bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Organometallic Nucleophilic Reagents Via Photoredox Catalysis
Authors: Gualandi Andrea , Cozzi Pier Giorgio , Calogero Francesco , Pinosa Emanuele , Corbisiero Dario
Published: June 2023

The addition of organometallic reagents to the carbonyl group represents a key transformation, both in academia and industry. Most of these transformations rely on a mechanism in which accessible and reactive halides are transformed into the corresponding nucleophilic organometallic reactive compounds through a redox mechanism, using a metal (Cr, Mg, In, etc.) in low oxidation state, by electron transfer. With the advent of photoredox catalysis, the formation of radicals, through oxidation or reduction of suitable and tailored organic precursors, was merged with transition metal catalysis. By radical-to-polar crossover (RPCO­), a radical metal is combined with an organic radical to produce, via radical-radical trapping, a polar nucleophilic organometallic reagent. Using dual photoredox catalysis (metallaphotoredox catalysis), a reactive organometallic reagent can be prepared, avoiding the use of metals in low oxidation state. Herein, in addition to the description of the results obtained by our group and the contributions of others on the connection between carbonyl addition and radical-based photochemistry, we provide core guidance for further synthetic developments. We anticipate that extending the photoredox dual strategy beyond the Barbier reactions described here, taming less-activated carbonyls, studying other important electrophiles, will soon realize important breakthroughs.

1 Introduction

2 Photoredox Catalysis: A Survival Guide for the ‘Photo-Curious’

3 Chromium Nucleophilic Organometallic Reagents

3.1 Allylation of Aldehydes

3.2 Allylation of Aldehydes via Dienes

3.3 Propargylation of Aldehydes via 1,3-Enynes

3.4 Alkenylation of Aldehydes

3.5 Alkylation of Aldehydes

3.6 Enantioselective Chromium-Mediated Photoredox Reactions

4 Titanium Nucleophilic Organometallic Reagents

4.1 Allylation Reactions

4.2 Propargylation Reactions

4.3 Allylation Reactions via Dienes

4.4 Benzylation Reactions

4.5 Alkylation Reactions

5. Cobalt Nucleophilic Organometallic Reagents

5.1 Allylation Reactions

6 Conclusion
Cervical Trident-Shaped Neurofibroma: A Rare Variant
Authors: Haque Inamul , Barua Navanil , Borah Nabajyoti , Gang Sneha , Barman Ananya , Ahmed Shabnam A.
Published: June 2023

Spinal nerve root tumors can arise throughout the spine and at multiple levels, likely representing plexiform neurofibromas that grow from the nerve root into the intraspinal space either intradurally or epidurally and exit through the neural foramen, producing a dumbbell-shaped appearance. Although many cases of dumbbell-shaped extramedullary neurofibromas in the cervical spine have been reported, to the best of our knowledge, there are no reports of trident-shaped extramedullary neurofibromas. A 26-year-old woman presented with swelling over the right side of her neck. Diagnostic workup included magnetic resonance imaging (MRI) and contrast-enhanced computed tomography (CECT) of the neck, which revealed an intradural, extramedullary tumor mass at the right C2–C6 level with an extraspinal extension. Spinal cord compression or canal compromise is the most reliable indication for surgery. The solitary cervical neurofibroma was treated surgically in a single stage through laminoplasty and excision of the intradural tumor along with that of the neck component. This was performed without any complications. A single-stage double approach was adopted in this case. After total excision, the shape of the tumor was found to be more like a trident than a dumbbell. Hence, here we would like to suggest a new nomenclature for this neurofibroma, the trident neurofibroma.
Young people’s perceptions of the challenges and opportunities during the Mainland China–Hong Kong convergence
Authors: Lo T. Wing , Chan Gloria Hongyee , Lee Gabriel Kwun Wa , Guan Xin , Kwok Sharon Ingrid
Published: June 2023

Since the handover of the sovereignty of Hong Kong from Britain to China in 1997, convergence between Mainland China and Hong Kong has gradually emerged. During this process, young people have engaged in demonstrations to express their dissatisfaction with government policies and limited socio-economic progression. However, the underlying reasons for their dissatisfaction have not been fully investigated. This study investigates their perceived challenges and opportunities during the convergence, with the objective of identifying the factors affecting the Mainland China–Hong Kong convergence and examining young people’s perceived challenges and opportunities during the convergence. Mixed research methods of focus groups and a survey were adopted. Ten focus groups with 83 participants were conducted to collect qualitative data on the factors relating to convergence. Based on the qualitative data, a questionnaire was constructed to investigate young people’s perceived challenges and opportunities during the convergence, using a sample of 1253 young people. Ordinary least-squares regression was applied to analyse the relationships among identified factors. The study found that Hong Kong’s youth tended to regard the Mainland China–Hong Kong convergence as an opportunity for socio-economic progression, and they identified three challenges during the convergence. It also revealed that young people’s higher education, perceived housing challenges, and perceived socio-economic challenges are negatively related to the convergence, whereas their perceived challenges associated with entrepreneurship and innovation are positively related to the convergence. The development of more well-balanced and mutually beneficial policies that satisfy the needs of young people will lead to a higher acceptance of the convergence. As such, young people will be more willing to embrace the opportunities and face the challenges brought about by the convergence, resulting in a more harmonious society and socio-economic progression.
Owned media, influencer marketing, and unofficial brand ambassadors: differences between narratives, types of prescribers, and effects on interactions on Instagram
Authors: Barquero Cabrero José Daniel , Castillo-Abdul Bárbara , Talamás-Carvajal Juan Andrés , Romero-Rodríguez Luis M.
Published: June 2023

