bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering Co and Ru dual-metal atoms on nitrogen-doped carbon as highly efficient bifunctional oxygen electrocatalysts
Authors: Zhang Liang , Yao Junchuan , Zhang Jingyu , He Wenjun , Li Ying , Liang Limin , Liu Caichi , Liu Hui , Hao Qiuyan
Published: July 2022

Designing dual-metal atoms efficient bifunctional oxygen electrocatalyst by a one-step adsorption and a pyrolysis steps.
Preparation of a Mg2+-containing MOF through ion exchange and its high ionic conductivity
Authors: Niwa Shintaro , Sadakiyo Masaaki
Published: July 2022

A Mg2+-containing MOF was synthesized through ion exchange with an anionic framework. The Mg2+-containing MOF showed high ionic conductivity under a guest vapor at ambient temperature.
Mechanosynthesis and photophysics of colour-tunable photoluminescent group 13 metal complexes with sterically demanding salen and salophen ligands
Authors: Leon Felix , Li Chenfei , Reynes Javier F. , Singh Varun K. , Lian Xiao , Ong How Chee , Hum Gavin , Sun Handong , García Felipe
Published: July 2022

A series of four photoluminescent Al and In complexes were synthesised using an environmentally-benign mechanosynthesis strategy.
Integrated design of an amination process of lignin oxygenated model compounds to synthesize cyclohexylamine: catalyst nanostructure engineering and catalytic conditional strategy
Authors: Ji Na , Lei Yaxuan , Yu Zhihao , Li Hanyang , Diao Xinyong , Lu Xuebin , Wang Shurong
Published: July 2022

This review summarizes the research progress in the one-pot catalytic amination of lignin oxygenated model compounds to cyclohexylamine, specifically from the catalyst nanostructure engineering and catalytic conditional strategy.
Lead-free AgBiI4 perovskite artificial synapses for a tactile sensory neuron system with information preprocessing function
Authors: Ye Haibo , Liu Zhiyong , Han Hangdi , Shi Tielin , Liao Guanglan
Published: July 2022

Organometal halide perovskites (OHPs) exhibit great potential in memristors and artificial synaptic devices.
Crystal actuation switching by crystal thickness and light wavelength
Authors: Hasebe Shodai , Hagiwara Yuki , Hirata Kazuya , Asahi Toru , Koshima Hideko
Published: July 2022

Light driven crystal actuators, where bending direction and speed are controlled by crystal thickness and light wavelength, are fabricated.
Functional silver nanoparticles as broad-spectrum antimicrobial agents
Authors: Zhang Juan , Gao Mengjiao , Gao Wenchao , Yang Peng , Meng Fanhui , Liu Qiang , Chang Honghong
Published: July 2022

Indole-functionalized silver nanoparticles were prepared by a simple one-pot method, which exhibited efficient antibacterial activity against Gram-positive and Gram-negative bacteria.
Synthesis of glycopeptides and glycopeptide conjugates
Authors: Doelman Ward , van Kasteren Sander I.
Published: July 2022

Synthetic glycopeptides are of key importance for unraveling the complexities of glycobiology. In this Review, the key approaches towards synthetic well-defined glycopeptides and glycopeptide conjugates are described.
Selective halocyclization and iodosulfonylation ofN-benzothiazol-2-yl alkynamides under mild conditions
Authors: Fang Yu , Ren Shangfeng , He Chen , Han Huiqi , Liu Jin-Biao , Liao Fumin , Yang Min
Published: July 2022

The selective halocyclization and iodosulfonylation ofN-benzothiazol-2-yl alkynamides under mild conditions is described, affording pyrimidobenzothiazoles and multisubstituted α,β-enones respectively.
First synthesis of an ABCE ring substructure of daphnicyclidin A
Authors: Tu Jianzhuo , Clark Madison M. , Harmata Michael
Published: July 2022

The ABCE tetracyclic ring system of daphnicyclidin A was prepared using an intramolecular (4 + 3) cycloaddition of an oxidopyridinium ion as the key step.
Neutrally photoinduced MgCl2-catalyzed alkenylation and imidoylation of alkanes
Authors: Zhang Xiaomin , Zeng Rong
Published: August 2022

A practical protocol for the oxidation of the chloride ion (Cl−) to the chlorine radical (Cl˙)viaphotoinduced MgCl2catalysis is reported. Efficient alkenylation and imidoylation were developed under redox-neutral and acid-free conditions.
A flexible, robust cellulose/phytic acid/polyaniline hydrogel for all-in-one supercapacitors and strain sensors
Authors: Wan Huixiong , Qin Chaoran , Lu Ang
Published: July 2022

An easy handing method was designed to prepare a cellulose-based conductive hydrogel for high performance all-in-one supercapacitors and highly sensitive strain sensors.
Insight into the optoelectronic and thermoelectric nature of NaLiX (X = S, Se, Te) novel direct bandgap semiconductors: a first-principles study
Authors: Khan Muhammad Salman , Gul Banat , Abu-Farsakh Hazem , Khan Gulzar
Published: July 2022

The computed density of states for NaLiS material.
Validation of strategies for coupling exoplanet PSFs into single-mode fibres for high-dispersion coronagraphy
Authors: El Morsy M. , Vigan A. , Lopez M. , Otten G. P. P. L. , Choquet E. , Madec F. , Costille A. , Sauvage J.-F. , Dohlen K. , Muslimov E. , Pourcelot R. , Floriot J. , Benedetti J.-A. , Blanchard P. , Balard P. , Murray G.
Published: July 2022

