bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relationship between respiratory symptoms and frailty: findings from observational and Mendelian randomization analyses
Authors: Ruan Zhishen , Li Dan , Cong Xiaodong , Yuan Shasha , Fan Yiling , Xu Bo , Miao Qing 
Published: December 2024

Abstract
Introduction
As ageing accelerates, frailty increasingly impacts public health. Cough, sputum, wheezing and dyspnea are common respiratory symptoms, and the relationship to frailty is unclear. We aimed to analyze the relationship between respiratory symptoms and frailty.

Methods
Cross-sectional and Mendelian randomization (MR) studies were used. Cross-sectional data involved 14,021 participants from the National Health and Nutrition Examination Survey (NHANES). Logistic and linear regression were used to analyze the relationship between respiratory symptoms (cough, sputum, wheezing, dyspnea) and frailty. We adjusted for multiple variables and used propensity score matching (PSM). Mediation analysis was used to explore the role of inflammatory markers and age in the relationship between the two. We analyzed the relationship using a two-sample MR approach with data from genome-wide association studies (GWAS) to enhance causal inference.

Results
Observational studies have shown that cough (OR 1.74, 95 CI% 1.44, 2.09), sputum (OR 1.87, 95 CI% 1.57, 2.22), wheezing (OR 2.01, 95 CI% 1.68, 2.40), and dyspnea (OR 2.60, 95 CI% 2.28, 2.97) are associated with an elevated risk of frailty. The PSM results were stable. Mediation analyses indicated that elevated inflammatory markers and advancing age were mediators between respiratory symptoms and frailty. The results of the MR study showed that sputum and wheezing were associated with an elevated frailty index; and in the study of FI on respiratory symptoms, all respiratory symptoms were elevated with elevated FI.

Conclusions
Our study identified a potential association between frailty and respiratory symptoms. Inflammation and ageing may be essential factors mediating this association.
Extend the ProFamy cohort-component method to conduct probabilistic households and living arrangement projections
Authors: Zeng Yi , Wang Zhenglian , Feng Qiushi , Gu Danan , Zhang Junni , Tang Wei , Land Kenneth 
Published: December 2024

AbstractIn this commentary, we first briefly review the significant utilities of household and living arrangement projections and the main types of methods for conducting household projections. In the second and third sections, we summarize basic ideas, data needed, assessments and applications of ProFamy extended cohort-component methods/software for households and living arrangement projections; and we emphasize the importance to extend the ProFamy methods and software from deterministic to probabilistic households and living arrangement projections. In section 4, we demonstrate that the ProFamy approach provides an adequate and highly feasible modelling framework to extend probabilistic households and living arrangement projections (PHPs), in which the population size/structure projection outcomes are in consistence with those of probabilistic population projections (PPPs) released by United Nations Population Division (UNPD). In the last Section, we discuss and recommend applying the user-friendly R package DemoRates of ProFamy software to estimate rural/urban (or race)-sex-age-specific standard schedules and the demographic summary measures, to conduct analyses and projections, such as single-parent households, caregivers, and care needs/costs for disabled older adults, age-friendly housing and households-based energy demands, etc. for healthy aging and sustainable development studies. Finally, we discuss the prospects of our ongoing international collaborative research project to substantially extend ProFamy cohort-component method from deterministic into probabilistic households and living arrangement projection (PHPs). As compared with ProFamy deterministic projection method, the PHPs produces a lot of additional outcomes of probabilistically projected households and living arrangements in 2021–2100 with uncertainty intervals that are crucial for healthy aging and sustainable development studies.
Balance between photoreduction efficiency, cofactor affinity, and allosteric coupling of halogenase flavoenzymes
Authors: Diepold Niklas , Reese Friederike , Prior Tina , Schnepel Christian , Sewald Norbert , Kottke Tilman 
Published: December 2024

