bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified Iliac Screw in Lumbopelvic Fixation After Sacral Tumor Resection: A Single-Center Case Series
Authors: Huang Wending , Cai Weiluo , Cheng Mo , Hu Xianglin , Fang Meng , Sun Zhengwang , Wang Shengping , Yan Wangjun
Published: January 2023

BACKGROUND:

Traditional iliac screw, S2-alar iliac screw, and modified iliac screw are the 3 common techniques for lumbopelvic fixation. The application of the modified iliac technique in sacral spinal tumors has been rarely reported.

OBJECTIVE:

To report the feasibility and safety of modified iliac screws after sacral tumor resection and their preliminary clinical outcomes.

METHODS:

Twenty-seven patients who underwent sacral tumor resection with modified iliac screw fixation between August 2017 and August 2021 at our center were clinically and radiographically evaluated.

RESULTS:

A total of 59 iliac screws were inserted by freehand according to the anatomic landmarks. The mean operation time was 207 minutes (range, 140-435 minutes). The average estimated blood loss was 1396 mL (300-4200 mL). Computed tomography scans showed that 2 (3.4%) screws penetrated the iliac cortex, indicating a 96.6% implantation accuracy rate. There were no iatrogenic neurovascular or visceral structure complications observed. The mean minimal distances from the screw head to the skin were 24.9 and 25.8 mm on the left and right sides, respectively. The mean minimal distances from the screw head to the horizontal level of the posterior superior iliac spine were 7.9 and 8.3 mm on the left and right sides, respectively. Two patients (7.4%) underwent reoperation for wound infection. At the latest follow-up, no patient had complications of screw head prominence, pseudarthrosis, or instrument failure.

CONCLUSION:

The modified iliac screw is characterized by its minimal invasiveness and simplicity of placement. It is an ideal alternative for lumbopelvic fixation after sacral tumor resection.
Interposition Intracranial-Intracranial Bypass Based on Anterior Cerebral Artery A1 Donor Anastomosis: Technical Advances, Outcomes, and Literature Review
Authors: Liu Peixi , Shi Yuan , Li Zongze , Liu Yingjun , Quan Kai , Liu Yingtao , An Qingzhu , Zhu Wei
Published: January 2023

BACKGROUND:

The bypass technique is important for treating complex intracranial aneurysms and is infrequently performed. Intracranial-intracranial (IC-IC) bypass has shown many advantages in recent years.

OBJECTIVE:

To review the techniques and outcomes of bypass based on anterior cerebral artery (ACA) A1 donor anastomosis in patients with intracranial aneurysm.

METHODS:

We retrospectively reviewed the clinical and imaging data, surgical strategy, and follow-up outcomes of 7 patients treated from 2019 to 2022. Neurological function was assessed by the modified Rankin Scale (mRS). A literature review was performed using PubMed.

RESULTS:

All 7 patients (3 male patients and 4 female patients; mean age, 50.4 ± 15.5 years) underwent aneurysm trapping or clipping using interposition IC-IC bypass based on ACA-A1 donor anastomosis. There were 6 middle cerebral artery (MCA) aneurysms and 1 posterior cerebral aneurysm in the series. One IC-IC bypass failed and was changed to extracranial-intracranial bypass. Three patients with MCA M1 aneurysm showed perforator-related infarction after the operation. The modified Rankin Scale score was 0 in 4 patients, 2 in 2 patients, and 1 in 1 patient. The long-term graft patency rate was 100%.

CONCLUSION:

Interposition IC-IC bypass based on ACA-A1 donor anastomosis provides an effective way to achieve blood flow reconstruction in the treatment of complex aneurysms. This technique provides better caliber and volume compatibility and diminishes neck incision. Perforator-related infarction was the main complication because of involvement of the MCA M1 aneurysm location. Proximal clipping is preferred to avoid perforator-related infarction.
Refining the Anatomy of Percutaneous Trigeminal Rhizotomy: A Cadaveric, Radiological, and Surgical Study
Authors: Xu Yuanzhi , El Ahmadieh Tarek Y. , Nunez Maximiliano Alberto , Zhang Qi , Liu Yaohua , Fernandez-Miranda Juan Carlos , Cohen-Gadol Aaron A. , Mao Ying
Published: January 2023

BACKGROUND:

Percutaneous trigeminal rhizotomy (PTR) is a widely used procedure for trigeminal neuralgia. However, comprehensive analyses that combine anatomic, radiological, and surgical considerations are rare.

OBJECTIVE:

To present high-quality anatomic dissections and radiological studies that highlight the technical nuances of this procedure.

METHODS:

Six silicon-injected postmortem heads underwent PTR. The surgical corridors were dissected, and the neurovascular relationships were studied. In addition, 20 dried human skulls and 50 computed tomography angiography and MRI scans were collected to study the anatomic relationships for a customized puncture corridor.