On large ground-based telescopes, the combination of extreme adaptive optics (ExAO) and coronagraphy with high-dispersion spectroscopy (HDS), sometimes referred to as high-dispersion coronagraphy (HDC), is starting to emerge as a powerful technique for the direct characterisation of giant exoplanets. The high spectral resolution not only brings a major gain in terms of accessible spectral features, but also enables a better separation of the stellar and planetary signals. Ongoing projects such as Keck/KPIC, Subaru/REACH, and VLT/HiRISE base their observing strategy on the use of a few science fibres, one of which is dedicated to sampling the planetŠs signal, while the others sample the residual starlight in the speckle field. The main challenge in this approach is to blindly centre the planet’s point spread function (PSF) accurately on the science fibre, with an accuracy of less than 0.1 λ/D to maximise the coupling efficiency. In the context of the HiRISE project, three possible centring strategies are foreseen, either based on retro-injecting calibration fibres to localise the position of the science fibre or based on a dedicated centring fibre. We implemented these three approaches, and we compared their centring accuracy using an upgraded setup of the MITHiC high-contrast imaging testbed, which is similar to the setup that will be adopted in HiRISE. Our results demonstrate that reaching a specification accuracy of 0.1 λ/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We studied the contributors to the centring error in the case of MITHiC and we propose a quantification for some of the most impacting terms.
Detection of an unidentified soft X-ray emission feature in NGC 5548
Authors: Gu Liyi , Mao Junjie , Kaastra Jelle S. , Mehdipour Missagh , Pinto Ciro , Grafton-Waters Sam , Bianchi Stefano , Landt Hermine , Branduardi-Raymont Graziella , Costantini Elisa , Ebrero Jacobo , Petrucci Pierre-Olivier , Behar Ehud , di Gesu Laura , De Marco Barbara , Matt Giorgio , Mitchell Jake A. J. , Peretz Uria , Ursini Francesco , Ward Martin
Published: July 2022

Context.NGC 5548 is an X-ray bright Seyfert 1 active galaxy. It exhibits a variety of spectroscopic features in the soft X-ray band, in particular including the absorption by the active galactic nucleus (AGN) outflows of a broad range of ionization states, with column densities up to 1027m−2, and having speeds up to several thousand kilometers per second. The known emission features are in broad agreement with photoionized X-ray narrow and broad emission line models.

Aims.We report on an X-ray spectroscopic study using 1.1 MsXMM-Newtonand 0.9 MsChandragrating observations of NGC 5548 spanning two decades. The aim is to search and characterize any potential spectroscopic features in addition to the known primary spectral components that are already modeled in high precision.

Methods.For each observation, we modeled the data using a global fit including an intrinsic spectral energy distribution of the AGNs and the known distant X-ray absorbers and emitters. We utilized as much knowledge from previous studies as possible. The fit residuals were stacked and scanned for possible secondary features.

Results.We detect a weak unidentified excess emission feature at ∼18.4 Å (18.1 Å in the restframe). The feature is seen at > 5σstatistical significance taking the look-elsewhere effect into account. No known instrumental issues, atomic transitions, or astrophysical effects can explain this excess. The observed intensity of the possible feature seems to anticorrelate in time with the hardness ratio of the source. However, even though the variability might not be intrinsic, it might be caused by the time-variable obscuration by the outflows. An intriguing possibility is the line emission from charge exchange between a partially ionized outflow and a neutral layer in the same outflow, or in the close environment. Other possibilities, such as emission from a highly ionized component with high outflowing speed, cannot be fully ruled out.
Age and growth rates of a translocated chub Squalius cephalus chalk-stream population with comparison to indigenous riverine populations in England
Authors: Warren Bertram I.C. , Pinder Adrian C. , Britton J. Robert
Published: July 2022

Introduced fishes into lowland rivers can result in invasive populations establishing and then dispersing, where knowledge of their life history traits contributes to understandings of their invasion ecology. Here, the age and growth rates of a translocated chub Squalius cephalus population were assessed in the River Frome, a lowland chalk-stream in Southern England, where chub was introduced approximately 15 years ago. The results were assessed in relation to 35 riverine indigenous chub populations in England. Across these populations, individual chub were present to lengths over 550 mm and aged to at least 19 years old. In samples collected from the River Frome, however, no fish were present over 300 mm and age 4+years. Growth rate analyses of both the annual length increment produced between age 1 and 2 years (juvenile growth rate) and length at the last annulus (adult growth rate) revealed that both of these were relatively high in the River Frome population, being among the fastest of all sampled populations. It is suggested these fast growth rates were the response of the fish to their new environment, facilitating their establishment and colonisation through, for example, enabling reproduction at relatively young ages.
Degree-biased advection–diffusion on undirected graphs/networks
Authors: Miranda Manuel , Estrada Ernesto
Published: July 2022

