bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors
Authors: di Filippo Luigi , Frara Stefano , Nannipieri Fabrizio , Cotellessa Alice , Locatelli Massimo , Rovere Querini Patrizia , Giustina Andrea
Published: April 2023

Context

Long COVID is an emerging syndrome affecting 50% to 70% of COVID-19 survivors that still lacks predicting factors.

Objective

Due to the extraskeletal effects of vitamin D, we retrospectively assessed the association between 25(OH) vitamin D levels and long COVID in COVID-19 survivors 6 months after hospitalization.

Methods

Long COVID was defined according to NICE guidelines. Fifty long COVID and 50 non–long-COVID subjects matched on a 1:1 basis were enrolled from an outpatient clinic post-COVID cohort seen from August to November 2020. Therapies/comorbidities affecting calcium/vitamin D/bone metabolism, and/or admission to the intensive care unit during hospitalization were exclusion criteria. 25(OH) Vitamin D was measured at hospital admission and 6 months after discharge.

Results

We observed lower 25(OH) vitamin D levels, evaluated at follow-up, in subjects with long COVID than those without (20.1 vs 23.2 ng/mL, P = .03). Regarding the affected health areas evaluated in the entire cohort, we observed lower 25(OH) vitamin D levels in those with neurocognitive symptoms at follow-up (n = 7) than those without (n = 93) (14.6 vs 20.6 ng/mL, P = .042). In patients presenting vitamin D deficiency (<20 ng/mL), both at admission and at follow-up (n = 42), those affected by long COVID (n = 22) presented lower 25(OH) vitamin D levels at follow-up than those not affected (n = 20) (12.7 vs 15.2 ng/mL, P = .041). In multiple regression analyses, lower 25(OH) vitamin D levels at follow-up were the only variable significantly associated with long COVID in our cohort (P = .008, OR 1.09, CI 1.01-1.16).

Conclusion

COVID-19 survivors with long COVID have lower 25(OH) vitamin D levels than matched patients without long COVID. Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge. The role of vitamin D supplementation as a preventive strategy of COVID-19 sequelae should be tested in randomized controlled trials.
Creating Space: Capitalism, Mining, and the Evolution of Central European Economic Thought
Authors: Lingg Andreas Friedolin
Published: April 2023

There were a number of economists in early modern Germany who, as their works indicate, faced regular criticism and personal attacks. Again and again, they had to defend and legitimize their work. Such apologetic formulas appear for the first time in the work of the Saxon councilor and writer Melchior von Osse (1506–57). This was no coincidence. Starting from the large and dynamic mining districts of the region, a new variant of economic thinking emerged at the end of the fifteenth century, characterized in particular by the fact that it extended the princely household over the entire territory. Ideas of this kind violated centuries-old scholarly traditions. This concerned both the question of occupations suitable for people of high status as well as the scope of what could legitimately be called a household or economy. The reason for this break with convention was the increasingly capitalist organization of mining, which fostered new forms of spatial imagination and governmental practice. However, irrespective of how important the idea of a territorial economy would become, it also placed a burden on economic scholars who were involved in its early dissemination. The legacy of disrupting the medieval politico-economic order will accompany them for centuries to come.
Patient characteristics and prediction of CoViD-19 in-hospital mortality: a retrospective cohort study in Crete, Greece before and after the onset of a targeted vaccination strategy in 2021
Authors: Makris George , Tzanaki Eirini , Bachlitzanaki Maria , Pasparaki Eirini , Amargianitakis Vasilis , Naska Androniki , Sypsa Vassiliki-Anastasia , Paraskevis Dimitrios
Published: April 2023

Background: CoviD-19 in-hospital mortality rates show variations across time, setting, patient populations and health-systems.
Aim: The aim of the present study was to explore the association of patient characteristics with in-hospital mortality taking into consideration temporal changes of CoViD-19 prevention and treatment, focusing on the negative predictive value of specific biomarker thresholds for death and oxygen requirements.
Methods: This retrospective study included a sample of 425 vaccine-naive patients hospitalized for CoViD-19 in Crete, Greece. Time-specific mortality rates and negative predictive values of biomarkers on admission were calculated. The association of patient characteristics with mortality was assessed using multivariate logistic regression models.
Results: The overall in hospital case fatality rate (CFR) was 19.53%.  The in-hospital CFR [95% CI] dropped from 22.74% [17.96-27.52] to 11.9% [6.17-17.63] before and after 31/03/2021, as did the mean age of hospitalized patients. LDH & D-dimers ≥240 or ≥0.5), CRP & D-dimers (≥3 or ≥0.5), CRP & Ferritin (≥3 or ≥205) had negative predictive values [95% CI] for mortality of 100% [86.7-100], 96.1% [80.3-99.9] and 95.4% [84.5-99.4] %, but the respective negative predictive values for oxygen requirements were 19.2% [6.5-39.3], 19.2% [6.5-39.3] and 27.2% [14.9-42.7] .
Conclusion: A decreasing trend of in-hospital case fatality rates over the course of our study was associated with a decreasing age of hospitalized patients, which could be associated with community vaccination uptake in people over 60 in Greece through reduction of persons “susceptible” to severe disease. Mortality prediction formulas incorporating biomarkers should be used cautiously for the risk stratification of patients with CoViD-19 in the setting of the emergency department assessment.
Waning anti-SARS-CoV-2 receptor-binding domain total antibody in CoronaVac-vaccinated individuals in Indonesia
Authors: Harapan Harapan , Ar Royan Hibban , Tyas Islam Ing , Nadira Auda , Abdi Irham Faraby , Anwar Samsul , Husnah Milda , Ichsan Ichsan , Pranata Agung , Mudatsir Mudatsir , Syukri Maimun , Rizal Samsul , . Razali , . Hamdani , Kurniawan Rudi , Irwansyah Irwansyah , Sofyan Sarwo Edhy
Published: April 2023