RESULTS:

The PTR corridor was divided into 3 segments: the buccal segment (length, 34.76 ± 7.20 mm), the inferior temporal fossa segment (length, 42.06 ± 6.92 mm), and the Meckel cave segment (length, 24.75 ± 3.34 mm). The puncture sagittal (α) and axial (β) angles measured in this study were 38.32° ± 4.62° and 19.13° ± 2.82°, respectively. The precondylar reference line coincided with the foramen ovale in 75% of the computed tomography angiography scans, and the postcondylar line coincided with the carotid canal in 70% of the computed tomography angiography scans; these lines serve as the intraoperative landmarks for PTR. The ovale-carotid-pterygoid triangle, delineated by drawing a line from the foramen ovale to the carotid canal and the lateral pterygoid plate, is a distinguished landmark to use for avoiding neurovascular injury during fluoroscopy.

CONCLUSION:

Knowledge of the anatomic and radiological features of PTR is essential for a successful surgery, and a customized technical flow is a safe and effective way to access the foramen ovale.
A novel class of sulphonamides potently block malaria transmission by targeting a Plasmodium vacuole membrane protein
Authors: Yahiya Sabrina , Saunders Charlie N. , Hassan Sarah , Straschil Ursula , Fischer Oliver J. , Rueda-Zubiaurre Ainoa , Haase Silvia , Vizcay-Barrena Gema , Famodimu Mufuliat Toyin , Jordan Sarah , Delves Michael J. , Tate Edward W. , Barnard Anna , Fuchter Matthew J. , Baum Jake
Published: January 2023

Phenotypic cell-based screens are critical tools for discovering candidate drugs for development, yet identification of the cellular target and mode of action of a candidate drug is often lacking. Using an imaging-based screen, we recently discovered an N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compound, DDD01035881, that blocks male gamete formation in the malaria parasite life cycle and subsequent transmission of the parasite to the mosquito with nanomolar activity. To identify the target(s) of DDD01035881, and of the N-4HCS class of compounds more broadly, we synthesised a photoactivatable derivative, probe 2. Photoaffinity labelling of probe 2 coupled with mass spectrometry identified the 16 kDa Plasmodium falciparum parasitophorous vacuole membrane protein Pfs16 as a potential parasite target. Complementary methods including cellular thermal shift assays confirmed that the parent molecule DDD01035881 stabilised Pfs16 in lysates from activated mature gametocytes. Combined with high-resolution, fluorescence and electron microscopy data, which demonstrated that parasites inhibited with N-4HCS compounds phenocopy the targeted deletion of Pfs16 in gametocytes, these data implicate Pfs16 as a likely target of DDD01035881. This finding establishes N-4HCS compounds as being flexible and effective starting candidates from which transmission-blocking antimalarials can be developed in the future.
Tuning Emission Color and Efficiency of 1,2,5-Triaryl-3,4-cycloalka[c]arsoles
Authors: Iwasaki Suzuka , Imoto Hiroaki , Naka Kensuke
Published: January 2023

A variety of 1,2,5-triaryl-3,4-cycloalka[c]arsoles were synthesized in this study to control emission color and efficiency. The torsion between the arsole center and the aryl groups at the 2,5-positions was dependent on the size of the fused cycloalkane, resulting in different absorption maxima. In addition, structural relaxation was affected by the fused cycloalkane, which changed the emission color and efficiency. Notably, the cyclopentane-fused arsole showed aggregation-caused quenching (ACQ) in the solid state, while cyclohexane and cycloheptane offered aggregation-induced emission enhancement (AIEE). This trend was also seen in heterocycle-fused arsoles; five- and six-membered rings offered ACQ and AIEE, respectively. The p-(dimethylamino)phenyl and p-(dimesitylboryl)phenyl groups at the 2,5-positions exhibited red-shifted emission owing to the charge transfer character, and they could detect ions such as protons and fluoride anions, respectively.
Alert the Inert? Switching Costs and Limited Awareness in Retail Electricity Markets
Authors: Dressler Luisa , Weiergraeber Stefan
Published: January 2023

We quantify how switching costs and limited awareness affect consumer inertia in liberalized retail electricity markets by developing and estimating a structural demand model using a novel dataset on electricity contract choices in Belgium. Our data allow us to disentangle different sources of inertia by using a rich combination of macromoments and micromoments. We find that consumers perceive contracts as differentiated and both limited awareness and switching costs hinder efficient choices. Our counterfactuals reveal substantial welfare gains from alleviating both frictions, in particular switching costs, and that a well-regulated monopoly can generate similar consumer surplus as the current deregulated market. (JEL D12, D83, L13, L43, L94, L98)
Product Quality and Consumer Search
Authors: Moraga-González José L. , Sun Yajie
Published: January 2023

An increase in quality shifts up the distribution of match utilities offered by firms and makes consumers pickier. The number of products that consumers inspect does not necessarily increase in quality. Higher search costs may lead to less quality investment, and the equilibrium price may decrease. If the equilibrium is inefficient, it is because of the inadequacy of quality investment. The market level of quality investment is excessive (insufficient) and consumers are too (little) picky from the point of view of welfare maximization if and only if a rise in quality results in consumers inspecting a higher (lower) number of products. (JEL D11, D21, D83, G31, L15)
Texture analysis of diffusion kurtosis imaging for differentiating malignant from benign sinonasal lesions: added value to conventional imaging features
Authors: Su Guo-Yi , Xu Yong-Kang , Liu Jun , Hu Hao , Lu Mei-Ping , Yin Min , Xu Xiao-Quan , Wu Fei-Yun
Published: January 2023

Objectives:

To evaluate the performance of texture analysis (TA) of diffusion kurtosis imaging (DKI) in differentiating malignant from benign sinonasal lesions, and its added value to the conventional imaging features.

