bluuebunny/crossref_metadata_2025 huggingface dataset:
Has the frequency of complicated appendicitis changed in children in the first year of the COVID-19 pandemic?
Authors: Öztaş Tülin , Bilici Salim , Dursun Ahmet
Published: January 2023

Background

The COVID-19 pandemic period suggests that the rate of complications may have increased in patients requiring surgical treatment due to the fact that they could not come to the hospital at the onset of the symptom. This study aims to evaluate the difference in the frequency of complicated appendicitis and postoperative complications in the COVID-19 pandemic.

Patients included those who underwent appendectomy in 1 year before the COVID-19 pandemic and in the first year of the pandemic. The patients were categorized into two groups: pre-pandemic and pandemic periods. Clinical and histopathology results were compared between the pre-pandemic and pandemic periods.

Results

A total of 407 patients were included in the study, 207 of whom were included during the pre-pandemic and 200 of whom during the pandemic period. The mean time to hospital admission after the onset of symptoms was 1.3 ± 0.9 days, pre-pandemic, and 1.4 ± 0.8 days during the pandemic group. In the pre-pandemic group, 0.4% intrabdominal abscess developed and 37.5% complicated appendicitis was detected. In the pandemic group, it was found that there were 1% abscess, 0.5% wound infection, 0.5% brid ileus, and 31.9% complicated appendicitis. The pre-pandemic group length of hospitalization was 2.4 ± 0.8 days, and the pandemic was 2.1 ± 0.9 days There was no difference between pre-pandemic and pandemic groups in terms of age, gender, white blood cell count, duration of symptoms, postoperative complications and frequency of complicated appendicitis, and duration of hospitalization.

Conclusions

In the first year of the COVID-19 pandemic, we found that the rate of complicated appendicitis and postoperative complications were not different from pre-pandemic.
A rare case of schwannoma of the nasal vestibule
Authors: Agarwal Ashish , Kumar Pallika , Gupta Noopur , Sharma Nishi
Published: January 2023

Background

Schwannomas of the nose and paranasal are extremely rare. Few schwannomas arising from within the lateral wall of the nose have been reported to date.

Case presentation

A 32-year-old male presented to us with complaints of left-sided nasal obstruction and a mass in his nasal cavity. The evaluation revealed a benign spindle cell lesion arising from within the lateral wall nose which was excised. The final histopathology report revealed a nasal schwannoma.

Discussion

Schwannomas are benign tumors arising from Schwann cells. Schwann cells are responsible for the formation of the myelin sheath. They are rare, slow-growing tumors. Twenty-five to 45% tumors arise in the head and neck, of which only 4% were arising from nasal cavity and paranasal sinuses.

Conclusion

To generate awareness about the varying clinical presentations of Schwannomas in the nose and paranasal sinuses and their management.
Ultrasound Assessment of Gastric Volume in Parturients After High-Flow Nasal Oxygen Therapy
Authors: Zhou Shuangqiong , Cao Xiuhong , Zhou Yao , Xu Zhendong , Liu Zhiqiang
Published: January 2023

BACKGROUND:

High-flow nasal oxygen (HFNO) therapy is widely used in critical care obstetrics to improve oxygenation. Much of the benefit of HFNO is linked to the creation of modest levels of positive airway pressure. Pregnant women are generally considered to be at high risk of regurgitation and aspiration. It is unknown whether HFNO may cause gas insufflation into the stomach and further increase this risk. Therefore, this study aimed to systematically evaluate the possible safety effects of HFNO on gastric volume in healthy fasted parturients.

METHODS:

Sixty fasted parturients scheduled for elective cesarean delivery were enrolled in an observer-blinded, prospective, interventional study. We used ultrasonography to assess changes of antral cross-sectional area (CSA) and gastric volume before and after a 20-minute treatment with HFNO at a rate of 50 L·min–1. The primary outcome was the change in gastric volume from before to after HFNO therapy, and the secondary outcome was the distribution of antral grades.

RESULTS:

In semirecumbent right lateral position, the antral CSA at baseline and after treatment with HFNO was 3.81 (3.01–4.72) cm2 and 3.79 (3.03–4.54) cm2, respectively. The estimated fluid volume at baseline and after treatment with HFNO was 38.51 (33.39–54.62) mL and 39.71 (32.00–52.82) mL, respectively. All participants had either a grade 0 or grade 1 antrum, and most of them had a grade 0 antrum. There was no significant difference in gastric volume and distribution of antral grades before and after HFNO therapy. Gastric air distension was not shown in any of the parturients either at baseline or after treatment with HFNO.

