bluuebunny/crossref_metadata_2025 huggingface dataset:
Phonon mode and dielectric function dynamics of Bi0.5Na0.5TiO3-xSm2Ti2O7 ceramics during the phase transitions discovered by Raman scattering and spectroscopic ellipsometry
Authors: Wang Jianing , Dai Kai , Jiang Kai , Liu Zhen , Li Yafang , Yan Yuting , Cui Anyang , Wang Genshui , Hu Zhigao
Published: December 2023

Recently, Bi0.5Na0.5TiO3-based ceramics have drawn widespread attention due to their excellent energy storage properties. Here, a comprehensive analysis of the composition- and temperature-driven transition processes in (1 − x)Bi0.5Na0.5TiO3-xSm2Ti2O7 (BNST-x) polycrystals have been presented using Raman scattering and spectroscopic ellipsometry. With increasing Sm2Ti2O7 content, BNST-x ceramic gradually becomes disordered and belongs to the superparaelectric state at x = 0.12 near room temperature. Moreover, the thermal evolution of the lattice kinetic behaviors shows two crucial temperatures: the depolarization temperature Td and the temperature at the maximum dielectric permittivity Tm, which suggest the transitions from nonergodic relaxor ferroelectric—ergodic relaxor (ER) ferroelectric and ER ferroelectric—superparaelectric, respectively. It is noteworthy that the series of changes is closely related to the ordering degree of the B-site ion affected by the doping and the temperature. This work gives an insight into the connection among the phonon behavior, electronic transition, and lattice structure of BNST-x ceramics, which can further understand the phase transition mechanisms under the doping and thermal field.
Energy storage enhancement of sandwich-structured nanocomposites with mono/adjacent-layer design and their synergistic effect optimization
Authors: Fu Tingyu , Hou Yafei , Zhu Zhibiao , Cuan Jing , Li Weiping
Published: December 2023

Currently, advanced electronic devices demand capacitors with superior discharge energy density (U
d) and charge–discharge efficiency (η). Sandwich-structured nanocomposites have been extensively studied to significantly enhance U
d through the synergistic effect of each component layer and their interfacial effects. Herein, sandwich-structured x wt.% Ni(OH)2 BPB nanocomposites are prepared, where upper and lower high breakdown strength (E
b, B) layers are composed of 3 wt.% Ni(OH)2 and blended PMMA/P(VDF-HFP), while middle high polarization (P) layer is composed by various weight fraction (x wt.%) of Ni(OH)2 and P(VDF-HFP). Interestingly, 3 wt.% Ni(OH)2 BPB achieves improvements in U
d of 22.2 J cm−3 as well as η of 81.7% at 586 MV m−1 simultaneously. Improved energy storage performances are mainly attributed to the individual B and P layer design, as well as their synergistic coupling effects in the sandwich-structured nanocomposites. The results of experiment and simulation have concurrently demonstrated Ni(OH)2, PMMA and the functionalized sandwiched structured design could enhance U
d and descend remanent polarization and leakage current to increase η, which helps to obtain a satisfactory energy storage performance. This study offers a valid strategy for nanocomposites possessing high energy storage performances designing.
All-optical logic gates based on topological edge and corner states in two-dimensional photonic crystals with square dielectric columns
Authors: Gao Yong-Feng , Zhou Shu-Yang , Li Yue , Pan Ji-Ning , He Yue , Yang Ming , Sun Ming-Yang
Published: December 2023

Recently, with the rapid progress in all-optical networks and optical computing, there is an increasing requirement for more appropriate methods to design all-optical logic gates. Photonic crystals (PCs) can be serving as a versatile platform for manipulating light propagation. The realization of topological edge states (TESs) and topological corner states (TCSs) within high-order topological photonic insulators has attracted extensive attention. In this paper, TESs and TCSs are achieved using honeycomb PCs with square dielectric columns instead of conventional cylindrical ones for obtaining a larger photonic energy band gap due to reduction of dielectric column symmetry. TESs with overlapping frequencies can be attained by different arrangements of combining two PCs with distinct topological properties. A sandwich structure comprising both topologically trivial and non-trivial PCs is proposed, and ‘AND Gate’ and ‘OR Gate’ logic gates are implemented through the coupling between edge state waveguides when controlling the number of coupling layers. Additionally, a triangular-shaped box structure composed of non-trivial PCs enveloped by trivial PCs is constructed. Within this structure, TCSs manifest only around each acute angle, and a ‘NOT Gate’ logic gate is realized through corner state coupling and edge state coupling. This work paves a new way of designing high-performance micro–nano all-optical logic gate devices.
All-optical modulation of Fano-like resonances in apodized fiber Bragg grating using Er/Yb doped fiber
Authors: Wang Fan , Lin Siyu , Qu Yanchen , Han Xiaopeng , Wei Yuan , Zhao Zhenyu , Zhang Yundong
Published: December 2023

A novel all-optical scheme for fast modulation of Fano-like resonance using Er/Yb doped fiber (EYDF) is proposed and demonstrated experimentally. In the integrated system, an apodized fiber Bragg grating (AFBG) is inserted into one arm of the fiber Mach–Zehnder interferometer (MZI), and the asymmetric Fano-like resonances is generated by the interference between the MZI mode and AFBG mode. In addition, a section of EYDF is inserted into the other arm of the MZI to control the phase difference between the two arms of the MZI. By adjusting the power of optical pump applied to the EYDF, the transmission spectrum lineshapes of the integrated device can be effectively modulated into asymmetric Fano-like resonances, symmetric transmission dip or electromagnetically induced transparency-like resonances, which has a fast response speed. The proposed all-optical Fano-like modulation scheme is simple in structure, and has advantages of remote control and long-term stability, providing potential applications in the fields of fast and slow light, optical filters and fiber sensing.
Absolute deformation potentials and absolute energy levels of III-N, ZnO, and II-IV-N2 semiconductors for optoelectronic applications
Authors: Luo Hongxu , Wu Wenhao , Lyu Sai
Published: December 2023

