bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoredox-Catalyzed C(sp2)–H Bond Functionalization Reactions: A Short Account
Authors: Loh Teck-Peng , Li Jinling , Zhao Junjie
Published: October 2023

Photoredox catalysis has been undergoing rapid development and wide application in the chemical community during the past several years because of its advantages for reaction engineering. Since 2016, Loh et al. started their research on photoredox-catalyzed reaction transformations, including β-C(sp2)–H fluoroalkylation, alkylation, and acylation of enamides, C(sp2)–H phosphorylation of alkenes converted from alcohols, C(sp2)–H bromination, and alkylation of (hetero)arenes. These transformations introduce a broad range of structural differences on the C(sp2)–H bond of compounds with an extensive array of functional groups and showcase the appealing synthetic utilities of the approach.

1 Introduction

2 Photoredox-Catalyzed β-C(sp2)–H Functionalization of Enamides

3 Photoredox-Catalyzed C(sp2)–H Functionalization of Alkenes

4 Photoredox-Catalyzed C(sp2)–H Functionalization of (Hetero)Arenes

5 Conclusion
Copper Nanoparticles on Montmorillonite K-10: A Versatile Catalyst for the One-Pot Synthesis of 3,5-Disubstituted Isoxazoles Using Various Methodologies
Authors: Radivoy Gabriel , Stabile Santiago , Bjerg Esteban E.
Published: October 2023

A readily prepared and versatile heterogeneous catalyst composed of copper nanoparticles supported on montmorillonite K-10 (CuNPs/MK-10) has proven to be highly effective in catalyzing the synthesis of isoxazoles through various one-pot methodologies with high atom economy. These methodologies allow for the use of readily available starting materials, including aldehydes and alkynes through 1,3-dipolar cycloaddition reactions, as well as via cycloisomerization of ynones. Additionally, the CuNPs/MK-10 catalyst promoted the in situ formation of the ynones via an acyl Sonogashira coupling. Furthermore, a three-step one-pot methodology was also developed, starting from carboxylic acids and involving the in situ generation of acyl chlorides.
A Rearrangement of 4-Phenylbenzo[d]oxazoles to Phenanthridin-4-ols
Authors: Fisyuk Alexander S. , Shatsauskas Anton L. , Keyn Ekaterina S. , Stasyuk Anton J. , Kirnosov Sergey A. , Shuvalov Vladislav Yu. , Kostyuchenko Anastasia S.
Published: October 2023

A new approach was developed for the synthesis of phenanthridin-4-ols and 4-hydroxyphenanthridin-6(5H)-one derivatives in 43–89% yields based on the AlCl3-mediated rearrangement of available 4-phenylbenzo[d]oxazoles and 4-phenyl-1,3-benzoxazol-2(3H)-one. The quantum chemical calculations were used to describe the mechanism and predict the thermodynamic parameters of the reaction under study.
Direct Reductive Coupling of Nitro Compounds for the Synthesis of Advanced Amines
Authors: Chan Albert S. C. , Meng Shan-Shui , Li Tao
Published: October 2023

Direct reductive coupling of nitro compounds with C-coupling partners is an atom- and step-economical strategy to access polyfunctional advanced amines. Due to the extremely complex process involved in the reduction of nitro compounds and the high reactivity of N,O-intermediates, few reliable methodologies have been reported for the reductive coupling of nitro compounds since the initial studies. To address this significant challenge, numerous endeavors have been devoted to this important area over the past hundred years. In this short review, we summarize recent advances in this domain and discuss the mechanisms of these appealing reductive coupling transformations.

1 Introduction

2 Reductive Coupling of Nitro Compounds with Organometallic Reagents

3 Reductive Coupling of Nitro Compounds with Arylboronic Acids

4 Reductive Coupling of Nitro Compounds with Alkenes

5 Reductive Coupling of Nitro Compounds with Alkyl/Aryl Halides

6 Reductive Coupling of Nitro Compounds with Alcohols and Their Derivatives

7 Conclusion
A Dual Center Experience with a Locking Intramedullary Nail for Wrist Fusion
Authors: Heifner John J. , Rowland Robert J. , Gomez Osmanny , Rubio Francisco , Kardashian George S.
Published: October 2023

Background In aggregate, there is varied efficacy for total wrist fusion (TWF) with a locking intramedullary (IM) nail which indicates the need for further investigation. It remains unclear whether preparation of the third carpometacarpal joint (CMCJ) will reduce the risk of complications including distal screw loosening.

Purpose Our objectives were (a) to report clinical outcomes for wrist arthrodesis using a locking IM nail and (b) to determine whether maintenance of the native third CMCJ articulation would contribute to short-term complications.

Patients and Methods A chart review from 2010 to 2022 was performed at two institutions for cases of TWF fixed with the IMPLATE locking nail (Skeletal Dynamics, Miami, FL). Clinical and radiographic outcomes were collected.

Results Radiographic union was achieved in 93.8% of cases, including one case of delayed union. The mean patient-rated wrist evaluation score was 30.4, the mean visual analog scale score for pain at rest was 1.7, and the mean visual analog scale score during activities of daily living was 3.2. There were seven cases of distal screw loosening (21.8%), and three cases of revision surgery (9.4%) which included two implant removals. A long radial nail was used in 24 (75%) of cases and a short metacarpal nail was used in 3 (9%) cases.

