις συνθήκες δύο πειραματικών αγρών στην Αμοργό και φυτοχημικών προσδιορισμών του Η. amorginum προκειμένου να διερευνηθούν οι δυνατότητες αξιοποίησης του συγκεκριμένου φυτού. Μέσα από μία σειρά πειραμάτων καταδείχτηκε η εφικτότητα του πολλαπλασιασμού και της καλλιέργειάς του αλλά και η δυνατότητα του παραγόμενου υλικού να αποδώσει εκχυλίσματα πλούσια σε βιοδραστικές ενώσεις. Με βάση τα αποτελέσματα που συλλέχθηκαν και επεξεργάστηκαν στατιστικά στα περάματα αγρού στην Αμοργό διαπιστώθηκε η αγρονομική υπεροχή του αγρού της Αιγιάλης έναντι των Καταπόλων, ο ενισχυτικός ρόλος της λίπανσης, η δυνατότητα μεγαλύτερης απόδοσης των φυτών σε πιο αραιές πυκνότητες φύτευσης ενώ αποτυπώθηκε ένα μοντέλο πορείας ανάπτυξης σε διάρκεια δύο ετών τουλάχιστον. Από την άλλη μεριά η εφαρμογή μυκόρριζας δεν φάνηκε να έχει ιδιαίτερη επίδραση στα αγρονομικά χαρακτηριστικά και τις αποδόσεις για το φυτό αυτό. Στα πειράματα που σχετίστηκαν με τον πολλαπλασιασμό του φυτού καταδείχτηκε υψηλότερη φυτρωτική ικανότητα σπόρου στους 20 0C υπό το φως ενώ βιολογικές μέθοδοι in vitro αγενούς πολλαπλασιασμού αποδείχτηκαν εξίσου αποτελεσματικές με συμβατική μέθοδο με υψηλά ποσοστά ριζοβολίας μοσχευμάτων. Μεθανολικά εκχυλίσματα φυτικού υλικού που προήλθε από πρώιμες συγκομιδές αποδείχτηκαν πιο πλούσια σε συγκέντρωση φαινολικών ενώσεων ενώ εκχυλίσματα τεχνολογίας NaDES εμφάνισαν υψηλότερη συγκέντρωση φαινολικών ενώσεων (TPC), φλαβονοειδών (TFC) και υψηλότερη αντιοξειδωτική ικανότητα όταν παρασκευάστηκαν από φυτικό υλικό που παρήχθη από φυτά δεχόμενα άρδευση σε αραιότερα χρονικό διάστημα.Τα πειραματικά αποτελέσματα της διατριβής μπορούν να αποτελέσουν τη βάση για τη δημιουργία πρωτόκολλου καλλιέργειας και αναπαραγωγής τους φυτού Helichrysum amorginum Boiss. & Orph στο νησί της Αμοργού ανοίγοντας τον δρόμο για τη μελλοντική αξιοποίησή του.
Podiatry risk in diabetic pilgrims: a prospective study in Tunisia
Authors: HASNI Yosra , ELFEKIH Hamza , SALAH Ameni , KAMMOUN Zomorda , AMARA Safa , AMARA Nour , MRAD Sawssen , SAAFI Wiem , CHADLI-CHAIEB Molka
Published: October 2024

Background Each year, over 340,000 diabetic patients across the world travel to Saudi Arabia for the Hajj pilgrimage. As they carried out important rituals, several complications might be encountered, particularly foot lesions. We’ve been therefore interested, through this study, in the assessment of podiatric risk in diabetic pilgrims. Methods A prospective longitudinal study was conducted in the region of Sousse, Tunisia. The evaluation of diabetic patients preparing for the pilgrimage was conducted in two phases, before and after the pilgrimage. Results Forty-three diabetic patients planning to perform pilgrimage were included in the study. Post-pilgrimage clinical exams revealed hyperkeratosis (96.8%) and superficial fungal infections (61.3%) as the most common podiatric lesions. Foot ulcers attributed to trauma from walking were found in 7% of patients. Our data showed a significant association between foot ulcer risk and lower total cholesterol (p=0.02), HDL cholesterol (p=0.02), LDL cholesterol (p=0.01), as well as higher triglyceride levels (p=0.04) only in univariate analysis. Other diabetes-related risk factors did not show significant correlations. Conclusion Given the increased risk of foot lesions in diabetic pilgrims, a thorough assessment and tailored management based on individual risk levels are essential before, during, and after the pilgrimage.
Protocol for a cross-sectional study on factors affecting health-related quality of life among Afghan refugees in Pakistan
Authors: Ur Rehman Atta , Zakar Rubeena , Zakar Muhammad Zakria , Hani Ume , Fischer Florian
Published: October 2024