In the current era of the attention economy, users find themselves in social networks over-saturated with advertising that tends not to catch the public’s attention or have great credibility. In this sense, brands are trying to get closer to their audiences by using non-invasive, user-generated storytelling strategies with a more natural and experience-focused message. This research aims to compare which narrative elements used by the official accounts of 5 Ibero-American nation brands on Instagram and by the users (UGC) of hashtags promoted from those official accounts generate greater organic interaction on that social network (likes and comments). With a correlational view, we seek to compare whether the promotion of countries generates greater interaction between those generated by owned media and by users (UGC). For this purpose, two analysis sheets were designed and validated to perform quantitative, descriptive, and correlational content analysis and were applied, on the one hand, to 5 official profiles of Ibero-American countries (Argentina, Ecuador, Mexico, Panama, and Venezuela) and on the other hand, using the hashtags promoted from these official accounts, the 100 posts of user-generated content (UGC) with greater relevance according to the platform were chosen. The main results show that Reels reach almost five times higher than any other type of posts in UGC accounts, while on the contrary, in corporate accounts, they are the types of content with the least interactions. Unlike what one might think, contests (giveaways) on official accounts generated fewer likes and social responsibility content, and posts featuring influencers and celebrities also failed to achieve significant interactions. Overall, official accounts generate the same amount of likes as UGC but significantly fewer comments. Brands only outperform UGC in likes in individual Photographs or Photo Rolls, while UCG outperforms brands in Reels for both metrics.
Alpha-heating analysis of burning plasma and ignition experiments on the National Ignition Facility
Authors: Christopherson A. R. , Hurricane O. A. , Weber C. , Kritcher A. , Nora R. , Salmonson J. , Tran R. , Milovich J. , Maclaren S. , Hinkel D. , Betti R.
Published: June 2023

A recent experiment conducted on the National Ignition Facility (NIF) described in the study by Abu-Shawareb et al. [Phys. Rev. Lett. 129, 075001 (2022)] achieved a fusion yield output of 1.3 MJ from ∼ 220 kJ of x-ray energy absorbed by the capsule, demonstrating remarkable progress in the field of laser driven inertial confinement fusion. In the study by A. R. Christopherson [“Effects of charged particle heating on the hydrodynamics of inertially confined plasmas,” Ph.D. thesis (2020)], the plasma conditions needed to claim the onset of ignition and burn propagation were outlined and multiple criterion were provided to assess progress in inertial fusion experiments. In this work, we modify the metrics from A. R. Christopherson [“Effects of charged particle heating on the hydrodynamics of inertially confined plasmas,” Ph.D. thesis (2020)] to accurately calculate performance metrics for indirect-drive experiments on the NIF. We also show that performance metric trends observed in NIF data are consistent with theory and simulations. This analysis indicates that all the identified criterion for ignition and burn propagation have been exceeded by experiment 210 808.
Modulation of the plasma radial uniformity in pulsed dual-antenna inductively coupled plasmas
Authors: Lu Chang , Huang Jia-Wei , Zhang Yu-Ru , Gao Fei , Wang You-Nian
Published: June 2023

Pulse modulation in inductively coupled plasmas (ICPs) has been proven as an effective method not only to restrain the charging effect in etching trenches but also as a potential approach to ameliorate the plasma uniformity. In this paper, a two-dimensional fluid model is employed to systematically study the modulation of the radial uniformity in pulsed dual-antenna Ar ICPs. The inner four-turn coils are connected to a continuous wave at the current of 5.0 A, and the outer three-turn coils are pulse modulated at various duty cycles and currents. The results indicate that when the outer coil current is fixed at 7.0 A, the electron density always shows an off-center distribution during the active-glow period when the duty cycle increases from 20% to 60%, due to the stronger electric field induced by the higher outer coil current. Although the ionization mainly happens at the reactor center during the after-glow period, the electron density distribution evolves from a center-high profile to a rather uniform distribution as duty cycle increases. Under the combined influence, the time-averaged electron density over one pulse period shifts from center-high over uniform to edge-high. When the pulse duty cycle is fixed at 50%, the time-averaged electron density distribution shifts from a center-high profile over uniform to an edge-high profile, as the outer coil current increases from 5.7 to 7.7 A. The results obtained in this work could help to optimize the plasma radial uniformity, which plays a significant role in improving the large-area plasma processing.
A novel in-situ Raman spectroscopic cell for aqueous geochemistry at the solid–liquid interface
Authors: Li Sophia , Alcorn Christopher , Neil Chelsea
Published: June 2023