There are several phenomena in nature governed by simultaneous or intermittent diffusion and advection processes. Many of these systems are networked by their own nature. Here we propose a degree-biased advection processes to undirected networks. For that purpose we define and study the degree-biased advection operator. We then develop a degree-biased advection-diffusion equation on networks and study its general properties. We give computational evidence of the utility of this new model by studying artificial graphs as well as a real-life patched landscape network in southern Madagascar. In the last case we show that the foraging movement of the speciesL. cattain this environment occurs mainly in a diffusive way with important contributions of advective motions in agreement with previous empirical observations.
Solving the multi-modal transportation problem via the rough interval approach
Authors: Mardanya Dharmadas , Maity Gurupada , Roy Sankar Kumar , Yu Vincent F.
Published: July 2022

This research studies a transportation problem to minimize total transportation cost under the rough interval approximation by considering the multi-modal transport framework, referred to here as the rough Multi-Modal Transportation Problem (MMTP). The parameters of MMTP are rough intervals, because the problem is chosen from a real-life scenario. To solve MMTP under a rough environment, we employ rough chance-constrained programming and the expected value operator for the rough interval and then outline the main advantages of our suggested method over those existing methods. Next, we propose an algorithm to optimally solve the problem and present a numerical example to examine the proposed technique. Finally, the solution is analyzed by the proposed method with rough-chance constrained programming and expected value operator.
Correlation of Trigeminopontine Angle with Severity of Trigeminal Neuralgia due to Neurovascular Conflict over Medial Aspect of Nerve: Can We Prognosticate the Reduction in Pain in Patients on Medical Management?
Authors: Lamani Pundalik Umalappa , Arora Abhishek J. , Kona Kiran Kumar Reddy , Yarlagadda Jyotsna
Published: August 2022

Background Neurovascular conflicts (NVCs) are one of the major causative factors in patients presenting with trigeminal neuralgia (TN). We found a wide range of variation in degrees of acute angle formed between medial border of trigeminal nerve and anterior border of pons in patients with TN, i.e., medial trigeminopontine angle (mTPA), and tried to find its correlation with pain severity due to NVC over the medial aspect of nerve (mNVC).

Aims and Objectives To correlate mTPA measurement with severity of TN due to mNVC. To calculate the reduction in pain in patients kept on medical management and its correlation with mTPA.

Materials and Methods This was a retrospective observational study conducted between May 2018 and October 2020. A total of 41 patients presenting with TN and showing corresponding NVC were included in the study. Out of the total cases with NVC, 30 cases showed NVC over the medial surface of the nerve. All the patients were evaluated on MAGNETOM Skyra 3T magnetic resonance imaging (MRI; Siemens). Using the two-line Cobb angle method, the trigeminopontine angle was calculated. Pretreatment pain intensity and posttreatment pain relief of each patients were assessed by using the numeric rating scale (NRS) with numbers from 0 to 10 (“no pain” to “worst pain imaginable”). Relevant clinical details regarding pre- and posttreatment pain score, after a standard treatment plan of 600 mg of oxcarbazepine for 2 weeks, were collected.

Results Patients showing response of more than or equal to 50% (≥50%) are considered as “good response” and those with response of less than 50% (<50%) are considered as “poor response.” In our study with trigeminopontine angle threshold of 45 degrees, 7 out of 8 (87.5%) patients with >45° mTPA showed poor response and 15/22 (68.2%) patients with ≤45° showed good response to medical management for TN with statistical significance difference with a p-valve of 0.007.

Conclusion We found a negative correlation between the mTPA and percentage pain relief in patients kept on medical management and realized that mTPA measurement could become an important tool for prognosticating pain relief for patients of TN on medical therapy; however, more evidence and multicentric studies are required for the same.
Multidetector Computed Tomography Perfusion in Head and Neck Squamous Cell Carcinomas: Evaluation of a Dose Reduction Strategy
Authors: Bhatt Shuchi , Mandal Samrat , Mehrotra Gopesh , Arora Vipin , Singh Usharani
Published: August 2022

Background Computed tomography perfusion (CTp), a useful technique in oncology, is not widely utilized due to the high radiation dose delivered from it. It involves scanning the region of interest every second for 50 seconds following intravenous contrast administration. Doubling sampling interval (SI) to 2 seconds will half the radiation dose, but may impact its effectiveness, which needs to be evaluated.

Objectives To evaluate a dose reduction strategy in CTp by determining agreement between standard dose (SD) CTp (acquisition with SI 1 second) and low-dose CTp techniques with SI of 2 seconds (achieved either by reconstruction only or true low-dose acquisition).

Materials and methods This cross-sectional study was conducted on histopathology-proven head and neck squamous cell carcinoma (HNSCC) patients who underwent CTp on 64 slice multidetector CT. A total of 56 patients had SD and 24 patients underwent true low dose (LD) acquisition. SD data were also reconstructed at SI 2 seconds to obtain a dataset simulating low dose (low-dose reconstruction [LDr]). Paired t-test was applied to compare CTp in SD and LDr groups and the Bland–Altman plot drawn to calculate 95% confidence limit of agreement. The Kolmogorov–Smirnov test compared CTp parameters for LDr and LD groups.

Results There was no statistical difference in CTp parameters (except blood flow in malignant) in SD and LDr groups for both malignant and normal tissues. CTp of malignant tissue was not statistically different in LDr and LD groups but the radiation dose was half in the LD group.