Conclusion The current series demonstrated satisfactory function with low rates of revision surgery following IM nail TWF without inclusion of the third CMCJ into the fusion mass. Cases with distal screw loosening had variable clinical presentation and our current practice is to offer outpatient screw removal for cases which reach the threshold for intervention.

Level of Evidence IV retrospective series.
The evolution and development of ecotranslatology studies based on the analysis of CiteSpace mapping knowledge domains
Authors: Xiong Xin , Qin Hui , Liu Xiangtao
Published: October 2023

The present study endeavors to unveil the progression of research subjects within the realm of China’s ecotranslatology studies through the examination of journal papers in the databases of China National Knowledge Infrastructure (CNKI) and Web of Science (WOS) from 2001 to 2022, utilizing CiteSpace software for mapping and analyzing cooccurrences among authors, institutions, and keywords. The findings indicate that within ecotranslatology studies, a prominent theory-founding research group represented by Hu Gengshen has been established, yet no comparable clusters have been identified among scholars engaged in debate or applied studies. Additionally, a lack of effective cooperation and diversity among research entities as well as inadequate responses to questions and concerns have been observed. Furthermore, research focuses have undergone a shift, progressing from theory founding studies (2001–2008) to confirmation and verification studies (2009–2014) and finally to revision and applied studies (since 2015). Additionally, research topics have transitioned from grand, abstract theoretical foundations to subtle, specific theory revisions and applied translation studies, yet a dearth of quantitative research, comparative studies, or field studies have been conducted. In conclusion, it is suggested that future ecotranslatology studies should be more responsive to doubts and questions, cultivate diverse research entities, and place greater emphasis on field investigation within qualitative research.
Businesses in high-income zip codes often saw sharper visit reductions during the COVID-19 pandemic
Authors: Kulkarni Aditya , Kim Minkyong , Bhattacharya Jayanta , Bhattacharya Joydeep
Published: October 2023

As the COVID-19 pandemic unfolded, the mobility patterns of people worldwide changed drastically. While travel time, costs, and trip convenience have always influenced mobility, the risk of infection and policy actions such as lockdowns and stay-at-home orders emerged as new factors to consider in the location-visitation calculus. We use SafeGraph mobility data from Minnesota, USA, to demonstrate that businesses (especially those requiring extended indoor visits) located in affluent zip codes witnessed sharper reductions in visits (relative to parallel pre-pandemic times) outside of the lockdown periods than their poorer counterparts. To the extent visits translate into sales, we contend that post-pandemic recovery efforts should prioritize relief funding, keeping the losses relating to diminished visits in mind.
Algebraic aspects of boundaries in the Kitaev quantum double model
Authors: Cowtan Alexander , Majid Shahn
Published: October 2023

We provide a systematic treatment of boundaries based on subgroups K ⊆ G for the Kitaev quantum double D(G) model in the bulk. The boundary sites are representations of a *-subalgebra Ξ ⊆ D(G) and we explicate its structure as a quasi-Hopf *-algebra dependent on a choice of transversal R. We provide decomposition formulae for irreducible representations of D(G) pulled back to Ξ. As an application of our treatment, we study patches with boundaries based on K = G horizontally and K = {e} vertically and show how these could be used in a quantum computer using the technique of lattice surgery. More abstractly, we also provide explicitly the monoidal equivalence of the category of Ξ-modules and the category of G-graded K-bimodules and use this to prove that different choices of R are related by Drinfeld cochain twists. Examples include Sn−1 ⊂ Sn and an example related to the octonions where Ξ is also a Hopf quasigroup.
Evaluating an electric field modulated plasma enhanced atomic layer deposition of platinum layers on different substrates
Authors: Yan Mingming , Zhang Tianchong , Wang Bo , Liu Jing , Liang Xiaoxiao , Xu Yuanze , Yi Futing
Published: October 2023

Atomic layer deposition is a key technique for preparing large area uniformity, three-dimensional conformal, and ultrathin films due to its sequential self-limiting saturated chemisorption properties. Electric fields of varying magnitudes and directions were applied on Si, Al2O3, Au, and Ni substrates in Pt plasma enhanced atomic layer deposition processes. Studying the influences of electric fields on the initial nucleation and growth of Pt films on different substrates helps to understand the dynamic knowledge and underlying physical mechanisms so as to obtain ultrathin, continuous films and full control over the morphology and distribution of deposited materials. The XPS results reveal that the Pt coverage rate increases on all substrates with applied voltages. The induced dipole moment causes the (MeCp)PtMe3 molecule to rotate in a certain direction resulting in a more compact arrangement, and the energy generated by electric fields also helps the dissociation of methyl, ethyl, Cp, and MeCp ligands, which greatly mitigate the spatial site resistance effect, thus improving initial monolayer chemisorption efficiency and the Pt coverage. We also find that Pt prefers to grow in the (111) direction due to the increase in adsorption of (MeCp)PtMe3 molecules caused by the gradient forces under electric fields. However, applied electric fields can also influence the morphology by inducing surface diffusion and acting on plasma species.
Anti-correlation phenomena in quantum cascade laser frequency combs
Authors: Chomet B. , Gabbrielli T. , Gacemi D. , Cappelli F. , Consolino L. , De Natale P. , Kapsalidis F. , Vasanelli A. , Todorov Y. , Faist J. , Sirtori C.
Published: October 2023