Background Pakistan served as a host for more than 1.4 million Afghan refugees for more than 40 years. Access to health care is the most important issue faced by refugees, because they might be at a higher risk for certain diseases. This risk can be attributed to a lack of awareness of health care facilities, health beliefs, inadequate hygiene, cultural differences, and malnutrition. Health of individuals is closely associated with their quality of life. Quality of life over the whole lifespan is pivotal to overall life satisfaction. It includes physical wellbeing, mental health, education, occupation, income, personal safety, as well as (religious) freedom. Until now, the health status of Afghan refugees has never been comprehensively investigated in Pakistan. Therefore, an assessment in this regard is needed to explore their health-related quality of life, for securing their human right to health. Methods A cross-sectional study has been designed to describe and explain the health-related quality of life of Afghan refugees in Pakistan. Multistage cluster sampling was applied for selection of study participants. The number of respondents from two regions in Pakistan was drawn through a proportionate sampling technique. A quantitative research method using pre-validated questionnaires was used for data collection. The questionnaire included items to assess well-being, mental health, health literacy, and factors affecting health and health care. Descriptive analysis was used, whereas inferential statistical tests (binary logistic regression model) was also performed. The study received ethically permission by the Advanced Studies and Research Board of the University of the Punjab, Lahore, Pakistan. Discussion The assessment of Afghan refugee’s quality of life in Pakistan should lead to recommendations disseminated to public and health care officials. This evidence is needed for policymaking related to adequate measures for improving health conditions of Afghan refugees in Pakistan.
What’s in it for citizen scientists? An analysis of participant’s gains from a democratisation perspective
Authors: Unterfrauner Elisabeth , Fabian Claudia Magdalena , Hemming Gary , Garcia Beatriz
Published: October 2024

Citizen science projects optimise the democratisation of the production of scientific knowledge. In these initiatives, research processes do not rely solely on scientists’ but on citizens’ engagement likewise with benefits on both sides. As previous work shows, the democratisation perspective of citizen science projects might be viewed critically as some groups of citizens tend to be overrepresented in these initiatives while other are left out. This paper explores the claim of democratisation and the citizens’ benefits based on four citizen science projects in the fields of astrophysics and particle physics on the citizen science platform Zooniverse. Besides a general engagement strategy, the citizen science projects addressed two groups specifically, the elderly and people with visual impairments. The claim for democratisation is reflected in the analysis of citizens’ demographic variables as an indicator for accessibility of the research projects. We used a pre-post design with questionnaires on science attitudes, motivations, skills, self-efficacy, and knowledge to assess what citizen scientists gained from participating in the project. The demographic analysis of the data reveals that participants were quite heterogeneous and that people who feel that they belong to a group that is discriminated against are particularly motivated to participate in citizen science projects. In terms of benefits, the results indicate knowledge and scientific skills gains, but no changes on other evaluative dimensions. Their attitude towards science was, in general, already rather positive when joining the projects, thus not leaving much room for change. These results confirm the importance of and call for a diversified citizen science engagement strategy and show that even in citizen science projects where the citizens’ task is limited to classifying data lead to scientific knowledge and skills gains.
Hygienic basics of physical culture and sports activities
Authors: Bagnetova Elena
Published: October 2024