Abstract
Flavin-dependent halogenases (FDHs) are promising candidates for the sustainable production of halogenated organic molecules by biocatalysis. FDHs require only oxygen, halide and a fully reduced flavin adenine dinucleotide (FADH−) cofactor to generate the reactive HOX that diffuses 10 Å to the substrate binding pocket and enables regioselective oxidative halogenation. A key challenge for the application of FDHs is the regeneration of the FADH−. In vitro, FADH− can be regenerated by photoreduction of the oxidized FAD inside the protein using blue light, turning the halogenase into an inefficient artificial photoenzyme. We aimed to improve the photochemical properties of the tryptophan 5-halogenase PyrH from Streptomyces rugosporus by structure-guided mutagenesis. W279 and W281 of the conserved WxWxIP-motif close to FAD were exchanged against phenylalanine. Time-resolved UV-vis spectroscopy showed that the W281F exchange indeed increased the quantum yield of the one- and two-electron reduction, respectively. The cofactor binding affinity decreased slightly with dissociation constants rising from 31 to 74 μM, as examined by fluorescence anisotropy. FTIR difference spectroscopy demonstrated that the allosteric coupling between the FAD and substrate binding sites was mostly preserved. In contrast, the double mutant did not improve the yield further, while negatively affecting binding affinity and structural coupling. The distal W279F exchange was less effective in all parameters. Photoreductions were additionally delayed by a reversible inactive conformation. We conclude that there is a delicate balance to be considered for screening of FDHs for biocatalysis. Variant PyrH-W281F was found to be the most promising candidate for the application as artificial photoenzyme.

Graphical abstract
Tectono‐Geomorphic Features Related to the 1606 Jianshui Earthquake in the Southernmost Segment of the Xiaojiang Fault System, SE Tibet
Authors: Dong Shaopeng , Han Zhujun , Guo Peng , Hu Nan , Tan Xibin , Xie Zhangdi , Ran Hongliu 
Published: December 2024

AbstractThe activity and seismicity of the southern segment of the Xianshuihe‐Xiaojiang fault system (XXFS) are both crucial for differentiating kinematic models along the southeastern margin of the Tibetan Plateau. Based on tectono‐geomorphic interpretations of optical imagery, digital elevation model (DEM)‐derived hillshades, contour maps, and field observations of geomorphic features, we document a surface rupture zone with a maximum length of ∼75 km and a maximum offset of ∼6.8 m along the Jianshui fault (JSF) in the southern segment of the XXFS. By correlating geologic, chronological, and historical data, we suggest that an Mw 7.1–7.9 earthquake occurred on 30 November 1606, along the JSF that was previously considered as a minimal active fault, and the magnitude of this earthquake was cited as M63/4. A large surface offset and relatively short rupture length are likely related to the immaturity of the JSF, and this also implies southeastward growth of the SE Tibetan Plateau during the late Quaternary.
Revisiting the 10th‐Century Eldgjá Eruption: Modeling the Climatic and Environmental Impacts
Authors: Fuglestvedt Herman F. , Gabriel Imogen , Sigl Michael , Thordarson Thorvaldur , Krüger Kirstin 
Published: December 2024

AbstractThe 10th‐century Eldgjá eruption in Iceland is the largest basaltic flood lava eruption of the Common Era. However, the extent of its impacts is unclear due to limited historical records. Combining volcanology and ice‐core analyses from both recent and earlier studies, we present a gas emissions scenario for the Eldgjá eruption spanning 937 to 940 CE, co‐injecting volcanic sulfur and halogens. The combined tropospheric and stratospheric sulfur emissions are 3–8 times higher than those adopted for Eldgjá in existing paleoclimate simulations. Earth system modeling of this scenario under pre‐industrial conditions reveals a compound event with maximum northern extratropics surface cooling of C in summer‐autumn of 939 and 940 CE, prolonged Arctic sea ice growth, and large‐scale precipitation changes, concurrent with stratospheric ozone depletion and elevated pollution. These results imply that the combined climatic and environmental effects of the Eldgjá eruption may have significantly impacted human populations at the time.
Antarctic Wide Subglacial Hydrology Modeling
Authors: Ehrenfeucht Shivani , Dow Christine , McArthur Koi , Morlighem Mathieu , McCormack Felicity S. 
Published: December 2024