Absolute deformation potentials and absolute energy levels for III-N, ZnO, and II-IV-N2 semiconductors are systematically determined from hybrid-functional calculations. Separate bulk and slab calculations are combined and the vacuum level is taken as the common reference. The trends in the absolute deformation potentials are rationalized by the kinetic energy effect and the bonding (or antibonding) character of the band edge states. The calculated absolute energy levels can be used to obtain the natural band alignment between these semiconductors and are in accordance with the available results. The determined parameters are of practical importance to the optoelectronic devices designs.
Attention mechanism guided sparse filtering for mechanical intelligent fault diagnosis under variable speed condition
Authors: Han Rui , Wang Jinrui , Wan Yanbin , Bao Jihua , Jiang Xue , Zhang Zongzhen , Han Baokun , Ji Shanshan
Published: December 2023

Variable speed is one of the common working conditions of mechanical equipment, which poses an important challenge to equipment fault diagnosis. The current solutions have the shortcomings of low computational efficiency and large diagnostic errors. The ability of attention mechanism to automatically extract useful features has begun to attract widespread attention in the field of mechanical intelligent fault diagnosis. Combining the advantages of attention mechanism and unsupervised learning, this paper proposes a squeeze-excitation attention guided sparse filtering (SESF) method for mechanical intelligent fault diagnosis method under variable speed. Firstly, the squeeze-excitation attention mechanism is embedded in sparse filtering algorithm to guide model training. Then, unsupervised feature extraction is carried out on multi-scale inputs from the variable speed signal samples. The training results are adaptively screened and weighted to make the model pay more attention to the region with the most classify discrimination, so as to improve the feature extraction ability of the model to obtain useful information. Finally, two sets of gear and bearing tests under variable speed condition are adopted to testify the performance of the proposed method. The experimental results show that the SESF method can overcome the influence of variable speed to achieve accurate recognition of different mechanical faults and is superior to the other methods.
Oxalic acid-assisted preparation of LTO-carbon composite anode material for lithium-ion batteries
Authors: Murashko Kirill , Karhunen Tommi , Meščeriakovas Arūnas , Subedi Nabin , Lähde Anna , Jokiniemi Jorma
Published: December 2023

This study presents an oxalic acid-assisted method for synthesizing spinel-structured lithium titanate (Li4Ti5O12; LTO)/carbon composite materials. The Ag-doped LTO nanoparticles (NPs) are synthesized via flame spray pyrolysis (FSP). The synthesized material is used as a precursor for synthesizing the LTO-NP/C composite material with chitosan as a carbon source and oxalic acid as an additive. Oxalic acid improves the dissolution of chitosan in water as well as changes the composition and physical and chemical properties of the synthesized LTO-NP/C composite material. The oxalic acid/chitosan ratio can be optimized to improve the electrochemical performance of the LTO-NP/C composite material, and the electrode synthesized with a high mass loading ratio (5.44 mg cm−2) exhibits specific discharge capacities of 156.5 and 136 mAh g−1 at 0.05 C- and 10 C-rate currents, respectively. Moreover, the synthesized composite LTO-NP/C composite material exhibits good cycling stability, and only 1.7% decrease in its specific capacity was observed after 200 charging–discharging cycles at 10 C-rate discharging current.
Coulomb blockade and Coulomb staircases in CoBi nanoislands on SrTiO3 (001)
Authors: Xia Yumin , Cai Desheng , Gao Jiaqing , Li Pengju , Xie Kun , Liu Yuzhou , Gu Yitong , Yu Gan , Cui Ping , Qin Shengyong
Published: December 2023

We successfully fabricated two-dimensional metallic CoBi nanoislands on SrTiO3 (001) substrate by molecular beam epitaxy, and systematically investigated their electronic structures by scanning tunneling microscopy and spectroscopy in situ at 4.2 K. Coulomb blockade and Coulomb staircases with discrete and well-separated levels are observed for the individual nanoisland, which is attributed to single-electron tunneling via two tunnel junction barriers. They are in excellent agreement with the simulations based on orthodox theory. Furthermore, we demonstrated that the Coulomb blockade becomes weaker with increasing temperature and almost disappears at ∼22 K in our variable temperature experiment, and its full-width at half-maximum of dI/dV peaks with temperature is ∼6 mV. Our results provide a new platform for designing single-electron transistors that have potential applications in future microelectronics.
4D printing of porous PLA-TPU structures: effect of applied deformation, loading mode and infill pattern on the shape memory performance
Authors: Rahmatabadi Davood , Soltanmohammadi Kianoosh , Aberoumand Mohammad , Soleyman Elyas , Ghasemi Ismaeil , Baniassadi Majid , Abrinia Karen , Bodaghi Mahdi , Baghani Mostafa
Published: December 2023