Methods:

Fifty-eight patients with malignant and 40 patients with benign sinonasal lesions were retrospectively enrolled. Conventional CT and MRI features were reviewed. Texture parameters were obtained and compared between two groups. Multivariate logistic regression analysis was used to identify the most valuable variables. Receiver operating characteristic curves were performed to assess the differentiating performance of independent variables and their combination.

Results:

There were significant differences in tumor necrosis, bone erosion and soft tissue invasion between the two groups (all p < 0.05). There were significant differences in the 10th and entropy of Apparent diffusion coefficient map, the mean, 10th and entropy of D map, the mean and 90th of K map between the two groups (all p < 0.002). The bone erosion, entropy of D, and mean of K were independent variables associated with malignant tumors. Receiver operating characteristic analyses indicated that the combination of three features possessed better differentiating performance than bone erosion alone (p = 0.003).

Conclusion:

TA of DKI could supply incremental value to conventional imaging features for pre-operative differential diagnosis between benign and malignant sinonasal lesions.

Advances in knowledge:

The present study is the first to combine conventional imaging features and the TA of DKI in the differential diagnosis between benign and malignant sinonasal lesions. Our findings suggest that TA of DKI could supply incremental value to conventional imaging features.
The Frontline War: A Case-control study of risk factors for COVID-19 among health care workers
Authors: Sukumar Cynthia Amrutha , Bolanthakodi Nandakrishna , Venkatramanan Aarthi , Nagraj Ravishankar , Vidyasagar Sudha
Published: January 2023

Purpose:

The global pandemic of COVID-19 has infected several people worldwide. World Health Organization(WHO) has reported that an alarming number of health care workers (HCWs) have been affected and have also succumbed to this disease. Though health infrastructure can be boosted in a short period, the number of HCWs cannot. Hence understanding the risk factors that the HCWs are exposed to and strategically protecting them is of paramount importance.

Methods:

A case-control retrospective study was carried out on 116 HCWs at a tertiary care hospital treating COVID-19 patients in South India. We attempted to investigate and stratify the specific risk factors for COVID-19 transmission among HCWs. Data was collected regarding their exposure to COVID-19 patients, infection control precautions used, possible breaches in the protocol, and details of Hydroxychloroquine (HCQ) prophylaxis.

Results:

The demographics were equally distributed among the cases and controls. Exposure to surgical procedures on suspected/positive COVID patients was also found to affect contracting the COVID-19 illness. HCWs who wore face shields instead of eye goggles along with the use of scrubs and hospital gowns were found to have a lesser incidence of COVID-19 illness.

Conclusion:

This study helped us understand the varied risk factors that health care workers are exposed to while treating COVID-19 patients. It helped us contextualize and strategize our infection control practices to prevent further morbidity and mortality due to COVID-19.
The social isolation enforced by the COVID-19 pandemic reduces the Health-Related Quality of Life score in the adult population of Metropolitan Lima, Peru
Authors: Morales-Ancajima Valeria C. , Vasquez-Velasquez Cinthya , De la Cruz Melany , Marull Maria , Tapia Vilma , Gonzales Gustavo F.
Published: January 2023

Background: The objective of this study was to determine the association between health-related quality of life (HRQoL) in adults in Metropolitan Lima, Peru, with experienced social isolation during the coronavirus disease 2019 (COVID-19) pandemic regardless of if the person was infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) adjusted by age, sex and body mass index (BMI).

Methods: This cross-sectional study evaluated 256 men and 382 women living in Metropolitan Lima, who were administered the Health-Related Quality of Life (HRQoL) questionnaire (SF-20) virtually to assess their health-related quality of life. A Generalized Linear Model (GLM) was used to determine the relationship between HRQoL with BMI, sex, age, COVID-19 status and obligatory social isolation; with a significance level of p<0.05.

Results: Obesity (beta coefficient, 95%CI [95% confidence interval]: -262 – -116), female sex (beta coefficient, 95%CI: -151 – -59), the longest time of mandatory social confinement (beta coefficient, 95%CI: -6.8 – -0.2), and the existence of chronic disease (beta coefficient, 95%CI: -147 – -44) were associated with a low total score of the HRQoL questionnaire.

Conclusions: Mandatory social confinement may have harmed the perception of health-related quality of life.
The missing piece. The perceived marginalization of CSOs and HRGs in SOSTs’ decision-making processes: a review
Authors: De Sabbata Lorenzo , Laterza Riccardo , Del Bianco Daniele , Ferrari Olivia , Benedetti Ezio
Published: January 2023

This review represents the first contribution of a research diptych which stems from the activities implemented in the framework of the H2020 ARESIBO project (Augmented Reality Enriched Situation awareness for Border security). The general objective of ARESIBO is to improve the efficiency of border surveillance systems by providing the operational teams, as well as the tactical command and control level with accurate and comprehensive information related to border control considering different issues and perspectives. These perspectives also include the analysis of the level of engagement and the (possible) enhancement of citizens’ involvement in the development and decision making related to border surveillance.