AbstractGlobal sea levels are rising due, in large part, to the increase in the rate of melting of ice sheets as a direct result of climate change. A large fraction of uncertainty in future sea level rise comes from limited understanding of basal conditions under ice sheets. Specifically, subglacial hydrology, which describes the volume and movement of meltwater underneath glaciers and resulting basal water pressures. This system exerts a strong control on ice basal sliding and the rate of ice shelf melt, both of which can destabilize glaciers and lead to enhanced sea level rise. Here, we present subglacial hydrology model results of the full Antarctic Ice Sheet derived using the Glacier Drainage System model. We examine water pressures of the distributed drainage system, the distribution of the channelized system, and freshwater discharge across grounding lines of major drainage basins in the steady state subglacial system under present day conditions.
Sea Ice Modulates Air–Sea Methane Flux in the Southern Ocean
Authors: Zhang Gong , Yang Qinghua , Han Bo , Prytherch John , Thornton Brett F. , Chen Dake 
Published: December 2024

AbstractThe Southern Ocean (SO) is predicted to be a weak sink for atmospheric CH4, although the magnitude is uncertain due to a lack of observations of the marginal ice zone (MIZ). Using both eddy covariance and bulk formula flux measurements from the icebreaker R/V Xuelong2, we found that the eastern SO during an austral summer was a sink for CH4. The strongest downward CH4 fluxes occurred in areas of low sea ice concentration (10%–40%), where sea‐ice melting resulted in low temperature and salinity, increasing CH4 solubility. The CH4 fluxes are weak in regions of high sea ice concentration (>50%) due to the blocking effect of sea ice. We estimate that the uptake of CH4 during one summer month in the study region offsets 1.2%–2.6% of annual global oceanic CH4 emissions. Suggesting that the Antarctic MIZ is more important in the global CH4 budget than previously thought.
Slip Deficit Rate and Seismic Potential on Crustal Faults in Tibet
Authors: Li Yanchuan , Shan Xinjian , Qu Chunyan , Zhang Guohong , Wang Xuening , Xiong Haicheng 
Published: December 2024

AbstractQuantifying slip deficit rates on active faults in Tibet is essential for understanding fault kinematics and assessing seismic hazards, but has not been fully characterized, particularly on secondary faults. In this study, we integrate an updated interseismic Global Navigation Satellite Systems velocity field from 4,458 stations across continental China and its surroundings to calculate surface strain rates in Tibet, which we then use to invert for slip deficit rates on 263 crustal faults (383 segments). Our results reveal that ∼73% of strain rates are due to elastic strain accumulation on fault planes, and only a portion of the remaining strain rates may originate from unmodeled fault deformation. Quantitative calculations of seismic moment budgets on these fault segments indicate that they can produce earthquakes ranging from Mw 5.8 to 8.6, with 43 segments capable of generating earthquakes of Mw ≥ 7.5. Our findings provide a foundation for probabilistic seismic hazard analysis in Tibet.
Saturation Characteristics of Multi‐Band EMIC Waves in the Inner Magnetosphere and Observational Evidence for the Second Saturation Process
Authors: Xue Zuxiang , Yuan Zhigang , Deng Dan , Yu Xiongdong 
Published: December 2024

AbstractThe wave amplitude is vital for quantifying the impact of electromagnetic ion cyclotron (EMIC) waves on inner magnetospheric dynamics. Previous numerical studies mainly focused on the evolution of total wave energy/amplitude, whose maximum is usually modeled as a function of initial conditions. Recent quasilinear theory analysis shows existence of a second saturation of multi‐band EMIC waves which exhibits a dip of the total amplitude, emphasizing the need for more precise band‐specific models. Through one‐dimensional hybrid simulations, we reproduce the second saturation phenomenon and separately model wave characteristics for H+‐ and He+‐bands waves, including the maximum amplitudes and the time to maximum as a function of the initial maximum growth rate. Moreover, new parameters for the anisotropy‐beta inverse correlation of hot protons are obtained at the second saturation stage. We further present an in situ observation that first demonstrates the existence of the second saturation.
Coupled Thermosphere‐Ionosphere Tongue‐Like Structure During the Recovery Phase of the Geomagnetic Storm on 12 May 2021
Authors: Yu Tingting , Ren Zhipeng , Zhao Biqiang , Pedatella Nicholas , Wei Yong , Li Shaoyang , Zhai Changzhi , Zhao Lingxin 
Published: December 2024