For the first time, the synergy of shape memory polymer (SMP) blending, 4D printing, and cold programming (CP) are investigated for improving the functionality of the shape memory effect (SME), increasing medical applications of porous structures, direct programming, and removing current limitations. Porous PLA-TPU structures with different printing patterns and applied deformation were CPed under constrained and non-constrained compression modes at room temperature and were recovered in the rubbery phase. The shape fixity and shape recovery ratios were calculated and the cross-section morphology was examined with scanning electron microscopy (SEM). The shape fixity values were in the range of 39.75%–71.27%, while almost complete shape recovery ratios (100%) were observed for all porous samples. Low shape fixity ratios can be justified due to the existence of two steps of spring-back and structure relaxation after unloading in cold programming, resulting from elastic and viscoelastic behavior. The glass transition temperature of the PLA-TPU blend was 69 °C and shifted to raw materials, indicating the possibility of some interaction between the two components. SEM images showed the uniform distribution of TPU particles and matrix-droplet morphology in the PLA-TPU blend. After printing, TPU droplets were stretched and the sea-island morphology was observed in some segments.
Tight focusing of azimuthally polarized Laguerre–Gaussian vortex beams by diffractive axicons
Authors: Alkelly Abdu A , Al-Ahsab Hassan T , Cheng Mingjian , Loqman Ibrahim G H
Published: December 2023

This study presents a comprehensive theoretical investigation into the focusing properties of azimuthally polarized Laguerre–Gaussian vortex (APLGV) beams when interacting with different optical elements, including a linear axicon, binary axicon, and lens based on the Debye approximation. The research findings highlight the intriguing combination of polarization and vortex singularities within the APLGV beam, which result in distinctive focal shapes when interacting with these optical elements. The focal shapes achieved include multiple tightly focused spots and optical needles, which can be controlled by adjusting optical system parameters and beam characteristics such as the numerical aperture (NA), truncation parameter, beam order, and annular obstruction. These parameters can be carefully selected to achieve specific focal shapes with applications in multi-optical manipulation, particle acceleration, and trapping. By harnessing the unique properties of APLGV beams and optimizing the optical setup, researchers can explore new possibilities for advanced optical manipulation and control.
Electromagnetic scattering of cylindrical artificial electron cloud by using parabolic equation method
Authors: Wang Yao-Wu , Xu Zheng-Wen , Zhao Hai-Sheng , Xue Kun
Published: December 2023

The ionizable metal vapor released in the ionosphere can artificially generate space electron clouds. They can scatter radio waves at decameter and meter wavelengths so as to realize over-the-horizon propagation. Based on the parabolic equation (PE) method and using Padé-(1,1) polynomial, the electromagnetic scattering characteristics of cylindrical artificial electron clouds are preliminarily studied in this letter. The bistatic radar scattering cross section (RCS) and the ground received field distribution via artificial electron cloud are calculated for various incidence angles at different radio frequencies and distances. The PE method is used here since its advantages of high precision, fast computing and less computing resource occupation over traditional methods. The study of electromagnetic scattering is valuable to the follow-up release experiments for generating electron cloud. It throws a new light on the practical utilization of over-the-horizon radio communication via scattering channel of artificial electron clouds.
Novel data encryption scheme and its application to secure multi-party communication
Authors: Wu Jingjin , Long Guoqiang , Wang Canhua , Wu Jianhua
Published: December 2023

Recent advances in cellular mobile telecommunication field have dramatically facilitated the multi-party collaborative work in social networks. However, the privacy issues exposed by insecure network channels and semi-trusted service providers, such as underlying data analysis and mining, have gradually aroused public concerns. In this context, a novel Multi-Party Privacy Data Encryption (MP-PDE) scheme built upon the deep learning framework is proposed. In this scheme, a four-dimensional autonomous chaotic system is initially leveraged to configurate the key-controlled cipher streams. Under the guidance of a multi-objective optimization function, the proposed encryption network manipulates the multi-party private data into a cipher image with the statistical pseudo-randomness. At the recipient side, distinct participants can decrypt the corresponding data availing their own licensing key from the identical cipher image. Furthermore, the encryption and decryption networks are equivalent except for their trainable network parameters. Finally, numerous experiments are conducted to verify the effectiveness and security of the proposed scheme.
Dynamics of high-power coupled nonlinear oscillator arrays for electronic beam steering technique: case of the triode based van der Pol oscillator
Authors: Tsefack Merlin Brice Saatsa , Tegnitsap Joakim Vianney Ngamsa , Fotsin Hilaire Bertrand , Ngouonkadi Elie Bertrand Megam
Published: December 2023

This paper presents the dynamics of coupled nonlinear oscillator arrays (CNOAs) as phase shifter for electronic beam steering technique. The proposed phase shifter uses oscillators of van der Pol type with a fifth-order nonlinear resistance and is built on the two architectures based injection-locked oscillator array (ILOAs) and coupled oscillator arrays (COAs). The dynamics equations of the phase shifter are proposed in the frequency and time domain. With the help of mathematical tools such as bifurcation diagrams, maximum Lyapunov exponent and Hilbert transform, important cartography of different oscillating states is deduced over large range of system parameters. Different behavior of the CNOAs including chaos, 2D-torus, multistability, locked and unlocked states are depicted. The phase shift between output voltages of each pair of coupled oscillators is presented for both architectures. A detailed analysis of locked states shows that the required phase shift is synthesized by slightly varying the frequency of the injected signal, or simply by detuning the free-running frequencies of the edge oscillators in equal but opposite directions. The proposed circuit of the phased shifter is built using the original van der Pol oscillator based on a vacuum triode. The maximal phase shift reaches

63
°

and

75
°

respectively for ILOAs and COAs. With the presence of triode in the circuit, the output voltage of each oscillating element in the array reaches

100

V

around

60

KHz

and is boosted by increasing the value of the triode bias potential to more than

420

V
.