The principal human rights and migration International Organisations (IOs), as well as EU institutions dealing with security and external borders (i.e., Frontex), agree and state that human rights groups (HRGs) and civil society organisations (CSOs) should be more involved and integrated in border surveillance. That stated, the main goal of this paper is to analyse this perceived marginalisation of CSOs and HRGs, as it emerges from several HRGs’ and CSOs’ statements on that regard in order to explore the reasons of this perceived marginalisation, as well as the elements that on the contrary seem to make this marginalisation less sustantial. The results of this systematic review in the framework of ARESIBO led to the elaboration of an innovative participatory model that will be analysed in detail in the second article of this research diptych, entitled “Towards the engagement of citizens in SOSTs decision-making: participatory models setting a common ground for border surveillance and respect of fundamental rights. The case of ARESIBO H2020 project”.
Improving the effectiveness of regional economic policy in the field of support and development of small business
Authors: Averin Aleksandr , Baltgaylis Yu. , Svagzhdene B. , Grigor'eva V.
Published: January 2023

The monograph consists of an introduction, three chapters, conclusion and appendices, as well as a list of references.
The first chapter substantiates theoretical approaches to the essence, conditions and factors of ensuring the sustainable development of small business in modern socio-economic conditions. The factors influencing the development of small business, methodological approaches and indicators for assessing the effectiveness of economic policy for the sustainable development of small business are considered.
The second chapter analyzes the international experience of the economic policy of small business development, on the basis of economic analysis, trends and problems of ensuring the sustainable development of small business in the Baltic States and in the Moscow agglomeration are identified. Using mathematical modeling tools, the effectiveness of the state policy in the field of small business development in the Moscow agglomeration was assessed.
In the third chapter, the directions of increasing the effectiveness of the regional economic policy of small business development are defined. An economic and mathematical model of the factors of small business development in the regions and tools for assessing the impact of factors on the sustainable development of entrepreneurship have been developed. In order to increase the efficiency and effectiveness of the work of the executive and legislative authorities and authorities in the field of support and development of small and medium-sized businesses in the region, based on the principles of the OECD methodology for assessing the impact of the OECD on competition, recommendations were developed to improve tools for assessing the best municipal practices of the Russian Federation in terms of their impact on the entrepreneurial competition of small and medium-sized enterprises. business.
The main text of the study consists of 150 pages and is illustrated with 18 figures and 10 tables. The work contains 15 applications. The list of bibliographic sources includes 248 titles.
A dynamic perspective on the evolution of perceived stress levels in Switzerland: drivers before and during the COVID-19 pandemic
Authors: Klaas Hannah S. , Kuhn Ursina , Ryser Valérie-Anne , Refle Jan-Erik , Tillmann Robin , Voorpostel Marieke
Published: January 2023

As a major socio-historical event affecting different aspects of life, the COVID-19 pandemic presents a unique opportunity to study how different population groups adapt. We investigate the impact of this crisis on the evolution of perceived stress in the short and medium term in Switzerland, using data of the Swiss Household Panel from 2016 to early 2021, which include annual measures of perceived stress and a study between waves, conducted in May and June 2020 at the end of the first semi-lockdown. Using the longitudinal structure of the data with pre-crisis measurements, we estimate pooled OLS, fixed effects and first difference models, which include socio-demographic variables, life events, socio-economic status, work-related variables, stress-reducing resources and restrictions in place.

Results for the overall population show a continuous increase in stress levels between 2016 and 2019 and a stress reduction right after the first semi-lockdown followed by a return to pre-pandemic levels. Privileged groups with higher levels of stress before the pandemic were most likely to reduce perceived stress. Characteristics related to more favourable trajectories include stable or improved financial situations and high levels of education (short-term effects), and high-pressure jobs and working hours (short- and medium-term effects). Our analyses reveal the importance of resources, such as social relations and work–life balance, to individuals’ management of the effects of the pandemic.

Our results show that the effects of the pandemic on perceived stress are context-specific. They underline the importance of longitudinal analyses to understand the complexity of vulnerability and adaptation processes.
Wrestling with unevenness: Sino-American rivalry, state strategy and the reformation of German capitalism
Authors: Germann Julian
Published: January 2023

This article focuses on the case of Germany to demonstrate how the lens of ‘uneven and combined development’ (U&CD) can help critical scholars of Global Political Economy (GPE) make sense of a worldwide but nationally specific movement towards an augmented role for the state in the regulation of capitalism. The first section finds that the prevailing comparative-institutional literature suffers from a narrow conception of the international environment in which the German political economy is drifting in the direction of its main organisational rival – US-style neoliberalism. By contrast, the second section shows that the alternative lens of U&CD provides a richer picture of the systemic forces experienced by German state actors: they flow from a technologically leading US as well as a leapfrogging China, they increase competition but also present commercial opportunities, and they do not point towards freer markets but rather novel forms of state intervention that are best explored as a creative, if contested, process of ‘re-combination’. The third section details the structural, strategic and institutional reasons for why the German state cannot emulate either the US or China. It concludes that – in lieu of strong support from capital and labour and independent state capacities like the Chinese party apparatus or the US military-industry complex – German attempts to expand the remit of the state follow a substitutive process of ‘bricolage’ that patches together foreign and domestic techniques and a motley of special interests.
Partial Mueller matrix polarimeter using liquid crystal modulators
Authors: Salamaga Monika , Woźniak Władysław A.
Published: January 2023

