bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of the geometry, absorption spectrum, and first hyperpolarizability of 4,5-dicyanoimidazole derivatives in solution. A multiscale ASEC–FEG study
Authors: Brandão Idney , Georg Herbert C. , Castro Marcos A. , Fonseca Tertius L.
Published: July 2024

We investigate the effects of solvents on the geometry, absorption spectrum, and first hyperpolarizability of six push–pull molecules, each containing a 4,5-dicyanoimidazole group as an electron acceptor and a N,N-dimethylamino group as an electron donor, with systematically extended π-conjugated systems. Geometry optimizations in dichloromethane, methanol, water, and formamide under normal thermodynamic conditions were performed using the average solvent electrostatic configuration–free energy gradient method, which employs a discrete solvent model. The conformational structure of molecules is moderately affected by the environment, with the π-conjugated system becoming more planar in protic solvents. Solvent effects on the first hyperpolarizability result in marked increases that are in line with the red shifts of the absorption spectrum. The hyperpolarizability of smaller molecules within the set may be significantly influenced by the effects of geometry relaxation in highly polar protic solvents. The results illustrate the role of hydrogen bonds in the structure and electronic properties of push–pull molecules in protic environments. For smaller molecules, hydrogen bonds significantly contribute to enhancing the hyperpolarizability, but the effect of these specific interactions becomes less significant with the length of the π-conjugated system.
Quantum gate control of polar molecules with machine learning
Authors: Zhang Zuo-Yuan , Hu Jie-Ru , Fang Yu-Yan , Li Jin-Fang , Liu Jin-Ming , Huang Xinning , Sun Zhaoxi
Published: July 2024

We propose a scheme for achieving basic quantum gates using ultracold polar molecules in pendular states. The qubits are encoded in the YbF molecules trapped in an electric field with a certain gradient and coupled by the dipole–dipole interaction. The time-dependent control sequences consisting of multiple pulses are considered to interact with the pendular qubits. To achieve high-fidelity quantum gates, we map the control problem for the coupled molecular system into a Markov decision process and deal with it using the techniques of deep reinforcement learning (DRL). By training the agents over multiple episodes, the optimal control pulse sequences for the two-qubit gates of NOT, controlled NOT, and Hadamard are discovered with high fidelities. Moreover, the population dynamics of YbF molecules driven by the discovered gate sequences are analyzed in detail. Furthermore, by combining the optimal gate sequences, we successfully simulate the quantum circuit for entanglement. Our findings could offer new insights into efficiently controlling molecular systems for practical molecule-based quantum computing using DRL.
Optimization of noncollinear magnetic ordering temperature in Y-type hexaferrite by machine learning
Authors: Li Yonghong , Zhang Jing , Jiang Linfeng , Zhang Long , Zhang Yugang , Wu Xueliang , Chai Yisheng , Zhou Xiaoyuan , Zhou Zizhen
Published: July 2024

Searching the optimal doping compositions of the Y-type hexaferrite Ba2Mg2Fe12O22 remains a long-standing challenge for enhanced non-collinear magnetic transition temperature (TNC). Instead of the conventional trial-and-error approach, the composition-property descriptor is established via a data driven machine learning method named sure independence screening and sparsifying operator. Based on the chosen efficient and physically interpretable descriptor, a series of Y-type hexaferrite compositions are predicted to hold high TNC, among which the BaSrMg0.28Co1.72Fe10Al2O22 is then experimentally validated. Test results indicate that, under appropriate external magnetic field conditions, the TNC of this composition reaches up to 568 K, and its magnetic transition temperature is also elevated to 735 K. This work offers a machine learning-based route to develop room temperature single phase multiferroics for device applications.
Impact of helical grooves on drag force and flow-induced noise of a cylinder under subcritical Reynolds numbers
Authors: Xu Mingyang , Hu Wulong , Jiang Zhangze
Published: July 2024

The drag force and flow-induced noise of underwater vehicles significantly affect their hydrodynamic and stealth performance. This paper investigates the impact of helical grooves on the drag force and flow-induced noise of underwater vehicles through numerical simulations of the flow around cylinders with two types of helical grooves under various subcritical Reynolds numbers. The simulation scheme employs the large-eddy simulation framework combined with the Lighthill acoustic analogy method. The results show that the helical-groove structure can achieve reductions of up to 30% in drag and 5 dB in noise. These helical grooves have a significant effect in terms of suppressing the formation of a Karman vortex street downstream of the cylinder. Under subcritical Reynolds numbers, the drag-reduction effect of the helically grooved cylinder decreases as the number of helical grooves increases, while the noise-reduction effect increases with increasing number of helical grooves.
Whispering gallery mode sensing through the lens of quantum optics, artificial intelligence, and nanoscale catalysis
Authors: Zossimova Ekaterina , Jones Callum , Perera Kulathunga Mudalige Kalani , Pedireddy Srikanth , Walter Michael , Vollmer Frank
Published: July 2024