Conclusion Reduction of radiation dose to half achieved by doubling the SI does not affect the CTp parameters significantly. So LD acquisitions will increase the use of CTp in HNSCC.
Study on jet characteristics of a dual-structure converter oxygen lance based on hydrodynamics
Authors: Jia Hongbin , Li Yanxin , Liu Kun , Feng Lianghua
Published: July 2022

Oxygen lance is the key piece of equipment for iron and steel smelting. During the entire steelmaking process, the performance of the oxygen lance determines the occurrence of decarburization, slagging, heating, and splashing. In this paper, the influence of structural and process parameters on converter steelmaking is studied using a six-nozzle staggered oxygen lance and the traditional six-nozzle oxygen lance by performing jet tests, numerical simulation, and water model experiments. The research results show that, compared with the traditional oxygen lance nozzle, a stepwise fusion of the jet streams of the staggered oxygen lance nozzles occurs, which increases the fusion distance to varying degrees, reduces the amount of splash at the furnace mouth, and increases the effective impact area. For the six-nozzle staggered oxygen lance nozzle, the most ideal structure and maximum performance are obtained at an inner nozzle angle of 14° with a flow ratio of 55% and an outer nozzle angle of 18° with a flow ratio of 45%. The results show that the fusion distance of the inner nozzle and outer nozzle is 2.1 and 2.25 m, respectively; compared to the traditional oxygen lance nozzle, the splash amount of 0.19 g at the furnace mouth is reduced to only 16%, while the effective impact area has doubled to reach a value of 0.47 m2. With the increase in the oxygen lance position, the effective impact area of the jet of the oxygen lance nozzle on the molten pool first increases and then decreases, and the best position of the traditional and staggered oxygen lance nozzles is determined as 30.0 and 35.0–37.5 de, respectively.
Wearable microfluidic patch with integrated capillary valves and pumps for sweat management and multiple biomarker analysis
Authors: Zhang Hengjie , Qiu Ye , Yu Sihang , Ding Chen , Hu Jiahui , Qi Hangcheng , Tian Ye , Zhang Zheng , Liu Aiping , Wu Huaping
Published: July 2022

Wearable sweat sensors are essential for providing insight into human physiological health. The currently developed microfluidic sweat sensors have demonstrated the function of collecting and storing sweat. However, they detect more average concentrations of substances based on time periods, which leads to the fact that in situ real-time measurement for multiple biomarkers remains a grand challenge. Here, we propose a wearable epidermal microfluidic patch with integrated microfluidic pumps and micro-valves for accelerated and continuous collection of the sweat, where the micro-pumps ensure the complete separation of old and new sweat for real-time detection of real concentration of biomarkers in sweat. The biomarker concentration at different time periods is detected by introducing a burst valve, which is used to assist in the analysis of the real-time detection. A quantitative relationship between the minimum burst pressure difference required for sequential collection and the size of the microchannel structure is established to overcome the effects of additional resistance at the gas–liquid interface. Additionally, the sensing modules, including sodium ion, chlorine ion, glucose, and pH level in sweat, are integrated into the patch to realize in situ, real-time detection of multiple biomarkers in the human sweat, decoding the correlation between changes in substance concentrations and physiological conditions. This work provides a unique and simplifying strategy for developing wearable sweat sensors for potential applications in health monitoring and disease diagnostics.
A hybrid method to calculate optical torque: Application to a nano-dumbbell trapped by a metalens
Authors: Sun Chuang , Yan Jize
Published: July 2022

The hyper-fast rotation frequency realized in an optical levitation system provides an essential platform for various applications. Benefiting from the development of integrated photonics, optically trapping and manipulating a micro-particle via a metalens has been a significant development trend. The metalens’ powerful and flexible controlling ability of the optical field opens the door to tailoring optical trapping potential. However, the existing methods are difficult to compute optical forces and torques on a non-spherical particle trapped by a metalens-based trapping system, especially when the trapping potential is tailored by a delicately designed metalens. Therefore, a hybrid method by combining the finite difference in time-domain and discrete dipole approximation method is proposed in this paper to realize this goal. The relative error of this method is verified to be below 10%. Based on this hybrid method, the fractional vortex field is found in a metalens-based trapping system for the first time. Then, the optical torque’s dependency on a nano-dumbbell’s geometrical parameters and spatial orientation angles are studied. It is found that there is a torque driving the nano-dumbbell to rotate about the optical axis, and the long axis of the nano-dumbbell tends to be aligned to the polarization plane because of the transverse optical torques if the long axis of the nano-dumbbell is not aligned to the optical axis.
Effect of amorphous ternary AlBN passivations on the performance of AlGaN/GaN HEMTs
Authors: Cheng Jiantao , Liu Fengfeng , Jiang Chunping , Zhu Wenqing
Published: July 2022

In this article, an amorphous ternary AlBN dielectric passivation layer is proposed for GaN/AlGaN high-electron mobility transistors (HEMTs). The source–gate–drain access regions with both AlBN and AlN amorphous dielectric films deposited by pulsed laser deposition are investigated to understand their effects on the device performance. Compared with the AlN-passivated HEMTs, the electrical characteristics of AlBN-passivated HEMTs are significantly improved with the same passivation layer thickness. An increase in maximum drain saturation current of AlBN-passivated HEMTs is ∼19.74% at Vgs = 2 V, and the corresponding peak extrinsic transconductance is improved by 38.08% at Vgs = −2 V and Vds = 2 V. Such excellent properties are ascribed to large surface potential change, due to the effect of boron dopants on AlBN films.
Experimental investigation of total electron emission yield of polyimide film under various temperatures
Authors: Wu Jiang , Li Shuaiqiang , Zhang Bo , Cao Wen , Li Yunhong , Toyoda Kazuhiro
Published: July 2022