A simple partial Mueller polarimeter is
described, consisting of two linear polarizers and two liquid crystal
variable retarders. The measurement leads to an incomplete
Mueller–Scierski matrix, in which the elements from the third
row and the third column are simultaneously missing. The proposed
procedure for determining information about the birefringent medium
from such an incomplete matrix is based on numerical methods and
carrying out measurements with the rotated azimuthal sample. Acquired
from the obtained results, the missing elements of the
Mueller–Scierski matrix are reconstructed. The correctness of
the method was verified by numerical simulations and test
measurements.
Simple multi-band linearly frequency-modulated signal generation with a multiplying bandwidth based on a gain-switching laser
Authors: Wu Gengze , Zheng Jilin , Pu Tao , Li Jin , Zhang Xin , Chen Shilin , Zhao Jiaqi , Zhang Yunshan , Chen Xiangfei
Published: January 2023

Multi-band linearly frequency-modulated (LFM) signal generation with a multiplying bandwidth is proposed and experimentally demonstrated. It is a simple photonics method based on the gain-switching state in a distributed feedback semiconductor laser without a complex external modulator and high-speed electrical amplifiers. With N comb lines, the carrier frequency and bandwidth of generated LFM signals are N times those of the reference signal. (N is the number of comb lines.) The number of bands and time-bandwidth products (TBWPs) of the generated signals could be easily adjusted by tuning the reference signal from an arbitrary waveform generator. Three-band LFM signals with carrier frequencies ranging from the X-band to K-band are given as an example, and the TBWP up to 20000. The results of auto-correlations of the generated waveforms are also given.
Modal spectral element method with modified Legendre polynomials to analyze binary crossed gratings
Authors: Granet Gérard
Published: January 2023

In a previous paper, a modal spectral element method (SEM), the originality of which comes from the use of a hierarchical basis built with modified Legendre polynomials, was shown to be very powerful for the analysis of lamellar gratings. In this work, keeping the same ingredients, the method has been extended to the general case of binary crossed gratings. The geometric versatility of the SEM is illustrated with gratings whose patterns are not aligned with the boundaries of the elementary cell. The method is validated by a comparison to the Fourier modal method (FMM) in the case of anisotropic crossed gratings and with the FMM with adaptive spatial resolution in the case of a square-hole array in a silver film.
Generalized Hough transform for 3D object recognition and visualization in integral imaging
Authors: Fernández Ariel , Umpiérrez Julieta , Alonso Julia R.
Published: January 2023

Object recognition is an automated image processing application of great interest in
areas ranging from defect inspection to robot vision. In this regard,
the generalized Hough transform is a well-established technique for
the recognition of geometrical features even when they are partially
occluded or corrupted by noise. To extend the original
algorithm—aimed at detecting 2D geometrical features out of
single images—we propose the robust integral generalized Hough
transform, which corresponds to transformation under the generalized
Hough transform of an elemental image array obtained from a 3D scene
under integral imaging capture. The proposed algorithm constitutes a
robust approach to pattern recognition in 3D scenes that takes into
account information obtained not only from the individual processing
of each image of the array but also from the spatial restrictions
arising from perspective shifts between images. The problem of global
detection of a 3D object of given size, position, and orientation is
then exchanged under the robust integral generalized Hough transform
for a more easily solved maximum detection in an accumulation (Hough)
space dual to the elemental image array of the scene. Detected objects
can then be visualized following refocusing schemes of integral
imaging. Validation experiments for the detection and visualization of
partially occluded 3D objects are presented. To the best of our
knowledge, this is the first implementation of the generalized Hough
transform for 3D object detection in integral imaging.
Stigmatic aspherical refracting surfaces from Cartesian ovoids
Authors: Silva-Lora Alberto , Torres Rafael
Published: January 2023

A theory for Descartes ovoids has been developed in terms of four form parameters, (GOTS). This theory allows the design of optical imaging systems that, in addition to a rigorous stigmatism, exhibit the property of aplanatism, necessary for the proper imaging of extended objects. As a decisive step for the production of these systems, in this work, we propose a formulation of Descartes ovoids in the form of standard aspherical surfaces (ISO 10110-12: 2019), by means of explicit formulas for the corresponding aspheric coefficients. Thus, with these results, the designs developed with Descartes ovoids are finally translated into the language of aspherical surfaces for their production, inheriting the aspherical surfaces of all optical properties of Cartesian surfaces. Consequently, these results make this optical design methodology viable for the development of technological solutions using the current optical fabrication capabilities of the industry.
Improved fabrication of scalable hybrid silicon nitride–thin-film lithium niobate electro-optic modulators
Authors: Mere Viphretuo , Valdez Forrest , Mookherjea Shayan
Published: January 2023