This, therefore, increases the total power dissipation of a single oscillator in the array to more than

47

dB

(

50.12

W

). This circuit is a candidate for high-power electronics beam steering at ultrasonic frequency.
Behavioral propagation influenced by fluctuating personality on single-layer limited-contact network
Authors: Zhu Xuzhen , Zhang Junheng , Liu Siyuan , Tian Yang , Cui Yajuan , Li Yujie , Ma Jinming
Published: December 2023

In daily life, everyone has some degree of fluctuating personality, which is often manifested when making major decisions. To study the influence of fluctuating personality in behavioral propagation, we build a network model that is distinguished by a single layer and limited contact, and involves individuals with fluctuating personalities. At the same time, the impact of individual limited contact ability and network heterogeneity on information dissemination is studied. Based on this, we analyze the effect of personality fluctuations on the information propagation mechanism in complex networks using the theory of generalized edge partitioning. Finally, the study found a crossover phase transition phenomenon in the propagation process. In this model, as the fluctuation of personality becomes stronger, the final adoption range increases continuously with the increase of the propagation rate. In addition, when the frequency of psychological fluctuations of individuals reaches a certain value, the model’s outbreak threshold and the final propagation range tend to be consistent. The outcomes of the theoretical analysis and the findings of the practical simulation accord well.
Mimicking states with limited resources: passing quantum quiz via global control
Authors: Pyshkin P V , Sherman E Ya , Gábris A , Wu Lian-Ao
Published: December 2023

Precise control of quantum systems with a moderate number of degrees of freedom, being of interest for application in quantum technologies, becomes experimentally feasible. Various types of quantum scenarios and protocols are being widely discussed in scientific literature. We propose, analyze, and optimize a protocol which allows fast simulation of properties of unknown quantum states relying on minimum relevant information. Our protocol, having common features with quantum identification and shortcuts to adiabaticity, permits avoiding orthogonality catastrophe, where transitions between physically very similar systems are characterized by zero or a very low fidelity.
Multi-chalcogenides CuAg-II-IV-VI: a first-principles exploration of promising absorbing materials for solar cell applications
Authors: Zhu Hanming , Liu Yingkai , Li Decong , Kang Kunyong
Published: December 2023

Cu2ZnSnS4 quaternary chalcogenides have attracted considerable attention owing to their remarkable photoelectric properties. However, the presence of antisite defects poses a significant obstacle to the further advancement of these chalcogenides. In this study, we employed a first-principles approach to assess 540 CuAg-II-IV-VI compounds based on structural stability, band gap, effective mass, and optical properties. The objective was to identify promising candidate materials for solar absorption. As indicated by the results, CuAgZnGeSe4, CuAgBeSnSe4, CuAgBeGeSe4, CuAgZnSiTe4, and CuAgBeSiTe4 exhibit ideal band gaps ranging from 1.45 to 1.58 eV, low effective masses, and high absorption coefficients in the visible light spectrum, comparable to the benchmark material Cu2ZnSnS4. The findings of this study present novel insights for the development of highly efficient multi-chalcogenide solar cells.
First-principles study of the effect of alkali metals on the electronic and optical properties of SnS2
Authors: Ma Mengting , Liu Guili , Su Dan , Wei Ran , Yang Zhonghua , Zhang Guoying
Published: December 2023

In this paper, the photovoltaic properties of alkali metal atom X ( X is Li, Na, K, and Rb) doped monolayer SnS2 system have been investigated based on first principles calculations. After the doping of alkali metal atoms, the bond lengths of the doped systems increase compared to the pure SnS2 system. When alkali metal atoms are doped in the pure SnS2 system, the band gap of the doped systems increases and the SnS2 system changes from an indirect band gap to a direct band gap. It is found that the density of states in the valence band near the Fermi energy level of all doped systems is primarily contributed by S atoms, and the conduction band is primarily contributed by Sn and S atoms. The ionic bonds are formed between X and S atoms. The polarizability of the doped SnS2 systems is enhanced. Moreover, the absorption and reflection peaks of the SnS2 doping systems are redshifted, which improves the effective utilization rate of the infrared light region.
The effect of micro-gap discharge paths on ionization coefficients and similarity theory
Authors: Zhang Hao , Zhao Laijun , Wang Guoda , Ma Guokai , Sun Yanzhou
Published: December 2023

In order to investigate the impact of discharge paths at the micrometer scale on breakdown, two sets of different electrodes were arranged with electrode gaps ranging from 10 μm to 100 μm and gas pressures varying from 1 kPa to 100 kPa. The research has revealed that without an insulating layer at the edge of the electrode, when the product of gas pressure (p) and electrode gap (d) is less than 60Pa·cm, the number of positive ions cannot satisfy the conditions for self-sustaining discharge at the electrode gap (d). As a result, the discharge path varies along a longer path (s) to satisfy the conditions for self-sustained discharge, thereby maintaining the minimum breakdown voltage. This long-path discharge mechanism affects the ionization coefficient, resulting in an inconsistency between the ionization coefficient ratio at different distances and their respective scale factor (k) values. Therefore, on a micrometer scale, changes in the path make the application of similarity theory no longer applicable.
Design and full analysis of a metafiber-based photothermal bio-probe with perfect conversion efficiency
Authors: Zhu Zebin , Jiang Liyong , Zhao Xiangwei
Published: December 2023