Ultra-sensitive sensors based on the resonant properties of whispering gallery modes (WGMs) can detect fractional changes in nanoscale environments down to the length and time scales of single molecules. However, it is challenging to isolate single-molecule signals from competing noise sources in experiments, such as thermal and mechanical sources of noise, and—at the most fundamental level—the shot noise limit of classical light. Additionally, in contrast to traditional bulk refractive index measurements, analyzing single-molecule signals is complicated by the localized nature of their interactions with nanoscale field gradients. This perspective discusses multifaceted solutions to these challenges, including the use of quantum light sources to boost the signal-to-noise ratio in experiments and leveraging the power of supercomputers to predict the electronic response of molecules to WGM optoplasmonic fields. We further discuss the role of machine learning in WGM sensing, including several advanced models that can predict molecular polarizability and solvent effects. These advancements in WGM spectroscopy and computational modeling can help to decipher the molecular mechanics of enzymes, enable studies of catalysis on the nanoscale, and probe the quantum nature of molecules.
Accurate ab initio based potential energy surface and kinetics of the Cl + NH3 → HCl + NH2 reaction
Authors: Tu Zhao , Li Jiaqi , Yang Mingjuan , Chen Yizhuo , Wang Yan , Song Hongwei
Published: July 2024

The gas-phase reaction Cl + NH3 → HCl + NH2 is a prototypical hydrogen abstraction reaction, whose minimum energy path involves several intermediate complexes. In this work, a full-dimensional, spin–orbit corrected potential energy surface (SOC PES) is constructed for the ground electronic state of the Cl + NH3 reaction. About 52 000 energy points are sampled and calculated at the UCCSD(T)-F12a/aug-cc-pVTZ level, in which the data points located in the entrance channel are spin–orbit corrected. The spin–orbit corrections are predicted by a fitted three-dimensional energy surface from about 7520 energy points in the entrance channel at the level of CASSCF (15e, 11o)/aug-cc-pVTZ. The fundamental-invariant neural network method is utilized to fit the SOC PES, resulting in a total root mean square error of 0.12 kcal mol−1. The calculated thermal rate constants of the Cl + NH3 → HCl + NH2 reaction on the SOC PES with the soft-zero-point energy constraint agree reasonably well with the available experimental values.
Unlocking the unfolded structure of ubiquitin: Combining time-resolved x-ray solution scattering and molecular dynamics to generate unfolded ensembles
Authors: Nijhawan Adam K. , Leshchev Denis , Hsu Darren J. , Chan Arnold M. , Rimmerman Dolev , Hong Jiyun , Kosheleva Irina , Henning Robert , Kohlstedt Kevin L. , Chen Lin X.
Published: July 2024

The unfolding dynamics of ubiquitin were studied using a combination of x-ray solution scattering (XSS) and molecular dynamics (MD) simulations. The kinetic analysis of the XSS ubiquitin signals showed that the protein unfolds through a two-state process, independent of the presence of destabilizing salts. In order to characterize the ensemble of unfolded states in atomic detail, the experimental XSS results were used as a constraint in the MD simulations through the incorporation of x-ray scattering derived potential to drive the folded ubiquitin structure toward sampling unfolded states consistent with the XSS signals. We detail how biased MD simulations provide insight into unfolded states that are otherwise difficult to resolve and underscore how experimental XSS data can be combined with MD to efficiently sample structures away from the native state. Our results indicate that ubiquitin samples unfolded in states with a high degree of loss in secondary structure yet without a collapse to a molten globule or fully solvated extended chain. Finally, we propose how using biased-MD can significantly decrease the computational time and resources required to sample experimentally relevant nonequilibrium states.
Intelligent reconstruction of unsteady combustion flow field of scramjet based on physical information constraints
Authors: Deng Xue , Guo Mingming , Zhang Yi , Tian Ye , Wu Jingrun , Wang Heng , Zhang Hua , Le Jialing
Published: July 2024

To alleviate the problem of high-fidelity data dependence and inexplicability in pure data-driven neural network models, physical informed neural networks (PINNs) provide a new learning paradigm. This study constructs an efficient, accurate, and robust PINN framework for predicting unsteady combustion flow fields based on Navier–Stokes (NS) equation constraints. To achieve fast prediction of a multi-physical field in a scramjet combustion chamber, we propose a U-shaped residual neural network model based on feature information fusion. The model uses a residual neural network module as the backbone, uses jump connection to improve model generalization, and uses the U-shaped structure to fuse the receptive field features with different scales to enhance the feature expression ability of the model. To prevent improper assumptions from leading to wrong method constraints, we consider the flow characteristic mechanism of each physical field to constrain the neural network and verify its accuracy through numerical simulation of the unsteady flow field in the scramjet combustor with Mach number (Ma) 2.0. This method can accurately predict the multi-physical field of unsteady turbulent combustion based on the time, space, Ma and turbulent eddy viscosity coefficients of a small number of samples. Specially, the proposed physical driven and data driven fusion proxy model can predict the unsteady combustion flow field in milliseconds. It has important reference value to solve the problem of low calculation efficiency of a traditional numerical simulation method of a combustion process.
Aerodynamic design of supersonic compressor cascade and vorticity dynamic diagnosis of flow field structure
Authors: Yan Tingsong , Yan Peigang , Liang Zhuoming , Chen Huanlong
Published: July 2024

