bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning Professional Knowledge: Bachelor Nursing Students’ Experiences in Learning and Knowledge Quality Outcomes in a Competence-Based Curriculum
Authors: den Hertog Ria , Boshuizen Henny P. A.
Published: September 2021

Since decades, nursing education struggles with a persistent gap between the theoretical knowledge offered in the study program and its application in professional practice. To bridge this gap competence-based curricula were developed with instructional designs as authentic learning contexts and self-directed learning. In this project we explored final year Bachelor Nursing (BN) students’ experiences in learning in a newly developed curriculum, and their knowledge quality outcomes and the degree of agreement with knowledge requirements. An instrumental multiple case study was conducted with interviews, concept mapping and a domain knowledge list. Results show that a third of the participants had positive learning experiences and got high appraisals for their knowledge quality. Similar to the medium and low scoring participants, they developed instrumental knowledge but integrated other forms of learning into a system of meaning, which is needed to solve non-routine problems in future practice. Medium and low scoring participants did not profit from learning in authentic contexts and self-directed learning. In conclusion, developing sufficient professional knowledge in a constructivist competence-based curriculum is influenced by students’ intrinsic motivation to build a strong knowledge base, by their perception of how to learn and use professional knowledge, and their expectations of the degree of supervision and guidance by the teacher. It is recommended to evaluate the extent to which the intended curriculum is being taught.
The fascinating world of mayenite (Ca12Al14O33) and its derivatives
Authors: Intiso Adriano , Rossi Federico , Proto Antonio , Cucciniello Raffaele
Published: September 2021

Mayenite (12CaO·7Al2O3) is a mesoporous calcium aluminum oxide, with a characteristic crystalline structure. The framework of mayenite is composed of interconnected cages with a positive electric charge per unit cell that includes two molecules [Ca24Al28O64]4+, and the remaining two oxide ions O2−, often labelled “free oxygen”, are trapped in the cages defined by the framework. Starting from mayenite structure several derivatives have been prepared through advanced synthetic protocols by free oxygen substitution with various anions. Mayenite and its derivates have been intensively investigated in many applications which include catalysis (oxidation and reduction, ammonia synthesis, pinacol coupling), environmental sensors and CO2 sorbent materials. In this review, we summarize our recent results on the main applications of mayenite and its derivatives.
Million node fracture: size matters?
Authors: Lavrov A.
Published: September 2021

Transmissivity of self-affine fractures was computed numerically as a function of the grid size. One-million-node fractures (1024 × 1024 nodes) with fractal dimensions of 2.2–2.6 were cut into successively smaller fractures (“generations”), and transmissivities computed. The number of fractures in each generation was increased by a factor of 4. Considerable scatter in transmissivity was observed for smaller grid sizes. Average transmissivity of the fractures in the generation decreased with the grid size, without approaching any asymptotic value, which indicates no representative elementary volume (REV). This happened despite the average mean aperture being the same in each generation. The results indicate that it is not possible to estimate the transmissivity of a large fracture by cutting it into smaller fractures, running flow simulations on those and averaging the results. The decrease in transmissivity with the grid size was found to be due to an increase in the flow tortuosity.
Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics
Authors: Wang Haiquan , Li Shixuan , Wang Kangguo , Chen Xiuli , Zhou Huanfu
Published: September 2021

This study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.
Descriptive understanding and prediction in COVID-19 modelling
Authors: Findl Johannes , Suárez Javier
Published: September 2021

COVID-19 has substantially affected our lives during 2020. Since its beginning, several epidemiological models have been developed to investigate the specific dynamics of the disease. Early COVID-19 epidemiological models were purely statistical, based on a curve-fitting approach, and did not include causal knowledge about the disease. Yet, these models had predictive capacity; thus they were used to ground important political decisions, in virtue of the understanding of the dynamics of the pandemic that they offered. This raises a philosophical question about how purely statistical models can yield understanding, and if so, what the relationship between prediction and understanding in these models is. Drawing on the model that was developed by the Institute of Health Metrics and Evaluation, we argue that early epidemiological models yielded a modality of understanding that we call descriptive understanding, which contrasts with the so-called explanatory understanding which is assumed to be the main form of scientific understanding. We spell out the exact details of how descriptive understanding works, and efficiently yields understanding of the phenomena. Finally, we vindicate the necessity of studying other modalities of understanding that go beyond the conventionally assumed explanatory understanding.
Investigating deep feedforward neural networks for classification of transposon-derived piRNAs
Authors: da Costa Alisson Hayasi , Santos Renato Augusto Corrêa dos , Cerri Ricardo
Published: September 2021