In-situ Raman spectroscopy has the potential to be a powerful technique for monitoring geochemical reactions at a solid–liquid interface in real time. In this article, we present the development and testing of an in-situ Raman spectroscopic cell, which can be used for reaction systems at moderate temperatures and pressure [<1000 psi (6.89 MPa), <100 °C, relevant to subsurface geologic systems] and can hold samples large enough for chemical mapping of heterogeneous rock surfaces. The system is validated by measuring the temperature-dependent conversion of gypsum to calcite over time. Near total conversion of gypsum to calcite on the mineral surface took 29 hours at room temperature and 150 minutes at 100 °C, corresponding to an 11.6-fold increase in the conversion rate. We anticipate that this cell can be an important tool in quantifying the rates of carbon mineralization relevant to geologic carbon sequestration, particularly for the elevated rates recently observed in mafic/ultramafic rocks.
9E analysis of a flat plate solar collector system implementation: A new approach based on digital twin model coupled with global sensitivity analysis and multi-objective optimization
Authors: Cetina-Quiñones A. J. , Sánchez-Domínguez I. , Casillas-Reyes A. , Bassam A.
Published: June 2023

Flat plate solar collectors are technology with the most solar thermal energy field applications, and different studies based on artificial intelligence have been used to model these systems. This research study presents a 9E analysis based on a digital twin model coupled with global sensitivity analysis and multi-objective optimization of a solar system integrated with an array of flat plate solar collectors to satisfy residential hot water demand that represents a case study with different applications. A model based on artificial neural networks was trained, and a global sensitivity analysis using the Sobol method and a multi-objective optimization study using a genetic algorithm were also implemented. The main outcomes revealed that the digital twin model presented a high correlation above 0.99, and the 9E analysis reported a maximum value of 25.18% for thermal efficiency and 0.266% for exergetic efficiency. Also, a value of 1798.5 kgCO2/year was obtained for the amount of CO2 mitigated, $1342.9 USD for net present value, $0.0104 USD/kWh for levelized cost of energy, and 92.62, 0.519 kgCO2/year, $3.43, $1.34, and $0.00752 USD/year for energoenvironmental, exergoenvironmental, enviroeconomic energoenviroeconomic, and exergoenviroeconomic indicators, respectively. The methodology and the 9E analysis results provide a comprehensive approach that determines the optimal choice by analyzing the system's viability with different assessments and goes beyond the conventional analyses currently presented in the literature as it shows an untapped market potential for the best decision-making.
Active sites and intermediates adsorption regulation of Ni5P4 porous nanosheets arrays through Ce doping toward efficient electrocatalytic overall water splitting
Authors: Yang Yong , Liu Yuan , Yao Shenman , Gong Wufei , Liang Yan , Yu Ting , Yuan Cailei
Published: June 2023

The development of non-noble metal-based bifunctional electrocatalysts toward overall water splitting is urgent recently. However, their catalytic activity is still limited by the insufficient active sites and unsatisfactory adsorption toward reaction intermediates. Here, a self-supported rare earth Ce-doped Ni5P4 porous nanosheets array is designed as an efficient bifunctional electrocatalyst, which requires a competitive overall water splitting potential of 1.56 V to drive the current density of 10 mA/cm2 under alkaline condition. It is shown that the introduction of Ce can greatly reduce the charge transfer resistance and increase the active sites of Ni5P4, which promotes fast charge transfer and facilitates the kinetics to maintain high catalytic activity. Especially, systematic DFT theoretical calculation is further conducted to study the electrocatalytic process, and it is shown that Ce doping can regulate the center of the d band and adsorption of reaction intermediates, thus reducing the overall speed-decisive step of water splitting reaction. This work demonstrates an efficient strategy for enhancing the overall water splitting properties of bifunctional electrocatalysts through rare earth Ce doping, which also has guiding significance for the study of electrocatalytic mechanism in atomic scale.
SNP associations and genetic-parameter estimation for nose and hoof pigmentation in Corriedale sheep
Authors: Aldersey J. E. , Khatkar M. S. , Blackwood P. J. , Blackwood C. E. , Pitchford J. M. , Gordon H. , Welsh S. C. , Pitchford W. S.
Published: June 2023

Context Quantity and quality of both meat and wool are important for selection programs of the dual-purpose Corriedale sheep. In Corriedales, black pigmentation of nose skin and hooves is preferred as part of the breed standard. However, within the breed, pigmentation can vary from none to complete pigmentation. Aims The aim was to discover single-nucleotide polymorphisms (SNPs) and genes associated with nose and hoof pigmentation and to estimate genetic parameters of nose and hoof pigmentation, wool traits and meat traits. Methods The phenotype and genotype data on Corriedale lambs (n = 764) produced from 44 sires (12 studs) and 300 ewes in 2017–2019 were used in this study. Lambs were slaughtered at 6–7 months of age. Nose pigmentation and hoof pigmentation were scored on a five-point scale, where no pigmentation was scored 0 and complete pigmentation was scored 5. Wool- and meat-quality traits were measured, including greasy fleece weight, fibre diameter, weaning weight, hot standard carcass weight and intramuscular fat percentage. The lambs were genotyped with the GGPOvine50K SNP chip. A genome-wide association study (GWAS) was conducted. Genetic parameters and bivariate analyses were estimated using ASReml-R. Results The lambs had a mean nose-pigmentation score of 3.69 and hoof-pigmentation score of 4.12. The nose pigmentation (h2 = 0.58) and hoof pigmentation (h2 = 0.51) were highly heritable and highly correlated (rG = 0.73). The GWAS identified a genome-wide significant SNP (OAR19_33278780.1) associated with nose pigmentation (q-value = 0.04). This SNP is positioned in a known pigmentation gene, melanocyte-inducing transcription factor (MITF). The same SNP was the sixth-most associated SNP for hoof pigmentation but did not reach significance level. OAR19_33278780.1 also had a significant effect on back conformation and weaning weight. Conclusions The results of these analyses have provided information and an understanding of the genetics for pigmentation of nose and hooves in Corriedale sheep. Implications Nose and hoof pigmentation are highly genetically correlated with each other, but with no negative effects on production traits.
Generation and Control of Shock Waves in Exciton-Polariton Condensates
Authors: Wang Jin-Ling , Wen Wen , Lin Ji , Li Hui-Jun
Published: June 2023