CONCLUSIONS:

Treatment with HFNO for 20 minutes at flow rates up to 50 L·min–1 did not increase gastric volume in term pregnant women breathing spontaneously when evaluated by gastric ultrasonography.
American Conservatism Unmoored
Authors: Stoneman Ethan , Packer Joseph
Published: January 2023

The last decade witnessed a drastic reconfiguration of American conservatism by way of a newly emergent and energized dissident right. Beyond the question of ideology, this article argues that an essential aspect of this realignment occurs at the level of strategy, specifically with the adoption of agitational tactics pioneered by the progressive left. It attempts to make sense of this sea change, first, by tracing in broad strokes the history of American conservatism's opposition to much of what passes for agitational politics. It then examines the right's seemingly abrupt adoption of three species of agitational practice: Alinsky-styled radicalism, identity politics, and accelerationism. It concludes by discussing the implications of this shift, in terms of what it means both for the future of conservative discourse and for leftist groups who must now take into account the possibility of having to outmaneuver their own set of tactics.
Individual response in body mass and basal metabolism to the risks of predation and starvation in passerines
Authors: Broggi Juli , Nilsson Jan-Åke
Published: January 2023

Wintering energy management in small passerines has focused on the adaptive regulation of the daily acquisition of energy reserves within a starvation–predation trade-off framework. However, the possibility that the energetic cost of living, i.e. basal metabolic rate (BMR), is being modulated as part of the management energy strategy has been largely neglected. Here, we addressed this possibility by experimentally exposing captive great tits (Parus major) during winter to two consecutive treatments of increased starvation and predation risk for each individual bird. Body mass and BMR were measured prior to and after each week-long treatment. We predicted that birds should be lighter but with a higher metabolic capacity (higher BMR) as a response to increased predation risk, and that birds should increase internal reserves while reducing their cost of living (lower BMR) when exposed to increased starvation risk. Wintering great tits kept a constant body mass independently of a week-long predation or starvation treatment. However, great tits reduced the cost of living (lower BMR) when exposed to the starvation treatment, while BMR remained unaffected by the predation treatment. Energy management in wintering small birds partly relies on BMR regulation, which challenges the current theoretical framework based on body mass regulation.
Risk of mental disorders and malnutrition in elderly COVID-19 survivors: An observational study
Authors: Theresa Ria Maria , Dewiastuti Marlina , Ningsih Sri Rahayu , Safira Lisa
Published: January 2023

Background: The incidence rate of COVID-19 is around 11-15% in the elderly. The case fatality rate (CFR) of COVID-19 in the elderly is around 8.9% and increases with age. The risk of mental disorders and malnutrition is increased in COVID-19 survivors. Continuous inflammatory conditions result in a state of hypercatabolism that can disrupt brain neuroendocrine and protein consumption for the formation of acute-phase reactant proteins. Mental disorders and malnutrition can lead to fragility. The aim of this study was to assess the risk of mental disorders and malnutrition in elderly survivors of COVID-19.

Methods: This research was a cross-sectional study. The results of the research on age, disease symptoms, and comorbidities have proven that they are risk factors for mental disorders and malnutrition in elderly COVID-19 survivors. This study used total sampling and included 100 study subjects. The research was conducted in Depok for two months; data was collected directly through shared questionnaires and direct anthropometric measurements. The questionnaires used were the SRQ-20 tool for mental disorder screening and MNA for malnutrition screening.

Results: The risk factors for mental disorders were age over 70 years old OR 3 (CI 1.0-8.8), severe COVID-19 symptoms OR 4.5 (CI 1.2-16.17), and multi-comorbidity OR 2.3 (CI 0.6-8.8). The risk factors for malnutrition were age higher than 70 years old OR 2.5 (CI 0.8-7.9), moderate COVID-19 symptoms OR 6.3 (CI 2.0-19.81), and multi-comorbidity OR 6.6 (CI 1.5-28.5).

Conclusions: Those infected with COVID-19 have a risk of mental disorders and malnutrition, especially in geriatrics, and this risk increases with age.
Equatorial Plasma Bubbles Identification with Single Frequency GNSS Receiver Data
Authors: Padma Tatiparti , Raghunath Swapna , Chintalapati Usha Kumari
Published: January 2023

Ionosphere is the highest contributor of positional error in Global Navigation Satellite System (GNSS) owing to the trans-ionospheric signal delay, distortion and possible outage. Equatorial and Low latitudinal ionosphere experiences frequent perturbations in plasma density most of which is due to the presence of Equatorial Plasma Bubbles (EPBs). In order to improve positional and navigational precision of GNSS signals, EPBs must be identified and corrected. EPBs begin to manifest post-sunset and continue to thrive past midnight. This paper proposes a Rate of TEC Index (ROTI) based EPB identifier using single frequency GNSS receiver data. GNSS data has been collected from the archives of Scripps Orbit and Permanent Array Center (SOPAC). The raw data has been downloaded from the global continuous network station, IISC, located at Bangalore (13.0219°N, 77.5671°E) in Receiver Independent Exchange (RINEX) format. Analysis of EPB occurrence has been carried out for six consecutive years in the second half of the 24th solar cycle (2014-2019). The results show a clear surge in the number of EPBs identified in the course of equinoxes.
Developing the next generation of renewable energy technologies: an overview of low-TRL EU-funded research projects
Authors: Pérez Caballero Laura María , Neira D'Angelo Fernanda , Tschentscher Roman , Gottschalk Axel , Salem Ahmed M. , Carbonell Daniel , Dudita-Kauffeld Mihaela , Bruch Arnaud , Alamaro Eleonora , Pasquini Luca , Ceroni Paola , Grozdanova Anastasia , Privitera Stefania , Vermang Bart , Schulz Philip , Mencarelli Davide , Pierantoni Luca , Midrio Michele , Leithead William , Gurruchaga Ignacio , Haberl Robert , Vermaut Jasper , Kauffeld Michael
Published: January 2023