PIWI-interacting RNAs (piRNAS) form an important class of non-coding RNAs that play a key role in gene expression regulation and genome integrity by silencing transposable elements. However, despite the importance of piRNAs and the large application of deep learning in computational biology, there are few studies of deep learning for piRNAs prediction. Still, current methods focus on using advanced architectures like CNN and variations. This paper presents an investigation on deep feedforward network models for classification of human transposon-derived piRNAs. We developed a lightweight predictor (when compared to other deep learning methods) and we show by practical evidence that simple neural networks can perform as well as better than complex neural networks when using the appropriate hyperparameters. For that, we train, analyze and compare the results of a multilayer perceptron with different hyperparameter choices, such as numbers of hidden layers, activation functions and optimizers, clarifying the advantages and disadvantages of each choice. Our proposed predictor reached a F-score of 0.872, outperforming other state-of-the-art methods for human transposon-derived piRNAs classification. In addition, to better access the generalization of our proposal, we also showed it achieved competitive results when classifying piRNAs of other species.
Silylated Thiol-Containing Cellulose Nanofibers as a Bio-Based Flocculation Agent for Ultrafine Mineral Particles of Chalcopyrite and Pyrite
Authors: Coelho Braga de Carvalho Ana Luiza , Ludovici Feliciana , Goldmann Daniel , Silva André Carlos , Liimatainen Henrikki
Published: September 2021

A considerable amount of very fine particles can be found, e.g., stored in tailing ponds, and they can include valuable or hazardous minerals that have the potential to be recovered. Selective flocculation, i.e., the formation of larger aggregates from specific minerals, offers a promising approach to improve the recovery of ultrafine particles. This study focuses on the use of a new bio-based flocculation agent made of silylated cellulose nanofibers containing a thiol-functional moiety (SiCNF). Flocculation was performed in separated systems of ultrafine mineral dispersions of pyrite, chalcopyrite, and quartz in aqueous alkaline medium. The flocculation performance of SiCNF was addressed in terms of the turbidity reduction of mineral dispersions and the floc size, and the results were compared with the performance of a commercial anionic polyacrylamide. SiCNF exhibited a turbidity removal efficiency of approximately 90%–99% at a concentration of 4000–8000 ppm with chalcopyrite and pyrite, whereas the turbidity removal of quartz suspension was significantly lower (a maximum of approximately 30%). The sulfide particles formed flocs with a size of several hundreds of micrometers. The quartz in turn did not form any visible flocs, and the dispersion still had a milky appearance after dosing 12,000 ppm of the flocculant. These results open a promising path for the investigation of SiCNF as a selective flocculation agent for sulfide minerals.

Graphical Abstract
Influence of the nitrided layer thickness of dies made of two types of tool steel used in hot extrusion of valve forgings made of nickel–chromium steel on the durability of these tools
Authors: Hawryluk Marek , Lachowicz Marzena , Janik Marta , Ziemba Jacek , Gronostajski Zbigniew
Published: September 2021

The study constitutes an analysis of the durability of dies used in the first operation of producing valve forgings from chromium–nickel steel (NCF 3015) for motor trucks. The average durability of the dies (subjected to standard thermal treatment and nitriding) in this operation equals about 800 forgings. To perform an in-depth analysis of the effect of the nitrided layer thickness (0.1 mm and 0.2 mm) and the tool material (W360 and QRO90) on the possibilities of increasing the die durability, complex studies were carried out, which included: a macroscopic analysis combined with 3D scanning, microstructural examinations using a scanning microscope and a metallographic microscope, as well as hardness measurements. A minimum of three tools were tested for different variants, and for each of them, one representative die was selected for detailed examinations. The research showed the presence of abrasive wear, thermo-mechanical fatigue and traces of adhesive wear as well as plastic deformation on the surface of the working impressions. Also observed was the effect of the extruded material sticking to the tools (high friction and the presence of intermetallic phases in the extruded material) and the forging being blocked in the smallest section of the die, which is a critical factor causing a production shutdown and the necessity of tool replacement. The highest mean durability equalling 2600 forgings was obtained for the dies with a lower carbon content and a higher content of vanadium and the nitrided layer thickness at the level of 0.2 mm. The lowest mean durability (after one forging item) was recorded for the dies made of steel with a higher carbon content and a higher chromium content, forming less stable compound carbides and the thickness layer at the level of 0.1 mm.
Microstructure and mechanical properties of Titanium grade 23 produced by selective laser melting
Authors: Nikiel Piotr , Wróbel Mirosław , Szczepanik Stefan , Stępień Michał , Wierzbanowski Krzysztof , Baczmański Andrzej
Published: September 2021