High-load counter-rotating compressor plays a crucial role in reducing the axial length and weight of the compressor and increasing the thrust-to-weight ratio of the aero-engine. However, the boundary layer flow separation induced by shock waves in the channel of high adverse pressure gradient also brings more aerodynamic losses. This paper proposed a supersonic compressor cascade modeling method based on the unique inlet angle theory and the superimposing thickness on the suction surface method. It carried out aerodynamic optimization design of cascade with inlet Mach number of 1.85 combined with numerical optimization technology, vorticity dynamics diagnosis, and planar cascade experiment. The results show that multiple shock wave combination pressurization can be realized in the supersonic cascade channel. At the design point, the static pressure ratio is 3.285, and the total pressure recovery coefficient reaches 86.82%, and the experimental results of planar cascade also verify the correctness of the simulation method. In addition, the correlation laws between the distribution of the vorticity dynamic parameter, shock wave structure, and aerodynamic performance of cascade were analyzed by the vorticity dynamic flow field diagnosis method, which provides a beneficial reference for the subsequent compressor design.
Infrared signature of the hydroperoxyalkyl intermediate (·QOOH) in cyclohexane oxidation: An isomer-resolved spectroscopic study
Authors: Roy Tarun Kumar , Qian Yujie , Sojdak Christopher A. , Kozlowski Marisa C. , Klippenstein Stephen J. , Lester Marsha I.
Published: July 2024

Infrared (IR) action spectroscopy is utilized to characterize carbon-centered hydroperoxy-cyclohexyl radicals (·QOOH) transiently formed in cyclohexane oxidation. The oxidation pathway leads to three nearly degenerate ·QOOH isomers, β-, γ-, and δ-QOOH, which are generated in the laboratory by H-atom abstraction from the corresponding ring sites of the cyclohexyl hydroperoxide (CHHP) precursor. The IR spectral features of jet-cooled and stabilized ·QOOH radicals are observed from 3590 to 7010 cm−1 (∼10–20 kcal mol−1) at energies in the vicinity of the transition state (TS) barrier leading to OH radicals that are detected by ultraviolet laser-induced fluorescence. The experimental approach affords selective detection of β-QOOH, arising from its significantly lower TS barrier to OH products compared to γ and δ isomers, which results in rapid unimolecular decay and near unity branching to OH products. The observed IR spectrum of β-QOOH includes fundamental and overtone OH stretch transitions, overtone CH stretch transitions, and combination bands involving OH or CH stretch with lower frequency modes. The assignment of β-QOOH spectral features is guided by anharmonic frequencies and intensities computed using second-order vibrational perturbation theory. The overtone OH stretch (2νOH) of β-QOOH is shifted only a few wavenumbers from that observed for the CHHP precursor, yet they are readily distinguished by their prompt vs slow dissociation rates to OH products.
Tunable cold/warm white light emitting devices based on carbon dots with multiple emissive centers
Authors: Zhu Yi-Lin , Zhao Hao , Gu Shi-Ying , Cao Hai-Yan , Gan Zhi-Xing , Shi Chuan-Guo
Published: July 2024

The correlated color temperature (CCT) of lighting is closely related to human emotions. However, there is still a relative lack of white light emitting devices (W-LEDs) with tunable CCT to meet application demands in different scenarios. Here, we develop a W-LED with tunable CCT based on multiple emissive centers of carbon dots (CDots) synthesized through controlled thermal carbonization of citric acid and urea. The reaction at 160 °C for 4 h results in amorphous CDots, which exhibit excitation wavelength dependent photoluminescence (PL) containing two peaks at 446 and 520 nm. However, by increasing the reaction temperature and duration, crystalline CDots are obtained, which show broad PL peaking at 650 nm. Based on their complementary spectral ranges, a W-LED with an extremely high color rendering index of 96 is demonstrated. Moreover, a W-LED with both 365 and 405 nm electroluminescent chips is designed. The W-LED shifts from cold to warm white, when the excitation chips switch from 365 to 405 nm. This adjustable CCT can create a harmonious, enjoyable, and safe lighting environment to meet the demands of different scenes.
Obesity and sexual health trends among a large, national sample of men who have sex with men on Grindr in the USA
Authors: Zaliznyak Michael , Gonzales Manuel , Gaither Thomas W.
Published: July 2024

Background A growing number of men who have sex with men (MSM) utilise Grindr for seeking relationships and immediate/casual sexual encounters. Grindr and other mobile applications can be a valuable source of information on sociological predictors of health. One topic that is under reported is the use of Grindr by MSM with obesity. We described differences in Grindr use between MSM with and without obesity, and to use Grindr information to reveal trends which may serve as potential predictors of health. Methods Data was collected from 3744 Grindr users (mean age [s.d.], 32.3 years [9.1]) from the largest 50 metropolitan centres in the USA between February and May 2018. Users were divided into two cohorts based on BMI: (1) MSM with obesity (BMI > 30), n = 253; and (2) MSM without obesity, n = 3491. Profile characteristics were compared. Results When evaluating potential predictors for obesity, we found that black/African-American and older MSM were significantly more likely to have obesity. Further, we found that obesity among MSM was significantly inversely associated with the population percent lesbian, gay, bisexual, and transgender (LGBT) within a city. Additionally, we found that MSM with obesity were significantly more likely to indicate interest in immediate sexual encounters. Conclusions These results highlight important trends that may serve as predictors of health in urban settings. Furthermore, our results suggest that MSM with obesity may be more likely to engage in risky sexual behaviours. These findings may be useful in informing providers and healthcare officials on when and how to provide outreach to this unique population.
First-line treatment with ceftriaxone for Neisseria gonorrhoeae infection less likely to be prescribed to patients with a penicillin allergy label: a retrospective audit of medical records
Authors: Durban E. , English K. , Evans R. , Martin S.
Published: July 2024