The textbook contains material covering the main sections of the discipline "Hygienic foundations of physical culture and sports activities", allows students to organize independent work on the assimilation of theoretical material, to form professional competencies for hygienic support of physical education and sports.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for full-time and part-time students at the Faculty of Physical Culture and Sports at all levels of higher professional education.
Theory of State and law
Authors: Mursalimov Kamil' , Habibulin Alik
Published: October 2024

The textbook combines the latest state-legal developments with well-established knowledge of the national theory of state and law, the most important of which is the provision on the unity and interaction of state and law. The information on the modern development and functioning of the state and law is summarized, their role and importance in the global integration process are outlined; the methodological basis of legal science is determined, socio-economic and political-legal characteristics of the interaction between the state and society are given.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
The textbook is intended for students studying in the field of Law, for students of various forms of training, retraining and advanced training, studying the discipline "Theory of State and Law".
La Revista de Bellas Artes en Santiago de Chile y las voces de Grez, Lira y Mochi (1889-1890).
Authors: Cinelli Noemi , Sergio Iván
Published: October 2024

La efervescencia artística que animó la segunda mitad del siglo XIX en Chile queda plasmada en varios periódicos dedicados a las Bellas Artes que llevan las firmas de personajes ilustres de la escena cultural chilena. Entre estas publicaciones nos centraremos en la Revista de Bellas Artes que circuló en Santiago entre 1889 y 1890. Tras el análisis del contexto cultural en el que se insertó su fundación, nos dedicaremos a analizar algunos escritos publicados en la revista por Pedro Lira, Vicente Grez y Giovanni Mochi. Demostraremos que la RBA fue la voz del sector más acomodado de la sociedad chilena decimonónica, que puso en evidencia las falencias del Estado en cuanto a p
Una pintura de Francisco Pacheco en el testamento de Felipe de Cuadros, primo de Rodrigo Caro, y otras noticias afines.
Authors: Amores Martínez Francisco
Published: October 2024

En este trabajo damos a conocer una pintura de la Virgen María realizada por Francisco Pacheco que se hallaba en 1620 entre las posesiones de Felipe de Cuadros Caro, primo de Rodrigo Caro. Esta obra no se ha conservado o no ha sido identificada todavía. Se aportan asimismo otras noticias sobre el entramado de relaciones entre los principales personajes que aparecen en el documento analizado.
Yeasts: Thrush and beyond
Authors: Greener Mark
Published: October 2024

Mark Greener looks at how yeasts have affected human health and history
Long-term functional outcome of limb-sparing surgery for paediatric bone sarcoma around the knee
Authors: Sekita Tetsuya , Asano Naofumi , Kobayashi Hiroshi , Yonemoto Tsukasa , Kobayashi Eisuke , Ishii Takeshi , Kawai Akira , Nakayama Robert
Published: October 2024

Aims

Surgical limb sparing for knee-bearing paediatric bone sarcoma is considered to have a clinically significant influence on postoperative function due to complications and leg-length discrepancies. However, researchers have not fully evaluated the long-term postoperative functional outcomes. Therefore, in this study, we aimed to elucidate the risk factors and long-term functional prognosis associated with paediatric limb-sparing surgery.

Methods

We reviewed 40 patients aged under 14 years who underwent limb-sparing surgery for knee bone sarcoma (15 cases in the proximal tibia and 25 in the distal femur) between January 2000 and December 2013, and were followed up for a minimum of five years. A total of 35 patients underwent reconstruction using artificial materials, and five underwent biological reconstruction. We evaluated the patients’ postoperative complications, survival rate of reconstruction material, and limb, limb function, and leg-length discrepancy at the final follow-up, as well as the risk factors for each.

Results

Complications were observed in 55% (22/40) of patients. The limb survival and reconstruction material rates at five and ten years were 95% and 91%, and 88% and 66%, respectively. Infection was the only risk factor in both survivals (p < 0.001, p = 0.019). In the 35 patients with limb preservation, the median International Society of Limb Salvage (ISOLS) score at the final follow-up was 80 (47% to 97%). Younger age (p = 0.027) and complications (p = 0.005) were poor prognostic factors. A negative correlation was found between age and leg-length discrepancy (R = −0.426; p = 0.011). The ISOLS scores were significantly lower in patients with a leg-length discrepancy of more than 5 cm (p = 0.005).