The metafiber, which involves fabricating metasurfaces at optical fiber tips, has shown potential as an integrated optical sensing or photothermal conversion platform. In this study, we present a metafiber-based photothermal bio-probe with a high optical absorption efficiency of 99.83%. Physical mechanisms underlying the efficiency are elucidated using coherent perfect absorption and multiple reflection theories. In our simulation, the probe exhibits ultra-fast heating/cooling rates, high temperature localization, steep temperature gradients, and robust response to environmental factors. In particular, only 1.0 mW of incident power is needed to generate the temperature gradient required for cell capture or drug delivery, while the corresponding temperature near the fiber tip is still safe for biological tissue. These advantages make our designed bio-probe as an ideal platform in various of applications, such as living cells capture, drug delivery, and local hyperthermia.
Quantum tunnelling in hafnia-based metal-insulator-metal diodes: atomistic-to-continuum modelling approach and experimental validation
Authors: Pavoni Eleonora , Laudadio Emiliano , Joseph Christopher Hardly , Zampa Gian Marco , Russo Paola , Mohebbi Elaheh , Mencarelli Davide , Dragoman Mircea , Stipa Pierluigi , Pierantoni Luca , Aldrigo Martino
Published: December 2023

In this work, we present a metal-insulator-metal (MIM) diode, based on quantum tunnelling phenomena. Its model is based on a multilevel modelling approach consisting of atomistic and continuum simulations, fully validated by extensive measurements. The MIM structure comprises a hafnium oxide (or hafnia, HfO2) dielectric layer, less than 4 nm thick and a square contact area of only 4 μm2, placed between two metallic electrodes, namely platinum as the source and titanium as the drain. The current–voltage (I–V) curve has been estimated by Density Functional Theory (DFT) calculations through an optimisation of the interfaces between metals and monoclinic HfO2. The dielectric parameters arising from ab initio computations have then been used as inputs for the successive circuit and electromagnetic simulations. Finally, the multilevel model has been validated with great accuracy, first measuring the I–V characteristics by applying a drain-source voltage between −1 V and +1 V, and then extracting the scattering parameters up to 40 GHz, thus demonstrating that DFT and circuit/electromagnetic simulations match almost perfectly the experimental ones. These outcomes represent the first study of such nanoscale devices investigated by means of a rigorous atomistic-to-continuum approach, providing invaluable information in order to improve fabrication and correctly assess the macroscale performance of nanoelectronics systems.
Quantum super-resolution with balanced homodyne detection in low-earth-orbit
Authors: Gosalia Ronakraj K , Malaney Robert , Aguinaldo Ryan , Green Jonathan
Published: December 2023

Quantum super-resolution involves resolving two sources below the Rayleigh limit using quantum optics. Such a technique would allow high-precision inter-satellite positioning and tracking on communication and navigation constellations. Due to the size, weight and power constraints typical of low-earth-orbit (LEO) satellites, a simple solution is often preferred. Here, we show that a balanced homodyne detection (BHD) setup using a shaped single-mode local oscillator can achieve super-resolution despite typical photonic losses. We further analyze the impact of a fluctuating and fixed centroid misalignment due to satellite pointing issues, and find that fixed misalignment is comparatively more detrimental to the performance of a BHD setup. Thus, our study provides a practical assessment of BHD to achieve super-resolution on a modern LEO satellite platform. Finally, we discuss how our analysis can be extended to stellar sources for astronomical applications.
Resilience of Amazon rainfall to CO2 removal forcing
Authors: Zhang Suqin , Qu Xia , Huang Gang , Hu Peng , Yang Xianke , Wang Ya , Wu Liang
Published: December 2023

Over the Amazon region, rainfall-induced changes to CO2 pathways significantly impact humans and multiple ecosystems. Its resilience is of vital importance, and idealized CO2 removal experiments indicate that declining trends in rainfall amounts are irreversible and exhibit a deficiency when the CO2 concentration returns to the pre-industrial level. The irreversible decline in Amazon rainfall is mainly due to the weakened ascent, further led by two main causes. (1) Enhanced tropospheric warming and a wetter atmospheric boundary layer over the tropics during CO2 removal generate a strong meridional gradient of temperature and specific humidity; driven by prevailing northeasterly winds, negative moist enthalpy advection occurs, which in turn weakens the ascent over the Amazon and results in anomalous drought. (2) The enhanced radiative cooling of atmospheric column. Driven by the negative lapse-rate feedback, the outgoing longwave radiative flux increases in the clear-sky atmosphere. As a result, the anomalous diabatic descent generates to maintain the energy balance of the atmospheric column. This result implies that the symmetric removal of CO2 does not guarantee full recovery of regional precipitation.
Applying polygenic risk score methods to pharmacogenomics GWAS: challenges and opportunities
Authors: Zhai Song , Mehrotra Devan V , Shen Judong
Published: December 2023