Background Gonorrhoea notifications have increased substantially in Australia over the past decade. Neisseria gonorrhoeae is already highly resistant to several antibiotics and so, alternatives to first-line treatment are generally strongly discouraged. The penicillin allergy label (AL) on patient medical records has previously been shown to influence prescribing practices, to the detriment of best-practice management and antimicrobial stewardship. This study aimed to understand how the penicillin AL influences antibiotic selection for gonorrhoea treatment at Canberra Sexual Health Centre. Methods A retrospective chart audit of gonorrhoea cases treated at Canberra Sexual Health Centre between January 2020 and October 2023 (n = 619 patients, n = 728 cases). Antibiotic selection was assessed according to penicillin AL status. Ceftriaxone selection was assessed according to penicillin allergy severity reported in the medical records and as determined using a validated antibiotic allergy assessment tool. Results Cases with a penicillin AL were more likely to receive antibiotics other than ceftriaxone (n = 7/41, 17.1%) than cases without the label (n = 8/687, 1.2%, P < 0.000). Most penicillin ALs had non-specific severity ratings in the medical records, but had insufficient information (n = 28/41, 68.3%) to apply the assessment tool. Those reported as low-severity in the records were more likely to receive ceftriaxone (n = 21/22, 95.5%) than those reported as moderate–high (n = 7/11, 63.6%) or unreported (n = 6/8, 0.75%). Conclusions Treatment of gonorrhoea in outpatient settings requires an understanding of penicillin allergy, and the ability to quickly and accurately identify penicillin-AL patients who can safely tolerate ceftriaxone. Institutionally endorsed penicillin allergy de-labelling protocols and access to easy-to-navigate prescribing advice within national sexually transmitted infection management guidelines would support this.
Hypermetabolic state is associated with circadian rhythm disruption in mouse and human cancer cells
Authors: Iascone Daniel Maxim , Zhang Xue , Brafford Patricia , Mesaros Clementina , Sela Yogev , Hofbauer Samuel , Zhang Shirley L. , Madhwal Sukanya , Cook Kieona , Pivarshev Pavel , Stanger Ben Z. , Anderson Stewart , Dang Chi V. , Sehgal Amita
Published: July 2024

Crosstalk between metabolism and circadian rhythms is a fundamental building block of multicellular life, and disruption of this reciprocal communication could be relevant to disease. Here, we investigated whether maintenance of circadian rhythms depends on specific metabolic pathways, particularly in the context of cancer. We found that in adult mouse fibroblasts, ATP levels were a major contributor to signal from a clock gene luciferase reporter, although not necessarily to the strength of circadian cycling. In contrast, we identified significant metabolic control of circadian function across a series of pancreatic adenocarcinoma cell lines. Metabolic profiling of congenic tumor cell clones revealed substantial diversity among these lines that we used to identify clones to generate circadian reporter lines. We observed diverse circadian profiles among these lines that varied with their metabolic phenotype: The most hypometabolic line [exhibiting low levels of oxidative phosphorylation (OxPhos) and glycolysis] had the strongest rhythms, while the most hypermetabolic line had the weakest rhythms. Pharmacological enhancement of OxPhos decreased the amplitude of circadian oscillation in a subset of tumor cell lines. Strikingly, inhibition of OxPhos enhanced circadian rhythms only in the tumor cell line in which glycolysis was also low, thereby establishing a hypometabolic state. We further analyzed metabolic and circadian phenotypes across a panel of human patient-derived melanoma cell lines and observed a significant negative association between metabolic activity and circadian cycling strength. Together, these findings suggest that metabolic heterogeneity in cancer directly contributes to circadian function and that high levels of glycolysis or OxPhos independently disrupt circadian rhythms in these cells.
Drosophila
neuronal Glucose-6-Phosphatase is a modulator of neuropeptide release that regulates muscle glycogen stores via FMRFamide signaling
Authors: Miyamoto Tetsuya , Hedjazi Sheida , Miyamoto Chika , Amrein Hubert
Published: July 2024

Neuropeptides (NPs) and their cognate receptors are critical effectors of diverse physiological processes and behaviors. We recently reported of a noncanonical function of the
Drosophila Glucose-6-Phosphatase
(
G6P
) gene in a subset of neurosecretory cells in the central nervous system that governs systemic glucose homeostasis in food-deprived flies. Here, we show that
G6P-
expressing neurons define six groups of NP-secreting cells, four in the brain and two in the thoracic ganglion. Using the glucose homeostasis phenotype as a screening tool, we find that neurons located in the thoracic ganglion expressing FMRFamide NPs (

FMRFa
G6P

neurons) are necessary and sufficient to maintain systemic glucose homeostasis in starved flies. We further show that
G6P
is essential in

FMRFa
G6P

neurons for attaining a prominent Golgi apparatus and secreting NPs efficiently. Finally, we establish that
G6P-
dependent FMRFa signaling is essential for the build-up of glycogen stores in the jump muscle which expresses the receptor for FMRFamides. We propose a general model in which the main role of
G6P
is to counteract glycolysis in peptidergic neurons for the purpose of optimizing the intracellular environment best suited for the expansion of the Golgi apparatus, boosting release of NPs and enhancing signaling to respective target tissues expressing cognate receptors.
A social foraging trade-off in echolocating bats reveals that they benefit from some conspecifics but are impaired when many are around
Authors: Krivoruchko Ksenia , Koblitz Jens C. , Goldshtein Aya , Biljman Katarina , Guillén-Servent Antonio , Yovel Yossi
Published: July 2024