Background: The decrease of immunity acquired from COVID-19 vaccines is a potential cause of breakthrough infection. Understanding the dynamics of immune responses of vaccine-induced antibodies post-vaccination is important. This study aimed to measure the level of anti-SARS-CoV-2 receptor-binding domain (RBD) total antibody in individuals at different time points upon the receipt of the second dose of CoronaVac vaccine, as well as evaluate the plausible associated factors.

Methods: A cross-sectional study was conducted among CoronaVac-vaccinated residents in Banda Aceh, Indonesia. The level of anti-SARS-CoV-2 RBD total antibody was measured using Elecsys immunoassay. A set of standardized and validated questionnaires were used to assess the demographics and other associated factors.

Results: Our results showed waning anti-SARS-CoV-2 RBD total antibody titres over time post-vaccination. Compared to samples of the first month post-vaccination, the antibody titres were significantly lower than those of five-months (mean 184.6 vs. 101.8 U/mL, p = 0.009) and six-months post-vaccination (mean 184.6 vs. 95.59 U/mL, p = 0.001). This suggests that the length of time post-vaccination was negatively correlated with titre of antibody. A protective level of antibody titres (threshold of 15 U/mL) was observed from all the samples vaccinated within one to three months; however, only 73.7% and 78.9% of the sera from five- and six-months possessed the protective titres, respectively. The titre of antibody was found significantly higher in sera of individuals having a regular healthy meal intake compared to those who did not (mean 136.7 vs. 110.4 U/mL, p = 0.044), including in subgroup analysis that included those five to six months post-vaccination only (mean 79.0 vs. 134.5 U/mL, p = 0.009).

Conclusions: This study provides insights on the efficacy of CoronaVac vaccine in protecting individuals against SARS-CoV-2 infection over time, which may contribute to future vaccination policy management to improve and prolong protective strategy.
Evaluation of antimicrobial susceptibility of Escherichia coli isolated from contaminated areas of Majengo slum in Meru County, Kenya
Authors: Ombuya Jared , Gachoka Kennedy , Dorothy Kagendo , Mutea Naomi
Published: April 2023

Background: Antimicrobial drug resistance is of great concern today. Infections by the antimicrobial resistant strains of Escherichia coli, including enteropathogenic as well as enterotoxigenic strains have been reported as a major cause of deaths, especially among young children in low- and middle-income countries. This has been augmented by antimicrobial misuse, over the counter availability and poor sanitation especially in low income areas.

This study aimed at characterizing antimicrobial resistant strains of Escherichia coli isolated from sanitation environments of the Majengo slum in Meru County, Kenya

Methods: A cross-sectional study was conducted on 61 samples from soil, water and drains swabs. These were tested against five antimicrobial drugs by the Kirby disk diffusion method.

Results: A total of 42 (69%) of the samples had Escherichia coli. These recorded antimicrobial drug susceptibility as follows: Out of the five antimicrobial agents used, ceftazidime 28 (66.67%) showed the highest sensitivity followed by ciprofloxacin 26 (61.90%) and imepenem 25 (59.52%) respectively. cefotaxime and cefoxitin showed least sensitivity at 14 (33.33%) and 13 (30.95%) respectively. In intermediate imepenem and ciprofloxacin were the highest with 12 (28.57%) followed by cefotaxime 10 (23.81%). The least intermediate was observed in ceftazidime and cefoxitin both at 7 (16.67%).  The highest resistance was observed in cefoxitin 22 (52.38%), followed by cefotaxime at 18 (42.86%). Ciprofloxacin, imepenem and ceftazidime had the lowest resistance 4 (9.52%), 5 (11.91%) and 7 (16.67%) respectively. The p-value <0.05 was considered significant to the study.  

Conclusions: This study showed that Escherichia coli isolated from Majengo is pathogenic and resistant to antibiotics. Detection of Escherichia coli poses a great risk in the spread of resistant strains in human. Proper sanitation and hygiene awareness practices should be provided through education to the residents of this area.
Effects of Consumer Dispositional Attitude on Purchase Intention in an Emerging Market
Authors: Shanbhogue A. Venugopal , Ranjith V. K.
Published: April 2023

Background: Globalization trends have compelled multinational companies to change their marketing approach from multi-domestic marketing to global marketing. This strategy has had a major impact on the branding of companies. Due to these efforts by international companies, there has been a negative impact on local brands. Strong local brands always maintained the advantage of a high level of awareness among consumers, due to consumers’ close relationship with these brands, hence this resulted in strong and positive marketing investments in the home market. The purpose of this research is to evaluate the attitudinal dispositions towards global and local brands and purchase intention. The objective is to understand the underlying motives of consumers’ purchase decision.

Methods: Consumer disposition and attitude towards brands are evaluated based on respondents’ purchase intention of a select brand. Data are collected from Bangalore and Chennai using the convenience sampling method. Evaluation of the measurement model was performed using the Smart PLS 4 software.