A cluster of eleven research and innovation projects, funded under the same call of the EU’s H2020 programme, are developing breakthrough and game-changing renewable energy technologies that will form the backbone of the energy system by 2030 and 2050 are, at present, at an early stage of development. These projects have joined forces at a collaborative workshop, entitled ‘Low-TRL Renewable Energy Technologies’, at the 10th Sustainable Places Conference (SP2022), to share their insights, present their projects’ progress and achievements to date, and expose their approach for exploitation and market uptake of their solutions.
Intellectual disability in the children of the Avon Longitudinal Study of Parents and Children (ALSPAC)
Authors: Madley-Dowd Paul , Thomas Richard , Boyd Andy , Zammit Stanley , Heron Jon , Rai Dheeraj
Published: January 2023

Background: Intellectual disability (ID) describes a neurodevelopmental condition involving impaired cognitive and functional ability. Here, we describe a multisource variable of ID using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). 

Methods: The multisource indicator variable for ID was derived from i) IQ scores less than 70 measured at age 8 and at age 15, ii) free text fields from parent reported questionnaires, iii) school reported provision of educational services for individuals with a statement of special educational needs for cognitive impairments, iv) from relevant READ codes contained in GP records, iv) international classification of disease diagnoses contained in electronic hospital records and hospital episode statistics and v) recorded interactions with mental health services for ID contained within the mental health services data set. A case of ID was identified if two or more sources indicated ID. A second indicator, labelled as “probable ID”, was created by relaxing the cut off in IQ scores to be less than 85. An indicator variable for known causes of ID was also created to aid in aetiological studies where ID with a known cause may need to be excluded. 

Results: 158 of 14,370 participants (1.10%) were indicated as having ID by two or more sources and 449 (3.12%) were indicated as having probable ID when the criteria for IQ scores was relaxed to less than 85. There were 476 participants (3.31%) with 1 or fewer sources of available information on ID; these participants had their multisource variable set to missing. The number of cases of ID with known cause was 31 (0.22% of the cohort, 19.6% of those with ID).  

Conclusions: The multisource variable of ID can be used in future analyses on ID in ALSPAC children.
The genome sequence of the Gold Triangle, Hypsopygia costalis (Fabricius, 1775)
Authors: Boyes Douglas ,   University of Oxford and Wytham Woods Genome Acquisition Lab,   Wellcome Sanger Institute Tree of Life programme,   Wellcome Sanger Institute Scientific Operations: DNA Pipelines collective,   Tree of Life Core Informatics collective, Hammond James ,   Darwin Tree of Life Consortium
Published: January 2023

We present a genome assembly from an individual male Hypsopygia costalis (the Gold Triangle; Arthropoda; Insecta; Lepidoptera; Pyralidae). The genome sequence is 818 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules with the Z sex chromosome assembled. The mitochondrial genome has also been assembled and is 15.3 kilobases in length. Gene annotation of this assembly on Ensembl identified 19,248 protein coding genes.
Trends and Determinants of Birth Registration Completeness in Zimbabwe, 2005-2015
Authors: Musizvingoza Ronald , Wekwete Naomi N. , Mangombe Kudzaishe , Zinumwe Garikai
Published: January 2023

Childbirth registration in Zimbabwe has decreased over the years, yet the risk factors associated with this incompleteness have not been explored. This study investigates the trends in birth registration completeness and factors associated with the decrease in birth registration among children aged 0-5 years from 2005-2015. We use data from the, 2005-06, 2010-11 and 2015 Zimbabwe Demographic and Health Survey. Trends in birth registration completeness based on survey year were calculated and multivariable logistic regression models were used to estimate the predictors of birth registration. Birth registration completeness was 75.4 percent, 47.3 percent, and 43.8 percent in 2005, 2010, and 2015, respectively. Inequities in birth registration completeness become apparent when examined by wealth, urban/rural location, geographical region, maternal education, healthcare utilisation, and marital status. Child age, maternal education, marital status, household wealth status, residence, province, and delivery place were significant predictors of birth registration. Efforts to improve birth registration in Zimbabwe should target children born at home, children born to single and young mothers, and children whose mothers are poor and reside in rural areas.
Malignant Syphilis: A Rare Case of Early Secondary Syphilis in an Immunocompetent Patient
Authors: Sá Lopes Ramiro , Monteiro Ana Sara , Saez Rosário , Candeias Carlos , Mendonça Catarina
Published: January 2023

Early malignant syphilis is an uncommon form of secondary syphilis and characterized by pleomorphic multiple round-to-oval papules, some with necrosis, and associated with systemic signs and symptoms. Usually seen in immunosuppressed patients, mainly those infected with HIV, it can also be observed in immunocompetent patients. We report a case in a young healthy woman with the characteristic features of the disease and with favourable skin lesion evolution after appropriate treatment with penicillin.
‘Granulitis’: defining a common, biofilm-induced, hyperinflammatory wound pathology
Authors: Murphy Christine A , Bowler Philip G , Chowdhury M Fahad
Published: January 2023