In quantum cascade laser frequency combs, the intensity distribution of the optical spectrum can be split into two well-separated lobes of longitudinal modes that, even when far apart, have a common phase relation and preserve equal frequency separation. The temporal dynamics of two lasers emitting at 4.4 and 8.1 µm operating in this bilobed regime are here investigated. The laser intensity shows a peculiar temporal behavior associated with the spectral features whereby, every half a round-trip, the total emitted power switches from one lobe to the other, with a perfect temporal anti-correlation. The anti-correlation between the lobes is also observed in the intensity noise figure of the emission. This coherent phenomenon arises from gain nonlinearities induced by spatial hole burning and the extremely fast gain dynamics typical of quantum cascade lasers.
Spectral insight into the interface evolution of a carbon/carbon composite under high-enthalpy, nonequilibrium flow
Authors: Fang Sihan , Lin Xin , Yang Junna , Zeng Hui , Zhu Xingying , Zhou Fa , Ou Dongbin , Li Fei , Yu Xilong
Published: October 2023

Gas–surface interactions between thermal protection materials and high-enthalpy nonequilibrium flow are one of the greatest challenges in accurately predicting aerodynamic heating during supersonic flights. Finer microscopic details of flow properties are required for elaborate simulation of these interactions. Spectral insight, with quantum-state-specific characteristics, is provided in this work to investigate the physico-chemical processes in high temperature interface of a carbon/carbon (C/C) composite. The nonequilibrium air flow is produced by a 1.2 MW inductively coupled plasma wind tunnel at an enthalpy of 20.08 MJ/kg. The duration of each test is up to 100 s, and quartz is also tested for comparison. Spectral insights into the reaction mechanisms of the gas–surface interactions are acquired by the optical emission spectroscopy and laser absorption spectroscopy. Dynamic evolution of the chemical reaction pathways and thermal nonequilibrium are discussed based on the results of optical emission spectroscopy. Temporally and spatially resolved results of the translational temperature and number density of atomic oxygen are quantified by laser absorption spectroscopy. Controlling mechanisms in the surface chemistry are further analyzed in conjunction with the surface temperature, scanning electron microscopy, and energy dispersive spectroscopy. Reaction mechanisms on the C/C composite surface sequentially experience an oxidation-dominant, an intense competitive, a nitridation-dominant, and a recession dominant period. Distributions in the axial direction and dynamic characteristics of the translational temperature and number density of atomic oxygen are found closely related with surface swelling, recession, and chemical reactions. The results herein are consistent with each other and are instructive to further investigate the interface evolution on C/C composites.
Response of interlayer-bonded bilayer graphene to shear deformation
Authors: Mostafa Afnan , Weerasinghe Asanka , Ramasubramaniam Ashwin , Maroudas Dimitrios
Published: October 2023

We report results on the mechanical and structural response to shear deformation of nanodiamond superstructures in interlayer-bonded twisted bilayer graphene (IB-TBG) and interlayer-bonded graphene bilayers with randomly distributed individual interlayer C–C bonds (RD-IBGs) based on molecular-dynamics simulations. We find that IB-TBG nanodiamond superstructures subjected to shear deformation undergo a brittle-to-ductile transition (BDT) with increasing interlayer bond density (nanodiamond fraction). However, RD-IBG bilayer sheets upon shear deformation consistently undergo brittle failure without exhibiting a BDT. We identify, explain, and characterize in atomic-level detail the different failure mechanisms of the above bilayer structures. We also report the dependence of the mechanical properties, such as shear strength, crack initiation strain, toughness, and shear modulus, of these graphene bilayer sheets on their interlayer bond density and find that these properties differ significantly between IB-TBG nanodiamond superstructures and RD-IBG sheets. Our findings show that the mechanical properties of interlayer-bonded bilayer graphene sheets, including their ductility and the type of failure they undergo under shear deformation, can be systematically tailored by controlling interlayer bond density and distribution. These findings contribute significantly to our understanding of these 2D graphene-based materials as mechanical metamaterials.
Molecular thermal motion harvester for electricity conversion
Authors: Luan Yucheng , Huo Fengwei , Lu Mengshi , Li Wei , Wu Tonghao
Published: October 2023

Molecular thermal motion has been studied but yet never been utilized as an energy source. In this work, we demonstrate that the energy of liquid molecular thermal motion can be converted into electrical energy by a novel harvesting device, the molecular thermal motion harvester (MTMH). The MTMH was made by using two ZnO-based nano-arrays and one of which was gold coated to form a Schottky junction. The assembled electrodes were immersed in different liquid phase environments. The device was demonstrated to convert the molecule thermal energy of the liquid into a continuous and stable electric current. The output voltage and current can achieve 2.28 mV and 2.47 nA, respectively, and increase with the liquid temperatures. This strategy opens new insights into the development of mini- and micro-scale energy sources, and it can be expected the MTMH will have broad applications in the future.
Proximity-induced superconductivity in type-II Weyl semimetal NbIrTe4
Authors: Li Dingding , Zhang Ping , Du Hongmei , Wei Zihan , Tian Wanghao , Chen Shixian , Xu Zuyu , Li Jun , Lyu Yang-Yang , Sun Hancong , Sun Guozhu , Chen Jian , Jin Biaobing , Wang Huabing , Wu Peiheng
Published: October 2023