Conclusion

Young age and complications were linked to an unfavourable functional prognosis. Leg-length correction was insufficient, especially in very young children, resulting in decreased function of the affected limb. Limb-sparing surgery for these children remains a considerable challenge.

Cite this article: Bone Jt Open 2024;5(10):868–878.
Synthesis, Characterization and Influence of Copper Nanoparticles on Growth of Vigna mungo L. Hepper CO-7 Variety
Authors: Chitra Krishnasamy  , P. Srinithi  , R. Naveena  , J. Merlin Seles  , A. Aksharadevi
Published: October 2024

The copper nanoparticle was synthesized by employing Cnidoscolus aconitifolius (Mill) leaf extract. The nanoparticles were characterized by UV, FTIR and SEM studies. The SEM image showed a spherical structure. The bio-stimulant effect of green synthesized copper nanoparticles on Vigna mungo L. Hepper was investigated. Seed germination, biochemical, antioxidant, and enzyme activities of the copper nanoparticles were studied. The germination and morphological characteristics were superior at 100 mg/L copper nanoparticle-treated seeds. The biochemical parameters such as chlorophyll (0.701±0.107 mg/g), carbohydrate (4.657±0.090 mg/g), protein (4.396±0.335 mg/g), amino acid (18.557±0.638 mg/g), phenol (10.824±0.53 mg/g), flavonoid (3.644±0.171 mg/g), alkaloid (6.529±0.45 mg/g), and tannin (12.159±0.218 mg/g) were higher at a nanoparticle concentration of 100 mg/L. As far as the enzymatic activities, the maximum activity of nitrate reductase (4.505±0.203 mg/g) and α-amylase (13.195±0.285 mg/g) were observed with 100 mg/L copper nanoparticle-treated seedlings. The in vitro antioxidant activities were also studied.
Experimental study for a field diversity phase retrieval wavefront sensing approach
Authors: Zou Ziheng , Xu Boqian , Bai Xiaoquan , Gao Yan , Xu Shuyan , Ju Guohao
Published: October 2024

Field diversity wavefront sensing is one of the image-based wavefront methods, where the intensity measurements with phase diversities are directly obtained from different field positions of one image, without the need for any additional instruments (e.g., beam splitter) or operations (e.g., focus adjusting). While the phase diversities between different positions are unknown to us, this method is realized based on an in-depth understanding of the net aberration fields induced by misalignments and figure errors. However, this novel, to the best of our knowledge, image-based wavefront sensing method has not been experimentally studied, which restricts the application and promotion of this method. In this work, the analytic gradient of the field diversity wavefront sensing is derived, and the accuracy and effectiveness of this method in the active alignment of real three-mirror anastigmatic (TMA) optical systems are systematically demonstrated. The results show that this method can be applicable to wavefront sensing of large space telescopes.
Dynamically variable intensity patterns projected using an optofluidic phase-shifter array
Authors: Sieben Merit , Zappe Hans
Published: October 2024

We present a concept for the dynamically variable definition of arbitrary intensity distributions using an array of optofluidic phase-shifters. These components consist of cylindrical fluidic surfaces whose interface may be controllably shaped using electrowetting-on-dielectrics actuation. Key to the generation of defined intensity distributions is the ability to calculate the required shape for this phase-shifting interface and to this end we present a novel procedure, to our knowledge, that combines a real-time optimization algorithm with an influence matrix approach to generate the required surface. We illustrate the effectiveness of this approach by reconstructing arbitrary surface profiles with one optofluidic phase-shifting component that is then used to project a desired two-dimensional intensity distribution. Using this approach, we further demonstrate the capability of a two-dimensional phase-shifter array to generate larger dynamically programmable intensity patterns by combining individual intensity distributions.
3D reconstruction from focus for lensless imaging
Authors: Li Ying , Li Zhengdai , Chen Kaiyu , Guo Youming , Rao Changhui
Published: October 2024