Results: Findings suggest that consumer attitudinal disposition has a significant impact on consumers’ purchase intention. Attitude formation is the first step in consumers’ behavioural decision and making a purchase decision. Marketing managers/practitioners need to focus on forming this attitude in consumers’ minds, so that this attitude formation leads to a purchase decision.

Conclusions: This research provides theoretical and managerial implications for marketers, especially those operating in an emerging market like India as this study has examined the role of consumer disposition on attitude formation and purchase intention. From a theoretical perspective, this study developed and tested a conceptual model describing the relationship between attitudinal disposition and purchase intention.
Satisfactory result of great saphenous vein endovenous laser ablation until below the knee on active venous leg ulcer: a case series
Authors: Taofan Taofan , Dakota Iwan , Kartamihardja Achmad Hafiedz Azis , Afandy Jonathan Edbert , Indriani Suci , Adiarto Suko
Published: April 2023

Background: Active venous leg ulcer (VLU) is the most severe manifestation of chronic venous disease which not only affects patients’ health, but also decreases the quality of life, and delivers economic burdens. Treatment of superficial venous reflux with early endovenous laser ablation (EVLA) has been proven to reduce ulcer recurrence levels and promote faster VLU healing. We reported three cases of patients with active VLU undergoing EVLA with different approaches.

Case illustration: Three patients came with complaint of leg ulcer, diagnosed with C6sEpAsdPr, with venous clinical severity scores (VCSS) of 15, 23, and 22 respectively. Severe great saphenous veins (GSV) reflux was found in all patients by duplex ultrasound examination. The second patient had undergone above-the-knee EVLA. All patients underwent EVLA using 1470-nano meter wavelength laser device and ELVeS radial fiber (Biolitec, Bonn, Germany). The laser energy protocol used was 6 W linear endovenous energy density (LEED) 50 J/cm for proximal until media ATK GSV ablation, 5 W LEED 40 J/cm for media ATK until proximal below-the-knee (BTK) GSV, and 2 W LEED 20 J/cm for proximal until distal BTK GSV. The third patient was also treated with EVLA for small saphenous vein severe reflux. Follow-up until 6 months post-EVLA showed significant healing of the ulcer with 14, 16, and 17 VCSS reduction consecutively without any complication.

Conclusion: We’ve reported three cases of patients with active VLU undergoing EVLA until BTK with significant results. The EVLA of GSV until BTK is safe and provides satisfactory results in patients with VLU.
A socio-legal imperative of domestic violence prohibition in Africa vis-a-vis Nigerian legal structure for sexually abused women
Authors: AINA-PELEMO Adetutu Deborah , Olujobi Olusola Joshua , YEBISI EBENEZER TUNDE
Published: April 2023

Domestic violence is a major issue globally. It is one of the most heinous crimes which has and still results in numerous deaths, still receives the least amount of attention, and its negative influence is being underrated. In Africa, it is customarily acceptable for a woman to be beaten by her husband as a form of discipline, and Nigeria is not an exception. To think otherwise, that it cannot be socially acceptable and legally upheld for a man to beat his wife as a form of discipline, is to deny an existing reality. Section 282 of the Nigerian Penal Code encourages men to beat their wives when necessary. This form of permissible violence is often viewed as a family issue. Hence women are hesitant or reluctant to speak up about their experiences. The stigma that usually follows speaking up or voicing out is better imagined than experienced. This study, therefore, provides credible information on domestic violence incidents in Nigeria and Africa. The methodology utilised is the doctrinal legal research method with reports from existing literature and tertiary data sources such as newspapers and website sources. It discusses legislation enacted to prevent and prohibit domestic violence in Nigeria and how influential they have been on the nation at large. By way of comparative analysis, we examine domestic violence occurrences in some selected African countries and the European continents in relation to Nigeria. It also delves into the violation of the principles of gender equality by some Nigerian customs and traditional practices. This study then makes recommendations on how to address the issue. Through its insightful engagement, this study found, among others, that domestic violence is widespread in Africa and that a national law prohibiting the act and holding perpetrators accountable is not only imperative in Nigeria but across the African continent.
Open Data and transparency in artificial intelligence and machine learning: A new era of research
Authors: Rodgers Caellin M. , Ellingson Sally R. , Chatterjee Parag
Published: April 2023

Artificial Intelligence (AI) and machine learning are the current forefront of computer science and technology. AI and related sub-disciplines, including machine learning, are essential technologies which have enabled the widespread use of smart technology, such as smart phones, smart home appliances and even electric toothbrushes. It is AI that allows the devices used day-to-day across people’s personal lives, working lives and in industry to better anticipate and respond to our needs. However, the use of AI technology comes with a range of ethical questions – including issues around privacy, security, reliability, copyright/plagiarism and whether AI is capable of independent, conscious thought. We have seen several issues related to racial and sexual bias in AI in the recent times, putting the reliability of AI in question. Many of these issues have been brought to the forefront of cultural awareness in late 2022, early 2023, with the rise of AI art programs (and the copyright issues arising from the deep-learning methods employed to train this AI), and the popularity of ChatGPT alongside its ability to be used to mimic human output, particularly in regard to academic work. In critical areas like healthcare, the errors of AI can be fatal. With the incorporation of AI in almost every sector of our everyday life, we need to keep asking ourselves— can we trust AI, and how much?