Strategies for improved fabrication of integrated thin-film lithium
niobate electro-optic (EO) Mach–Zehnder modulators (MZMs) are
reported using scalable processes and designs. The MZM devices utilize
direct bonding of unetched and unpatterned thin-film lithium niobate
to patterned and planarized silicon photonic microchips. The latter
contains silicon nitride waveguide structures of various widths that
are used to form hybrid modes that are suitable for high-bandwidth
low-voltage EO modulators based on Pockels effect. We report that the
incorporation of appropriately designed outgassing channels and
certain modifications to key processing steps helped achieve a greater
than 99% reduction in void density during bonding. Void reduction is
critically important for these traveling-wave hybrid MZM devices in
which the optical mode is controllably distributed between multiple
thin layers and propagates over millimeter-scale lengths.
All-optical image edge detection based on the two-dimensional photonic spin Hall effect in anisotropic metamaterial
Authors: Zhang Jin , Zhou Su , Dai Xin , Huang Mian , Yu Xiaoyan
Published: January 2023

Optical image processing based on the photonic spin Hall effect (SHE) has been gaining significant attention as a convenient and an accurate way for image edge detection. However, the recent edge imaging techniques depending on optical differentiation is mainly achieved by modulation of one-dimensional photonic SHE. Here, we theoretically predict the two-dimensional photonic SHE in the anisotropic metamaterial, and find that its longitudinal and transverse displacements exhibit spin-dependent property at filling factors with increasing incidence angle. As the transverse and in-plane displacements induced by the photonic SHE can be controlled by the filling factor of the crystal structure, the optical axis angle, and the incident angle, this intrinsical effect can be used to realize a tunable edge imaging. Interestingly, by changing the optical axis of the anisotropic metamaterial, the in-plane displacements are equal to the transverse displacements for a certain filling factor and the corresponding incident angle. Therefore, we propose a two-dimensional image edge detection method based on the photonic SHE in anisotropic metamaterial. Further numerical results validate the theoretical proposal.
Fano asymmetry in zero–detuned exciton–plasmon systems
Authors: Nodar Álvaro , Neuman Tomas , Zhang Yao , Aizpurua Javier , Esteban Ruben
Published: January 2023

Plasmonic resonances in metallic nanostructures can strongly enhance the emission from quantum emitters, as commonly used in surface-enhanced spectroscopy techniques. The extinction and scattering spectrum of these quantum emitter-metallic nanoantenna hybrid systems are often characterized by a sharp Fano resonance, which is usually expected to be symmetric when a plasmonic mode is resonant with an exciton of the quantum emitter. Here, motivated by recent experimental work showing an asymmetric Fano lineshape under resonant conditions, we study the Fano resonance found in a system composed of a single quantum emitter interacting resonantly with a single spherical silver nanoantenna or with a dimer nanoantenna composed of two gold spherical nanoparticles. To analyze in detail the origin of the resulting Fano asymmetry we develop numerical simulations, an analytical expression that relates the asymmetry of the Fano lineshape to the field enhancement and to the enhanced losses of the quantum emitter (Purcell effect), and a set of simple models. In this manner we identify the contributions to the asymmetry of different physical phenomena, such as retardation and the direct excitation and emission from the quantum emitter.
Ultracompact Vernier-effect-improved sensor by a single microfiber-knot resonator
Authors: Yu Yang , Yu Ya-Nan , Chen Zhao-Kun , Li Chun-Ran , Tian Nong , Yan Hao-Chen , Luo Jian-Yi , Xiao Ting-Hui
Published: January 2023

Fiber-optic sensors are an indispensable element of modern sensing technologies by virtue of their low cost, excellent electromagnetic immunity, and remote sensing capability. Optical Vernier effect is widely used to enhance sensitivity of fiber-optic sensors but requires bulky and complex cascaded interferometers. Here we propose and experimentally demonstrate an ultracompact (∼2 mm by ∼2 mm) Vernier-effect-improved sensor by only using a single microfiber-knot resonator. With the Vernier effect achieved by controlling the optical beating with the spectral ripple of a super light emitting diode (SLED), we show ∼20x sensitivity enhancement for quantitative temperature monitoring. Our sensor creates a new practical method to realize Vernier effect in fiber-optic sensors and beyond.
Investigating exceptional points in dark-bright mode-coupled plasmonic systems
Authors: Pei Yuan , Huang Wanxia , Zhang Ning , Wang Maosheng , Zhou Yong , Li Kuanguo , Shi Fenghua
Published: January 2023