The hard-to-heal (chronic) wound condition, now believed to be inextricably linked to the presence of microbial biofilm, has posed challenges in translating scientific understanding to clinical practice in recent decades. During this time, multiple descriptive terms of the wound pathology have been described, including critical colonisation, biofilm infection and inflammatory stasis. However, the absence of naming this disease state as a specifically identified condition that is tangible to treat has led to some confusion and delay in possible therapeutic approaches. When there is clinical uncertainty of wound status, antibiotics are too often inappropriately administered as a precaution. We therefore propose that introducing the term ‘granulitis’ (inflamed, unhealthy granulation tissue) could be used to identify the biofilm-induced, persistent inflammatory wound condition. This will help to raise clinician and public awareness of the condition, guide appropriate and prompt local wound hygiene, and encourage allocation of adequate resources to improve wound healing outcomes globally.
Stomal and peristomal complications management: a retrospective study
Authors: Michalak Jill , Spitler Carey , Simman Richard , Sharp Kaitlyn , Pei Mitchell
Published: January 2023

Objective:

Correctly identifying and managing stomal and peristomal complications are key to assisting individuals with an ostomy when they are facing challenges with self-care. Providers that are knowledgeable and experienced with stomal and peristomal care are vital when complications arise. Providing care that is consistent with findings in current high evidence-based literature supports the goal of providing optimal patient outcomes in a timely manner. The objective of this study was to explore stomal and peristomal that presented in an outpatient ostomy clinic and compare these interventions with information found in the literature.

Method:

This retrospective study used a sample population of convenience that included adult patients aged ≥18 years who presented for stomal or peristomal complications in an outpatient ostomy clinic in northwest Ohio, US. Electronic medical records were reviewed to determine the presenting stomal or peristomal complication(s) of each patient and treatment was provided or prescribed. The interventions were then compared with information found in the literature. Length of treatment and reasons for referral to the surgeon that created the stoma were also reviewed.

Results:

This study showed that interventions for adult individuals with a stomal or peristomal complications that presented to the clinic were consistent with that found in the literature. This study also sought to deliver information to healthcare providers that may not be directly involved in ostomy care, helping to increase their understanding of problems that patients with an ostomy may experience.

Conclusion:

This study showed that interventions completed in this setting where the research took place was consistent with information found in literature.
Computational Search of Long Skew-symmetric Binary Sequences with High Merit Factors
Authors: Brest Janez , Bošković Borko
Published: January 2023

In this paper, we present a computational search for best-known merit factors of longer binary sequences with an odd length. Finding low autocorrelation binary sequences with optimal or suboptimal merit factors is a very difficult optimization problem. An improved version of the heuristic algorithm is presented and tackled to search for aperiodic binary sequences with good autocorrelation properties. High-performance computations with the execution of our stochastic algorithmto search skew-symmetric binary sequences with high merit factors. After experimental work, as results, we present new binary sequences with odd lengths between 201 and 303 that are skew-symmetric and have the merit factor F greater than 8.5. Moreover, an example of a binary sequence having F > 8 has been found for all odd lengths between 201 and 303. The longest binary sequence with F > 9 found to date is of length 255.
Mathematical Incorrectness of So-Called Higuchi‘s Fractal Dimension
Authors: Martišek Dalibor
Published: January 2023

The so-called Higuchi’s method of fractal dimension estimation is widely used and the term Higuchi’s fractal dimension even occurs in many publications. This paper deals with this method from a mathematical point of view. Terms distance and dimension and its basic properties are explained and Higuchi’s dimension according the original source is defined. The definition of Higuchi’s dimension was compared with the mathematical definition of distance and dimension. It is shown, that the definition of Higuchi’s dimension does not satisfy axioms of distance and dimension. The so-called Higuchi’s method and Higuchi’s dimension are mathematically incorrect. Therefore, all results achieved by this method are scientifically unreliable.
Integrating evidence and public engagement in policy work: an empirical examination of three UK policy organisations
Authors: Hill O’Connor Clementine , Smith Katherine , Stewart Ellen
Published: January 2023

Alongside efforts to improve evidence use in policy, grassroots demands and governance-driven democratisation are informing an ever-increasing range of public engagement processes in UK policy. This article explores how these simultaneous efforts intersect within three policy organisations working at different levels of UK policy: local (Sheffield City Council), regional (Greater Manchester Combined Authority) and national (devolved) (Scottish Government). Employing documentary analysis and 51 interviews with individuals working in these organisations, we argue that there are organisational similarities in approaches to evidence and engagement, including: conceiving of both ‘data’ (statistics tracked by internal analysts) and ‘evidence’ (external analysis) in primarily quantified terms; and a tendency to limit the authority of publics to advising and consulting on predefined issues. Yet, we also find growing interest in more in-depth understandings of publics (for example, via ‘lived experiences’) but uncertainty about how to use these qualitative insights in settings that have institutionalised quantitative approaches to evidence. We identify four distinct responses: (1) prioritising public engagement; (2) strategically using public engagement and evidence to support policy proposals; (3) prioritising quantified evidence and data; and (4) attempting to integrate these distinct knowledge types. Surprisingly (given the organisational importance afforded to metrics), we categorised most interviewees in Cluster 4. Finally, we explore how interviewees described trying to do this kind of integration work, before reflecting on the promise and limitations of the various mechanisms that interviewees identified.
High-efficiency and CMOS compatible out-of-plane light emission based on a silicon coupler
Authors: She Xiaojuan , Huang Haiyang , Zhao Yingxuan , Liao Han , Zhu Junbo , Li Yang , Huang Rui , Liu Hongbao , Sheng Zhen , Gan Fuwan
Published: January 2023