Polygenic risk scores (PRSs) have emerged as promising tools for the prediction of human diseases and complex traits in disease genome-wide association studies (GWAS). Applying PRSs to pharmacogenomics (PGx) studies has begun to show great potential for improving patient stratification and drug response prediction. However, there are unique challenges that arise when applying PRSs to PGx GWAS beyond those typically encountered in disease GWAS (e.g. Eurocentric or trans-ethnic bias). These challenges include: (i) the lack of knowledge about whether PGx or disease GWAS/variants should be used in the base cohort (BC); (ii) the small sample sizes in PGx GWAS with corresponding low power and (iii) the more complex PRS statistical modeling required for handling both prognostic and predictive effects simultaneously. To gain insights in this landscape about the general trends, challenges and possible solutions, we first conduct a systematic review of both PRS applications and PRS method development in PGx GWAS. To further address the challenges, we propose (i) a novel PRS application strategy by leveraging both PGx and disease GWAS summary statistics in the BC for PRS construction and (ii) a new Bayesian method (PRS-PGx-Bayesx) to reduce Eurocentric or cross-population PRS prediction bias. Extensive simulations are conducted to demonstrate their advantages over existing PRS methods applied in PGx GWAS. Our systematic review and methodology research work not only highlights current gaps and key considerations while applying PRS methods to PGx GWAS, but also provides possible solutions for better PGx PRS applications and future research.
LncRNA CARD8-AS1 suppresses lung adenocarcinoma progression by enhancing TRIM25-mediated ubiquitination of TXNRD1
Authors: Pan Cheng , Wang Qi , Wang Hongshun , Deng Xiaheng , Chen Liang , Li Zhihua
Published: December 2023

Long non-coding RNAs (lncRNAs) play crucial roles in the tumorigenesis and progression of lung adenocarcinoma (LUAD). However, little was known about the role of lncRNAs in high-risk LUAD subtypes: micropapillary-predominant adenocarcinoma (MPA) and solid-predominant adenocarcinoma (SPA). In this study, we conducted a systematic screening of differentially expressed lncRNAs using RNA sequencing in 10 paired MPA/SPA tumor tissues and adjacent normal tissues. Consequently, 110 significantly up-regulated lncRNAs and 288 aberrantly down-regulated lncRNAs were identified (|Log2 Foldchange| ≥ 1 and corrected P < 0.05). The top 10 lncRNAs were further analyzed in 89 MPA/SPA tumor tissues and 59 normal tissues from The Cancer Genome Atlas database. Among them, CARD8-AS1 showed the most significant differential expression, and decreased expression of CARD8-AS1 was significantly associated with a poorer prognosis. Functionally, CARD8-AS1 overexpression remarkably suppressed the proliferation, migration and invasion of LUAD cells both in vitro and in vivo. Conversely, inhibition of CARD8-AS1 yielded opposite effects. Mechanistically, CARD8-AS1 acted as a scaffold to facilitate the interaction between TXNRD1 and E3 ubiquitin ligase TRIM25, thereby promoting the degradation of TXNRD1 through the ubiquitin–proteasome pathway. Additionally, TXNRD1 was found to promote LUAD cell proliferation, migration and invasion in vitro. Furthermore, the suppressed progression of LUAD cells resulting from CARD8-AS1 overexpression could be significantly reversed by simultaneous overexpression of TXNRD1. In conclusion, this study revealed that the lncRNA CARD8-AS1 played a suppressive role in the progression of LUAD by enhancing TRIM25-mediated ubiquitination of TXNRD1. The CARD8-AS1-TRIM25-TXNRD1 axis may represent a promising therapeutic target for LUAD.
Partisan Effects of Information Campaigns in Competitive Authoritarian Elections: Evidence from Bangladesh
Authors: Ahmed Firoz , Hodler Roland , Islam Asad
Published: December 2023

To study the effects of non-partisan information and get-out-the-vote campaigns on the partisan composition of the voting population in competitive authoritarian elections, we conducted a large-scale field experiment prior to the 2018 Bangladeshi general election. Our two treatments highlight that high turnout increases the winning party’s legitimacy and that election outcomes matter for policy outcomes. Both treatments increase turnout (measured by ink marks) in government strongholds, but decrease turnout in opposition strongholds. We explain the withdrawal of treated opposition supporters and conclude that non-partisan information and get-out-the-vote campaigns can further tilt the uneven playing field in competitive authoritarian elections.
Introduction to the special issue on positive psychology and wellbeing
Authors: Resnik Pia , Mercer Sarah
Published: December 2023

This introduction to the Special Issue on ‘Positive Psychology and Wellbeing’ begins by outlining the history and relevance of Positive Psychology (PP) for ELT. A key construct in PP is wellbeing, which all the papers in this Special Issue focus on. In this introductory article, we describe how the term wellbeing has been used and how it is defined in this collection. We discuss why wellbeing matters in language learning and teaching and point out some of the key controversies surrounding this term. We then introduce the nine articles highlighting their unique contributions to furthering our understandings in this field. We conclude by reflecting on key practical implications derived from the contributions and by presenting possible avenues for future research in this area. Our hope is that this collection of papers will serve as an impetus for innovations in practice, research, and theoretical thinking about this vitally important topic.
Anisotropic tomography and mantle dynamics of the North China Craton
Authors: Guo Huili , Zhao Dapeng , Ding Zhifeng
Published: December 2023