Exceptional points (EPs) of non-Hermitian systems are gaining more and more attention due to their important applications in unidirectional transmitters, sensors, etc. However, theoretical studies on EPs of reflection, transmission, and absorption spectra are less available. In this paper, in the dark-bright mode-coupled plasmonic systems, the variations of EPs of reflection, transmission, and absorption spectra are numerically investigated using temporal coupled-mode theory, and an assumption is given using the representation transformation theory. The intermediate representation (IR) is firstly proposed and related to the reflection spectrum, while the normal representation (NR) is associated with the absorption spectrum. In the region far from EPs, the IR (or NR) describes the reflection (or absorption) spectrum well. Near EPs, modified formulas similar to the representation transformation theory are given. In order to verify the correctness of the assumption, two metasurfaces are designed. And the simulation results are in good agreement with the assumption and it is found in the near-infrared and visible-light band that the absorption loss of the dark mode is linearly related to the EPs of reflection, transmission, and absorption spectra, while the radiation loss of the bright mode is only linearly related to the EPs of the absorption spectrum. These laws can help to manipulate the splitting of spectral lines for reflection, transmission, and absorption by adjusting the radiation loss and absorption loss of bright mode, the absorption loss of dark mode, and the coupling coefficients between two resonant modes. This research provides a guiding scheme for the design of micro and nano photonics devices.
Transition from electromagnetically-induced transparency to absorption in a single microresonator
Authors: Yi Chong-Jin , Shen Meng-Chong , Qin Qing , Zhang Yi-Fei , Lin Xiu-Min , Ye Ming-Yong
Published: January 2023

Electromagnetically induced transparency (EIT) and absorption (EIA) are two phenomena that can be observed in whispering-gallery-mode (WGM) optical microresonators. Transition from EIT to EIA has potential applications in optical switching, filtering and sensing. In this paper an observation of the transition from EIT to EIA in a single WGM microresonator is presented. A fiber taper is used to couple light into and out of a sausage-like microresonator (SLM) that contains two coupled optical modes with significantly different quality factors. By stretching the SLM axially the resonance frequencies of the two coupled modes are tuned to the same, a transition from EIT to EIA is then observed in the transmission spectra when the fiber taper is moved closer to the SLM. It is the special spatial distribution of the optical modes of the SLM that provide a theoretical basis for the observation.
Impact of figures of merit in photonic inverse design
Authors: Christiansen Rasmus E. , Trøst Kristensen Philip , Mørk Jesper , Sigmund Ole
Published: January 2023

The rates of optical processes, such as two-photon absorption and spontaneous photon emission, are strongly dependent on the environment in which they take place, easily varying by orders of magnitude between different settings. Using topology optimization, we design a set of compact wavelength-sized devices, to study the effect of optimizing geometries for enhancing processes that depend differently on the field in the device volume, characterized by different figures of merit. We find that significantly different field distributions lead to maximization of the different processes, and - by extension - that the optimal device geometry is highly dependent on the targeted process, with more than an order of magnitude performance difference between optimized devices. This demonstrates that a univeral measure of field confinement is meaningless when evaluting device performance, and stresses the importance of directly targeting the appropriate metric when designing photonic components for optimal performance.
Simplified LDPC-assisted CNC algorithm for entropy-loaded discrete multi-tone in a 100G flexible-rate PON
Authors: Mo Wenxuan , Zhou Ji , Liu Gengchen , Huang Yuanda , Li Liangchuan , Cui Han , Wang Haide , Lu Qingxin , Liu Weiping , Yu Changyuan
Published: January 2023

Passive optical networks (PONs) have been widely used in optical access networks to meet the requirement of the rapidly growing data traffic. However, the optical power budget of the worst optical network unit certainly limits the maximum capacity of PON. In this paper, we demonstrate a flexible-rate PON based on entropy-loaded clipping discrete multi-tone (DMT) for increasing the capacity. Meanwhile, clipping operation and simplified low-density parity-check (LDPC) assisted clipping-noise-cancellation (CNC) algorithm are proposed to improve the performance of DMT in peak-power constrained PON. In the simplified LDPC-assisted CNC algorithm, the iteration number of the sum-product algorithm in the LDPC decoding can be reduced to decrease the computational complexity almost without performance loss. The experimental results show that the simplified CNC algorithm can achieve approximately 1.8dB improvement of the optical receiver sensitivity at the 20% soft-decision forward-error-correction limit. The proposed flexible-rate PON has a wide-range data-rate adjustment from 12.5Gb/s to 100Gb/s under the optical power budget from 40dB to 26dB.
High-resolution oxygen-corrected laser heterodyne radiometer (LHR) for stratospheric and tropospheric wind field detection
Authors: Li Jun , Xue Zhengyue , Shen Fengjiao , Wang Guishi , Liu Kun , Chen Weidong , Gao Xiaoming , Tan Tu
Published: January 2023

We developed a near-infrared (NIR) dual-channel oxygen-corrected laser heterodyne radiometer (LHR) in the ground-based solar occultation mode for measuring vertical profile of wind field in the troposphere and low stratosphere. Two distributed feedback (DFB) lasers centered at 1.27 µm and 1.603 µm were used as local oscillators (LO) to probe absorption of oxygen (O2) and carbon dioxide (CO2), respectively. High-resolution atmospheric O2 and CO2 transmission spectra were measured simultaneously. The atmospheric O2 transmission spectrum was used to correct the temperature and pressure profiles based on a constrained Nelder-Mead’s simplex method. Vertical profiles of atmospheric wind field with an accuracy of ∼5 m/s were retrieved based on the optimal estimation method (OEM). The results reveal that the dual-channel oxygen-corrected LHR has high development potential in portable and miniaturized wind field measurement.
High performance laser-driven flyers based on a refractory metamaterial perfect absorber
Authors: Huang Xin , Ji Xiangbo , Qin Wenzhi , Wang Yao , Wang Liang , Gao Fuhua , Hou Yidong
Published: January 2023