This Editorial outlines the importance of openness and transparency in the development and applications of AI to allow all users to fully understand both the benefits and risks of this ubiquitous technology, and outlines how the Artificial Intelligence and Machine Learning  Gateway on F1000Research meets these needs.
Does receiving a cash grant improve individual earnings in a war-torn country? Evidence from a randomized experiment in Afghanistan
Authors: Kashefi Fatema , Naito Hisahiro
Published: April 2023

Background: In this study, the effect of receiving a non-trivial cash grant and mentorship for business practice on individual earnings in Afghanistan was assessed. 

Methods: This randomized control trial (RCT) included 2177 individuals (n=2177), with the age range of 18-35 years. The amount of cash grant (500 USD) was approximately equal to the gross domestic product (GDP) per capita in the country.  By a process of lottery, eligible applicants were equally divided into the group that received the grant (treatment group) and the group that did not (control group). 

Results: Almost two years after this study, the percentage of increased annual income to the size of this cash grant was approximately 173 % and 69 % for males and females, respectively. This result was much higher than the estimated percentage reported in previous literature assessing the effect of microfinance loans and cash grants in other countries.  The treatment group had 7% higher probability of having an officially registered business than the control group. The treatment group also increased labor supply and employed additional workers, compared to the control group. The male treatment group bought more capital equipment (e.g., trike and commercial carts) than the male control group, while the female treatment group bought more domestic animals.

Conclusion: A non-trivial cash grant has a strong positive effect on the earnings of the recipient of the cash grant in Afghanistan. If the state of increased income continues for the next few years, the sum of increased income will be more than the sum of the administration cost, the interest cost and the amount of cash grant given.  This implies that the project passes the standard criteria to determine the appropriateness of government program. Additionally, we did not find any economically and statistically significant positive effect of mentorship on income.
The science behind soft skills: Do’s and Don’ts for early career researchers and beyond. A review paper from the EU-CardioRNA COST Action CA17129
Authors: Acharya Shubhra , Preda Mihai Bogdan , Papatheodorou Ioanna , Palioura Dimitra , Giardoglou Panagiota , Tsata Vasiliki , Erceg Sanja , Barbalata Teodora , Ben-Aicha Soumaya , Martino Fabiana , Nicastro Laura , Lazou Antigone , Beis Dimitris , Martelli Fabio , Sopic Miron , Emanueli Costanza , Kardassis Dimitris , Devaux Yvan ,   EU-CardioRNA COST Action CA17129.
Published: April 2023

Soft skills are the elementary management, personal, and interpersonal abilities that are vital for an individual to be efficient at workplace or in their personal life. Each work place requires different set of soft skills. Thus, in addition to scientific/technical skills that are easier to access within a short time frame, several key soft skills are essential for the success of a researcher in today’s international work environment. In this paper, the trainees and trainers of the EU-CardioRNA COST Action CA17129 training school on soft skills present basic and advanced soft skills for early career researchers. Here, we particularly emphasize on the importance of transferable and presentation skills, ethics, literature reading and reviewing, research protocol and grant writing, networking, and career opportunities for researchers. All these skills are vital but are often overlooked by some scholars. We also provide tips to ace in aforementioned skills that are crucial in a day-to-day life of early and late career researchers in academia and industry.
The genome sequence of the Heath Knot-horn, Apomyelois bistriatella (Hulst, 1887)
Authors: Hammond James ,   University of Oxford and Wytham Woods Genome Acquisition Lab,   Darwin Tree of Life Barcoding collective,   Wellcome Sanger Institute Tree of Life programme,   Wellcome Sanger Institute Scientific Operations: DNA Pipelines collective,   Tree of Life Core Informatics collective,   Darwin Tree of Life Consortium
Published: April 2023

We present a genome assembly from an individual female Apomyelois bistriatella (the Heath Knot-horn; Arthropoda; Insecta; Lepidoptera; Pyralidae). The genome sequence is 389.6 megabases in span. Most of the assembly is scaffolded into 32 chromosomal pseudomolecules, including the Z and W sex chromosomes. The mitochondrial genome has also been assembled and is 15.2 kilobases in length.
Takayasu's arteritis - a summary of current, clinically relevant knowledge of the disease
Authors: Kłakowicz Philip , Siedlak Agnieszka , Kułakowska Aleksandra , Lepczyński Bartłomiej , Lechowski Sebastian
Published: April 2023

Takayasu's disease, also known as pulseless disease or aortic arch syndrome, is a rare inflammation of the aorta and its branches, and sometimes the pulmonary arteries, which, according to studies, occurs most frequently in people from the Far East and Asian countries. In addition, its incidence is significantly higher in women, and the mean age of affected patients is 45.4 years [1]. The first official clinical case report of the disease by Shimizu and Sano appeared in 1951, while the name of the disease was proposed by Cassamise and Okuda in 1954 to honour the first clinician, Mikito Takayasu, who as early as 1908 presented a case of a young female patient with characteristic fundus lesions associated with pulse disturbances [2].
A New Approach to Capacity Scaling Augmented with Unreliable Machine Learning Predictions
Authors: Rutten Daan , Mukherjee Debankur
Published: April 2023

Modern data centers suffer from immense power consumption. As a result, data center operators have heavily invested in capacity-scaling solutions, which dynamically deactivate servers if the demand is low and activate them again when the workload increases. We analyze a continuous-time model for capacity scaling, where the goal is to minimize the weighted sum of flow time, switching cost, and power consumption in an online fashion. We propose a novel algorithm, called adaptive balanced capacity scaling (ABCS), that has access to black-box machine learning predictions. ABCS aims to adapt to the predictions and is also robust against unpredictable surges in the workload. In particular, we prove that ABCS is [Formula: see text] competitive if the predictions are accurate, and yet, it has a uniformly bounded competitive ratio even if the predictions are completely inaccurate. Finally, we investigate the performance of this algorithm on a real-world data set and carry out extensive numerical experiments, which positively support the theoretical results.