Selective laser melted Titanium grade 23 was characterized by low porosity, relatively large surface roughness and pronounced surface texture (i.e. surface grooves orientation). The band/layer microstructure was built of mixed α and β phases. The as printed structure exhibited very high compressive residual stresses with strong anisotropy (i.e., − 512 ± 17 MPa and − 282 ± 14 MPa along the laser scanning direction and along the transverse direction, respectively) and strong fiber crystallographic texture. The latter one is responsible for the anisotropy of hardness in the material. Annealing at 600 °C during four hours significantly removed residual stresses (i.e. to − 14 ± 2.8 MPa) and slightly weakened the texture. Yield strength, 1120 ± 50 MPa, and ultimate tensile strength, 1210 ± 50 MPa, of the annealed material are significantly higher and tensile elongation, 3.9%, lower than for commercial Titanium grade 23. Final mechanical polishing to obtain flat and relatively smooth surface induced desired compression residual stress in the subsurface (i.e., equal to about − 90 MPa). Low absorbed gas contents (oxygen, nitrogen, hydrogen) and low porosity of the printed material indicates the correctness of the technology and allows the printed material to be classified as meeting the requirements of ASTM standards for Titanium grade 23. Besides traditional testing techniques, the optical profilometry, X-ray analysis (texture and residual stresses measurement) and infrared absorption method were applied for the product characterization and some potential of these testing methods and usefulness in technological practice was discussed, what can be particularly interesting both to practitioners from industry and researches from scientific laboratories.
Psychological well‐being of ruminative adolescents during the transition to COVID‐19 school closures: An EMA study
Authors: Swords Caroline M. , Lecarie Emma K. , Doane Leah D. , Hilt Lori M.
Published: September 2021

Introduction

Adolescents with moderate‐to‐severe levels of trait rumination are at heightened risk for psychopathology and may be particularly vulnerable to disruptions caused by the onset of the COVID‐19 pandemic. As most past research documenting the impact of COVID‐19 on adolescent well‐being has been cross‐sectional, it is unclear exactly how ruminative adolescents responded to the onset of the pandemic as it unfolded.

Methods

We used ecological momentary assessment (EMA) to explore changes in rumination among adolescents during the initial transition to distance learning in the United States. A subsample of 22 ruminative youth (Mage = 13.58; SD = 0.96; 54.5% male; 86.4% White) from a larger study provided EMA data throughout January–April 2020 (M responses per participant = 105.09, SD = 65.59). Following school closures, we hypothesized that adolescents would report greater rumination (i.e., focusing on emotions and problems) and depressive symptom level would moderate this effect.

Results

Surprisingly, rumination decreased, and this effect was moderated by depressive symptom level for emotion‐focused rumination, i.e., those with average and below‐average depressive symptoms experienced decreases in rumination.

Conclusions

These results suggest that the first wave of stay‐at‐home orders and the transition to distance learning were not immediately distressing to vulnerable adolescents. However, more research is needed to determine whether the results from recent research are generalizable to other adolescents and to examine the long‐term impact of the pandemic on adolescent well‐being.
Bassini inguinal hernia repair: Obsolete or still a viable surgical option? A single center cohort study
Authors: Tse Wayne , Johns William , Maher James , Rivers Jeannie , Miller Thomas
Published: September 2021

ABSTRACT

Background:

Most inguinal hernias are presently repaired using some type of mesh technique. This mesh can be placed through an inguinal incision or positioned through a laparoscopic approach. Either way, results have been impressive including a low recurrence rate, minimal pain and a rapid return to work and normal activity compared to tissue based approaches. Notwithstanding these results, there is still a subset of patients who, for various reasons, are strongly opposed to having a mesh repair. This study summarizes our 13 year experience with such patients and why the Bassini hernia repair is a viable surgical option in these individuals.