We propose a scheme to generate and control supersonic shock waves in a non-resonantly incoherent pumped exciton-polariton condensate, and different types of shock waves can be generated. Under conditions of different initial step waves, the ranges of parameters about various shock waves are determined by the initial incidence function and the cross-interaction between the polariton condensate and the reservoir. In addition, shock waves are successfully found by regulating the incoherent pump. In the case of low condensation rate from polariton to condensate, these results are similar to the classical nonlinear Schrödinger equation, and the effect of saturated nonlinearity resulted from cross interaction is equivalent to the self-interaction between polariton condensates. At high condensation rates, profiles of shock waves become symmetrical due to the saturated nonlinearity. Compared to the previous studies in which the shock wave can only be found in the system with repulsive self-interaction (defocusing nonlinearity), we not only discuss the shock wave in the exciton-polariton condensate system with the repulsive self-interaction, but also find the shock wave in the condensates system with attractive self-interaction. Our proposal may provide a simple way to generate and control shock waves in non-resonantly pumped exciton-polariton systems.
Glimmers of a post-geometric perspective
Authors: Piazza Federico
Published: June 2023

Quantum gravitational effects can become important at low energy if the wavefunction of the metric field fails to be peaked around a classical configuration. We try to understand such deviations from classicality within canonical quantum gravity by introducing a ‘fluid of observers’ in the low energy theory and defining a distance operator ‘at equal time’ among them. We find that, even in the presence of relevant fluctuations in the metric field, a ‘locally flat’ limit is recovered in the neighbourhood of each observer. Deviations from classicality have no particular consequence, locally. However, at larger separations the expectation value of the distance operator behaves differently than a standard Riemannian distance. In particular, it is non-additive and thus cannot be obtained by the integral of a differential line element. This emerging ‘beyond Riemannian’ geometry is a metric space similar to embedded Riemannian manifolds equipped with chord distances that ‘cut through’ the ambient space. We study deviations from flat space by looking at triangles in the limit where their sizes go to zero. Beyond-Riemannian deviations with respect to flat space are of the same order as standard Riemannian ones, but qualitatively different. Possible connections with holography and with the black hole information paradox are briefly discussed.
Real centrifugal forces in relativistic rotating spacetimes: a simple introduction
Authors: Benedetto Elmo , Di Mauro Marco , Feoli Antonio , Iannella Antonella Lucia , Naddeo Adele
Published: June 2023

During typical general relativity courses, the so-called frame-dragging effect is explained by emphasizing the presence of a gravitational Coriolis-like force term. The key difference is that, unlike the usual Coriolis force, this is not a fictitious force but agravitational force caused by the rotating body. In general, textbooks do not discuss also the possibility of a gravitational centrifugal-like force. In this paper, which has a didactic aim, we analyze this further gravitational term. The analysis we perform can be valuable in undergraduate courses of general relativity.
Structural and optical properties of Zn-implanted silica: effect of fluence and annealing
Authors: Makhavikou M A , Milchanin O V , Parkhomenko I N , Vlasukova L A , Komarov F F , Yuvchenko V N , Wendler E , Korolev D S , Mudryi A V , Zhivulko V D , Janse van Vuuren A
Published: June 2023

The phase-structural composition of silica films grown on Si substrates implanted with different fluences of Zn ions has been studied using transmission electron microscopy (TEM) and electron diffraction. Small clusters (2–3 nm) and larger clusters (5–7 nm) were formed in the as-implanted silica films with Zn concentration of 6–8 at % and 16%–18%, respectively. Furnace annealing at 750 °С for two hours in air resulted in the formation of an orthorhombic Zn2SiO4 phase (space group R-3) in the case of low fluence (5 × 1016 cm−2) and in the formation of a zinc blended ZnO phase (space group F-43m) in the case of high fluence (1 × 1017 cm−2). Based on the Rutherford backscattering spectrometry (RBS) data, it has been shown that impurity losses during implantation and subsequent annealing increase with the fluence of the implanted ions. The photoluminescence data were consistent with the TEM and RBS.
A novel hybrid generative adversarial network for CT and MRI super-resolution reconstruction
Authors: Xiao Yueyue , Chen Chunxiao , Wang Liang , Yu Jie , Fu Xue , Zou Yuan , Lin Zhe , Wang Kunpeng
Published: June 2023