Photonic antennas are critical in applications such as spectroscopy,
photovoltaics, optical communications, holography, and sensors. Metal
antennas are widely used because of their small size, but they are
difficult to be compatible with a CMOS. All-dielectric antennas are
easier to integrate with Si waveguides, but are generally larger in
size. In this paper, we propose the design of a small-sized,
high-efficiency semicircular dielectric grating antenna. The antenna’s
key size is only

2.37

µ

m

×

4.74

µ

m

, and the emission efficiency reaches
over 64% in the wavelength range from 1.16 to 1.61 µm. The
antenna provides a new, to the best of our knowledge, approach for
three-dimensional optical interconnections between different decks of
integrated photonic circuits.
Random laser emission from neodymium doped alumina lead–germanate glass powder
Authors: Câmara Josivanir G. , da Silva Davinson M. , Kassab Luciana R. P. , de Araújo Cid B.
Published: January 2023

Random lasing is reported for the first time, to our knowledge, in neodymium doped alumina lead–germanate (GPA) glass powder. The samples were fabricated by a conventional melt-quenching technique at room temperature, and x-ray diffraction was used to confirm the amorphous structure of the glass. Powders with average grain size of about 2 µm were prepared by grinding the glass samples and using sedimentation in isopropyl alcohol to remove the coarsest particles. The sample was excited using an optical parametric oscillator tuned to 808 nm, in resonance with the neodymium ion (

N
d

3
+

) transition

4

I

9

/

2

→

{
4

F

5

/

2

,

2

H

9

/

2

}

. Random laser (RL) emission at 1060 nm (

N
d

3
+

transition:

4

F

3

/

2

→

4

I

11

/

2

) was observed for an energy fluence excitation threshold (

E
F

E

r
m
t
h

) of about

0.3

m
J

/

m
m

2

. Above the

E
F
E

t
h

, a short RL pulse in the nanosecond range is observed, corroborating the lasing process. Contrary to what one might suppose, the use of large quantities of neodymium oxide (10% wt. of

N
d

2

O

3

) in the GPA glass, which leads to luminescence concentration quenching (LCQ), is not a disadvantage, once stimulated emissions (RL emission) occur faster than the nonradiative energy-transfer time among

N
d

3
+

ions responsible for the LCQ.
Calibration reinforcement regularizations for optimized snapshot spectral imaging
Authors: Garcia Hans , Bacca Jorge , Wohlberg Brendt , Arguello Henry
Published: January 2023

Optical coding is a fundamental tool in snapshot computational spectral imaging for capturing encoded scenes that are then decoded by solving an inverse problem. Optical encoding design is crucial, as it determines the invertibility properties of the system sensing matrix. To ensure a realistic design, the optical mathematical forward model must match the physical sensing. However, stochastic variations related to non-ideal characteristics of the implementation exist; therefore, these variables are not known a priori and have to be calibrated in the laboratory setup. Thus, the optical encoding design leads to suboptimal performance in practice, even if an exhaustive calibration process is carried out. This work proposes an algorithm to speed up the reconstruction process in a snapshot computational spectral imaging, in which theoretically optimized coding design is distorted by the implementation process. Specifically, two regularizers are proposed that perform the gradient algorithm iterations of the distorted calibrated system in the direction of the originally, theoretically optimized system. We illustrate the benefits of the reinforcement regularizers for several state-of-the-art recovery algorithms. For a given lower bound performance, the algorithm converges in fewer iterations due to the effect of the regularizers. Simulation results show an improvement of up to 2.5 dB of peak signal-to-noise ratio (PSNR) when fixing the number of iterations. Furthermore, the required number of iterations reduces up to 50% when the proposed regularizers are included to obtain a desired performance quality. Finally, the effectiveness of the proposed reinforcement regularizations was evaluated in a test-bed implementation, where a better spectral reconstruction was evidenced when compared with a non-regularized system’s reconstruction.
Unifying fast computer-generated hologram calculation and prepress for new and existing production techniques
Authors: Brkić Antun Lovro , Cviljušac Vladimir , Skenderović Hrvoje , Rakić Mario
Published: January 2023