Methods:

Patients undergoing a Bassini repair at our institution from 2006 to 2014 were analyzed for long-term durability of the repair, complications and recurrence rate.

Results:

Of 203 patients studied (average age 65; 99% male), 205 repairs (two patients had bilateral repairs) were evaluated. Seven documented recurrences (3.7%) were identified. Post-operative complications were relatively minor and easily managed. They included 22 patients (10.8%) with a wound hematoma/seroma, 17 (8.4%) with urinary retention, and four (2%) with testicular ischemia not requiring orchiectomy. Pain problems (10.3%) were generally transient and resolved in a period of weeks. In those patients who did not die from co-morbid disease, long term durability of repair (≥5 years) was quite common.

Conclusion:

Low recurrence rate, long term durability and relatively minor complications indicate that the Bassini repair is still a good surgical option in patients opposed to a mesh repair. As such, we argue that it is not obsolete but still remains a viable surgical option in selected patients.

Highlights
Positioning documentaries as vehicles for developing preservice teachers’ analytic skills
Authors: Hilburn Jeremy , Buchanan Lisa Brown , Journell Wayne
Published: September 2021

In this study, preservice teachers viewed clips from three documentary films that presented multiple experiences of contemporary immigrants and refugees. Our focus in the study was how preservice teachers analyzed the three films. Specifically, we examined how elementary, middle grades, and secondary preservice teachers analyzed, both from a cognitive and affective stance, clips of documentary films about the difficult topic of contemporary immigration.
Saving the International Justice Regime
Authors: Hillebrecht Courtney
Published: September 2021

While resistance to international courts is not new, what is new, or at least newly conceptualized, is the politics of backlash against these institutions. Saving the International Justice Regime: Beyond Backlash against International Courts is at the forefront of this new conceptualization of backlash politics. It brings together theories, concepts and methods from the fields of international law, international relations, human rights and political science and case studies from around the globe to pose - and answer - three questions related to backlash against international courts: What is backlash and what forms does it take? Why do states and elites engage in backlash against international human rights and criminal courts? What can stakeholders and supporters of international justice do to meet these contemporary challenges?
Segmentation of Static and Dynamic Atomic-Resolution Microscopy Data Sets with Unsupervised Machine Learning Using Local Symmetry Descriptors
Authors: Wang Ning , Freysoldt Christoph , Zhang Siyuan , Liebscher Christian H , Neugebauer Jörg
Published: September 2021

We present an unsupervised machine learning approach for segmentation of static and dynamic atomic-resolution microscopy data sets in the form of images and video sequences. In our approach, we first extract local features via symmetry operations. Subsequent dimension reduction and clustering analysis are performed in feature space to assign pattern labels to each pixel. Furthermore, we propose the stride and upsampling scheme as well as separability analysis to speed up the segmentation process of image sequences. We apply our approach to static atomic-resolution scanning transmission electron microscopy images and video sequences. Our code is released as a python module that can be used as a standalone program or as a plugin to other microscopy packages.
Mental Health Status of Healthcare Workers During the COVID-19 Outbreak
Authors: Nicolaou Christiana , Menikou Joanna , Lamnisos Demetris , Lubenko Jelena , Presti Giovambattista , Squatrito Valeria , Constantinou Marios , Papacostas Savvas , Aydın Gokcen , Chong Yuen Yu , Chien Wai Tong , Cheng Ho Yu , Ruiz Francisco J. , Segura-Vargas Miguel A. , Garcia-Martin Maria B. , Obando-Posada Diana P. , Vasiliou Vasilis S. , McHugh Louise , Höfer Stefan , Baban Adriana , Neto David Dias , da Silva Ana Nunes , Monestès Jean-Louis , Alvarez-Galvez Javier , Paez-Blarrina Marisa , Montesinos Francisco , Valdivia-Salas Sonsoles , Ori Dorottya , Kleszcz Bartosz , Lappalainen Raimo , Ivanović Iva , Gosar David , Dionne Frederick , Merwin Rhonda M. , Kassianos Angelos P. , Karekla Maria , Gloster Andrew T.
Published: September 2021