Heterostructures between conventional superconductors and materials with different electronic ground states have emerged as a powerful method for exploring the exotic superconducting properties induced by the proximity effect. Here, we investigate Andreev transport through the interface between an s-wave superconductor Nb and a type-II Wely semimetal NbIrTe4. The differential conductance measurement reveals an anomalous zero-bias conductance peak and prominent subgap structures at low temperatures. Furthermore, we found that these subgap structures are not only related to the interface coupling strength but also influenced by the thickness of the NbIrTe4 flake. For thin devices (≤100 nm), the differential conductance spectra only exhibit a single-gap structure. While in thicker devices (∼150 nm), we observed the distinct double-gap structure, which is likely to originate from the proximity-induced superconductivity gap on the bulk and surface of the NbIrTe4 flakes. These results can provide a good reference for understanding the superconducting phase in type-II Weyl semimetals and take a step toward its future application in the field of superconducting electronics.
Acoustofluidics exfoliation mechanism of metal-organic framework nanosheets
Authors: Liu Xia , Wang Chaohui , Zheng Tengfei
Published: October 2023

Liquid-phase exfoliation using surface acoustic waves (SAWs) has been applied to two-dimensional transition metal materials and layered metal-organic frameworks (MOFs). Nevertheless, the underlying mechanisms are not fully understood. According to the proposal, the acoustic stripping mechanism is mainly caused by the effect of fluid shear force on bulk layered materials induced by acoustic streaming. Due to the lack of actual real-time in situ experimental evidence, most of the research described to date has been inconclusive. This paper reports that the motion of MOF particles is driven by acoustic streaming generated by standing SAWs in a de-ionized water droplet. The distributions of acoustic pressure and acoustic streaming inside a droplet, and the trajectories of polystyrene beads of different diameters under the influence of acoustic radiation force and drag force induced by acoustic streaming were calculated by numerical simulation to predict the motion of MOF particles. The whole process of MOF exfoliation is observed using a high speed camera. The dynamic sequence of exfoliation events was determined using ultrafast optical imaging, which has not been reported before. The exfoliation of MOFs is not only caused by acoustic streaming but also by particle–particle collisions, as shown by the in situ observation.
Visualizing multi-physical spatiotemporal evolution of dielectric breakdown in high-performance polymeric capacitors
Authors: Liu Zhigang , Fan Xuhui , Liu Kaixin , Zhang Fengyuan , Huang Boyuan , Wang Yao , Li Jiangyu
Published: October 2023

Pulse power has many important technological applications, for which the dielectric capacitors are essential. It is imperative to understand the breakdown mechanism to improve the dielectric energy storage density, yet the breakdown process involves multi-physical coupling spanning multiple spatial and temporal scales, making its characterization very challenging. Recognizing local field concentration results in local strain concentration through Maxwell's stress, we develop an effective method to visualize the dielectric breakdown process via optic strain measurement. Utilizing high-performance biaxially oriented polypropylene as a demonstration, we find dielectric breakdown is an ultrafast process with breakdown current rising and dropping in just tens of nanoseconds. Rapid temperature rise is observed after breakdown as well due to Joule heating, though both current measurement and temperature mapping offer little insight before breakdown actually occurs. Nevertheless, substantial strain concentration is observed before breakdown, reflecting electric field concentration that eventually leads to breakdown. A well-defined upper bound on the electric field concentration is also noted.
Estimation of population variance using the actual ranks and values: Properties and application
Authors: Alzahrani Salem Mubarak
Published: October 2023

Background: Of all measures of variability, the variance is by far the most popular. This paper argues an alternative index of variability, shares many properties with the variance, but can be more informative about the properties of distributions that depart from normality. Procedures: An estimator for the population variance is proposed. The proposed estimator is based, in its calculations, on the actual variable values and their ranks. A simulation study is employed to compare the performance of the proposed estimator with that of eight other estimators appearing in the literature using the mean square error criterion. The influence of sample size, normality, and non-normality is investigated. We suggest a new measure of skewness based on the new proposed estimator for the population variance. The mean value, median, and the new estimator for the population variance are the only three summary statistics that may be effectively used to derive the suggested coefficient of skewness. A limited Monte Carlo simulation is used to examine the potential of the suggested statistic to identify skewness. The covariance between a random variable and its rankings is how the new estimator is stated. This format is used to derive new correlation coefficients. Results and conclusion: The simulation study shows that the proposed estimator, under conditions of normality, performs better than most estimators considered, whereas it fails to give better results than some others. In cases of non-normality considered, the proposed estimator was superior to eight competitors. According to preliminary results, the new coefficient of skewness performs well overall in a limited simulation. The new correlation coefficient outperforms Pearson’s correlation for the non-normal model, as demonstrated by simulation analysis. Furthermore, it has been demonstrated that the new estimator is a useful tool for extracting a straightforward method to obtain novel skewness and correlation coefficients.
Social science to advance wildfire adaptation in the southwestern United States: a review and future research directions
Authors: Edgeley Catrin M.
Published: October 2023