Objective. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used in medical imaging modalities, and provide valuable information for clinical diagnosis and treatment. However, due to hardware limitations and radiation safety concerns, the acquired images are often limited in resolution. Super-resolution reconstruction (SR) techniques have been developed to enhance the resolution of CT and MRI slices, which can potentially improve diagnostic accuracy. To capture more useful feature information and reconstruct higher quality super-resolution images, we proposed a novel hybrid framework SR model based on generative adversarial networks. Approach. The proposed SR model combines frequency domain and perceptual loss functions, which can work in both frequency domain and image domain (spatial domain). The proposed SR model consists of 4 parts: (i) the discrete Fourier transform (DFT) operation transforms the image from the image domain to frequency domain; (ii) a complex residual U-net performs SR in the frequency domain; (iii) the inverse discrete Fourier transform (iDFT) operation based on data fusion transforms the image from the frequency domain to image domain; (iv) an enhanced residual U-net network is used for SR of image domain. Main results. Experimental results on bladder MRI slices, abdomen CT slices, and brain MRI slices show that the proposed SR model outperforms state-of-the-art SR methods in terms of visual quality and objective quality metric such as the structural similarity (SSIM) and the peak signal-to-noise ratio (PSNR), which proves that the proposed model has better generalization and robustness. (Bladder dataset: upscaling factor of 2: SSIM = 0.913, PSNR = 31.203; upscaling factor of 4: SSIM = 0.821, PSNR = 28.604. Abdomen dataset: upscaling factor of 2: SSIM = 0.929, PSNR = 32.594; upscaling factor of 4: SSIM = 0.834, PSNR = 27.050. Brain dataset: SSIM = 0.861, PSNR = 26.945). Significance. Our proposed SR model is capable of SR for CT and MRI slices. The SR results provide a reliable and effective foundation for clinical diagnosis and treatment.
Modified photodiode equivalent circuit model considering coplanar waveguide electrodes
Authors: Li Tonghui , Duan Xiaofeng , Li Gongqing , Li Ke , Yuan Weifang , Liu Kai , Huang Yongqing
Published: June 2023

Accurate equivalent circuit models can assist in better analyzing the performance of photodetectors. This study proposes a modified photodiode (PD) equivalent circuit model that considers coplanar waveguide (CPW) electrodes. First, the CPW electrodes of the PD are analyzed using high-frequency structure simulation software and advanced design simulation software. Skin effect occurs inside the electrode at high frequencies, increasing the PD loss and reducing the bandwidth. Subsequently, the extraction formula for the proposed model is derived, and the proposed model is compared with two conventional CPW electrode models. The proposed model effectively eliminates the frequency-dependency issue in the parameter extraction process of previous models, thereby demonstrating its accuracy. Furthermore, simulation and experimental results validate the reliability of the proposed model. Among the entire frequency band, the proposed model has good stability and a low error rate and can achieve excellent fitting with the measured results. Compared with previous studies, the average error rate is reduced by over 10%, demonstrating a significant improvement. Finally, the influence of the skin effect and high-impedance transmission lines on PD performance is analyzed and a viable approach to improve the bandwidth of PDs is proposed. The proposed model provides a viable approach to model and optimize CPW structures and is significant for the design of high-performance PDs.
Vortex matter and critical magnetic fields in mesoscopic superconducting strips
Authors: Ge Jun-Yi , Gladilin Vladimir N , Van de Vondel Joris , Moshchalkov Victor V
Published: June 2023

As compared with bulk materials, superconducting strips with lateral dimensions limited to the mesoscopic region exhibit non-trivial properties, among which the critical magnetic fields related to both vortex penetration

B

p

and full vortex expulsion

B

m

still remain elusive. By using low-temperature scanning Hall probe microscope, the critical magnetic fields are studied experimentally in a series of superconducting Pb strips with different widths. It is found that the penetration magnetic field follows a power law dependence with strip width, and vortices can only penetrate the strips when the energy barrier at the edges is completely suppressed. In the field-cooling process, vortices are fully expelled from the strips below

B

m

, above which the number of trapped vortices linearly increases with magnetic field. Compared with various theoretical predictions, we have found that the experimentally observed

B

m

corresponds to the field at which the Gibbs free energy in the strip center is minimized. Our study provides important implications for designing nanostructured devices with superconducting strips.
Study of energies spectra and thermodynamic properties of the relativistic Dirac equation using Feynman path integral method
Authors: Douici Mohamed , Boukabcha Hocine , Fermous Rachid
Published: June 2023

In the current paper, the contribution of a Coulomb-like potential tensor interaction on the solution of the Dirac equation with a new generalized Morse-like potential is investigated using the Feynman path integral method. Relativistic and non-relativistic energy spectra were obtained. It has been established that the Coulomb-like potential eliminates the degeneracy of all pairs of spin doublets. Using the resulting non-relativistic energy eigenvalues equation, three diatomic molecules (H2, LiH, and HCl) were investigated and their thermodynamic properties, including mean energy, free energy, entropy, and specific heat capacity were shown. A comparison with the available literature shows that the thermodynamic plots obtained are consistent with previous work.
The emergence of lines of hierarchy in collective motion of biological systems
Authors: Greene James M , Tadmor Eitan , Zhong Ming
Published: June 2023

The emergence of large-scale structures in biological systems, and in particular the formation of lines of hierarchy, is observed at many scales, from collections of cells to groups of insects to herds of animals. Motivated by phenomena in chemotaxis and phototaxis, we present a new class of alignment models that exhibit alignment into lines. The spontaneous formation of such ‘fingers’ can be interpreted as the emergence of leaders and followers in a system of identically interacting agents. Various numerical examples are provided, which demonstrate emergent behaviors similar to the ‘fingering’ phenomenon observed in some phototaxis and chemotaxis experiments; this phenomenon is generally known to be a challenging pattern for existing models to capture. A novel protocol for pairwise interactions provides a fundamental alignment mechanism by which agents may form lines of hierarchy across a wide range of biological systems.
Multifunctional light-field modulation based on hybrid nonlinear metasurfaces
Authors: Qian 钱 Shuhang 树航 , Wang 王 Kai 凯 , Yang 杨 Jiaxing 加兴 , Guan 关 Chao 超 , Long 龙 Hua 华 , Lu 陆 Peixiang 培祥
Published: June 2023