Abstract. Background: The COVID-19 pandemic is a massive health crisis that has exerted enormous physical and psychological pressure. Mental healthcare for healthcare workers (HCWs) should receive serious consideration. This study served to determine the mental-health outcomes of 1,556 HCWs from 45 countries who participated in the COVID-19 IMPACT project, and to examine the predictors of the outcomes during the first pandemic wave. Methods: Outcomes assessed were self-reported perceived stress, depression symptom, and sleep changes. The predictors examined included sociodemographic factors and perceived social support. Results: The results demonstrated that half of the HCWs had moderate levels of perceived stress and symptoms of depression. Half of the HCWs ( n = 800, 51.4%) had similar sleeping patterns since the pandemic started, and one in four slept more or slept less. HCWs reported less perceived stress and depression symptoms and higher levels of perceived social support than the general population who participated in the same project. Predictors associated with higher perceived stress and symptoms of depression among HCWs included female sex, not having children, living with parents, lower educational level, and lower social support. Discussion: The need for establishing ways to mitigate mental-health risks and adjusting psychological interventions and support for HCWs seems to be significant as the pandemic continues.
Symbiont Photosynthesis and Its Effect on Boron Proxies in Planktic Foraminifera
Authors: Hönisch Bärbel , Fish Carina R. , Phelps Samuel R. , Haynes Laura L. , Dyez Kelsey , Holland Kate , Fehrenbacher Jennifer , Allen Katherine A. , Eggins Stephen M. , Goes Joaquim I.
Published: September 2021

Boron proxies in the calcium carbonate shells of planktic foraminifera are sensitive to seawater acidity, but B/Ca ratios and isotopic composition (i.e., δ11B) recorded by different foraminifer species grown under identical environmental conditions differ significantly and systematically. Specifically, Globigerinoides ruber displays higher B/Ca and δ11B than Trilobatus sacculifer and Orbulina universa. It has been hypothesized that these differences are caused by species‐specific rates of symbiont photosynthesis and habitat depth with greater symbiont photosynthesis elevating the microenvironmental pH of G. ruber relative to T. sacculifer and O. universa. Here we test this hypothesis by applying fast repetition rate fluorometry (FRRF), Chlorophyll a quantification, and symbiont counts in laboratory grown specimens of G. ruber (pink), T. sacculifer and O. universa to study species‐specific differences in symbiont photochemical quantum efficiencies. In addition, we report B/Ca shell profiles measured by laser ablation on the same specimens previously monitored by FRRF, and δ11B data of discrete populations of all three species grown under high and low light conditions in the laboratory. While the light experiments document that symbiont photosynthesis elevates pH and/or δ11B in the calcifying microenvironment of all three foraminifer species, the FRRF, Chl. a and symbiont abundance data are relatively uniform among the three species and do not scale consistently with intrashell B/Ca, or with observed species‐specific offsets in B/Ca or δ11B. Implications of these findings for foraminiferal physiology and biomineralization processes are discussed.
Beyond 4 × 100 Gbps Optical Backhaul Network With DSP Assistance Based Nonlinear Impairments Mitigation
Authors: Ali Farman , Armghan Ammar , Muhammad Fazal , Habib Usman , Ali Asar , Qamar Muhamamd Salman , Ali Usman , Khan Maqsood Ahmad
Published: September 2021

Backhaul networking is the highlighted objective of today telecommunication structure. Additionally, the backhaul networking can be possible easily utilizing optical fiber networks (OFNs). This paper studies 4 × 100 Gbps framework of long haul capacity wavelength division multiplexing (WDM) system, taking into account the impairments of nonlinearities, amplified spontaneous emission (ASE) fiber dispersion. Digital signal processing based receiver is proposed to maintain performance of OFNs in presence of nonlinear issues. The complete procedure of proposed WDM based OFNs is verified theoretically. The simulation analysis proved the validation of presented model against nonlinear impairments and provides 2.1 bit error rate (BER) at 25 and 50 GHz channel spacing, 90 μm2 effective area and 500 km transmission length.
On the Implementation and Usability of Crystal Preferred Orientation Evolution in Geodynamic Modeling
Authors: Fraters M. R. T. , Billen M. I.
Published: September 2021