As the thermal variation may change the total electron emission yield (TEEY) of materials and may ultimately result in unexpected surface charging, it is necessary to study the TEEY at various temperatures. In this research, we first updated the TEEY measurement system with a newly designed sample stage for different temperatures (−50, 25, and 100 °C) and the primary electron from 25 eV to 10 keV. By using the 30 μs/20 nA primary electron beam and sample scanning method to mitigate surface charging, the TEEY could be accurately obtained for dielectrics. Then, we chose a kind of polyimide film (Kapton 100H) used on spacecraft and a gold film sample to compare the TEEY at various temperatures. The results show that high temperature leads to higher TEEY of Kapton films, whereas 25 and −50 °C also leads to the same. On the other hand, the TEEY of gold remains the same at different temperatures. In the view of surface hole density and charge transportation, the TEEY variation of Kapton films was analyzed by bulk conduction, charge mobility, and the electron–hole recombination property. It is considered that the dissipation rate of holes is sensitive to temperature, and furthermore, the TEEY of Kapton films is dependent on temperature.
Numerical investigation of the fishbone instability effect on thermal pressure in EAST tokamak
Authors: Ren Zhenzhen , Shen Wei , Li Guoqiang , Wu Muquan , Yang Jinhong , Wang Weihua
Published: July 2022

The formation of the internal transport barrier (ITB) is observed after the emergence of fishbone instabilities on the Experimental Advanced Superconducting Tokamak (EAST). The kinetic–magnetohydrodynamic hybrid code M3D-K has been applied to investigate the fishbone instability effect on thermal pressure based on EAST Shot No. 71320. Without fluid nonlinearity, it is found that when the central gradient of the total pressure profile is above a threshold, the thermal pressure profile becomes more peaked due to the nonlinear evolution of the fishbone instability, which confirms that the fishbone instability can transport the thermal pressure radially inward and promote the ITB formation. When fluid nonlinearity is included, the poloidal zonal flow prevents the thermal pressure to become more peaked in the core region. As the neoclassical effect can cause the damping of the poloidal zonal flow and is neglected in our simulation, the actual promotion of ITB formation due to the fishbone instability is expected to be between that without fluid nonlinearity and with fluid nonlinearity.
Sharing the electric bus charging stations by scheduling the charging strategy
Authors: Jin Kun , Wang Wei , Li Xinran , Hua Xuedong , Long Weiyi
Published: July 2022

Electric cars (ECs) play a vital role in reducing carbon emissions and improving sustainable development. Due to the lack of public charging facilities, the application of private ECs is limited. Motivated by the sharing economy, this is the first study to investigate the idea of sharing electric bus (EB) charging stations to alleviate the plight of private EC owners. However, existing EB charging strategies do not cater to the sharing and hinder the implementation of the policy. Therefore, this paper proposed a general mathematic mixed-integer non-linear programming model to coordinate the optimal charging strategy and sharing operation to meet the external and internal goals of bus systems, namely, maximizing charging station availability and satisfying the EB charging demand. Harnessing real-world bus operating data, the proposed model effectively generates multiple charging strategies. The results show that some hybrid strategies can achieve a similar sharing availability period as the public-oriented strategy with lower costs. In addition, sensitivity analysis indicates that increasing battery capacity can extend the sharing availability period while increasing charging power has only a minor impact. Overall, the proposed model obtains desired charging scheduling and provides concrete suggestions to promote the sustainable development of ECs and EBs.
Physics … is for girls?
Authors: Behrman Joanna
Published: August 2022

Contrary to modern stereotypes, the laws of the natural world used to be considered a fundamental part of young women’s education.
Random encounters and amoeba locomotion drive the predation of
Listeria monocytogenes
by
Acanthamoeba castellanii
Authors: de Schaetzen Frédéric , Fan Mingzhen , Alcolombri Uria , Peaudecerf François J. , Drissner David , Loessner Martin J. , Stocker Roman , Schuppler Markus
Published: August 2022

Predatory protozoa play an essential role in shaping microbial populations. Among these protozoa,
Acanthamoeba
are ubiquitous in the soil and aqueous environments inhabited by
Listeria monocytogenes
. Observations of predator–prey interactions between these two microorganisms revealed a predation strategy in which
Acanthamoeba castellanii
assemble
L. monocytogenes
in aggregates, termed backpacks, on their posterior. The rapid formation and specific location of backpacks led to the assumption that
A. castellanii
may recruit
L. monocytogenes
by releasing an attractant. However, this hypothesis has not been validated, and the mechanisms driving this process remained unknown. Here, we combined video microscopy, microfluidics, single-cell image analyses, and theoretical modeling to characterize predator–prey interactions of
A. castellanii
and
L. monocytogenes
and determined whether bacterial chemotaxis contributes to the backpack formation. Our results indicate that
L. monocytogenes
captures are not driven by chemotaxis. Instead, random encounters of bacteria with amoebae initialize bacterial capture and aggregation. This is supported by the strong correlation between experimentally derived capture rates and theoretical encounter models at the single-cell level. Observations of the spatial rearrangement of
L. monocytogenes
trapped by
A. castellanii
revealed that bacterial aggregation into backpacks is mainly driven by amoeboid locomotion. Overall, we show that two nonspecific, independent mechanisms, namely random encounters enhanced by bacterial motility and predator surface-bound locomotion, drive backpack formation, resulting in a bacterial aggregate on the amoeba ready for phagocytosis. Due to the prevalence of these two processes in the environment, we expect this strategy to be widespread among amoebae, contributing to their effectiveness as predators.
Religious leaders can motivate men to cede power and reduce intimate partner violence: Experimental evidence from Uganda
Authors: Boyer Christopher , Levy Paluck Elizabeth , Annan Jeannie , Nevatia Tvisha , Cooper Jasper , Namubiru Jackline , Heise Lori , Lehrer Rachel
Published: July 2022