We present high-resolution 3-D images of isotropic P-wave velocity (Vp), azimuthal anisotropy (AAN) and radial anisotropy (RAN) down to 700 km depth beneath the North China Craton (NCC) and adjacent areas, which are obtained by inverting a great number of high-quality arrival time data recorded at 1374 portable seismic stations and 635 permanent stations in the study region. Our results reveal new and detailed features of the upper mantle structure beneath the NCC. Varying structural heterogeneities are revealed beneath different tectonic blocks, and differences also exist between northern and southern parts of each block. The fast velocity directions (FVDs) of azimuthal anisotropy are mainly NW–SE under the Alaxa block, and NE–SW beneath the Tibetan Plateau. The FVDs present an arc transition along the boundary faults separating the Tibetan Plateau, the Alaxa block, the western NCC, and the Sichuan basin. Low-Vp anomalies with positive RANs (i.e. horizontal Vp > vertical Vp) are revealed at 100–200 km depths under the Tibetan Plateau, reflecting frozen-in anisotropy in the thick lithosphere. Significant low-Vp anomalies with a circular AAN pattern exist at 0–700 km depths beneath the Datong volcano. In addition, negative RAN occurs right below the volcano, whereas positive RANs appear around it, suggesting that the Datong volcano is fed by hot upwelling flow from the lower mantle associated with collapsing of subducted slab materials down to the lower mantle. The eastern NCC shows complex Vp AANs and RANs. Seismic anisotropy exhibits east–west variations in the upper mantle across the Tanlu fault zone. The west of the Tanlu fault shows negative RANs (vertical Vp > horizontal Vp), whereas its east shows positive RANs at 300–500 km depths. The low-Vp anomaly under the Datong volcano is connected with a large low-Vp anomaly beneath the eastern NCC above ∼250 km depth, suggesting that the hot upwelling flow under Datong may migrate laterally to the asthenosphere under the eastern NCC and contribute to the lithospheric delamination and destruction there.
A detailed characterization of drug resistance during darunavir/ritonavir monotherapy highlights a high barrier to the emergence of resistance mutations in protease but identifies alternative pathways of resistance
Authors: Abdullahi Adam , Diaz Ana Garcia , Fopoussi Olga Mafotsing , Beloukas Apostolos , Fokom Defo Victoire , Kouanfack Charles , Torimiro Judith , Geretti Anna Maria
Published: December 2023

Background

Maintenance monotherapy with ritonavir-boosted darunavir has yielded variable outcomes and is not recommended. Trial samples offer valuable opportunities for detailed studies. We analysed samples from a 48 week trial in Cameroon to obtain a detailed characterization of drug resistance.

Methods

Following failure of NNRTI-based therapy and virological suppression on PI-based therapy, participants were randomized to ritonavir-boosted darunavir (n = 81) or tenofovir disoproxil fumarate/lamivudine +ritonavir-boosted lopinavir (n = 39). At study entry, PBMC-derived HIV-1 DNA underwent bulk Protease and Reverse Transcriptase (RT) sequencing. At virological rebound (confirmed or last available HIV-1 RNA ≥ 60 copies/mL), plasma HIV-1 RNA underwent ultradeep Protease and RT sequencing and bulk Gag-Protease sequencing. The site-directed mutant T375A (p2/p7) was characterized phenotypically using a single-cycle assay.

Results

NRTI and NNRTI resistance-associated mutations (RAMs) were detected in 52/90 (57.8%) and 53/90 (58.9%) HIV-1 DNA samples, respectively. Prevalence in rebound HIV-1 RNA (ritonavir-boosted darunavir, n = 21; ritonavir-boosted lopinavir, n = 2) was 9/23 (39.1%) and 10/23 (43.5%), respectively, with most RAMs detected at frequencies ≥15%. The resistance patterns of paired HIV-1 DNA and RNA sequences were partially consistent. No darunavir RAMs were found. Among eight participants experiencing virological rebound on ritonavir-boosted darunavir (n = 12 samples), all had Gag mutations associated with PI exposure, including T375N, T375A (p2/p7), K436R (p7/p1) and substitutions in p17, p24, p2 and p6. T375A conferred 10-fold darunavir resistance and increased replication capacity.

Conclusions

The study highlights the high resistance barrier of ritonavir-boosted darunavir while identifying alternative pathways of resistance through Gag substitutions. During virological suppression, resistance patterns in HIV-1 DNA reflect treatment history, but due to technical and biological considerations, cautious interpretation is warranted.
Resistance to first-line antibiotic therapy among patients with uncomplicated acute cystitis in Melbourne, Australia: prevalence, predictors and clinical impact
Authors: Curtis Stephanie J , Kwong Jason C , Chaung Yee Lin , Mazza Danielle , Walsh Calum J , Chua Kyra Y , Stewardson Andrew J
Published: December 2023

Background

Australian guidelines recommend trimethoprim or nitrofurantoin as first-line agents for uncomplicated urinary tract infections (UTIs). Laboratory surveillance indicates high rates of trimethoprim resistance among urinary bacterial isolates, but there are scant local clinical data about risk factors and impact of trimethoprim resistance.

Objectives

To determine the prevalence, risk factors, mechanism and impact of resistance to first-line antibiotic therapy for uncomplicated UTIs in the community setting.

Methods

A prospective observational study from October 2019 to November 2021 in four general practices in Melbourne, Australia. Female adult patients prescribed an antibiotic for suspected or confirmed uncomplicated acute cystitis were eligible. Primary outcome was urine isolates with resistance to trimethoprim and/or nitrofurantoin.

Results

We recruited 87 participants across 102 UTI episodes with median (IQR) age of 63 (47–76) years. Escherichia coli was the most common uropathogen cultured (48/62; 77%); 27% (13/48) were resistant to trimethoprim (mediated by a dfrA gene) and none were resistant to nitrofurantoin. Isolates with resistance to a first-line therapy were more common among patients reporting a history of recurrent UTIs [risk ratio (RR): 2.08 (95% CI: 1.24–3.51)] and antibiotic use in the previous 6 months [RR: 1.89 (95% CI: 1.36–2.62)]. Uropathogen resistance to empirical therapy was not associated with worse clinical outcomes.