The lensless camera is an ultra-thin imaging system that utilizes encoding elements instead of lenses to perceive the light field and reconstruct it through computational methods. Early studies have demonstrated that lensless cameras can encode 3D scenes at various depths in caustic patterns with varying sizes, known as point spread functions (PSFs). By deconvolving measurements with these PSFs, the reconstruction exhibits distinct focusing effects: objects in the focal plane appear sharp, while objects in other planes become blurred. Building upon this feature, we propose a feedforward network based on depth from focus to generate the depth map and the all-in-focus image by reconstructing the focal stack and deriving the probability of pixel clarity. Using our optimization framework, we present superior and more stable depth estimation than previous methods in both simulated data and real measurements captured by our lensless camera.
Cognitive learning enabled agile optical network
Authors: Cheng Yijun , Chen Zejun , Hu Zihe , Xiang Meng , Yan Zhijun , Qin Yuwen , Fu Songnian
Published: October 2024

Nonlinear equalization (NLE) is essential for guaranteeing the performance of an optical network (ON). Effective NLE implementation relies on key parameters of the transmission link, including the modulation format (MF) and the launch power. As ONs become more agile, the parameters of fiber optical transmission need to be adaptive and relevant to the routing condition. Therefore, successful NLE implementation relies on the realization of transmission awareness (TA). Although machine learning-enabled optical performance monitoring (OPM) has been extensively investigated in the past few years, current NLE algorithms cannot autonomously perceive transmission parameters. Furthermore, current TA implementation still needs human intervention to guide the NLE. In addition, existing ML-based OPM and NLE cannot be trained autonomously, leading to the incapability of environmental change and mislabeling. Here, we propose cognitive learning (CL) for TA-guided NLE in agile ONs. We perform an experiment involving 32 Gbaud polarization-division-multiplexed (PDM)-quadrature phase shift keying (QPSK)/16-quadrature amplitude modulation (QAM) transmission over 1500 km of standard single-mode fiber (SSMF) with a variable launch power from 0 to 3 dBm. When a deep neural network (DNN) with amplitude histograms (AHs) as inputs and one step per span-learned digital back-propagation (1stps-LDBP) are developed, the CL simultaneously enables both TA and NLE, with the capability of self-learning, mislabeling resistance, and dynamic adaptation. The proof-of-concept experimental results indicate that both the accuracy of TA and the Q-factor of PDM-16QAM can be improved by 34.8% and 0.84 dB, respectively, when the launch power is 3 dBm. Moreover, the accuracy of TA is enhanced by 35.3%, even when the used data has 30% mislabeling. Therefore, the CL framework can be customized to satisfy various NLE implementations, thereby supporting the adaptive transmission of agile ONs.
Estimation of direction and zero errors of satellite laser terminals in low-light conditions based on machine learning
Authors: Zhang Jie , Cao Yubin , Guo Pengzhen , Li Zekun , Du Hairui , Chen Nanxing , Cao Kairui , Tan Liying
Published: October 2024

In the assembly, launch, and on-orbit operation of satellite optical communication terminals, small deviations are difficult to avoid, which can lead to pointing errors and challenges to the establishment of optical communication links. To estimate the pointing errors of on-orbit satellite terminals, a calibration algorithm is developed based on lunar surface imagery. First, a feature extraction algorithm for low-light images is employed to process consecutive frames of low-light images to obtain a lunar surface feature map. Then, by combining the feature map and error estimation model, predictions of direction errors and zero errors were achieved. The ground validation results demonstrate the effectiveness and feasibility of the proposed on-orbit error estimation algorithm under low-signal-to-noise-ratio conditions.
Near-field probing of surface plasmon polariton formation in imprinted gold nanoisland arrays
Authors: Lastras-Martínez L. F. , Martínez-Zepeda G. A. , Espinosa-Cuellar L. D. , Golibrzuch M. , Balderas-Navarro R. E.
Published: October 2024