Funding: This work was partially supported by the Division of Computing and Communication Foundations [Grant 2113027]. The authors also acknowledge financial support for this project from the Algorithm and Randomness Center–Transdisciplinary Research Institute for Advancing Data Science Fellowship at Georgia Tech.
Resorbed upper first permanent molars: a case study
Authors: Hardwick Constance , McNamara Catherine , Haworth Jennifer , Puryer James
Published: April 2023

This article describes a case of bilateral impaction of upper second premolars into the upper first permanent molars in a 12-year-old female patient. The extraction of both resorbed upper first molars, and subsequent orthodontic management is described.

CPD/Clinical Relevance: This case highlights the importance of thorough assessment and radiographic imaging of impacted premolars even after they have erupted intra-orally. This is especially important when planning dental extractions as part of an overall orthodontic treatment plan.
Cloud as a malware infiltration channel
Authors: Canzanese Ray
Published: April 2023

It sometimes seems like everything is moving to the cloud, from the apps we use on our phones to major enterprise infrastructure. The result is that your IT landscape is always, to some extent, hybrid, with connections out to, and in from, the cloud at multiple points. The question you need to ask is whether this is opening up holes in your defences by exploiting channels and protocols that you inherently trust. This article examines the increasing popularity of cloud apps as a malware infiltration channel based on real-world data, and highlights potential mitigation strategies.
Squeezing the security budget
Authors: Mansfield-Devine Steve
Published: April 2023

Organisations currently face huge economic pressures, and many of them are having to cut their budgets. But is cyber security really something you can afford to skimp on? And if savings have to be made, are there ways you can spend your security dollar more wisely?
EDUCAÇÃO E AS TDICS: FEEDBACK DOS SUJEITOS ESCOLARES COM SELFIE
Authors: Ramos Ruama , Bussolotti Juliana
Published: April 2023

Todas as escolas traçam e planejam metas, determinam sonhos a serem realizados para que se tornem concretos os projetos políticos pedagógicos. O presente artigo tem como tema Educação e as TDICs: Feedback dos sujeitos escolares com Selfie que objetivou investigar como os atores escolares lidaram com as TDICs desde o período pandêmico até o retorno presencial. Trata-se de uma pesquisa qualitativa e quantitativa utilizando a ferramenta Selfie para análise da autorreflexão dos atores envolvidos em duas instituições de ensino de escolas técnicas. Como conclusão observou-se a importância da formação continuada para docentesprincipalmente visando as competências digitais, fazendo-os ressignificarem suas práticas pedagógicas transformando-se em professores criativos e inovadores em um cenário de fragilidades educacionais, com limitações de infraestruturas, possibilitando ser agentes transformadores agregando as TDICs como ferramentas importantes para auxílio ao processo, tanto nos quesitos de conteúdos quanto em avaliações para o ensino e aprendizagem.
Selective hybrid EDFA/Raman amplifier placement to mitigate lightpath degradation in (C + L) networks
Authors: Sticca Giovanni , Ibrahimi Memedhe , Musumeci Francesco , Di Cicco Nicola , Castoldi Andrea , Pastorelli Rosanna , Tornatore Massimo
Published: April 2023

The sheer traffic increase stimulated by new 5G-and-beyond services requires continuous innovation in designing optical networks that scale in terms of capacity while minimizing equipment cost and ensuring lightpath quality-of-transmission (QoT). Multiband transmission is among the most prominent solutions for addressing capacity needs and consists of extending the transmission spectrum, e.g., to the (C+L)-band. Multiband transmission poses new challenges, mainly due to physical layer impairments such as interchannel stimulated Raman scattering, which causes power transfer among transmission bands with a consequent degradation in lightpaths’ QoT. To mitigate such degradation, we investigate how to introduce hybrid erbium-doped fiber amplifier (EDFA)/Raman amplification (HFA) by selectively upgrading an initial EDFA placement in the network. We propose a genetic algorithm approach to optimize the HFA upgrade process and compare its performance to baseline upgrade strategies. Based on when the HFA upgrade is performed, we consider two HFA upgrade strategies: (i) bulk HFA upgrade (bulk-HFA) and (ii) sequential HFA upgrade (seq-HFA). Bulk-HFA assumes a one-shot optimization that upgrades HFA only once, when all links are operating in the (C+L)-band, whereas seq-HFA assumes a sequential optimization considering an HFA upgrade in multiple steps, triggered by incremental traffic. Numerical experiments run through a national and continental network topology show that an optimized HFA upgrade allows us to avoid lightpath degradation while deploying up to 64% fewer amplifiers compared with baseline strategies that upgrade EDFAs to HFA amplifiers in all eligible spans, i.e., spans longer than 70 km. Moreover, we show that seq-HFA planning achieves higher spectral efficiency compared with bulk-HFA while upgrading a comparable number of EDFAs to HFA.
Scattering and absorption properties modification of optically cleared skeletal muscles: an ex vivo study
Authors: Sheet Ahmed H. , Hamdy Omnia , Abdel-Harith Mohamed
Published: April 2023