Social foraging is very common in the animal kingdom. Numerous studies have documented collective foraging in various species and many reported the attraction of various species to foraging conspecifics. It is nonetheless difficult to quantify the benefits and costs of collective foraging, especially in the wild. We examined the benefits and costs of social foraging using on-board microphones mounted on freely foraging
Molossus nigricans
bats. This allowed us to quantify the bats’ attacks on prey and to assess their success as a function of conspecific density. We found that the bats spent most of their time foraging at low conspecific densities, during which their attacks were most successful in terms of prey items captured per time unit. Notably, their capture rate dropped when conspecific density became either too high or too low. Our findings thus demonstrate a clear social foraging trade-off in which the presence of a few conspecifics probably improves foraging success, whereas the presence of too many impairs it.
Mitochondrial antioxidants abate SARS-COV-2 pathology in mice
Authors: Guarnieri Joseph W. , Lie Timothy , Albrecht Yentli E. Soto , Hewin Peter , Jurado Kellie A. , Widjaja Gabrielle A. , Zhu Yi , McManus Meagan J. , Kilbaugh Todd J. , Keith Kelsey , Potluri Prasanth , Taylor Deanne , Angelin Alessia , Murdock Deborah G. , Wallace Douglas C.
Published: July 2024

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection inhibits mitochondrial oxidative phosphorylation (OXPHOS) and elevates mitochondrial reactive oxygen species (ROS, mROS) which activates hypoxia-inducible factor-1alpha (HIF-1α), shifting metabolism toward glycolysis to drive viral biogenesis but also causing the release of mitochondrial DNA (mtDNA) and activation of innate immunity. To determine whether mitochondrially targeted antioxidants could mitigate these viral effects, we challenged mice expressing human angiotensin-converting enzyme 2 (ACE2) with SARS-CoV-2 and intervened using transgenic and pharmacological mitochondrially targeted catalytic antioxidants. Transgenic expression of mitochondrially targeted catalase (mCAT) or systemic treatment with EUK8 decreased weight loss, clinical severity, and circulating levels of mtDNA; as well as reduced lung levels of HIF-1α, viral proteins, and inflammatory cytokines. RNA-sequencing of infected lungs revealed that mCAT and Eukarion 8 (EUK8) up-regulated OXPHOS gene expression and down-regulated HIF-1α and its target genes as well as innate immune gene expression. These data demonstrate that SARS-CoV-2 pathology can be mitigated by catalytically reducing mROS, potentially providing a unique host-directed pharmacological therapy for COVID-19 which is not subject to viral mutational resistance.
Physics of microscale freeform 3D printing of ice
Authors: Garg Akash , Yang Feimo , Ozdoganlar O. Burak , LeDuc Philip R.
Published: July 2024

Ice is emerging as a promising sacrificial material in the rapidly expanding area of advanced manufacturing for creating precise 3D internal geometries. Freeform 3D printing of ice (3D-ICE) can produce microscale ice structures with smooth walls, hierarchical transitions, and curved and overhang features. However, controlling 3D-ICE is challenging due to an incomplete understanding of its complex physics involving heat transfer, fluid dynamics, and phase changes. This work aims to advance our understanding of 3D-ICE physics by combining numerical modeling and experimentation. We developed a 2D thermo-fluidic model to analyze the transition from layered to continuous printing and a 3D thermo-fluidic model for the oblique deposition, which enables curved and overhang geometries. Experiments are conducted and compared with model simulations. We found that high droplet deposition rates enable the continuous deposition mode with a sustained liquid cap on top of the ice, facilitating smooth geometries. The diameter of ice structures is controlled by the droplet deposition frequency. Oblique deposition causes unidirectional spillover of the liquid cap and asymmetric heat transfer at the freeze front, rotating the freeze front. These results provide valuable insights for reproducible 3D-ICE printing that could be applied across various fields, including tissue engineering, microfluidics, and soft robotics.
Substantial increase in perfluorocarbons CF
4
(PFC-14) and C
2
F
6
(PFC-116) emissions in China
Authors: An Minde , Prinn Ronald G. , Western Luke M. , Yao Bo , Zhao Xingchen , Kim Jooil , Mühle Jens , Chi Wenxue , Harth Christina M. , Hu Jianxin , Ganesan Anita L. , Rigby Matthew
Published: July 2024

The perfluorocarbons tetrafluoromethane (CF
4
, PFC-14) and hexafluoroethane (C
2
F
6
, PFC-116) are potent greenhouse gases with near-permanent atmospheric lifetimes relative to human timescales and global warming potentials thousands of times that of CO
2
. Using long-term atmospheric observations from a Chinese network and an inverse modeling approach (top–down method), we determined that CF
4
emissions in China increased from 4.7 (4.2-5.0, 68% uncertainty interval) Gg y
−1
in 2012 to 8.3 (7.7-8.9) Gg y
−1
in 2021, and C
2
F
6
emissions in China increased from 0.74 (0.66-0.80) Gg y
−1
in 2011 to 1.32 (1.24-1.40) Gg y
−1
in 2021, both increasing by approximately 78%. Combined emissions of CF
4
and C
2
F
6
in China reached 78 Mt CO
2
-eq in 2021. The absolute increase in emissions of each substance in China between 2011-2012 and 2017-2020 was similar to (for CF
4
), or greater than (for C
2
F
6
), the respective absolute increase in global emissions over the same period. Substantial CF
4
and C
2
F
6
emissions were identified in the less-populated western regions of China, probably due to emissions from the expanding aluminum industry in these resource-intensive regions. It is likely that the aluminum industry dominates CF
4
emissions in China, while the aluminum and semiconductor industries both contribute to C
2
F
6
emissions. Based on atmospheric observations, this study validates the emission magnitudes reported in national bottom–up inventories and provides insights into detailed spatial distributions and emission sources beyond what is reported in national bottom–up inventories.
The health risk of social disadvantage is transplantable into a new host
Authors: Turcotte Lucie M. , Wang Tao , Beyer Kirsten M. , Cole Steven W. , Spellman Stephen R. , Allbee-Johnson Mariam , Williams Eric , Zhou Yuhong , Verneris Michael R. , Rizzo J. Douglas , Knight Jennifer M.
Published: July 2024