Directed by successfully manufacturing the computer-generated hologram
(CGH) using the computer-to-film (CtF) process, we present, to the
best of our knowledge, a new method for low-cost and fast hologram
manufacturing. This new method allows for advances in the CtF process
and manufacturing using new techniques in hologram production. These
techniques include computer-to-plate, offset printing, and surface
engraving utilizing the same CGH calculations and prepress. With an
advantage in cost and the possibility to be mass manufactured, the
aforementioned techniques combined with the presented method have a
solid foundation to be implemented as security elements.
Reconfigurable photonic integrated transmitter for metro-access networks
Authors: Kaszubowska-Anandarajah Aleksandra , Ahmad Syed Tajammul , Roeloffzen Chris G. H. , van Dijk Paulus W. L. , Sharma Ankit , Srivastava Manas , Lakshmijayasimha Prajwal D. , Gutierrez Pascual M. Deseada , Smyth Frank , Braddell Jules , Anandarajah Prince M.
Published: January 2023

A reconfigurable photonic integrated transmitter, enabling dynamic resource allocation in the metro-access network, is proposed. The device consists of a multicarrier sliceable bandwidth variable transmitter (MC-SBVT) realized in indium phosphide and a silicon-nitride-based optical cross-connect (OXC). The proposed architecture delivers full flexibility in terms of the choice of data format/bandwidth, channel spacing, and wavelength assignment. The functional design of the MC-SBVT and OXC as well as their practical realization are discussed. Preliminary characterization results of the photonic-integrated-circuit-based MC-SBVT, demonstrating the reconfigurability of the device, are also presented.
Complete and robust energy conversion by sum frequency generation based on invariant engineering
Authors: Zhang Cong-Fu , Wang Zhao-Lu , Liu Hong-Jun
Published: January 2023

An analytical method is proposed in this paper to achieve complete energy conversion in sum frequency generation based on the Lewis-Riesenfeld invariants theory. In the proposed scheme, a quasi-adiabatic single control parameter model is established, and the value of single control parameter is selected to make the initial eigenstate perfectly converted to the final eigenstate as needed. Corresponding to the nonlinear frequency conversion process, a nonlinear crystal structure is designed by inverse engineering using the optimal control theory. It is robust against perturbations of the coupling coefficient and phase mismatch, including variations in the pump intensity and crystal polarization period, and achieves almost 100% conversion efficiency at any crystal length. Theoretical simulations show that frequency conversion can be achieved in the wavelength range of 2.6 µm–3.6 µm, and the spectral bandwidth of conversion efficiency exceeds 50% and approaches 400 nm when the crystal length L = 1 mm.
Performance investigation of an ambiguity function-shaped waveform (AFSW) using a photonics-based radar system
Authors: Almohimmah Esam M. , Aldayel Omar , Ali Jameel , Ragheb Amr M. , Almaiman Ahmed , Esmail Maged A. , Alshebeili Saleh A.
Published: January 2023

In this work, we investigate the performance of an ambiguity function-shaped waveform (AFSW) using a millimeter-wave photonics-based radar system at 100 GHz. An AFSW is a radar waveform whose ambiguity function can be shaped to increase the peak-to-sidelobe ratio (PSR) for better detectability of targets in a desired range/velocity region. To the best of the authors’ knowledge, this paper is the first in the literature that investigates the performance of such a waveform in a photonics-based radar system. We experimentally compare the AFSW performance to the conventional frequency-modulated continuous wave (FMCW). The experimental results show the ability of the AFSW to achieve a PSR of 38.35 dB compared to the PSR of 14.5 dB obtained using the conventional FMCW. Moreover, we investigate the effects of some optical system impairments on the AFSW, such as: (i) optical modulator nonlinearity, (ii) optical modulator bias drift, and (iii) sampling offset error between the transmitter and receiver.
Stand-alone optical spinning tweezers with tunable rotation frequency
Authors: Hameed N. , Zeghdoudi T. , Guichardaz B. , Mezeghrane A. , Suarez M. , Courjal N. , Bernal M.-P. , Belkhir A. , Baida F. I.
Published: January 2023

Advances in optical trapping design principles have led to tremendous progress in manipulating nanoparticles (NPs) with diverse functionalities in different environments using bulky systems. However, efficient control and manipulation of NPs in harsh environments require a careful design of contactless optical tweezers. Here, we propose a simple design of a fibered optical probe allowing the trapping of dielectric NP as well as a transfer of the angular momentum of light to the NP inducing its mechanical rotation. A polarization conversion from linearly-polarized incident guided to circularly transmitted beam is provoked geometrically by breaking the cylindrical symmetry of a coaxial nano-aperture that is engraved at the apex of a tapered metal coated optical fiber. Numerical simulations show that this simple geometry tip allows powerful light transmission together with efficient polarization conversion. This guarantees very stable trapping of quasi spherical NPs in a non-contact regime as well as potentially very tunable and reversible rotation frequencies in both directions (up to 45 Hz in water and 5.3 MHz in air for 10 mW injected power in the fiber). This type of fiber probe opens the way to a new generation of miniaturized tools for total manipulation (trapping, sorting, spinning) of NPs.
Electromagnetic fields between moving mirrors: singular waveforms inside Doppler cavities
Authors: Koutserimpas Theodoros T. , Valagiannopoulos Constantinos
Published: January 2023