Background Social science that seeks to advance wildfire adaptation in the southwestern US states of Arizona and New Mexico remains underdeveloped in comparison with other regions in the USA. Aim To identify key themes in the existing social science literature on wildfire in the Southwest and to determine future research needs that can inform more strategic adaptation across scales and contexts. Methods This article presents an in-depth literature review, organising findings using the Fire Adapted Communities Framework. Key results Research on social aspects of wildfire in the southwestern USA has continued to diversify and broaden in scope over time, but some foundational lines of inquiry (such as public support for prescribed fire) have become outdated while other areas of study (such as fire prevention) have not been explored at all. Conclusions Opportunities to advance wildfire social science efforts in the Southwest are abundant and well positioned to inform social understandings in other regions and countries. Implications Researchers wishing to conduct social science research related to wildfire in the Southwest should seek to update and diversify knowledge in this field both through strategic selection of study sites and populations and via intentional, rigorous research design that acknowledges and elevates the nuances of social interactions with wildfire.
Vestibular CCK signaling drives motion sickness–like behavior in mice
Authors: Machuca-Márquez Pablo , Sánchez-Benito Laura , Menardy Fabien , Urpi Andrea , Girona Mònica , Puighermanal Emma , Appiah Isabella , Palmiter Richard D. , Sanz Elisenda , Quintana Albert
Published: October 2023

Travel can induce motion sickness (MS) in susceptible individuals. MS is an evolutionary conserved mechanism caused by mismatches between motion-related sensory information and past visual and motion memory, triggering a malaise accompanied by hypolocomotion, hypothermia, hypophagia, and nausea. Vestibular nuclei (VN) are critical for the processing of movement input from the inner ear. Motion-induced activation of VN neurons recapitulates MS-related signs. However, the genetic identity of VN neurons mediating MS-related autonomic and aversive responses remains unknown. Here, we identify a central role of cholecystokinin (CCK)-expressing VN neurons in motion-induced malaise. Moreover, we show that CCK VN inputs onto the parabrachial nucleus activate
Calca
-expressing neurons and are sufficient to establish avoidance to novel food, which is prevented by CCK-A receptor antagonism. These observations provide greater insight into the neurobiological regulation of MS by identifying the neural substrates of MS and providing potential targets for treatment.
Correlating chemistry and mass transport in sustainable iron production
Authors: Zheng Xueli , Paul Subhechchha , Moghimi Lauren , Wang Yifan , Vilá Rafael A. , Zhang Fan , Gao Xin , Deng Junjing , Jiang Yi , Xiao Xin , Wu Chaolumen , Greenburg Louisa C. , Yang Yufei , Cui Yi , Vailionis Arturas , Kuzmenko Ivan , llavsky Jan , Yin Yadong , Cui Yi , Dresselhaus-Marais Leora
Published: October 2023

Steelmaking contributes 8% to the total CO
2
emissions globally, primarily due to coal-based iron ore reduction. Clean hydrogen-based ironmaking has variable performance because the dominant gas–solid reduction mechanism is set by the defects and pores inside the mm- to nm-sized oxide particles that change significantly as the reaction progresses. While these governing dynamics are essential to establish continuous flow of iron and its ores through reactors, the direct link between agglomeration and chemistry is still contested due to missing measurements. In this work, we directly measure the connection between chemistry and agglomeration in the smallest iron oxides relevant to magnetite ores. Using synthesized spherical 10-nm magnetite particles reacting in H
2
, we resolve the formation and consumption of wüstite (Fe
1-x
O)—the step most commonly attributed to whiskering. Using X-ray diffraction, we resolve crystallographic anisotropy in the rate of the initial reaction. Complementary imaging demonstrated how the particles self-assemble, subsequently react, and grow into elongated “whisker” structures. Our insights into how morphologically uniform iron oxide particles react and agglomerate in H
2
reduction enable future size-dependent models to effectively describe the multiscale aspects of iron ore reduction.
Increased homozygosity due to endogamy results in fitness consequences in a human population
Authors: Swinford N. A. , Prall S. P. , Gopalan S. , Williams C. M. , Sheehama J. , Scelza B. A. , Henn B. M.
Published: October 2023

Recessive alleles have been shown to directly affect both human Mendelian disease phenotypes and complex traits. Pedigree studies also suggest that consanguinity results in increased childhood mortality and adverse health phenotypes, presumably through penetrance of recessive mutations. Here, we test whether the accumulation of homozygous, recessive alleles decreases reproductive success in a human population. We address this question among the Namibian Himba, an endogamous agro-pastoralist population, who until very recently practiced natural fertility. Using a sample of 681 individuals, we show that Himba exhibit elevated levels of “inbreeding,” calculated as the fraction of the genome in runs of homozygosity (F
ROH
). Many individuals contain multiple long segments of ROH in their genomes, indicating that their parents had high kinship coefficients. However, we do not find evidence that this is explained by first-cousin consanguinity, despite a reported social preference for cross-cousin marriages. Rather, we show that elevated haplotype sharing in the Himba is due to a bottleneck, likely in the past 60 generations. We test whether increased recessive mutation load results in observed fitness consequences by assessing the effect of F
ROH
on completed fertility in a cohort of postreproductive women (n = 69). We find that higher F
ROH
is significantly associated with lower fertility. Our data suggest a multilocus genetic effect on fitness driven by the expression of deleterious recessive alleles, especially those in long ROH. However, these effects are not the result of consanguinity but rather elevated background identity by descent.
Physical Origin of Color Changes in Lutetium Hydride under Pressure
Authors: Lv 吕 Run 润 , Tu 涂 Wenqian 文倩 , Shao 邵 Dingfu 定夫 , Sun 孙 Yuping 玉平 , Lu 鲁 Wenjian 文建
Published: October 2023