Violence committed by men against women in intimate relationships is a pervasive problem around the world. Patriarchal norms that place men as the head of household are often to blame. Previous research suggests that trusted authorities can shift perceptions of norms and create behavior change. In many settings, a compelling authority on behavior in relationships is religious leaders, who are influential sources of information about proper conduct in relationships and gatekeepers of marriage, but may also uphold traditional gender roles. One way leaders exert their influence is through premarital or couples counseling courses. In this study, we test whether, if given an opportunity to offer a more progressive religious interpretation of gender roles during these courses, religious leaders could motivate men to share power and thereby reduce violence. Building on existing faith networks of Christian religious leaders in western Uganda, we conducted a large pair-matched, randomized controlled trial among 1,680 heterosexual couples in which participants were randomized to attend a 12-session group counseling course or wait-listed. We find that the program shifted power from men to women and reduced intimate partner violence by five percentage points, comparable with more intensive secular programs. These improvements were largest among couples counseled by religious leaders who held the most progressive views at baseline and who critically engaged with the material. Our findings suggest that religious leaders can be effective agents of change for reducing violence.
Geometrical frustration of phase-separated domains inCoscinodiscusdiatom frustules
Authors: Feofilova Maria , Schüepp Silvan , Schmid Roman , Hacker Florian , Spanke Hendrik T. , Bain Nicolas , Jensen Katharine E. , Dufresne Eric R.
Published: July 2022

Diatoms are single-celled organisms with a cell wall made of silica, called the frustule. Even though their elaborate patterns have fascinated scientists for years, little is known about the biological and physical mechanisms underlying their organization. In this work, we take a top-down approach and examine the micrometer-scale organization of diatoms from the Coscinodiscus family. We find two competing tendencies of organization, which appear to be controlled by distinct biological pathways. On one hand, micrometer-scale pores organize locally on a triangular lattice. On the other hand, lattice vectors tend to point globally toward a center of symmetry. This competition results in a frustrated triangular lattice, populated with geometrically necessary defects whose density increases near the center.
Unexpected role for IGF-1 in starvation: Maintenance of blood glucose
Authors: Fang Fei , Goldstein Joseph L. , Shi Xuanming , Liang Guosheng , Brown Michael S.
Published: August 2022

Wild-type (WT) mice maintain viable levels of blood glucose even when adipose stores are depleted by 6 d of 60% calorie restriction followed by a 23-h fast (hereafter designated as “starved” mice). Survival depends on ghrelin, an octanoylated peptide hormone. Mice that lack ghrelin suffer lethal hypoglycemia when subjected to the same starvation regimen. Ghrelin is known to stimulate secretion of growth hormone (GH), which in turn stimulates secretion of IGF-1 (insulin-like growth factor-1). In the current study, we found that starved ghrelin-deficient mice had a 90% reduction in plasma IGF-1 when compared with starved WT mice. Injection of IGF-1 in starved ghrelin-deficient mice caused a twofold increase in glucose production and raised blood glucose to levels seen in starved WT mice. Increased glucose production was accompanied by increases in plasma glycerol, fatty acids and ketone bodies, and hepatic triglycerides. All of these increases were abolished when the mice were treated with atglistatin, an inhibitor of adipose tissue triglyceride lipase. We conclude that IGF-1 stimulates adipose tissue lipolysis in starved mice and that this lipolysis supplies energy and substrates that restore hepatic gluconeogenesis. This action of IGF-1 in starved mice is in contrast to its known action in inhibiting adipose tissue lipase in fed mice. Surprisingly, the ghrelin-dependent maintenance of plasma IGF-1 in starved mice was not mediated by GH. Direct injection of GH into starved ghrelin-deficient mice failed to increase plasma IGF-1. These data call attention to an unsuspected role of IGF-1 in the adaptation to starvation.
Attitudes and motivation towards learning French in primary school
Authors: Myles Florence
Published: August 2022