Low socioeconomic status (SES) is a risk factor for mortality and immune dysfunction across a wide range of diseases, including cancer. However, cancer is distinct in the use of allogeneic hematopoietic cell transplantation (HCT) as a treatment for hematologic malignancies to transfer healthy hematopoietic cells from one person to another. This raises the question of whether social disadvantage of an HCT cell donor, as assessed by low SES, might impact the subsequent health outcomes of the HCT recipient. To evaluate the cellular transplantability of SES-associated health risk, we analyzed the health outcomes of 2,005 HCT recipients who were transplanted for hematologic malignancy at 125 United States transplant centers and tested whether their outcomes differed as a function of their cell donor’s SES (controlling for other known HCT-related risk factors). Recipients transplanted with cells from donors in the lowest quartile of SES experienced a 9.7% reduction in overall survival (
P
= 0.001) and 6.6% increase in treatment-related mortality within 3 y (
P
= 0.008) compared to those transplanted from donors in the highest SES quartile. These results are consistent with previous research linking socioeconomic disadvantage to altered immune cell function and hematopoiesis, and they reveal an unanticipated persistence of those effects after cells are transferred into a new host environment. These SES-related disparities in health outcomes underscore the need to map the biological mechanisms involved in the social determinants of health and develop interventions to block those effects and enhance the health of both HCT donors and recipients.
‘What we found is’
Authors: Berthe Florine , Fetzer Anita , Gaudy-Campbell Isabelle
Published: July 2024

This paper examines two variants of the pseudo-cleft construction which display a WHAT-NP-VP-be pattern with the
VP realised with cognitive verbs and the proform do in the context of spoken British English dyadic and
multi-party BBC podcasts. It is based on the premise that the construction’s referencing potentials are both cataphoric and
projective, and that depending on its contexts, one of the two referencing functions is foregrounded while the other is
backgrounded. The analysis focuses on those linguistic features and contextual configurations which either contribute to its
cataphoric referencing function, or which go beyond the local cataphoric referencing function and indicate its projective,
discourse-organising function. The research is corpus-based and uses quantitative and qualitative methodologies, filtering out the
linguistic features and contextual configurations which contribute to assigning the two variants the status of a projective
construction with a discourse-organising function. The features under investigation are (1) the semantics of the constitutive NPs
and VPs marking for tense, aspect and modality and their uptake in the discourse, (2) degrees of continuity and discontinuity in
the cohesive chains triggered by the constitutive parts of the construction. The paper shows that when semantic continuity between
the what-clause and what follows is discontinued and thus deferred, the construction’s projective function is
foregrounded.
UBAP2L contributes to formation of P-bodies and modulates their association with stress granules
Authors: Riggs Claire L. , Kedersha Nancy , Amarsanaa Misheel , Zubair Safiyah Noor , Ivanov Pavel , Anderson Paul
Published: July 2024

Stress triggers the formation of two distinct cytoplasmic biomolecular condensates: stress granules (SGs) and processing bodies (PBs), both of which may contribute to stress-responsive translation regulation. Though PBs can be present constitutively, stress can increase their number and size and lead to their interaction with stress-induced SGs. The mechanism of such interaction, however, is largely unknown. Formation of canonical SGs requires the RNA binding protein Ubiquitin-Associated Protein 2-Like (UBAP2L), which is a central SG node protein in the RNA–protein interaction network of SGs and PBs. UBAP2L binds to the essential SG and PB proteins G3BP and DDX6, respectively. Research on UBAP2L has mostly focused on its role in SGs, but not its connection to PBs. We find that UBAP2L is not solely an SG protein but also localizes to PBs in certain conditions, contributes to PB biogenesis and SG–PB interactions, and can nucleate hybrid granules containing SG and PB components in cells. These findings inform a new model for SG and PB formation in the context of UBAP2L’s role.
Anisotropic conformal change of conic pseudo-Finsler surfaces, I*
Authors: Youssef Nabil L , Elgendi S G , Kotb A A , Taha Ebtsam H
Published: July 2024

The present work is devoted to investigate anisotropic conformal transformation of conic pseudo-Finsler surfaces (M, F), that is,

F
(
x
,
y
)
⟼

F
―

(
x
,
y
)
=

e

ϕ
(
x
,
y
)

F
(
x
,
y
)

, where the function

ϕ
(
x
,
y
)

depends on both position x and direction y, contrary to the ordinary (isotropic) conformal transformation which depends on position only. If F is a pseudo-Finsler metric, the above transformation does not yield necessarily a pseudo-Finsler metric. Consequently, we find out necessary and sufficient condition for a (conic) pseudo-Finsler surface (M, F) to be transformed to a (conic) pseudo-Finsler surface