Conclusions

Resistance to trimethoprim is common in uncomplicated UTIs in Australia but may not impact clinical outcomes. Further research is warranted on the appropriateness of trimethoprim as empirical therapy, particularly for patients with antimicrobial resistance risk factors.
Prevalence of piperacillin/tazobactam resistance in invasive Haemophilus influenzae in Germany
Authors: Duske Helene , Claus Heike , Krone Manuel , Lâm Thiên-Trí
Published: December 2023

Background

Haemophilus influenzae (Hi) is a Gram-negative bacterium that may cause sepsis or meningitis, treatment of which mainly includes β-lactam antibiotics. Since 2019 EUCAST breakpoints for piperacillin/tazobactam have been available. Little is known about the prevalence and mechanisms of piperacillin/tazobactam resistance in Hi.

Objectives

To provide reliable prevalence data for piperacillin/tazobactam resistance in Hi in Germany, to evaluate different antibiotic susceptibility testing methods and to examine possible resistance mechanisms.

Methods

According to EUCAST breakpoints, the MIC for piperacillin/tazobactam resistance is >0.25 mg/L. All invasive Hi in Germany from 2019 were examined by gradient agar diffusion (GAD) for piperacillin/tazobactam susceptibility. Piperacillin/tazobactam broth microdilution (BMD), piperacillin GAD on tazobactam-containing agar [piperacillin GAD on Mueller–Hinton agar with horse blood (MH-F)/tazobactam) and piperacillin/tazobactam agar dilution (AD) were used for confirmation. Phenotypic testing was complemented by ftsI sequencing.

Results

Piperacillin/tazobactam GAD resulted in 2.9% (21/726) resistant Hi. BMD did not confirm piperacillin/tazobactam resistance. Two strains were found resistant by AD, of which one was also resistant using piperacillin GAD on MH-F/tazobactam. Overall, we found two strains with a piperacillin/tazobactam MIC >0.25 mg/L in at least two different tests (0.3%). Both were β-lactamase-producing amoxicillin/clavulanate-resistant with PBP3 mutations characterized as group III-like+. Relevant PBP3 mutations occurred in six strains without phenotypic piperacillin/tazobactam resistance. These mutations suggest a reduced efficacy of β-lactam antibiotics in these isolates.

Conclusions

Piperacillin/tazobactam resistance prevalence in invasive Hi is low in Germany. Reduced susceptibility was correlated with PBP3 mutations, in particular with group III mutations.
Rethinking c-Fos for understanding drug action in the brain
Authors: Sakurai Katsuyasu
Published: December 2023

Understanding the mechanisms of drug action in the brain, from the genetic to the neural circuit level, is crucial for the development of new agents that act upon the central nervous system. Determining the brain regions and neurons affected by a drug is essential for revealing its mechanism of action in the brain. c-Fos, a marker of neuronal activation, has been widely used to detect neurons activated by stimuli with high spatial resolution. In this review, the use of c-Fos for the visualization and manipulation of activated neurons is introduced. I also explain that a higher temporal resolution can be achieved by changing the staining method for visualization of c-Fos. Moreover, a new method that allows labeling and manipulating commonly activated neurons using two different stimuli is proposed.
Prevalence, intensity of infestation, and biomarker potential of the nemertean worm, Carcinonemertes carcinophila (Kölliker, 1845), on ovigerous blue crabs, Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae), in Chesapeake Bay, USA
Authors: Schneider Alexandra K , Pomroy Alexandria K , Shields Jeffrey D
Published: December 2023

The effect of individual and population-level egg mortality is important to quantify to maintain sustainable crustacean fisheries. The nemertean worm Carcinonemertes carcinophila (Kölliker, 1845) is an egg predator of the Atlantic blue crab, Callinectes sapidusRathbun, 1896; however, little is known about the impact this nemertean has on the reproduction of the blue crab. We assessed the prevalence and intensity of the infestation of nemerteans in ovigerous blue crabs using a fishery-independent trawl survey. During the primary spawning period of the crab, May–September 2022, 126 ovigerous females were collected and analyzed for worms. Prevalence over this time was 66.6% and mean brood infestation was 53.9 worms per infested crab host. Nemertean egg consumption was quantified with a six-day microcosm experiment. Of the 48 worms in the experiment, 71% actively fed on crab eggs and their consumption ranged 0.16–4.5 eggs day–1. Consumption rates were used to estimate population-level impact of nemertean feeding on crab brood mortality. Modeled proportions of brood loss per crab ranged 0–0.0044%. At the current prevalence and intensity of infestation, egg consumption by nemerteans has a negligible effect on blue crab reproductive output and batch fecundity in Chesapeake Bay. We also investigated the use of mature nemertean worms as a biomarker for establishing the spawning history of ovigerous female blue crabs and determined that the presence of worms in the clutch and in the gills can be used to indicate parity in ovigerous female crabs.
Mechanistic insights into the survival curve of HeLa cells with a short shoulder and their S phase-specific sensitivity
Authors: Komatsu Kenshi , Tauchi Hiroshi
Published: December 2023

HeLa cells are a cell line with two unique cellular features: a short-shouldered survival curve and two peaks of radioresistance during the cell cycle phase, while their underlying mechanisms remain unclear. We herein proposed that these radiobiological features are due to a common mechanism by which radiation suppresses homologous recombination repair (HRR) in a dose-dependent manner. This radio-suppression of HRR is mediated by an intra-S checkpoint and reduces survivals of cells in S phase, especially early S phase, resulting in both short shoulder and radioresistance with two peaks in the cell cycle. This new explanation may not be limited to HeLa cells since a similar close association of these features is also observed in other type of cells.