Flow in the Earth's mantle causes the preferred orientation of crystals called lattice/crystal preferred orientation (LPO or CPO). This preferred orientation is one of the main reasons why seismic anisotropy is observed. Seismic anisotropy observations could therefore be used to constrain the mantle flow in geodynamic models through tracking CPO evolution, and computing the resulting elastic tensor and the anisotropy predicted at the surface. Even though there are many types of CPO models, only a few studies include CPO calculations due to the complexity and computational cost. Here, we implemented an extended version of the CPO model D‐Rex into the open‐source community geodynamics code ASPECT. We show that the implementation is correct, how to use it, and that it is feasible and important to use in large 3D models. We also show that it is important to calculate CPO, especially for models focusing on plate boundary of smaller scale flow because the resulting fast axis directions can greatly deviate from the flow direction. The added infrastructure will also allow for future enhancement, testing, and even replacement of the CPO model.
Variability of Natural Methane Bubble Release at Southern Hydrate Ridge
Authors: Marcon Yann , Kelley Deborah , Thornton Blair , Manalang Dana , Bohrmann Gerhard
Published: September 2021

Current estimations of seabed methane release into the ocean (0.4–48 Tg yr−1) are based on short‐term observations and implicitly assume that fluxes are constant over time. However, the intensity of gas seepage varies significantly throughout a seep lifetime. We used instruments operated by the Ocean Observatories Initiative's Regional Cabled Array to monitor variations of gas emissions over the entire Southern Hydrate Ridge summit. We show that bubble plumes emanate from distinct and persistent vents. Multiple plumes can occur within each vent and the location of their outlets may shift progressively. Active bubble plumes vary temporally in number and intensity, even within single vents. Gas emission fluctuations are partly periodic and linked to the local tide. However, short‐term variability and high ebullition events unrelated to tidal cycles are also commonly observed. Our data indicate that small‐scale processes beneath or at the sediment surface are responsible for the short‐term variability of the venting activity that is otherwise modulated by tides. Furthermore, a decrease of venting at one vent may coincide with an increase in plume activity at other vents. Our results depict a spatially and temporally dynamic seep environment, the variability of which cannot be fully characterized without systematic and comprehensive monitoring of the entire area. These results indicate that flux estimations may be largely overestimated or underestimated depending on the time, duration, and place of observation. Although sudden ebullition bursts are hardly predictable, we argue that tidal cycles must be taken into consideration when estimating gas fluxes.
Temperature‐Regulated Turnover of Chromophoric Dissolved Organic Matter in Global Dark Marginal Basins
Authors: Wang Chao , Guo Weidong , Li Yan , Dahlgren Randy A. , Guo Xianghui , Qu Liyin , Zhuang Wei
Published: September 2021

Oceanic absorption of heat generated by greenhouse gas emissions has resulted in warming of the dark ocean (>200 m) that contains a large refractory DOM (RDOM) pool. However, changes in microbially mediated production and degradation dynamics for RDOM components in response to warming of dark marginal basins remain unclear. Herein, we integrated data from the dark South China, Mediterranean and Japan Seas (temperature range: 0.09–15.1°C) to demonstrate that in situ production efficiency of two ubiquitous humic‐like fluorophores increased at higher dark ocean temperature, whereas chromophores at a wavelength of 325 nm (aCDOM(325)) changed from production to degradation at higher temperature. Increased oxygen consumption and a reduction of labile substrates in future warmer dark ocean environments may initiate the final degradation of some semi‐refractory components, thereby increasing the recalcitrance of RDOM, but decreasing the DOM inventory in dark basins and creating a positive feedback to rising atmospheric CO2.
Understanding Lead Times of Warm Water Volumes to ENSO Sea Surface Temperature Anomalies
Authors: Zhao Sen , Jin Fei‐Fei , Stuecker Malte F.
Published: September 2021