Phenomena of wave propagation in dynamically varying structures have reemerged as the temporal variations of the medium’s properties can extend the possibilities for electromagnetic wave manipulation. While the dynamical change of the electromagnetic medium’s properties is a difficult task, the movement of scatterers is not. In this paper, we analyze the electromagnetic fields trapped inside two smoothly moving mirrors. We employ the method of characteristics and take into account the relativistic phenomena to show that the temporally and spatially local Doppler effects can filter and amplify the electromagnetic signal, tailoring the k − and ω −content of the transients. It is shown using the Doppler factor and the change of the distance between neighbor characteristics that the dynamical movement of the boundaries can lead to condensation or dilution of characteristics resulting in field amplification or attenuation, respectively. In the case of periodically moving mirrors the field distribution is shown that asymptotically leads to exponentially growing delta-like wave packets at discrete points of space with a limiting number of peaks due to the fact that the velocity of the mechanical vibrations cannot exceed that of light. The theoretical analysis is also verified by FDTD simulations and is connected with the theory of mode locking.
Kerr soliton frequency comb generation by tuning the coupling coefficient in coupled nonlinear microcavities
Authors: Cheng Zihao , Huang Dongmei , Li Feng , Lu Chao , Wai P. K. A.
Published: January 2023

Kerr soliton frequency comb generation in nonlinear microcavities with compact configurations are promising on-chip sources. Current Kerr comb generation by using a single microcavity with a tunable CW pump laser or high-power femtosecond pulse pump are difficult to be integrated on chip. In this paper, we propose an on-chip soliton comb generation scheme by tuning the coupling coefficient of two coupled microcavities instead of tuning the wavelength of the cw pump laser or using a pulsed pump laser in a single microcavity. The two microcavities are assumed to be identical. We showed by numerical simulation that Kerr comb generation is possible in both the blue and red detuned regions of the main microcavity in the coupled cavity system. We further found that the range and boundary of the soliton generation region of the couple microcavities depend on the coupling coefficient between the coupled cavities. To ensure that the modes being coupled have identical optical paths, we designed a Sagnac loop structure which couples the clockwise and counterclockwise modes in a single microcavity and demonstrated Kerr comb generation in both the blue and red detuned regions by tuning the coupling coefficient. The proposed Kerr comb generation scheme can be utilized for chip-scale integrated soliton comb sources, which will contribute to the development of on-chip applications.
High-quality factor mid-infrared absorber based on all-dielectric metasurfaces
Authors: Yang Fuming , Liang Zhongzhu , Meng Dejia , Shi Xiaoyan , Qin Zheng , Dai Rui , Sun Chunfang , Ren Yingzheng , Feng Jiajing , Liu Wenjun
Published: January 2023

The absorption spectrum of metasurface absorbers can be manipulated by changing structures. However, narrowband performance absorbers with high quality factors (Q-factor) are hard to achieve, mainly for the ohmic loss of metal resonators. Here, we propose an all-dielectric metasurface absorber with narrow absorption linewidth in the mid-infrared range. Magnetic quadrupole resonance is excited in the stacked Ge-Si3N4 nanoarrays with an absorption of 89.6% and a Q-factor of 6120 at 6.612 µm. The separate lossless Ge resonator and lossy Si3N4 layer realize high electromagnetic field gain and absorption, respectively. And the proposed method successfully reduced the intrinsic loss of the absorber, which reduced the absorption beyond the resonant wavelength and improved the absorption efficiency of Si3N4 in the low loss range. Furthermore, the absorption intensity and wavelength can be modulated by adjusting the geometric parameters of the structure. We believe this research has good application prospects in mid-infrared lasers, thermal emitters, gas feature sensing, and spectral detection.
Infrared spectral soot emission for robust and high-fidelity flame thermometry
Authors: Ma Liuhao , Du Wei , Wen Daxin , Wang Yu
Published: January 2023

Spectral soot emission (SSE) in the visible spectrum is a popular technique for non-intrusive thermometry in sooting flames. However, its accuracy is restricted by uncertainties in the wavelength dependence of soot optical properties. We propose a novel infrared spectral soot emission method that successfully addresses this issue. Comprehensive light extinction experiments were firstly conducted to explore the spectral variation of soot optical property. The results indicated a wavelength independence of the soot absorption function provided the wavelength of the incident light is larger than 1000 nm, thereby indicating through the Kirchhoff law the potential of a robust thermometry using infrared (>1000 nm) spectral soot emissions. Proof-of-concept experiments were performed for sooting premixed flames of ethylene with different equivalence ratios. The results demonstrated that the new method provided more accurate temperature results compared with its visible-NIR counterpart, particularly at flame positions where nascent soot particles are present. The proposed method is, to our knowledge, the first infrared spectral soot emission-based thermometry, and is believed to offer a solution to improving the fidelity of SSE with a cost-effective optical setup.
Stokes shift spectroscopy and machine learning for label-free human prostate cancer detection
Authors: Pu Yang , Wu Binlin , Mo Haiding , Alfano Robert R.
Published: January 2023