Large-area imprinting stamps with nanometer-scale features are a rapidly developing area of research in plasmonics. In integrated photonic structures, surface plasmon (SPs) and surface plasmon polaritons (SPPs) are tuned by selecting both the appropriate wavelength and the angle of incidence of the excitation light. The resulting exponential fields can be studied by an optical technique such as scanning near-field optical microscopy (SNOM). Here, we report on the application of the aperture-type SNOM technique to characterize, at nanoscopic and microscopic scales, the formation of the SPPs and the beat pattern formed with the superposition of SPs and the effective component of the probing light formed in discrete metallic nanostructures of Au fabricated on imprinting stamps. We discuss a model to describe the beat pattern in terms of this superposition and demonstrate that the dominant SPs have a transverse nature. Our experiments are supported by modeling the optical response and near-field in gold nanostructures using the simulation tool Tidy3D. Our results provide a straightforward way to investigate and characterize SPPs at the nanostructure level.
Tunable reflective filters and perfect mirrors using all-dielectric metasurfaces
Authors: Singhal Sridhar , Sharma Shubhanshi , Varshney Shailendra K.
Published: October 2024

For several years, extensive research has focused on narrow and broadband optical filters and mirrors. The aim has been to achieve highly specific spectral responses across different wavelength bands. All-dielectric materials have been preferred due to their low losses and high-quality factor values. In this study, we present meta-resonators with concave and convex shapes to achieve both narrow and broad spectral responses. Numerical simulations based on the finite element method reveal a full width at half-maximum (FWHM) of 0.65 nm and 346 nm. The concave and convex designs improve light-matter interaction and enable tunability. Using an appropriate thermo-responsive or electro-responsive material as a covering layer, we successfully achieved precise tunability of 0.3 nm/10°C and 0.18 nm/V within the concave metasurface. These metasurfaces demonstrate nearly perfect reflectance, allowing them to behave as perfect mirrors for narrow and broadband line width applications.
Three-dimensional Anderson localization of light in materials with fluctuating electric and magnetic properties
Authors: Schirmacher Walter , Franosch Thomas , Leonetti Marco , Ruocco Giancarlo
Published: October 2024

Anderson localization of electromagnetic waves, caused by the disorder-induced arrest of wave diffusion, has been experimentally observed in systems with spatially fluctuating permeability, but only in lower dimensions, not in three dimensions. This paper introduces what we believe to be a novel theoretical approach to the Maxwell equations considering both electric and magnetic disorder. It demonstrates that when both the dielectric constant and magnetic permeability fluctuate in space, the spectral range for three-dimensional Anderson localization significantly increases.
Quantum efficiency enhancement of reflective GaAs photocathodes with exponential-doping structure generating a favorable built-in electric field
Authors: Jiang Yu , Zhang Yijun , Tong Zehao , Tang Song , Guo Tao , Qian Yunsheng , Sun Jianning , Ren Lin , Jin Muchun , Shi Feng , Cheng Hongchang , Zeng Yugang
Published: October 2024

The rapid development of GaAs photocathodes has led to an increased focus on the attainment of high quantum efficiency. Three types of exponential-doping structures with a high to low doping concentration distribution from the interior to the surface are proposed for reflective GaAs emission layers. These three structures generate different built-in electric fields that facilitate photoelectron emission. The one-dimensional continuity equations for the increasing, constant, and decreasing types of built-in electric fields are derived, respectively. The electron concentration distribution and quantum efficiency varying with the wavelength are solved numerically by the finite difference method. The simulation results indicate that the quantum efficiency of the GaAs photocathode with the increasing type of built-in electric field is superior to that with the constant built-in electric field, while the GaAs photocathode with the decreasing type of built-in electric field shows the worst performance. Then, the designed GaAs photocathodes with the increasing and constant types of built-in electric fields are grown by metal-organic chemical vapor deposition and activated by cesium-oxygen alternating deposition. The measured spectral response curves show that the quantum efficiency of the GaAs photocathode with the increasing type of built-in electric field is higher in the whole band than that with the constant type of built-in electric field. In addition, the exponential-doping structure generating the increasing type of built-in electric field is beneficial for improving the surface potential barrier and increasing the surface electron escape probability.
Accurate loss measurement of optical bulk materials with the pulsed cavity ring-down technique
Authors: Cai Binghua , Li Bincheng , Wei Yaowei , Han Yanling , Wang Tianmin , Wang Jing , Cui Hao
Published: October 2024