AbstractA coupled thermosphere‐ionosphere tongue‐like structure was observed in the daytime at middle latitudes by ground‐based Global Navigation Satellite System (GNSS) and Global‐scale Observations of the Limb and Disk (GOLD) observations during the storm recovery phase on 12 May 2021. The storm‐induced variations in total electron content (TEC) and the column density ratio of O to N2 (∑O/N2) both showed a relatively narrow region of enhancement in latitude, originating from low latitudes and surrounded by depleted regions. The concurrent neutral temperature observations also showed a tongue‐like decrease surrounded by temperature enhancements. The Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM) qualitatively reproduced the observed thermosphere‐ionosphere structure. The simulations indicate that the formation of the TEC tongue‐like structure was dominated by the enhanced ΣO/N2. Unlike the previously reported tongue of ionization (TOI) driven by E × B drifts, the tongue‐like structure occurred at relatively lower geomagnetic latitudes (∼30–∼65) and had a smaller magnitude of enhancement. This is the first time that the concurrent tongue‐like structures in thermospheric composition, temperature and electron density are observed, which advances the understanding of thermosphere‐ionosphere coupling.
The Geometrical Features of Magnetic Flux Entanglement Events Observed by MMS
Authors: Ahmad Nisar , Shen Chao , Ji Yong , E Peng , Rehman Umer , Yao Guang‐Rui , Li Xiao‐Jie , Zhao Ying‐Jie , Ji Yan‐Fang 
Published: December 2024

AbstractFlux transfer events are momentary occurrences of self‐adjusting, rope‐like magnetized plasma structures near Earth's magnetopause, typically associated with a southward interplanetary magnetic field direction. This study aims to investigate the magnetic structural characteristics during three phases (initial, intermediate and final) of magnetic flux entanglement events and explore magnetic field gradient properties. Using the Nonlinear Magnetic Field Gradient Algorithm (NMG), we computed magnetic field curvature, helix angle, and torsion. Our analysis revealed that the central current sheet consistently exhibits the highest magnetic field curvature throughout all phases, while the lowest curvature occurs elsewhere. Notably, a polarity reversal in the normal component of magnetic field curvature is observed during the intermediate phase. The helix angle exhibits its maximum variation on both sides of the central current sheet during the initial phase. In the intermediate phase, however, the variation of the helix angle around the current sheet is minimal. By the final phase, the magnitude of the helix angle behaves in a manner opposite to that of the initial phase. Torsion around the current sheet initially undergoes significant changes during the initial phase but remains close to zero afterward. Conversely, in the intermediate phase, the magnetic flux regime shows minimal torsion initially, followed by an abrupt variations afterward. Nonetheless, during final phase, the magnetic flux regimes display a consistent pattern of increasing and decreasing torsion similar to the initial phase. In summary, flux tubes precede the emergence of flux ropes in the initial phase, structures resembling flux ropes dominate the intermediate phase, and both coexist in the final phase. This investigation sheds light on the interconnected nature of these structures, critical for understanding particle and energy exchange between the magnetosphere and solar wind.
Constraints on the Seismogenic Stress Tensor in Northeastern South Island, New Zealand
Authors: Walbert Olivia Leigh , Hetland Eric Andreas 
Published: December 2024

AbstractThe seismogenic tensorial stresses in the crust beneath northeastern South Island, New Zealand that are responsible for the 2010 Darfield and 22 February 2011 Christchurch earthquakes of the Canterbury Plains, South Island, New Zealand are compatible with an Andersonian strike‐slip regime with a NW–SE trending most compressive stress. The stresses we infer from coseismic slip models of these two earthquakes are consistent with previous estimates of stress from earthquake focal mechanisms near the Alpine Fault. The strike‐slip stress regime of the Canterbury Plains differs from the thrust stress regime that we previously estimated from coseismic models of the 2016 Kaikōura earthquake. We demonstrate that loading due to thick sediment deposits overlying the crust of the Canterbury Plains is a sufficient mechanism to rotate the principal stresses from a background thrust regime to a strike‐slip regime, constraining the absolute tectonic stress in the northeast of South Island to most likely be 26 MPa, and no larger than 80 MPa.
Intermediate‐Volatility Organic Compounds (IVOCs) Emissions Based on Source‐Specific Emission Ratios Relative to NonMethane Volatile Organic Compounds (NMVOCs) Give Better Representation of the Spatial Distribution of IVOCs in China
Authors: Yang Ning , Wang Qiaoqiao , Xiong Qi , Fan Zeman , Liu Guangjin , Li Fan , Zhu Shaowen , Zhou Yaqing , Tao Jiangchuan , Hong Juan , Wang Hongli , Huang Cheng , Sun Yele , Cheng Yafang , Su Hang , Ma Nan 
Published: December 2024