Optical clearing is a relatively new approach to enhancing the optical transparency of biological tissues by reducing their scattering properties. The optical clearing effect is achievable via various chemical, physical, and photo-thermal techniques. The present work studied optical parameters of bovine skeletal muscles under different clearing protocols: immersion optical clearing in 99% glycerol and photo-thermal optical clearing via exposure to IR laser irradiation. Moreover, the two techniques were combined with different immersion time intervals after multiple exposure periods to get optimum results. The muscle samples’ diffuse reflectance and total transmittance were measured using a single integrating sphere and introduced to the Kubleka–Munk mathematical model to determine the absorption and reduced scattering coefficients. Results revealed a 6% scattering reduction after irradiating the sample for 10 min and immersing it in glycerol for 18 min and 8% after 20 min of laser irradiation and 18 min of immersion. Moreover, increases of 6.5% and 7.5% in penetration depth were prominent for the total treatment times of 28 min and 38 min, respectively. Furthermore, the measurements’ accuracy and sensitivity were analyzed and evaluated using the receiver operating characteristic method. The accuracy ranged from 0.93 to 0.98, with sensitivity from 0.93 to 0.99 for each clearing protocol. Although laser irradiation and application of 99% glycerol separately produced scattering light reduction, the maximal clearing effect was obtained while irradiating the sample with a laser for 20 min and then immersing it in 99% glycerol for a maximum of 18 min.
Third and fifth order nonlinear susceptibilities in thin HfO2 layers
Authors: Zuber David , Kleinert Sven , Tajalli Ayhan , Steinecke Morten , Jupé Marco , Babushkin Ihar , Ristau Detlev , Morgner Uwe
Published: April 2023

Third harmonic generation (THG) from dielectric layers is investigated. By forming a thin gradient of HfO2 with continuously increasing thickness, we are able to study this process in detail. This technique allows us to elucidate the influence of the substrate and to quantify the layered materials third χ(3)(3ω: ω, ω, ω) and even fifth order χ(5)(3ω: ω, ω, ω, ω, − ω) nonlinear susceptibility at the fundamental wavelength of 1030 nm. This is to the best of our knowledge the first measurement of the fifth order nonlinear susceptibility in thin dielectric layers.
Linear extrapolation method based on multiple equiproportional models for thermal performance prediction of ultra-large array
Authors: Li Defang , Zhang Jinying , Xu Jiushuai , Peiner Erwin
Published: April 2023

Strong demand for developing the photothermal (PT) and electrothermal devices with ultra-large array is increasing. Thermal performance prediction is vital to optimize the key properties of the devices with ultra-large array. Finite element method (FEM) provides a powerful numerical approach for solving complex thermophysics issues. However, for calculating the performance of devices with ultra-large array, it is very memory-consuming and time-consuming to build an equal scale three-dimensional (3D) FEM model. For an ultra-large periodic array irradiated with a local heating source, the use of periodic boundary conditions could lead to considerable errors. To solve this problem, a linear extrapolation method based on multiple equiproportional models (LEM-MEM) is proposed in this paper. The proposed method builds several reduced-size FEM models to carry out simulation and extrapolation, which avoids dealing with the ultra-large arrays directly and greatly reduces the computation consumption. To verify the accuracy of LEM-MEM, a PT transducer with beyond 4000 × 4000 pixels is proposed, fabricated, tested and compared with the prediction results. Four different pixel patterns are designed and fabricated to test their steady thermal properties. The experimental results demonstrate that LEM-MEM has great predictability, and the maximum percentage error of average temperature is within 5.22% in four different pixel patterns. In addition, the measured response time of the proposed PT transducer is within 2 ms. The proposed LEM-MEM not only provides design guidance for optimizing PT transducers, but is also very useful for other thermal engineering problems in ultra-large array that requires facile and efficient prediction strategy.
Tm:CALGO lasers at 2.32 µm: cascade lasing and upconversion pumping
Authors: Dupont Hippolyte , Loiko Pavel , Tyazhev Aleksey , Giordano Luidgi , Pan Zhongben , Chu Hongwei , Li Dechun , Viana Bruno , Hideur Ammar , Guillemot Lauren , Braud Alain , Camy Patrice , Georges Patrick , Druon Frédéric
Published: April 2023

We report on the first laser operation of a disordered Tm:CaGdAlO4 crystal on the 3H4 → 3H5 transition. Under direct pumping at 0.79 µm, it generates 264 mW at 2.32 µm with a slope efficiency of 13.9% and 22.5% vs. incident and absorbed pump power, respectively, and a linear polarization (σ). Two strategies to overcome the bottleneck effect of the metastable 3F4 Tm3+ state leading to the ground-state bleaching are exploited: cascade lasing on the 3H4 → 3H5 and 3F4 → 3H6 transitions and dual-wavelength pumping at 0.79 and 1.05 µm combining the direct and upconversion pumping schemes. The cascade Tm-laser generates a maximum output power of 585 mW at 1.77 µm (3F4 → 3H6) and 2.32 µm (3H4 → 3H5) with a higher slope efficiency of 28.3% and a lower laser threshold of 1.43 W, out of which 332 mW are achieved at 2.32 µm. Under dual-wavelength pumping, further power scaling to 357 mW at at 2.32 µm is observed at the expense of increased laser threshold. To support the upconversion pumping experiment, excited-state absorption spectra of Tm3+ ions for the 3F4 → 3F2,3 and 3F4 → 3H4 transitions are measured for polarized light. Tm3+ ions in CaGdAlO4 exhibit broadband emission at 2.3 - 2.5 µm making this crystal promising for ultrashort pulse generation.
Metal-coated high-temperature strain optical fiber sensor based on cascaded air-bubble FPI-FBG structure
Authors: Liang Jianqiao , Yu Yang , Bian Qiang , Xu Wenjie , Wang Zhencheng , Zhang Shumao , Weng Junjie , Zhu Jiajian , Chen Yong , Hu Xiaoyang , Yang Junbo , Zhang Zhenrong
Published: April 2023