The generation characteristics of nonlinear optical signals and their multi-dimensional modulation at micro-nano scale have become a prominent research area in nanophotonics, and also the key to developing various novel nonlinear photonics devices. In recent years, the demand for higher nonlinear conversion efficiency and device integration has led to the rapid progress of hybrid nonlinear metasurfaces composed of nanostructures and nonlinear materials. As a joint platform of stable wavefront modulation, nonlinear metasurface and efficient frequency conversion, hybrid nonlinear metasurfaces offer a splendid opportunity for developing the next-generation of multipurpose flat-optics devices. This article provides a comprehensive review of recent advances in hybrid nonlinear metasurfaces for light-field modulation. The advantages of hybrid systems are discussed from the perspectives of multifunctional light-field modulation, valleytronic modulation, and quantum technologies. Finally, the remaining challenges of hybrid metasurfaces are summarized and future developments are also prospected.
Simulated Gravity Field Estimation for the Main Belt Comet 133P/Elst-Pizarro Based on a Satellite-to-satellite Tracking Mode
Authors: Sun Shang-Biao , Yan Jian-Guo , Gao Wu-Tong , Wang Bo , Wang Zhen , Ye Mao , Barriot Jean-Pierre
Published: June 2023

Most asteroids and comets are formed in the early stages of the solar system and therefore contain a wealth of information about their birth. The asteroid exploration mission planned in the coming years by China will likely target the celestial body named 133P/Elst-Pizarro (estimated diameter of about 4 km). The orbit of this asteroid stays within the asteroid belt, but nevertheless, it displays a comet-like dust tail. In this study, we used differential tracking data between two simulated probes and the data from an Earth station to estimate 133P gravity field model. This observation mode is similar to how the gravity field was estimated for large celestial objects in the GRAIL and GRACE missions, but here the object is the very small 133P asteroid. We compared the estimated gravity fields obtained for 133P from the satellite-to-satellite combined with the Earth-based two-way range-rate observation mode, with only the Earth-based two-way range rate mode. The results show that the accuracy of the low-degree (4 degree and order) estimate of the gravity field is improved by one order of magnitude by using the satellite-to-satellite combined with the Earth-based two-way range-rate observation mode with respect to the Earth-only tracking. Furthermore, another order of magnitude improvement in the gravity field solution is gained by decreasing the orbit altitude from 12 to 8 km.
Design of Broadband High-Efficiency DPA for 5G Micro Base Station
Authors: Li Guojin , Wang Yewen
Published: June 2023

To meet the requirements of the 5G communication system, the Doherty power amplifier has become a research hotspot because of its peak-to-average ratio and high backoff efficiency. At the same time, with the continuous development of mobile communication technology, the traditional Doherty power amplifier has gradually been difficult to meet the needs due to its structural problems. On the one hand, due to the limitation of the 1/4 wavelength transmission line in the traditional Doherty power amplifier, it is difficult to achieve broadband. This paper uses the post-matching technology to remove the 1/4 wavelength transmission line to achieve broadband matching. On the other hand, in response to energy conservation and emission reduction, there is a growing demand to reduce power consumption in base stations. In this design, a harmonic suppression network is introduced at the output matching end to further improve the efficiency of the Doherty power amplifier. Finally, the asymmetric structure is introduced to further improve the efficiency of the power amplifier. Main and auxiliary power amplifier transistors select Cree CGH40010F and CGH40025 respectively. Based on the ADS simulation design and test, a broadband high-efficiency Doherty amplifier working in a 3.3~3.6 GHz band is designed for a 5G communication base station. The maximum saturated output power is 44.5 dBm and the drain efficiency is 67%~73%. When power fallback is 8 dB, the drain efficiency is 43%~51%.
Indoor Three-Dimensional Positioning System Based on Visible Light Communication Using Improved Fish Swarm Algorithm
Authors: Fang Zhijing , Chen Yuan , Wang Junjie , Song Yuanzhang
Published: June 2023

In recent years, with the popularity of lighting infrastructure,indoor visible three-dimensional positioning has attracted extensive attention.However, in the visible three-dimensional positioning algorithm, the positioning error is relatively large due to the high complexity of the system. For the reason that reduce positioning error, an improved fish swarm algorithm is proposed. Adaptive step size and chaotic change are introduced in fish swarm algorithm. In order to reduce the search time in the algorithm, swallowing behavior is adopted to deal with fish, so that the remaining useless weak fish in the iteration process of the improved algorithm is far less than that of the traditional fish swarm algorithm. The positioning system can get sub-micron-level accuracy in the indoor positioning area.
Structure dominated two-dimensional turbulence: formation, dynamics and interactions of dipole vortices
Authors: Gürcan Ö D
Published: June 2023