The equatorial Pacific warm water volume (WWV) and western equatorial Pacific WWV (WWVw) are two important long‐lead time El Niño‐Southern Oscillation (ENSO) event precursors. Here, we utilize the recharge‐discharge oscillator framework to obtain the analytical solution of WWV and WWVw lead times to ENSO sea surface temperatures (SSTs). Both WWV and WWVw lead times show a strong dependence on the inherent ENSO periodicity, whereas WWV lead time is further modulated by the air‐sea coupling strength and ENSO SST spatial pattern. The derived solution is able to explain observed decadal variations in lead times of WWV to SST in terms of variations in ENSO periodicity and air‐sea coupling strength.
Atmospheric Circulation Sensitivity to Changes in the Vertical Structure of Polar Warming
Authors: Kim Doyeon , Kang Sarah M. , Merlis Timothy M. , Shin Yechul
Published: September 2021

This study examines the effects of the vertical structure of polar warming on the remote atmospheric circulation. We apply thermal forcing at different vertical levels in the Northern Hemisphere polar region in two atmospheric global climate models of different complexity, both coupled to an aquaplanet slab ocean. The efficacy of polar heating in perturbing the remote climate increases with the altitude at which it is applied. This robust sensitivity arises from the dominance of surface temperature contribution to the outgoing longwave radiation owing to the large emissivity of the polar troposphere. An upper‐level polar heating has a smaller fraction of forcing balanced by radiative flux changes and a larger contribution from atmospheric energy transport changes, which provokes larger shifts in the extratropical jet and Hadley circulation. Our results suggest increasingly far‐reaching impacts of Arctic warming as a less surface‐trapped profile is projected for seasonally ice‐free conditions in the near future.
Coupled Impacts of Atmospheric Circulation and Sea‐Ice on Late Pleistocene Terrigenous Sediment Dynamics in the Subarctic Pacific Ocean
Authors: Zhong Yi , Liu Yanguang , Gong Xun , Wilson David J. , Lu Zhengyao , Liu Jiabo , Song Tengfei , Gorbarenko Sergey A. , Shi Xuefa , Yang Xiaoqiang , Liu Qingsong
Published: September 2021

Processes controlling environmental change in the subarctic Pacific Ocean on millennial to orbital timescales are not well understood. Here we use a 230‐kyr sedimentary record from the northwest Pacific Ocean to assess the response of late Pleistocene sediment dynamics to orbital forcing. Combining a source‐to‐sink perspective based on sedimentological records with climate model reanalysis, we reveal that fluctuations in sediment provenance were closely linked to obliquity‐forced changes in atmospheric circulation modes. Specifically, the position of the Aleutian Low controlled sediment transport from the Bering Sea and Aleutian Arc sources. Furthermore, a distinct shift in North Pacific ocean circulation during the Last Glacial Maximum may have been related to a strengthened Siberian High. The coincidence of atmospheric mode switches with changes in sea‐ice extent and North Pacific Intermediate Water formation in the marginal seas suggests that this coupled ocean‐atmosphere system may have acted as a regional amplifier of global climate variability.
The Response of Middle Thermosphere (∼160 km) Composition to the November 20 and 21, 2003 Superstorm
Authors: Yu Tingting , Wang Wenbin , Ren Zhipeng , Cai Xuguang , Yue Xinan , He Maosheng
Published: September 2021

TIMED/GUVI limb measurements and first‐principles simulations from the Thermosphere Ionosphere Electrodynamics Global Circulation Model (TIEGCM) are used to investigate thermospheric atomic oxygen (O) and molecular nitrogen (N2) responses in the middle thermosphere on a constant pressure surface (∼160 km) to the November 20 and 21, 2003 superstorm. The consistency between GUVI observations and TIEGCM simulated composition changes allows us to utilize TIEGCM outputs to investigate the storm‐time behaviors of O and N2 systematically. Diagnostic analysis shows that horizontal and vertical advection are the two main processes that determine the storm‐induced perturbations in the middle thermosphere. Molecular diffusion has a relatively smaller magnitude than the two advection processes, acting to compensate for the changes caused by the transport partly. Contributions from chemistry and eddy diffusion are negligible. During the storm initial and main phases, composition variations at high latitudes are determined by both horizontal and vertical advection. At middle‐low latitudes, horizontal advection is the main driver for the composition changes where O mass mixing ratio decreases (N2 mass mixing ratio increases); whereas horizontal and vertical advection combined to dominate the changes in the regions where increases ( decreases). Over the entire storm period, horizontal advection plays a significant role in transporting high‐latitude composition perturbations globally. Our results also demonstrate that storm‐time temperature changes are not the direct cause of the composition perturbations on constant pressure surfaces.
Pore and Mineral Fabrics Control the Elastic Wave Velocities of Metapelite With Implications for Subduction Zone Tomography
Authors: Fliedner C. , French M. E.
Published: September 2021