Metal coatings can protect the fragile optical fiber sensors and extend their life in harsh environments. However, simultaneous high-temperature strain sensing in a metal-coated optical fiber remains relatively unexplored. In this study, a nickel-coated fiber Bragg grating (FBG) cascaded with an air bubble cavity Fabry-Perot interferometer (FPI) fiber optic sensor was developed for simultaneous high temperature and strain sensing. The sensor was successfully tested at 545 °C for 0-1000 µɛ, and the characteristic matrix was used to decouple temperature and strain. The metal layer allows easy attachment to metal surfaces that operate at high temperatures, enabling sensor-object integration. As a result, the metal-coated cascaded optical fiber sensor has the potential to be used in real-world structural health monitoring.
Ultrahigh-Q lithium niobate microring resonator with multimode waveguide
Authors: Wei Chuangchuang , Li Jinye , Jia Qianqian , Li Dechen , Liu Jianguo
Published: April 2023

Difficulty in etching lithium niobate (LN) results in a relatively high propagation loss, which necessitates sophisticated processes to fabricate high-quality factor (Q) microresonators. Here, we fabricate a multimode microring resonator with an intrinsic Q of 6 × 106, which exhibits a propagation loss 50 times lower than that of a single-mode LN microring fabricated under the same process. Notably, the excitation of higher-order modes in the multimode microring is effectively suppressed by utilizing the Euler bend. The highly regular transmission spectrum of the resonator demonstrates a free spectral range (FSR) of 56 GHz. Based on this microresonator, we implement a bandpass microwave photonic filter with an ultra-narrow 3 dB bandwidth of 47.5 MHz and a large tuning range of 2–26.5 GHz. It can be anticipated that the combination of existing advanced etching techniques with this work will drive the propagation loss of a LN waveguide closer to the material absorption loss, significantly facilitating the optimization of performance in applications requiring ultrahigh-Q LN microresonators, such as frequency combs, frequency conversion, electro-optic modulation, and quantum photonics.
Propagation of noninteger cylindrical vector vortex beams in a gradient-index fiber
Authors: Yin Xiaojin , Hao Pengqi , Zhang Yupei , Zhao Ziyue , Wu Jinze , Li Jinhong
Published: April 2023

The characteristics of two noninteger cylindrical vector vortex beams
(NCVVBs) propagating through a radial gradient-index (GRIN) fiber are
analyzed on the basis of the generalized Huygens–Fresnel
principle. The NCVVBs exhibit periodic and stable transmission
characteristics in the radial GRIN fiber. Polarization changes, the
presence of spin angular momentum (SAM), and changes in the orbital
angular momentum (OAM) of the NCVVBs are observed at the focal plane
of the radial GRIN fiber. Spin–orbit interactions of NCVVBs are
verified in the radial GRIN fiber for the first time, to the best of
our knowledge.
Fourier convolution–parallel neural network framework with library matching for multi-tool processing decision-making in optical fabrication
Authors: Guo Hao , Wan Songlin , Li Hanjie , Zhang Lanya , Zhang Haoyang , Gu Haojin , Lu Qing , Jiang Guochang , Liang Yichu , Wei Chaoyang , Shao Jianda
Published: April 2023

Intelligent manufacturing of ultra-precision optical surfaces is urgently desired but rather difficult to achieve due to the complex physical interactions involved. The development of data-oriented neural networks provides a new pathway, but existing networks cannot be adapted for optical fabrication with a high number of feature dimensions and a small specific dataset. In this Letter, for the first time to the best of our knowledge, a novel Fourier convolution–parallel neural network (FCPNN) framework with library matching was proposed to realize multi-tool processing decision-making, including basically all combination processing parameters (tool size and material, slurry type and removal rate). The number of feature dimensions required to achieve supervised learning with a hundred-level dataset is reduced by 3–5 orders of magnitude. Under the guidance of the proposed network model, a 260 mm × 260 mm off-axis parabolic (OAP) fused silica mirror successfully achieved error convergence after a multi-process involving grinding, figuring, and smoothing. The peak valley (PV) of the form error for the OAP fused silica mirror decreased from 15.153λ to 0.42λ and the root mean square (RMS) decreased from 2.944λ to 0.064λ in only 25.34 hours. This network framework has the potential to push the intelligence level of optical manufacturing to a new extreme.
Broadband depolarized perfect Littrow diffraction with multilayer freeform metagratings
Authors: Dong Siyu , Zhang Zhanyi , Xie Lingyun , Zhu Jingyuan , Liang Haigang , Wei Zeyong , Shi Yuzhi , Tikhonravov Alexander V. , Wang Zhanshan , Zhou Lei , Cheng Xinbin
Published: April 2023