Two dimensional turbulence in geophysical fluids and plasma physics tends to be spotty, intermittent and rich in large scale structures such as coherent vortices or zonal flows, due to various mechanisms of self organization. Nonlinear solutions that rely on the vanishing of nonlinearity, especially the dipole vortex solution, stand out as key aspects of this structure dominated turbulence state. Using numerical simulations, it is demonstrated that an initial condition with a small number of high intensity turbulent patches, evolves towards a state dominated by coherent structures, and in particular dipole vortices, as each patch is organized into a finite number of dipole vortices that are ejected from this initially active region. In order to study the details of this process, an initial condition of two Gaussian peaks of the stream function is considered, and it was shown to result in a Chaplygin–Lamb dipole if the peaks have the same amplitude, or a Flierl–Stern–Whitehead dipole that rotates in the direction implied by the excess of vorticity if they do not. Analytical estimates for the velocity, the radius and the radius of curvature of the resulting dipole vortex is given in terms of the peaks and widths of the initial conditions. These are then verified by a detailed comparison of the analytical form of the vorticity of the dipole vortex and its numerical realization. It is argued that since these coherent structures are spared from the strong shear forces normally exerted by the nonlinearities, and can coexist with other localized solutions, or large scale flow patterns, they provide the backbone of the structure dominated or ‘sporadic’ turbulent state in two dimensions, on top of which other structures, waves and instabilities can develop. In order to elucidate these, a number of collision scenarios are considered. It is also shown that a simple two point vortex approximation to a dipole vortex seems to be appropriate for describing their evolution far from each-other, or for computing head on collisions between two or more dipole vortices, but not in the case of close or grazing collisions or their interaction with a nontrivial large scale flow.
Monodromy dependence and symplectic geometry of isomonodromic tau functions on the torus
Authors: Del Monte Fabrizio , Desiraju Harini , Gavrylenko Pavlo
Published: June 2023

We compute the monodromy dependence of the isomonodromic tau function on a torus with n Fuchsian singularities and SL(N) residue matrices by using its explicit Fredholm determinant representation. We show that the exterior logarithmic derivative of the tau function defines a closed one-form on the space of monodromies and times, and identify it with the generating function of the monodromy symplectomorphism. As an illustrative example, we discuss the simplest case of the one-punctured torus in detail. Finally, we show that previous results obtained in the genus zero case can be recovered in a straightforward manner using the techniques presented here.
DNA barcoding of sea urchin species in the bird’s head seascape Papua-Indonesia
Authors: Dailami M , Jeni  , Lapadi I , Sabariah V , Saleh F I E , Paisey A S , Dwiranti F , Saleky Dandi , Toha A H A
Published: June 2023

The DNA barcoding of COI gene has been used for molecular identification of the numerous individuals of sea urchin present in Bird’s Head Seascape (BHS) Papua in Indonesia. We extracted, sequenced, and analysed DNA of a total of 29 individuals collected from Raja Ampat, Rumberpon, Fakfak and Manokwari. The fragment gene of cytochrome oxidase subunit 1, were amplified with polymerase chain reaction by using coif and coitri primers. Total 570 base pairs nucleotide from each sample were analysed with MEGA X. The results of sample sequence homology with the GenBank and BOLD System databases show that some samples can be identified at the species level, and some samples can only be identified at the genus level. The phylogenetic tree results show that all samples are separated into two large clades.
Identifying key factors determining dynamics of environmental characteristics in Lesser Sunda island, Indonesia
Authors: Lusiana E D , Astutik S , Nurjannah  , Sambah A B
Published: June 2023

The main purpose of this study was to identify the key factor of various environmental characteristics dynamics in Lesser Sunda island. This is significant to support effective and efficient conservation management planning that prioritized in the area. We retrieved the dataset for this study from a global database package. Moreover, a multivariate analysis for dimension reduction, such as Principal Component Analysis (PCA) was utilized. The result indicated that dimension of environmental characteristics in Lesser Sunda island be reduced to six dimensions by considering the eigen value. Moreover, the first two dimension that contribute most variance proportion suggested Sea Surface Temperature (SST), pH and distance to shore as the key determining factors of environmental changes in studied area. Therefore, these factors should be highly considered for marine conservation design in Lesser Sunda island.
Histopathological Study of Fish Gills in Situ Cikaret and Situ Cilodong, West Java
Authors: Phadmacanty N L P R , Yulianto  , Dina R , Wahyudewantoro G , Aisyah S , Prawira A Y
Published: June 2023

Human activity causes water pollution in Situ Cikaret and Situ Cilodong, in Bogor and Depok, West Java, respectively. The pollutant and toxicant altered the behaviour, anatomy, and physiology of fish in those habitats. This study aimed to analyze the histopathological features of fish gills in Situ Cikaret and Situ Cilodong. The physical and chemical parameters, including pH, temperature, and dissolved oxygen (DO), were measured. Four fish species, Spotted barb fish (Barbodes binotatus), Amazon sailfin catfish (Pterygoplichthys pardalis), Yellow rasbora fish (Rasbora lateristriata), and Louhan fish (Amphilopus citrinellus) were collected. The gills were processed with paraffin, cut into 5 μm, and stained with hematoxylin-eosin. The histological features of Amazon sailfin catfish showed a normal feature, whilst the others showed an abnormality, including hyperplasia, leucocyte proliferation, secondary lamella fusion, vasodilatation, oedema, necrosis, and hypertropia mucus cells, and chloride cells. Although the temperatures, pH, and DO in this study were within the normal values, the abnormality of histological features indicated that Situ Cikaret and Situ Cilodong were polluted.
Plankton composition in Milkfish’s (Chanos chanos) stomach cultivated in traditional pond
Authors: Arfiati D , Zebadiah Z , Safara R , Orchida K , Inayah R Z N , Pratiwi K
Published: June 2023