In a wide range of laser applications, the optical losses of optical materials used in the laser systems are closely linked to the laser-induced damage and laser beam quality deterioration. It is demonstrated in this paper that when the pulsed cavity ring-down (CRD) technique is employed to measure the optical loss of uncoated substrates inserted in the ring-down cavity with normal incidence, the surface reflection of the uncoated substrate causes a significant overestimation of the optical loss. The degree of overestimation increases rapidly with the increasing surface reflectance. By taking into consideration the influence of the surface reflection on the measured CRD signal and developing an approximately linear dependence of the measured loss on the actual loss, the actual loss of the solid substrate is determined accurately from the measured loss. A theoretical description is developed to establish a simple relationship between the CRD measured loss and the actual loss, so to eliminate the influence of the surface reflection on the optical loss measurement. Experimentally the optical losses of fused silica and KDP substrates with 10 mm thickness at 355 nm are determined to be 116 parts per million (ppm) and 567 ppm, respectively. The results demonstrate the usefulness of pulsed CRD for accurate determination of optical loss below the measurement limit (∼3000 ppm) of spectrophotometry.
Flat double-layer metal-only metasurface with polarization-dependent operation in a C/X dual band
Authors: Meng Xiangshuai , Zhang Haoyu , Wang Yujie , Wu Tao , Zhang Anxue , Chen Xiaoming
Published: October 2024

In this communication, a dual-band, orthogonal polarization transmission metasurface antenna operating at 6.5 GHz and 9.5 GHz is proposed. The element of this transmitarray is composed of only two identical layers of metal plates, with air medium filling the space between the upper and lower layers. Each layer has four sets of staggered I-slots, thus ensuring dual-frequency orthogonal polarization operation. Moreover the proposed element overcomes the challenge of achieving full 360-degree phase shift in dual-layer metal-only structures without any additional connecting elements. By altering the length of the slots, it can achieve a continuous full 360-degree phase shift while maintaining a transmission amplitude above −2 dB and exhibits co-polarized transmission in both bands. Then a prototype containing 16 × 16 elements is designed and fabricated to verify the feasibility of the design scheme. The measurement results, which are consistent with the simulation, demonstrate that the maximum gains of 24.85 and 27.64 dBi are obtained at 6.4 GHz and 9.4 GHz, with corresponding aperture efficiencies of 23.18% and 20.4% and a 3-dB gain bandwidth of 15.6% and 22.34%. The good transmission coefficients of the element and the dual-band capability make the design a competitive candidate for satellite and high-power applications.
3D shape measurement method for high-reflective surface based on a color camera
Authors: Wang Zhangying , Li Kui , Gao Nan , Meng Zhaozong , Zhang Zonghua
Published: October 2024

Fringe projection profilometry (FPP) has been widely utilized in many fields due to its non-contact, high accuracy, high resolution and full-field measurement capabilities. However, the limited dynamic range of the camera sensor can result in overexposure of high-reflective parts in industrial production measurement. To effectively solve the above issue, this paper proposes a 3D shape measurement method for the high-reflective surface based on a color camera. Firstly, the optimal exposure time for the low-reflective region is estimated using the relationship between the standard variance of the phase error and the modulation. Twelve blue phase-shifted fringe patterns and a uniform blue image are utilized to obtain 3D shape of high-reflective surface. Secondly, captured images are separated into red, green and blue components. The fused Gaussian low-pass filtering method with different cut-off frequencies is used to filter and denoise the green or red components and the true intensity of the blue component in the saturated regions is calculated by the unsaturated intensity of the green or red components based on the calibrated crosstalk matrix. Then the image in saturated regions is fused and normalized with the unsaturated region. The absolute phase obtained from the fused normalized fringe patterns is converted into 3D data. Finally, experiments have been carried out on measuring. The experimental results show that the proposed method is capable of obtaining the 3D shape of the surface of a high-reflective object with fewer patterns and high measurement accuracy.
Compound meta-atoms enabling ultra-compact multiband optical manipulation
Authors: Zhu Yechuan , He Siwen , Lan Yuxiang , Li Wenli , Zhou Shun , Wu Chunfang , Liu Weiguo
Published: October 2024