Young children have often been shown to be highly motivated towards learning foreign languages in primary school, but for their enthusiasm to decrease during secondary schooling. Many reasons have been put forward, such as novelty wearing off, teaching styles, or societal and peer pressure. Little is known about changes in attitudes and motivation in primary school aged children when these factors are kept constant, the only variable being the age of the children. The present study investigated differences in attitudes and motivation at two different ages (5 and 7) in such a setting. Two intact classes in the same school (53 children with no prior knowledge of French), taught the same material by the same teacher, took part in focus groups and one-to-one interviews during the course of a larger longitudinal project investigating the role of age in early classroom learning. Results show that changes in motivation might occur earlier than previously thought, and be shaped by developmental changes in children’s cognitive, social and emotional growth. Children as young as 5 and 7 were shown to exhibit differences in levels of self-regulation, self-efficacy, and thought and beliefs frames which had a direct impact on their attitudinal and motivational profiles.
Microstructure evolution and mechanical properties of CNT/Al composite joints via friction stir welding
Authors: Li Xiaopeng , Zhang Zeyu , Wang Yong , Peng Yong , Yan Dejun , Tan Zhanqiu , Zhou Qi , Wang Kehong
Published: July 2022

The traditional fusion welding of carbon nanotubes (CNTs) reinforcement aluminium matrix composites has serious welding defects due to the violent interfacial reaction and the brittle secondary phase. In this paper, friction stir welding (FSW), a solid-phase welding technique, was applied to join the CNT/Al matrix composites. The result shows that the tensile strength of the FSW joint fabricated at 800 rev min–1 and 100 mm min–1 is 511 MPa, reaching 92.1% of the CNT/Al composites. After FSW, the original CNTs were damaged and formed the nano Al4C3 phase. Orowan strengthening of the Al4C3 phase, dislocation strengthening and grain refinement of FSW are the predominant strengthening mechanism for the joints. The great interfacial bonding between nano Al4C3 and matrix benefits the joint mechanical properties as well.
Demonstrating free-fall weightlessness with a charged needle electroscope
Authors: Slisko Josip , Corona Adrian
Published: July 2022

Astronauts Yuri Gagarin, Gherman Titov and John Glenn, in their satellite flights around the Earth, were first humans who experienced extended period of weightlessness, although with different feelings. Soon after these history-making events, various articles appeared in pedagogical journals, proposing classroom demonstrations by which teachers could show to their students weightlessness-related physical phenomena in freely-falling systems. In this article, a new demonstration of free-fall weightlessness is described and illustrated by photos taken from its recorded video. When a charged needle electroscope is at rest, the inclined position of the needle is determined by the equilibrium of moments of repulsive electrostatic force and gravitational force. In free fall, only repulsive electrostatic force acts in electroscope-bounded reference frame, causing visible rotational motion of the needle.
Ritus functions for graphene-like systems with magnetic fields generated by first-order intertwining operators
Authors: Concha-Sánchez Y , Díaz-Bautista E , Raya A
Published: July 2022

In this work, we construct the exact propagator for Dirac fermions in graphene-like systems immersed in external static magnetic fields with non-trivial spatial dependence. Such field profiles are generated within a first-order supersymmetric framework departing from much simpler (seed) magnetic field examples. The propagator is spanned on the basis of the Ritus eigenfunctions, corresponding to the Dirac fermion asymptotic states in the non-trivial magnetic field background which nevertheless admits a simple diagonal form in momentum space. This strategy enlarges the number of magnetic field profiles in which the fermion propagator can be expressed in a closed-form. Electric charge and current densities are found directly from the corresponding propagator and compared against similar findings derived from other methods.
Mode-locked Er-doped fiber laser based on ZrSe2 saturable absorber
Authors: Zhao Lin , Xu Nannan , Shang Xinxin , Liu Xueyao , Huang Pu , Lu Hua , Zhang Huanian , Li Dengwang
Published: July 2022

In this study, zirconium selenide (ZrSe2) was successfully prepared as the saturable absorber in an erbium-doped fiber laser for demonstrating mode-locked operation, for which the saturation intensity and modulation depth were 10.12 MW cm−2 and 23.10%, respectively. The narrower pulse width of mode-locked operation was 1.27 ps. The maximum average output power and pulse energy were 16.75 mW and 3.75 nJ, which were significant improvements for a ZrSe2-based fiber laser. Our study results further proved that ZrSe2, as an ultra-fast optical device, has excellent performance in ultra-short pulse fiber lasers.
Methane remote sensing and emission quantification of offshore shallow water oil and gas platforms in the Gulf of Mexico
Authors: Ayasse Alana K , Thorpe Andrew K , Cusworth Daniel H , Kort Eric A , Negron Alan Gorchov , Heckler Joseph , Asner Gregory , Duren Riley M
Published: July 2022

Offshore oil and natural gas platforms are responsible for about 30% of global oil and natural gas production. Despite the large share of global production there are few studies that have directly measured atmospheric methane emanating from these platforms. This study maps CH4 emissions from shallow water offshore oil and gas platforms with an imaging spectrometer by employing a method to capture the sun glint reflection from the water directly surrounding the target areas. We show how remote sensing with imaging spectrometers and glint targeting can be used to efficiently observe offshore infrastructure, quantify methane emissions, and attribute those emissions to specific infrastructure types. In 2021, the Global Airborne Observatory platform, which is an aircraft equipped with a visible shortwave infrared imaging spectrometer, surveyed over 150 offshore platforms and surrounding infrastructure in US federal and state waters in the Gulf of Mexico representing ∼8% of active shallow water infrastructure there. We find that CH4 emissions from the measured platforms exhibit highly skewed super emitter behavior. We find that these emissions mostly come from tanks and vent booms or stacks. We also find that the persistence and the loss rate from shallow water offshore infrastructure tends to be much higher than for typical onshore production.
Solitons in media with mixed, high-order dispersion and cubic nonlinearity
Authors: Qiang Y Long , Alexander Tristram J , Martijn de Sterke C
Published: July 2022