Milkfish is a brackish-water cultured fish that is widely cultivated in traditional ponds because the business capital is relatively small and the feed provided is only from natural food in the form of plankton. This study aims to determine the type of plankton in the stomach and the frequency of feeding occurence milkfish in order to determine the type of plankton preferred by milkfish. This study used a survey method. The composition of plankton found in milkfish consists of 8 divisions, namely Bacillariophyta, Chlorophyta, Cryptophyta, Cyanophyta, Myozoa, Charophyta, Rotifera, and Arthropoda. However, Charophyta and Arthropoda divisions not found in the stomach of milkfish in the Probolinggo pond. The highest composition of plankton in the milkfish stomach in the Pasuruan pond was the Chlorophyta division (38%), while in the pond of Probolinggo, Bacillariophyta division (52.4%). Feeding occurrence frequency of milkfish is in the second pond 100% for the division of Chlorophyta, Cyanophyta, and Bacillariophyta. The similarity index based on the plankton composition in the milkfish stomach from two ponds was around 66.9%, indicating that the similarity of the plankton types consumed by milkfish was sufficiently high between the two ponds. Based on the results of this study, milkfish can be said to be herbivores because in their stomachs there are 99.8% phytoplankton and 0.2% zooplankton.
Effects of fentin acetate molluscicide on biological performance and haematological of the common carp, Cyprinus carpio cultivated at rice field water
Authors: Setijaningsih L , Setiadi E , Taufik I
Published: June 2023

Molluscicide of fentin acetate (C20H18O2Sn) is commonly used at the present due to effective in terms to control of molluscs in the rice field. The aims of this experiment is to determine toxicity effect of fentin acetate on growth, productivity, and blood glucose on the common carp, Cyprinus carpio cultured at rice field water. A 12 of rice field plots with size of 25m2 each were used. The stocking density of common carp was 25 fish/m2 for each rice plot. The culture period of the common carp was 21 days. The different fentin acetate concentration as treatments were as followed M0) without molluscicide; M1) 0.375 g/L of molluscicide; M2) 0.75 g/L of molluscicide); and M3) 1.5 g/L of molluscicide. Statistical analysis using one-way ANOVA with three replicates for each treatment was performed. The result showed that the treatment of molluscicide at 0.75 g/L was significantly different to the others on survival rate and productivity (p<0.05). Application of 0.75 g/L of molluscicide showed a positive correlation on blood glucose value.
The Growth, Biomass and Phycocyanin of Spirulina platensis Cultured with Liquid Organic (POC) and NPK Fertilizers
Authors: Maulana G D , Risjani Y , Taqiyyah A M
Published: June 2023

The purpose of this study was to determine the effect of NPK and liquid organic (POC) fertilizers on the growth, biomass, and phycocyanin of Spirulina platensis culture in a laboratory scale. The NPK fertilizer was carried out by giving 3 doses of 0.1 g/L, 0.2g/L, and 0.3 g/L and control. The POC Fertilizer was used in 3 doses of treatment of 10 mL/L, 15 mL/L, and 20 mL/L and control. The parameters observed for 8 days included growth rate, biomass, phycocyanin, and water quality parameters. The result showed the NPK fertilizer resulted in 80%, 70%, and 65% higher growth rates, biomass, and phycocyanin, respectively, than POC fertilizer. The application of NPK at a dose of 0.3 g/L gave the best treatment which resulted in a growth rate of 0.568 cells/day, biomass of 1.395 g/L and a phycocyanin content of 0.148 mg/L. The best treatment using POC was at a concentration of 20 mL/L which resulted in a growth rate of 0.459 cells/day, a biomass of 0.979 g/L, and a phycocyanin content of 0.097 mg/L. The culture with POC obtained a lower result than the NPK because the organic fertilizer requires a longer decomposition process to be utilized by Spirulina platensis.
Microplastics contamination in molluscs from mangrove forest of Situbondo, Indonesia
Authors: Yona D , Mahendra B A , Fuad M A Z , Sartimbul A
Published: June 2023

Mangrove ecosystem that lies between the land and the sea is vulnerable from the microplastics pollution caused by both land and marine-based activities. Mangrove ecosystem is home to many different faunas including molluscs and the presence of microplastics could be potential threats to the organisms. Thus, this study was conducted to evaluate the occurrence of microplastics in two different types of molluscs, which were bivalvia (Geloina erosa) and gastropoda (Telescopium telescopium) from the mangrove forest in Situbondo, East Java Province, Indonesia. Microplastics were analysed from 40 individual molluscs representing two different species. Overall, 459 particles of microplastics were retrieved from the samples. All samples of G. erosa contained microplastics particles and only one sample of T. Telescopium was found without microplastic. Four types of microplastics were identified from the samples: fiber, fragment, film and microbeads and fiber were the dominating type in both species. G. erosa contained higher number of microplastics particles than T. telescopium. The result of this study showed that there is a positive relationship between the size of organism and the occurrence of microplastics.