(
M
,

F
―

)

under the transformation

F
―

=

e

ϕ
(
x
,
y
)

F

. In general dimension, it is extremely difficult to find the anisotropic conformal change of the inverse metric tensor in a tensorial form. However, by using the modified Berwald frame on a Finsler surface, we obtain the change of the components of the inverse metric tensor in a tensorial form. This progress enables us to study the transformation of the Finslerian geometric objects and the geometric properties associated with the transformed Finsler function

F
―

. In contrast to isotropic conformal transformation, we have a non-homothetic conformal factor

ϕ
(
x
,
y
)

that preserves the geodesic spray. Also, we find out some invariant geometric objects under the anisotropic conformal change. Furthermore, we investigate a sufficient condition for

F
―

to be dually flat or/and projectively flat. Finally, we study some special cases of the conformal factor

ϕ
(
x
,
y
)

. Various examples are provided whenever the situation needs.
Stabilisation of the swing pattern of an anisotropic simple pendulum
Authors: McGlynn E , Saracut C , Cafolla A A
Published: July 2024

The suppression of the effects of anisotropy on a pendulum by use of a rotating mount was initially envisaged by Léon Foucault, based on his observations of the vibrations of a rod clamped in a lathe. However, the method seems to never have been tried due to the practical difficulties involved. We report a computational study of the stabilisation of the swing pattern of a simple pendulum, showing anisotropic behaviour in a static configuration, by rotation of the system mount. When the mount is static, for most initial conditions the swing patterns quickly evolves into unstable, complex Lissajous-like patterns. When the pendulum mount is rotated faster than the pendulum frequency effects of anisotropy are suppressed, and the swing pattern stabilises to that of an isotropic 3D simple pendulum. Suppression of mount anisotropy influence occurs for relatively low rotation rates. We also study swing evolution in the presence of random variations in the orientation of the mount principal axes. The use of computational techniques confirms Foucault’s original observations and hypothesis and provides an interesting avenue for students to engage meaningfully with this historically important and inspiring experiment in a novel and challenging manner.
Investigation of laser-assisted micromachining of NiTi SMA bimorph based actuators toward developing optical shutters
Authors: Gangwar Kaushal , Pandiyan Kailaash , Iyamperumal Anand Palani
Published: July 2024

This work explores laser-assisted micromachining for the precision cutting of NiTi shape memory alloy (SMA)-based bimorph in a single-pass laser scan. SMA thin film based optical shutters were developed with this method, which can generate the opening and closing via Joule’s heating rather than mechanical components. NiTi SMA bimorph was fabricated using the e-beam evaporation technique followed by micromachining using a 1064 nm fiber laser. The influence of laser power (LP), laser speed (LS), spot diameter (SP), and laser travel direction on kerf width and heat-affected zone after micromachining was studied using the design of experiments. The optimized parameter for micromachining was at LP 5 W with 5 mm s−1 LS and 50 μm SP. Various shapes were cut at the optimized parameter, including an optical shutter of a diameter of 30 mm. A LS of 6 mm s−1 has produced microchannels in the bimorph due to NiTi film removal only. The SEM analysis of the shutter reveals the formation of refined grains at micromachined edges compared to the center of the actuator. Fabricated optical shutter shows negligible optical transmittance in the 450–700 nm wavelength range.
Low energy elastic and inelastic scattering of positrons from formic acid
Authors: Stevens D , Datar Aaditya , Cheong Z , Sullivan J P
Published: July 2024

This paper presents a detailed study of low energy positron scattering from formic acid, examining elastic scattering, electronic excitation and ionisation processes. Through detailed comparisons with previous experimental and theoretical data, it is clear that the picture for positron scattering from this target remains incomplete, with significant disagreement between experiment and theory in the comparisons of differential cross section data. Calculations of elastic electron scattering are unexpectedly in better agreement with the positron scattering experiments, and give some hints as to potential areas for improvement in the modelling of scattering for targets which tend to be dominated by dipole interactions.
Mn-based noncollinear antiferromagnets and altermagnets
Authors: Chen Shaohai , Lin Dennis J X , Lim B C , Ho Pin
Published: July 2024

Antiferromagnets and altermagnets, with robustness, scalability and topological properties, emerge as promising contenders for next-generation spintronics, quantum and terahertz communication applications. Recent strides in Mn-based noncollinear antiferromagnetic (AF) and altermagnetic (AL) material platforms showcase remarkable progress and fascinating discoveries, such as in spin–orbit and tunnelling phenomena, affirming the viability of AF and AL-centric spintronic devices. This review explores the latest advancements in noncollinear Mn3X (X= Pt, Ir, Sn, Ga, Ge) AF and MnY (Y = F2, O2, Si0.6, Te) AL materials, wherein the quintessential phenomena originate from their intricate crystal structures. For the former, the article delves into their growth techniques, physical properties, as well as advancements in the electrical manipulation of AF order and multimodal electrical, optical, and thermal detection. For the latter, the review encapsulates theoretical understanding and experimental demonstration of AL materials and device physics pertinent to promising applications. This serves to direct efforts towards the imminent realization of AF and AL active elements in replacement of conventional ferromagnetic materials in spintronic devices.
Chemical pressure induced spin reorientation in the magnetic structure of

Ca
3

Mn

2
−
x

Sn
x

O
7

(

x
=
0
,
0.03
,
0.05

)
Authors: Mohan Ashwin , S Vaidya Salil , Jain Anil , Yusuf S M
Published: July 2024

The effect of partially substituting Tin (Sn) at the Manganese (Mn) site of

Ca
3

Mn
2

O
7

, viz.