AbstractIntermediate‐volatility organic compounds (IVOCs) and their contribution to secondary organic aerosols (SOA) in China are simulated in GEOS‐Chem with seven newly constructed IVOCs emission inventories (IEIs). The IEIs based on different references and source‐specific emission ratios show a large range of emissions in China (4.8–14 Tg yr−1) and also significant differences in major sources and spatial distributions. Among them, the IEI relative to nonMethane volatile organic compounds (NMVOCs) with a total emission of 12 Tg yr−1, dominated by solvent use, better captures observed spatial distributions of IVOCs and SOA. In contrast, IEIs relative to primary organic aerosols (POA) misinterpret the major sources and tend to have a negative bias in megacities even when the total emission is scaled up to 14 Tg yr−1. The study indicates that previous studies have underestimated IVOCs emission and hence the contribution to SOA. It also demonstrates the importance of using an appropriate reference to better represent the major sources and the spatial distribution of IVOCs.
On the Quantification of Thermodynamic Phases of Raining Clouds: Insights From Multi‐Year CloudSat and Ground‐Based Radar Observations Over Longmen, Southern China
Authors: Li Qinghui , Li Haoran , Sun Xuejin , Ruan Zheng , Liu Liping , Gao Wenhua , Liao Chenxi , Ding Han 
Published: December 2024

AbstractThe thermodynamic phase of clouds is fundamental to rain initiation and development. Although it is well established that majority of rainfall from mid‐ to‐high latitudes originates from ice, there is a lack of consensus on the major thermodynamic phase of raining clouds over low latitudes. Previous CloudSat‐based studies have yet reached consistent results on the fraction of ice‐phase raining clouds over Southern China. In this work, we found that CloudSat‐based approaches are subject to metrics used for flagging rainfall events, which may lead to different estimates. Analysis of multi‐year surface radar observations suggests that has diurnal variation and increases with rain rate, while the surface rainfall originating from warm clouds does not exceed 50 . Using disdrometer observations to flag surface rainfall events, we found that about 71 and 95 of surface rainfall events and rainfall accumulation come from cold clouds, respectively. In addition, the observed rainfall accumulations over Longmen are consistent with the fifth generation atmospheric reanalysis (ERA5), whereas the frequency of warm rainfall over Longmen is significantly underestimated in ERA5.
Insight Into the Molecular Photooxidation Evolution Mechanism of Brown Carbon Released From Residential Solid Fuel Combustion
Authors: Wang Diwei , Shen Zhenxing , Bai Gezi , Zhang Leiming , Huang Shasha , Sun Jian , Xu Hongmei , Cao Junji 
Published: December 2024

AbstractSolid fuels were one of the important emission sources of brown carbon (BrC). This study investigates molecular composition of BrC derived from combustion of five types of residential solid fuels (i.e., firewood, corn cob, bituminous coal, anthracite, and biomass briquette) and their photooxidation evolution mechanisms using an oxidation flow reactor. Results show that nitrogen‐containing and sulfur‐containing organic compounds are the main components of molecular composition of methanol‐soluble organic compounds (MSOC) emitted from these fuels, with their intensity being 33%–43% and 23%–56%, respectively, depending on fuel type. The photooxidation processes mediated by NO3⋅ and ⋅ OH significantly altered the molecular composition and distribution of aged MSOC. The formation of typical nitrogen‐containing BrC chromophores (e.g., nitro‐aromatic compounds) also proves the role of NO3 ⋅ in the photooxidation reaction. However, the photo‐enhancement effect of NO3 ⋅ mediated photooxidation reaction could not offset the destruction of the molecular conjugation degree and aromaticity of BrC by ⋅ OH oxidation, resulting in a significant reduction in the light absorption capacity of BrC. The mass absorption coefficient at 365 nm of BrC aged for 12 days derived from the remaining fuels decreased by 47.0%–55.8% compared to that of fresh BrC, except for firewood, which only decreased by 5.3%. These findings on the molecular evolution and oxidation mechanism of BrC generated from solid fuels are useful in reducing uncertainties in climate change studies involving BrC aerosol.