Laser-driven flyers (LDFs), which can drive metal particles to ultra-high speeds by feeding high-power laser, have been widely used in many fields, such as ignition, space debris simulation, and dynamic high-pressure physics. However, the low energy-utilization efficiency of the ablating layer hinders the development of LDF devices towards low power consumption and miniaturization. Herein, we design and experimentally demonstrate a high-performance LDF based on the refractory metamaterial perfect absorber (RMPA). The RMPA consists by a layer of TiN nano-triangular array, a dielectric layer and a layer of TiN thin film, and is realized by combing the vacuum electron beam deposition and colloid-sphere self-assembled techniques. RMPA can greatly improve the absorptivity of the ablating layer to about 95%, which is comparable to the metal absorbers, but obviously larger than that of the normal Al foil (∼10%). This high-performance RMPA brings a maximum electron temperature of ∼7500 K at ∼0.5 µs and a maximum electron density of ∼1.04 × 1016 cm-3 at ∼1 µs, which are higher than that the LDFs based on normal Al foil and metal absorbers due to the robust structure of RMPA under high-temperature. The final speed of the RMPA-improved LDFs reaches to about 1920 m/s measured by the photonic Doppler velocimetry system, which is about 1.32 times larger than the Ag and Au absorber-improved LDFs, and about 1.74times larger than the normal Al foil LDFs under the same condition. This highest speed unambiguously brings a deepest hole on the Teflon slab surface during the impact experiments. The electromagnetic properties of RMPA, transient speed and accelerated speed, transient electron temperature and density have been systematically investigated in this work.
Konstruktion einer Methode zur datenbasierten Schätzung von Logistikprozessdauern als Aufgabe im Projektmanagement
Authors: Kusturica Wibke
Published: January 2023

Die für die Planung des Materialflusses relevanten Fertigungsprozesse lassen sich sehr genau planen, beispielsweise über die Leistung der Maschine (Durchsatz je Zeiteinheit). Bei der Planung eines Projektes spielen logistische Prozesse, die zu den Kernprozessen eines Unternehmens gehören, eine wichtige Rolle. Jedoch werden sie meist nur grob terminiert und mit großen Puffern kalkuliert. Dies kann zu einer Verlängerung der Projektdauer führen. Für eine genauere Terminierung eines Projektes ist es daher entscheidend, die Dauer der logistischen Prozesse mindestens in dem Maße wie die Fertigungsprozesse zu ermitteln, um das Risiko einer Projektverzögerung zu minimieren.

In diesem Beitrag wird deshalb eine Methode zur datenbasierten Schätzung von Prozessdauern mit dem Ziel der Wiederverwendung von Projektwissen vorgestellt, die es dem Projektmanagement ermöglichen soll, Dauern von logistischen Prozessen präziser zu schätzen als das aktuell basierend auf Erfahrungswissen erfolgt. Besonderes Augenmerk liegt dabei auf der Herleitung der Entwurfsaktivitäten. Durch die Anwendung der Methode soll das Projektmanagement von einer genaueren, datenbasierten Schätzung von (Logistik‑)Prozessdauern profitieren und so entstandenes Wissen über einen Ontologieansatz wiederverwenden können.
Neural responses in macaque prefrontal cortex are linked to strategic exploration
Authors: Jahn Caroline I. , Grohn Jan , Cuell Steven , Emberton Andrew , Bouret Sebastien , Walton Mark E. , Kolling Nils , Sallet Jérôme
Published: January 2023

Humans have been shown to strategically explore. They can identify situations in which gathering information about distant and uncertain options is beneficial for the future. Because primates rely on scarce resources when they forage, they are also thought to strategically explore, but whether they use the same strategies as humans and the neural bases of strategic exploration in monkeys are largely unknown. We designed a sequential choice task to investigate whether monkeys mobilize strategic exploration based on whether information can improve subsequent choice, but also to ask the novel question about whether monkeys adjust their exploratory choices based on the contingency between choice and information, by sometimes providing the counterfactual feedback about the unchosen option. We show that monkeys decreased their reliance on expected value when exploration could be beneficial, but this was not mediated by changes in the effect of uncertainty on choices. We found strategic exploratory signals in anterior and mid-cingulate cortex (ACC/MCC) and dorsolateral prefrontal cortex (dlPFC). This network was most active when a low value option was chosen, which suggests a role in counteracting expected value signals, when exploration away from value should to be considered. Such strategic exploration was abolished when the counterfactual feedback was available. Learning from counterfactual outcome was associated with the recruitment of a different circuit centered on the medial orbitofrontal cortex (OFC), where we showed that monkeys represent chosen and unchosen reward prediction errors. Overall, our study shows how ACC/MCC-dlPFC and OFC circuits together could support exploitation of available information to the fullest and drive behavior towards finding more information through exploration when it is beneficial.