Littrow diffraction, the
ability to reflect light back
along incident direction, is a key functionality of retroreflectors,
exhibiting wide applications in nanophotonics. However,
retroreflectors have hitherto low working efficiencies and narrow
bandwidths, and work only for a specific polarization, being
unfavorable for integration-optics applications. Here, we propose
a type of metagrating
consisting of an all-dielectric Bragg reflector and a periodic
metasurface with freeform-shaped dielectric resonators, which enables
broadband depolarized perfect Littrow diffraction at optical
frequencies. The physics is governed by exact cancellations of
specular reflections contributed by two Bragg modes in metagratings,
enabled by careful structural optimization to yield the desired
reflection-phase difference of Bragg modes within a wide frequency
band and for two polarizations. As a proof of concept, we
experimentally demonstrate retroreflections with unpolarized absolute
efficiency higher than 98% (99% in design) at 1030–1090 nm using
multilayer freeform metagratings. Our results pave the way for
numerous applications based on high-efficiency Littrow diffraction
(e.g., spectral laser beam combining), which is not bonded to a
specific polarization or frequency.
OsbHLH067, OsbHLH068, and OsbHLH069 redundantly regulate inflorescence axillary meristem formation in rice
Authors: Xu Tingting , Fu Debao , Xiong Xiaohu , Zhu Junkai , Feng Zhiyun , Liu Xiaobin , Wu Changyin
Published: April 2023

Rice axillary meristems (AMs) are essential to the formation of tillers and panicle branches in rice, and therefore play a determining role in rice yield. However, the regulation of inflorescence AM development in rice remains elusive. In this study, we identified no spikelet 1-Dominant (nsp1-D), a sparse spikelet mutant, with obvious reduction of panicle branches and spikelets. Inflorescence AM deficiency in nsp1-D could be ascribed to the overexpression of OsbHLH069. OsbHLH069 functions redundantly with OsbHLH067 and OsbHLH068 in panicle AM formation. The Osbhlh067 Osbhlh068 Osbhlh069 triple mutant had smaller panicles and fewer branches and spikelets. OsbHLH067, OsbHLH068, and OsbHLH069 were preferentially expressed in the developing inflorescence AMs and their proteins could physically interact with LAX1. Both nsp1-D and lax1 showed sparse panicles. Transcriptomic data indicated that OsbHLH067/068/069 may be involved in the metabolic pathway during panicle AM formation. Quantitative RT-PCR results demonstrated that the expression of genes involved in meristem development and starch/sucrose metabolism was down-regulated in the triple mutant. Collectively, our study demonstrates that OsbHLH067, OsbHLH068, and OsbHLH069 have redundant functions in regulating the formation of inflorescence AMs during panicle development in rice.
Immune defense in Drosophila melanogaster depends on diet, sex, and mating status
Authors: Rai Kshama Ekanath , Yin Han , Bengo Arnie Lynn C. , Cheek Madison , Courville Robert , Bagheri Elnaz , Ramezan Reza , Behseta Sam , Shahrestani Parvin
Published: April 2023

Immune defense is a complex trait that affects and is affected by many other host factors, including sex, mating, and dietary environment. We used the agriculturally relevant fungal emtomopathogen,Beauveria bassiana, and the model host organismDrosophila melanogasterto examine how the impacts of sex, mating, and dietary environment on immunity are interrelated. We showed that the direction of sexual dimorphism in immune defense depends on mating status and mating frequency. We also showed that post-infection dimorphism in immune defense changes over time and is affected by dietary condition both before and after infection. Supplementing the diet with protein-rich yeast improved post-infection survival but more so when supplementation was done after infection instead of before. The multi-directional impacts among immune defense, sex, mating, and diet are clearly complex, and while our study shines light on some of these relationships, further study is warranted. Such studies have potential downstream applications in agriculture and medicine.
The geographical dynamics of global R&D collaboration networks in robotics: Evidence from co-patenting activities across urban areas worldwide
Authors: Scherngell Thomas , Schwegmann Katharina , Zahradnik Georg
Published: April 2023

The focus of this study is on the geography of robotics Research and Development (R&D) activities. The objectives are, first, to identify hotspots in robotics R&D worldwide, and second, to characterise structures and dynamics of global robotics R&D collaboration networks through detailed geographical lenses of global urban areas. We use patents as marker for R&D activities, and accordingly focus on technologically oriented R&D, drawing on information from patents applied for between 2002 and 2016. We employ an appropriate search strategy to identify relevant robotics patents based on detailed levels of the Cooperative Patent Classification (CPC) and assign patents to more than 900 global urban areas based on the inventor addresses. The co-patent networks are examined from a Social Network Analysis (SNA) perspective by means of robotics co-patents, contributing to a global network where urban areas are the nodes inter-linked by joint inventive activities recorded in robotics patents. Global SNA measures illustrate structures and dynamics of the network as a whole, while local measures indicate the specific positioning and roles of urban areas in the network. The results are original in characterising the global spatial emergence of this generic new industry, highlighting prominent urban hotspots in terms of specialisation in robotics R&D, pointing to a global shift reflected by the increasing role of emerging economies, in particular China. The global robotics R&D has grown significantly both in total patenting and also in terms of R&D collaboration activities between urban areas. Also, for the networks, growth is not equally distributed, but is rather characterised by significant spatial shifts, both in terms of cities declining or climbing up the specialisation ranking, but even more in terms of the spatial network structure.