Recently, near-ambient superconductivity was claimed in nitrogen-doped lutetium hydride (LuH3–δ
N
ε
). Unfortunately, all follow-up research still cannot find superconductivity signs in successfully synthesized lutetium dihydride (LuH2) and N-doped LuH2±x
N
y
. However, a similar intriguing observation was the pressure-induced color changes (from blue to pink and subsequent red). The physical understanding of its origin and the correlation between the color, crystal structure, and chemical composition of Lu–H–N is still lacking. In this work, we systematically investigated the optical properties of LuH2 and LuH3, and the effects of hydrogen vacancies and nitrogen doping using the first-principles calculations by considering both interband and intraband contributions. Our results demonstrate that the evolution of reflectivity peaks near blue and red light, which is driven by changes in the band gap and Fermi velocity of free electrons, resulting in the blue-to-red color change under pressure. In contrast, LuH3 exhibits gray and no color change up to 50 GPa. Furthermore, we investigated the effects of hydrogen vacancies and nitrogen doping on its optical properties. Hydrogen vacancies can significantly decrease the pressure of blue-to-red color change in LuH2 but do not have a noticeable effect on the color of LuH3. The N-doped LuH2 with the substitution of a hydrogen atom at the tetrahedral position maintains the color change when the N-doping concentration is low. As the doping level increases, this trend becomes less obvious, while other N-doped structures do not show a blue-to-red color change. Our results can clarify the origin of the experimental observed blue-to-red color change in lutetium hydride and also provide a further understanding of the potential N-doped lutetium dihydride.
Waves in a forest: a random forest classifier to distinguish between gravitational waves and detector glitches
Authors: Shah Neev , Knee Alan M , McIver Jess , Stenning David C
Published: October 2023

The LIGO-Virgo-KAGRA (LVK) network of gravitational-wave (GW) detectors have observed many tens of compact binary mergers to date. Transient, non-Gaussian noise excursions, known as ‘glitches’, can impact signal detection in various ways. They can imitate true signals as well as reduce the confidence of real signals. In this work, we introduce a novel statistical tool to distinguish astrophysical signals from glitches, using their inferred source parameter posterior distributions as a feature set. By modelling both simulated GW signals and real detector glitches with a gravitational waveform model, we obtain a diverse set of posteriors which are used to train a random forest classifier. We show that random forests can identify differences in the posterior distributions for signals and glitches, aggregating these differences to tell apart signals from common glitch types with high accuracy of over 93%. We conclude with a discussion on the regions of parameter space where the classifier is prone to making misclassifications, and the different ways of implementing this tool into LVK analysis pipelines.
Relaxation behavior of vibrationally excited N2(X1Σg
+
v″ = 6) collisions with H2
Authors: Mamatimin Ayxam , Liu Jing , Habibulla Nurali , Alghazi Abai
Published: October 2023

Relaxation behavior of vibrationally excited N2 (X1Σg
+
v″ = 6) induced by collisions with H2 has been investigated using coherent anti-Stokes Raman spectroscopy (CARS). The total pressure of the N2–H2 mixture was 500 Torr, and the molar ratios of H2 were 0.3, 0.4, 0.5, 0.6 and 0.8, respectively. The v″ = 6 vibrational state of the electronic ground-state manifold X1Σg
+ of N2 was selectively excited by overtone pumping, and the population evolution was monitored using CARS spectroscopy. The collisional deactivation rate coefficients of the excited state N2 (v″ = 6) with H2 and N2 are approximately 2.59 × 10−14 cm3s−1 and 1.04 × 10−14 cm3s−1 at 300 K, and 2.57 × 10−14 cm3s−1 and 0.54 × 10−14 cm3s−1 at 320 K, respectively. The relaxation rate coefficient of the N2–H2 collision was approximately 2.5 and 5 times that of the self-relaxation rate coefficient. The experimental results show that the population densities of the (1,2), (2,2), (3,5), and (3,6) levels of H2 have a maximum at 320 K, while the population densities of (2,3) and (2,4) show little change with increasing temperature. Simultaneously, the time-resolved CARS profiles of the vibrational levels v = 6,5,4 by preparing v = 6 of N2 also indicated that a near-resonant multi-quantum relaxation process occurred between N2–H2. The collision-induced population distribution of H2 was observed at molar ratios of 0.3, 0.4, 0.5, 0.6 and 0.8, respectively. The ro-vibrational population distribution of H2 after collision with N2 is given by the CARS signal intensity ratio, and the population of hydrogen molecules at v = 2, 3 vibrational states also provides strong experimental evidence for energy near-resonance collisions between N2–H2.
Enhanced marine predators algorithm optimized support vector machine for IGBT switching power loss estimation
Authors: Liu Jiaqi , Li Lingling , Liu Yuwei
Published: October 2023