Metasurfaces formed by subwavelength meta-atoms have continuously attracted interest owing to their flexible optical modulation, which offers unprecedented capability for the miniaturization of optical devices. Recently, broadband achromatic metalenses have been extensively reported for visible and mid-infrared light. However, it is a huge challenge to simultaneously manipulate the visible and mid-infrared light due to a large wavelength range. Here, a compound meta-atom is proposed to realize the multiband optical manipulation, which comprises two-layer decoupled meta-atoms. The lower-layer meta-atom and upper-layer ones are employed to modulate the mid-infrared and visible light, respectively. As a result, a compound metalens is designed to accomplish optical focusing at wavelengths of 0.65 µm and 3.7–4.8 µm. Numerical results demonstrate that the compound metalens can realize diffraction-limited focusing of visible light and broadband achromatic focusing of the mid-infrared light at the same focal plane. The compound metalens exhibits achromatic focusing for multiband light in a large wavelength range. Additionally, the design methodology of our meta-atoms is also applicable to other multiband optical modulation.
Growth, spectroscopy properties, and laser operation of single crystal fiber: Nd3+-doped CNGG
Authors: Xu Chong , Liu Jian , Guo Jun , Liang Zhiyong , Yang Chuang , Liu Longxin , Wang Zebin , Wang Hongping , Chen Peng , Xu Jie , Song Qingsong , Ma Jie , Xu Xiaodong , Xu Jun
Published: October 2024

Nd3+-doped calcium niobium gallium garnet single crystal fibers (Nd:CNGG SCFs) with varying Nd3+ concentrations were successfully grown using the laser-heated pedestal growth (LHPG) method. The study thoroughly examines the fundamental physical structure, optical properties, and laser characteristics of the as-grown Nd:CNGG SCFs. Results indicate that the Nd:CNGG SCF exhibits broader absorption and emission full width at half maximum (FWHM) compared to bulk single crystals. Moreover, pumped by a commercial 808 nm laser diode, continuous-wave laser operation at 1061 nm with a half-height width of 1.86 nm was achieved. The laser output power reached 1.04 W at an absorbed power of 7.46 W, with a slope efficiency of 25.4% relative to the absorbed pump power. These findings suggest that Nd:CNGG SCF holds promise as a practical and potent candidate for laser gain medium, offering significant research potential in the field of lasers.
An on-chip tunable single-mode high-power narrow-linewidth Fabry‒Pérot microcavity laser on Yb3+-doped thin film lithium niobate
Authors: Fang Zhiwei , HUANG QINFEN , Wang Zhe , ZHU YIRAN , Liu jian , Zhou Yuan , Yu Jianping , Wang Min , Cheng Ya
Published: October 2024

Ytterbium ion (Yb3+) doped lasers are widely used in precision machining and precision measurement fields because of their high efficiency and high power, which are primarily based on solid-state lasers and fiber lasers. Here, we demonstrate an on-chip Yb3+-doped thin film lithium niobate (Yb:TFLN) Fabry‒Pérot microcavity laser. We achieve single-frequency laser operation at 1030 nm and 1060 nm with a side-mode suppression ratios above 30 dB, an emission linewidth below 40 pm, and an output power up to 1.5 mW. In addition, using the electro-optic effect of lithium niobate, we achieve a laser tuning efficiency of 4 pm/V. This work opens the path to on-chip high-power and mode-locked ultrafast laser output.