Ca
3

Mn

2
−
x

Sn
x

O
7

with

x
=
0.03
,
0.05

, on its structural and magnetic properties have been investigated using synchrotron diffraction, neutron diffraction, and bulk magnetization measurements. It is observed that with a substitution of

x
=
0.03

, the minor (≈8%) tetragonal (

I
4

/

m
m
m

) structural phase that is present in the predominantly orthorhombic (

C
m
c

2
1

) undoped

Ca
3

Mn
2

O
7

, completely disappears. The compounds order antiferromagnetically, the ordering temperature decreases with increasing Sn-content, indicating a weakening of the antiferromagnetic exchange interactions. Interestingly, in the ordered state, the spin magnetic moments which were aligned along the a-axis of the unit cell in the undoped compound, are observed to have reoriented with their major components lying in the b − c plane in the Sn-doped compounds. The above influence of Sn-doping is seen to be stemming from a significant modification of the octahedral rotation and tilt mode geometry in the unit cell, that is known to be responsible for driving ferroelectricity in these compounds.
Improving the ambiguity resolution with the consideration of unmodeled errors in GNSS medium and long baselines
Authors: Wang Jiafu , Yu Xianwen
Published: July 2024

Ambiguity resolution (AR) is fundamental to achieve high-precision solution in global navigation satellite system relative positioning. Extensive research has shown that systematic errors are associated with the performance of AR. However, due to the physical complexity, some systematic errors would inevitably remain in the observation equations even after processed with some popular models and parameterization. In the medium and long baselines, these unmodeled errors are the leading cause of the slow or even incorrect fixation of ambiguity. Therefore, to improve the AR performance in the medium and long baselines, we present a procedure with the careful consideration of unmodeled errors. At first, we develop a method to estimate the unmodeled errors based on the float ambiguity bias. Then, the overall procedure and key steps to fix the float solutions corrected by the unmodeled error estimate is designed. Finally, some real-measured baselines (from 68 km to 120 km) are utilized to validate the proposed procedure. The experimental results are analyzed and discussed from the aspects of AR and positioning, respectively. For the AR performance, the time required for the first fixing have been reduced by about 41.58%–83.51%, from 12 to 100 min. Besides, 12.72%–48.59% and 2.96%–36.28% improvements of the ambiguity-fixed rate and the ambiguity-correct rate can be respectively obtained in the four baselines. As for the positioning performance, the mean values and RMSEs have improved by 0.2–4.8 cm (1.63%–22.43%) and 0.2–2.8 cm (1.47%–10.57%), respectively.
Research on transformer based online condition monitoring method for IPM
Authors: Tang Shengxue , Zhao Jinze , Tan Liqiang , Yan Jinjing
Published: July 2024

The Intelligent Power Module (IPM) has the integrated packaging, leading to the advantages of convenient use, safety and reliability. However, once it fails, it will cause the whole power supply system to be inoperative, and it is necessary to perform online Condition Monitoring (CM) of the IPM. In this paper, we extract the aging characteristics such as dynamic equivalent resistance, peak-to-peak value, switching frequency, and turn-off time only from the voltage and current of IPM drain–source port, and then propose a non-intrusive online CM method for the IPM based on the transformer neural network (TNN). We analyse the internal aging mechanism of the IPM, the changing law of aging features, and construct multi-dimensional aging fusion features, and then the TNN model is used to monitor early parameters drift of multi-dimensional fusion feature vectors and realize the accurate online prediction of IPM health condition. The experimental analysis results show that the fault prediction accuracy reaches 96%, and can realize the health CM under the condition of noise interference, weak aging features and few external observable points.
High-precision tropospheric correction method for NRTK regions with significant height differences
Authors: Lei Xiaoting , Xu Xiaolong , Tao Jun , Yang Tianyu , Zhao Qile , Guo Jing
Published: July 2024

In response to the issue of poor network real-time kinematic (NRTK) service performance in regions with significant height differences, an improved tropospheric height correction (ITHC) method is proposed. Precise point positioning (PPP) is employed to compute the troposphere delay at base stations. Subsequently, a tropospheric vertical profile fitting model (TVPFM) is established for the vertical reduction of the troposphere in regions with significant height differences. In this case, the tropospheric errors introduced by the height differences between the base and rover stations can be calculated. Finally, the tropospheric error can be corrected during the generation of virtual observations, ensuring high-accuracy positioning of NRTK rovers. With the troposphere delay computed based on the PPP approach, datum errors introduced by inaccurate tropospheric correction methods are mitigated. To reduce the dependence of the troposphere delay on height, ECMWF reanalysis v5 (ERA5) data are employed to fit the TVPFM. Experimental analysis demonstrates that the troposphere exhibits distinct vertical variation characteristics, allowing for its segmentation into three layers. Consequently, a piecewise TVPFM is established. Observations obtained from the continuously operating reference stations network located in Yunnan, China, are utilized for validation. The selected stations exhibit a maximum height difference of approximately 2 km. The experimental results exhibit a notable enhancement in correction accuracy with the ITHC in comparison to conventional correction methodologies. Specifically, the ambiguity fixing rate demonstrates a noteworthy improvement of 13.3%, accompanied by a substantial increase in positioning accuracy by 51.4%.