As the use of renewable energy generation continues to grow, improving power conversion efficiency has become an urgent task. This study aims to propose a high-precision power module loss estimation method, with a focus on predicting the switching losses of insulated gate bipolar transistor (IGBT) modules, which is crucial for the reliability assessment of IGBT modules. The main objective of this study is to establish a high-precision predictive model for IGBT module switching losses to enhance the reliability and efficiency of these devices. Firstly, a dynamic characteristic test platform was established to acquire relevant data for in-depth analysis of IGBT behavior. Secondly, given the excellent performance of support vector machine (SVM) in handling both strong and small-sized datasets, SVM was chosen as the foundational model for high-precision switching loss estimation. Subsequently, an enhanced marine predatory algorithm (EMPA), known for its superior convergence precision and speed, was introduced to optimize the random parameters of SVM. Finally, a method based on the optimized EMPA-SVM was constructed for predicting IGBT switching power losses. The proposed approach was validated using dynamic characteristic test data. And it indicated that the predictive model achieved the value of R
2 exceeding 99.8% for switching losses. Additionally, the mean absolute error and root mean square error metrics of EMPA-SVM model outperformed other models. Therefore, the research results unambiguously demonstrate the significant benefits of accurately predicting IGBT switching losses in enhancing device performance.
Point feature correction based rolling shutter modeling for EKF-based visual-inertial odometry
Authors: Zhang Kaijie , Zhang Menglong
Published: October 2023

The application of consumer-grade rolling-shutter (RS) cameras in visual inertial odometry (VIO) systems deserves attention. In previous works, VIO systems with RS cameras usually adopt different dimensions of RS modeling to represent the camera motion. Although the complex camera motion expression improves accuracy, adding more variables greatly increases the computation load. Therefore, considering the limitations of camera motion modeling, this paper introduces a point feature correction strategy to improve the performance of the system in terms of both speed and accuracy. The optimized camera poses and high-frequency inertial measurement unit (IMU) are employed to correct the point features in the RS image to new pixel coordinates in the global shutter view (in the middle of the RS image readout time) by epipolar transfer. At the same time, we handle the zero velocity and abnormal cases of RS modeling to improve the robustness of the system. Furthermore, the readout time of the RS camera is self-calibrated online during the state augmentation stage and can quickly converge and stabilize to near the true value. The readout time of the RS camera is locally observable, except for two degenerate motions. Experimental results demonstrate that the proposed method outperforms the state-of-the-art methods on a public dataset in terms of accuracy and computational cost. We port our algorithm to an Android-based mobile phone and our system outputs real-time trajectories on the mobile phone. Then, we use the motion capture system to obtain the ground truth phone pose to test the performance of our algorithm.
Pollution-free interface of 2D-MoS2/1D-CuO vdWs heterojunction for high-performance photodetector
Authors: Yang Hui , Luo Ruiqin , Shi Kaixi , Li Jinhua , Xu Mingze , Chu Xueying , Zhai Yingjiao , Qu Guannan , Fang Xuan
Published: October 2023

Van der Waals heterostructures provide a new opportunity for constructing new structures and improving the performance of electronic and optoelectronic devices. However, the existing methods of constructing heterojunctions are still faced with problems such as impurity introduction, or complex preparation process and limited scope of application. Herein, a physisorption method is proposed to composite CuO nanorods on the surface of MoS2 nanosheets. CuO nanorods and MoS2 form type-Ⅱ heterojunctions, which promotes the separation and transport of photo-generated charge carriers. More importantly, compared with the transfer and coating methods, the physical adsorption method avoids the introduction of auxiliary materials during the whole process of constructing the heterojunction, and therefore effectively reduces the damage and pollution at the interface. The optimized MoS2/CuO heterojunction photodetector achieves a high photoresponsivity of ∼680.1 A W−1 and a fast response speed of ∼29 μs. The results demonstrate that the physisorption method provides a feasible approach to realize high performance photodetectors with pollution-free interfaces, and it can also be extended to the development of other low-dimensional hybrid heterojunction electronic and optoelectronic devices.
The Kuramoto model on dynamic random graphs
Authors: Groisman Pablo , Huang Ruojun , Vivas Hernán
Published: October 2023

We propose a Kuramoto model of coupled oscillators on a time-varying graph, whose dynamics are dictated by a Markov process in the space of graphs. The simplest representative is considering a base graph and then the subgraph determined by N independent random walks on the underlying graph. We prove a synchronisation result for solutions starting from a phase-cohesive set independent of the speed of the random walkers, an averaging principle and a global synchronisation result with high probability for sufficiently fast processes. We also consider Kuramoto oscillators in a dynamical version of the random conductance model.
Influence of sex on the reliability of cerebral blood velocity regulation during lower body negative pressure and supine cycling with considerations of the menstrual cycle
Authors: Johnson Nathan E , Burma Joel S , Seok Jina , Miutz Lauren N , Smirl Jonathan D
Published: October 2023