The Stokes shift spectra (S3) of human cancerous and normal prostate tissues were collected label free at a selected wavelength interval of 40 nm to investigate the efficacy of the approach based on three key molecules—tryptophan, collagen, and reduced nicotinamide adenine dinucleotide (NADH)—as cancer biomarkers. S3 combines both fluorescence and absorption spectra in one scan. The S3 spectra were analyzed using machine learning (ML) algorithms, including principal component analysis (PCA), nonnegative matrix factorization (NMF), and support vector machines (SVMs). The components retrieved from the S3 spectra were considered principal biomarkers. The differences in the weights of the components between the two types of tissues were found to be significant. Sensitivity, specificity, and accuracy were calculated to evaluate the performance of SVM classification. This research demonstrates that S3 spectroscopy is effective for detecting the changes in the relative concentrations of the endogenous fluorophores in tissues due to the development of cancer label free.
Continuous-variable quantum key distribution with on-chip light sources
Authors: Li Lang , Wang Tao , Li Xinhang , Huang Peng , Guo Yuyao , Lu Liangjun , Zhou Linjie , Zeng Guihua
Published: January 2023

Integrated quantum key distribution (QKD) systems based on photonic chips have high scalability and stability, and are promising for further construction of global quantum communications networks. On-chip quantum light sources are a critical component of a fully integrated QKD system; especially a continuous-variable QKD (CV-QKD) system based on coherent detection, which has extremely high requirements for the light sources. Here, for what we believe is the first time, we designed and fabricated two on-chip tunable lasers for CV-QKD, and demonstrated a high-performance system based on these sources. Because of the high output power, fine tunability, and narrow linewidth, the involved on-chip lasers guarantee the accurate shot-noise-limited detection of quantum signals, center wavelength alignment of nonhomologous lasers, and suppression of untrusted excess noise. The system’s secret key rate can reach 0.75 Mb/s at a 50 km fiber distance, and the secure transmission distance can exceed 100 km. Our results mark a breakthrough toward building a fully integrated CV-QKD, and pave the way for a reliable and efficient terrestrial quantum-secure metropolitan area network.
Generating superposed terahertz perfect vortices via a spin-multiplexed all-dielectric metasurface
Authors: Huang Fan , Xu Quan , Liu Wanying , Wu Tong , Gu Jianqiang , Han Jiaguang , Zhang Weili
Published: January 2023

Perfect optical vortices (POVs), characterized as a ring radius independent of topological charge (TC), possess extensive application in particle manipulation and optical communication. At present, the complex and bulky optical device for generating POVs has been miniaturized by leveraging the metasurface, and either spin-dependent or spin-independent POV conversions have been further accomplished. Nevertheless, it is still challenging to generate superposed POVs for incidences with orthogonal circular polarization. Here, a spin-multiplexed all-dielectric metasurface method for generating superposed POVs in the terahertz frequency range is proposed and demonstrated. By using the multiple meta-atom comprised structure as the basic unit, the complex amplitude of two superposed POVs is modulated, decoupled, and subsequently encoded to left- and right-handed circular polarization incidences. Furthermore, two kinds of metasurfaces are fabricated and characterized to validate this controlling method. It is demonstrated that the measured intensity and phase distributions match well with the calculation of the Rayleigh–Sommerfeld diffraction integral, and the radius of superposed POVs is independent of TCs. This work provides promising opportunities for developing ultracompact terahertz functional devices applied to complex structured light generation and terahertz communication, and exploring sophisticated spin angular momentum and orbital angular momentum interactions like the photonic spin-Hall effect.
Automated grading system of retinal arterio-venous crossing patterns: A deep learning approach replicating ophthalmologist’s diagnostic process of arteriolosclerosis
Authors: Li Liangzhi , Verma Manisha , Wang Bowen , Nakashima Yuta , Nagahara Hajime , Kawasaki Ryo
Published: January 2023

The morphological feature of retinal arterio-venous crossing patterns is a valuable source of cardiovascular risk stratification as it directly captures vascular health. Although Scheie’s classification, which was proposed in 1953, has been used to grade the severity of arteriolosclerosis as diagnostic criteria, it is not widely used in clinical settings as mastering this grading is challenging as it requires vast experience. In this paper, we propose a deep learning approach to replicate a diagnostic process of ophthalmologists while providing a checkpoint to secure explainability to understand the grading process. The proposed pipeline is three-fold to replicate a diagnostic process of ophthalmologists. First, we adopt segmentation and classification models to automatically obtain vessels in a retinal image with the corresponding artery/vein labels and find candidate arterio-venous crossing points. Second, we use a classification model to validate the true crossing point. At last, the grade of severity for the vessel crossings is classified. To better address the problem of label ambiguity and imbalanced label distribution, we propose a new model, named multi-diagnosis team network (MDTNet), in which the sub-models with different structures or different loss functions provide different decisions. MDTNet unifies these diverse theories to give the final decision with high accuracy. Our automated grading pipeline was able to validate crossing points with precision and recall of 96.3% and 96.3%, respectively. Among correctly detected crossing points, the kappa value for the agreement between the grading by a retina specialist and the estimated score was 0.85, with an accuracy of 0.92. The numerical results demonstrate that our method can achieve a good performance in both arterio-venous crossing validation and severity grading tasks following the diagnostic process of ophthalmologists. By the proposed models, we could build a pipeline reproducing ophthalmologists’ diagnostic process without requiring subjective feature extractions. The code is available (https://github.com/conscienceli/MDTNet).