Although most soliton research has traditionally considered dominant quadratic dispersion, the recent discovery of pure-quartic solitons has inspired analysis of soliton solutions with large higher orders of dispersion. Here we present analytic expressions for families of bright soliton solutions at arbitrary dispersion orders and practical methods to obtain the associated dispersion relations. These results provide a framework for considering higher order dispersion solitons and show the potential for further investigation of solitons in higher order dispersion systems.
Spatio-temporal dynamics of random transmission events: from information sharing to epidemic spread
Authors: Giuggioli Luca , Sarvaharman Seeralan
Published: July 2022

Random transmission events between individuals occurring at short scales control patterns emerging at much larger scales in natural and artificial systems. Examples range from the spatial propagation of an infectious pathogen in an animal population to the spread of misinformation in online social networks or the sharing of target locations between robot units in a swarm. Despite the ubiquity of information transfer events, a general methodology to quantify spatio-temporal transmission processes has remained elusive. The challenge in predicting when and where information is passed from one individual to another stems from the limited number of analytic approaches and from the large fluctuations and inherent computational cost of stochastic simulation outputs, the main theoretical tool available to study such processes so far. Here we overcome these limitations by developing an analytic theory of transmission dynamics between randomly moving agents in arbitrary spatial domains and with arbitrary information transfer efficiency. We move beyond well-known approximations employed to study reaction diffusion phenomena, such as the motion and reaction limited regimes, by quantifying exactly the mean reaction time in presence of multiple heterogeneous reactive locations. To demonstrate the wide applicability of our theory we employ it in different scenarios. We show how the type of spatial confinement may change by many orders of magnitude the time scale at which transmission occurs. When acquiring information represents the ability to capture, we use our formalism to uncover counterintuitive evasive strategies in a predator–prey contest between territorial animals. When information transmission represents the transfer of an infectious pathogen, we consider a population with susceptible, infected and recovered individuals that move and pass infection upon meeting and predict analytically the basic reproduction number. Finally we show how to apply the transmission theory semi-analytically when the topology of where individuals move is that of a network.
Effect of bending stiffness on the polymer adsorption onto a heterogeneous stripe-patterned surface
Authors: Polotsky Alexey A , Ivanova Anna S
Published: July 2022

Adsorption of a single homopolymer chain with bending stiffness onto a heterogeneous regular stripe-patterned surface consisting of adsorbing and non-adsorbing stripes is studied theoretically in the framework of the lattice model and the generating functions approach. The stiffness is introduced by assigning a statistical weight to a trans-isomer (a straight segment) with respect to a gauche-isomer (a kink). The temperature is taken as the main control parameter since it affects both the strength of the monomer units’ attraction to the adsorbing stripes and the chain stiffness. It is shown that the adsorption transition temperature is a non-monotonic function on the bending energy having a minimum. The position of this minimum depends on the stripes’ width and only slightly deviates from zero bending energy. Temperature dependences of the main conformational and thermodynamic characteristics of the adsorbed chain are obtained. It is demonstrated that in most of the studied cases the adsorption is accompanied by the chain localization on a single adsorbing unit stripe and the chain stiffness enhances this effect.
Experimental investigation on three-body abrasive wear behaviour of novel natural cellulosic pigeon pea stalk fibre reinforced epoxy biocomposites
Authors: Pujar Nagaraj Malleshappa , Mani Yuvaraja , Mouleeswaran Senthilkumar
Published: July 2022

The current research explores the possibility of reinforcing massively available, less utilised, low-cost agro-residue fibres in an epoxy matrix to create a new tribo-material. This study focuses on determining the three-body abrasive wear behaviour (volume loss and specific wear rate (SWR)) of natural cellulosic pigeon pea (PP) stalk fibre reinforced epoxy composites. Further, abrasive wear characteristics of untreated and treated E/PP20 (20 wt.% PP stalk fibre-reinforced epoxy) composites were analysed using Taguchi and ANOVA techniques. Untreated and treated biocomposite specimens were developed using the hand lay-up (open mould) technique. At 11.77 N, 23.54 N, and 47 N loads, the SWR of untreated E/PP20 composite was reduced by almost 5.03%, 3.68%, and 22.30% compared to epoxy specimens. Results of the untreated E/PP20 composite showed that the applied load was the main contributing parameter (54.72%), followed by sliding distance (21.82%) and sliding speed (15.31%). Results of the treated E/PP20 composite showed that the applied load was the main contributing parameter (48.96%), followed by sliding speed (26.24%) and sliding distance (20.78%). The regression model predicted the SWR with a pooled error ranging from 2.37% to −17.77% for untreated composite and 9.87% to −11.49% for treated composite, respectively. The alkali-treated E/PP20 composite exhibited better abrasive resistance than the untreated E/PP20 composite. Scanning electron microscopy images of the treated composites showed good fibre adhesion with the matrix. In addition, the surface of the treated composite showed no fibre pullout or ploughing compared to that of the untreated composite. Surface topography revealed the formation of more craters on the surfaces of the untreated composites and small-sized dispersed craters on the treated composites.