Objective. To evaluate sex differences in the reliability of absolute and relative cerebral blood velocity (CBv) during concurrent supine cycling with lower body negative pressure (LBNP). Approach. A total of 19 participants (11 females; aged 20–33 years) completed five testing sessions, occurring on 7 d intervals. Visit 1 was a maximal-ramp-cycle test to ascertain peak CBv wattage. During visits 2–5, supine cycling protocol occurred at individualized peak CBv wattages with progressive decreases in LBNP from 0 to −20, −40, −60, −70, and −80 Torr. Menstrual cycle day was self-reported via the Rhinessa Women’s Questionnaire. Transcranial Doppler ultrasound insonated bilateral middle cerebral artery velocity (MCAv). Two-way ANOVA assessed potential day- and sex-differences at each LBNP stage. Reliability was determined using intraclass correlation coefficients (ICC) and coefficient of variation (CoV). Main results. For all physiological measures, no main-effects were present for day- or interaction-terms (p > 0.067; negligible-to-small effect sizes), while sex differences were noted for MCAv, blood pressure, and heart rate (p < 0.046). Across visits, males and females displayed excellent and good-to-excellent levels of reliability for MCAv metrics, respectively (ICC range: 0.745–0.999; CoV range: 0.33%–9.90%). Significance. During the current investigation, both relative and absolute CBv demonstrated high reliability in both male and female participants during a supine LBNP cycling protocol. An exploratory analysis revealed increased variance was found in female participants dependent on contraceptive use. Despite this, results indicate future LBNP studies may include females at any menstrual cycle stage.
Full cycle, self-consistent, two-dimensional analysis of a packed bed DBD reactor for plasma-assisted
CO2
splitting: spatiotemporal inhomogeneous, glow to streamer to surface discharge transitions
Authors: Kourtzanidis K
Published: October 2023

We investigate the full-cycle operation of a coaxial Packed Bed Dielectric Barrier Discharge (PB-DBD) reactor operating in pure

C

O

2

. The reactor is packed with high permittivity dielectric rods and is analyzed with a two-dimensional (2D) self-consistent plasma model. We show that the PB-DBD operation is governed by both glow and volume/surface streamer discharges, forming alternatively and non-uniformly inside the gas volume. The presence and surface charging of the dielectric rods and dielectric layer is crucial for the initiation, propagation, annihilation and afterglow of these microdischarges. Our calculations show maximum electron and

C

O

2

+

densities in the order 1020 m−3, an average discharge power of 353.42 W m−1 in the first cycle, microdischarge peak currents in the order of 50–400 A m−1, total half-cycle plasma charge of around 6 µC m−1, which compare well with experimental findings. Dominant negative ions are found to be

C

O

3

−

. CO molecules and O atoms are mainly formed during the MDs development and the streamer-surface ionization waves. Molecular oxygen (

O

2

) is preferentially formed during the glow, current-decaying and afterglow phase of each microdischarge. The spatially average reduced electric field inside the reactor lies in the 20–100 Td range. Each MD, presents distinct non-uniform and non-repeatable glow and volume/streamer discharges owed to the non-uniform surface charging processes which dictate the complex spatial distribution of produced neutral (and ion) species. These detailed results shed light on crucial, largely non-uniform plasma spatiotemporal characteristics that can help design efficient PB-DBD reactors for

C

O

2

splitting and beyond, while emphasizing the important insights obtained by 2D simulations which can not be captured with 0D-global or 1D models.
Experimental validation of particle-in-cell/Monte Carlo collisions simulations in low-pressure neon capacitively coupled plasmas
Authors: Park Chan-Won , Horváth B , Derzsi A , Schulze J , Kim J H , Donkó Z , Lee Hyo-Chang
Published: October 2023

Plasma simulations are powerful tools for understanding fundamental plasma science phenomena and for process optimisation in applications. To ensure their quantitative accuracy, they must be validated against experiments. In this work, such an experimental validation is performed for a one dimensional in space and three dimensional in velocity space particle-in-cell simulation complemented with the Monte Carlo treatment of collision processes of a capacitively coupled radio frequency plasma driven at 13.56 MHz and operated in neon gas. In a geometrically symmetric reactor the electron density in the discharge centre and the spatio-temporal distribution of the electron impact excitation rate from the ground into the Ne 2p1 level are measured by a microwave cutoff probe and phase resolved optical emission spectroscopy, respectively. The measurements are conducted for electrode gaps between 50 mm and 90 mm, neutral gas pressures between 20 mTorr and 50 mTorr, and peak-to-peak values of the driving voltage waveform between 250 V and 650 V. Simulations are performed under identical discharge conditions. In the simulations, various combinations of surface coefficients characterising the interactions of electrons and heavy particles with the anodised aluminium electrode surfaces are adopted. We find, that the simulations using a constant effective heavy particle induced secondary electron (SE) emission coefficient of 0.3 and a realistic electron–surface interaction model (which considers energy-dependent and material specific elastic and inelastic electron reflection, as well as the emission of true SEs from the surface) yield results which are in good quantitative agreement with the experimental data.
Characterization of PECVD Si3N4 thin film in multiple oxide–nitride stack for 3D-NAND flash memory
Authors: Baek Jaekeun , An Surin , Park Ahhyun , Kim Ki-Yeon , Hong Sang Jeen
Published: October 2023

3D-NAND flash memory is currently essential in the semiconductor industry due to the interference issue between memory cells of the conventional planar type. In order to vertically stack the memory, an oxide–nitride stack structure is formed using plasma enhanced chemical vapor deposition (PECVD) equipment. Thereafter, part of the silicon nitride (Si3N4) layer is removed by wet etching using phosphoric acid (H3PO4) to make space for the memory cell. At this time, it is important to selectively wet etch only the Si3N4 film while protecting the silicon oxide (SiO2). Therefore, in this study, the process parameters that affect the etch rate in PECVD were derived, and the correlation with the hydrogen content, surface roughness, and thin film density, which are the thin film characteristics that the parameters affect, were investigated. Through the experimental results, we confirmed that hydrogen content increases according to the deposition pressure, affects the surface roughness, and can be an important factor in improving the wet etching rate.