Seismic tomography is used to infer compositional variations and environmental conditions in active subduction zones. In some regions, low P‐wave and S‐wave velocities and high are documented near and along the plate boundary, and are interpreted to reflect high pore fluid pressures in metasedimentary rocks. However, there are limited experimental data with which to constrain the in‐situ wave speeds of metasedimentary rocks, particularly under elevated pore pressure. To determine whether the velocities of metasedimentary rocks are consistent with low wave speeds and high , we measured the ultrasonic velocities of the Orocopia schist, a greenschist facies metapelite, in the laboratory. Velocities were measured under dry and saturated conditions, at effective pressures between 1 and 136 MPa, parallel and normal to foliation, and at room temperature. We find that, under fluid‐saturated conditions, the velocities of the Orocopia schist and are consistent with anomalous values in subduction zones ( km/s, km/s, and ) at effective pressures less than 10 MPa and normal to foliation. We used differential effective medium models and microscopy to quantify the contributions of mineralogy, mineral fabric, porosity, and pore shape to , , and their anisotropies. We find that, although mineralogy and mineral anisotropy impart some control on the wave velocities, aligned, small aspect ratio pores (0.005–0.03) are required to explain the measured velocities and high . The low and and high in subduction zones can be explained by phyllosilicate‐rich metapelitic rocks under near‐lithostatic pore pressure.
Time Series of Near‐Inertial Gravity Wave Energy Fluxes: The Effect of a Strong Wind Event
Authors: Löb Jonas , Köhler Janna , Walter Maren , Mertens Christian , Rhein Monika
Published: September 2021

Low mode internal waves in the stratified ocean are partially generated by the wind field in the near‐inertial range and important for interior mixing and for the oceanic energy pathways. Long‐term observations of energy fluxes of internal waves are sparse. Here, we study the temporal variability of wind‐generated low mode near‐inertial internal waves inside an internal tide beam emanating from seamounts south of the Azores. We use 20 months of consecutive mooring observations to calculate the mode 1 and mode 2 near‐inertial energy flux as well as the near‐inertial kinetic and potential energy. The energy flux time series is not steady due to its intermittent forcing with modes 1 and 2 contributing in a similar way to the total. A peak in the energy flux time series that can be directly linked to a storm event allows us to split the time series into a background period and a storm event period. The relative contribution of mode 1 to mode 2 remains the same during a storm event and background period. This study provides new insights into the relative importance of single wind events for the near‐inertial energy flux and the opportunity to quantify the impact of an isolated strong wind event compared to a calm, tide‐dominated background state. Thus, an adequate representation of storm events in parameterizations used for mixing estimates by ocean general circulation models is needed, as they are potentially of similar importance as the internal tides.
Methane Emissions Offset Net Carbon Dioxide Uptake From an Alpine Peatland on the Eastern Qinghai‐Tibetan Plateau
Authors: Peng Haijun , Chi Jinshu , Yao Hu , Guo Qian , Hong Bing , Ding Hanwei , Zhu Yongxuan , Wang Jie , Hong Yetang
Published: September 2021

Peatlands store large amounts of carbon (C) and actively exchange greenhouse gases (GHGs) with the atmosphere, thus significantly affecting global C cycle and climate. Large uncertainty exists in C and GHG estimates of the alpine peatlands on Qinghai‐Tibetan Plateau (QTP), as direct measurements of CO2 and CH4 fluxes are scarce in this region. In this study, we provided 32‐month CO2 and CH4 fluxes measured using the eddy covariance (EC) technique in a typical alpine peatland on the eastern QTP to estimate the net C and CO2 equivalent (CO2‐eq) fluxes and investigate their environmental controls. Our results showed that the mean annual CO2 and CH4 fluxes were −68 ± 8 g CO2‐C m−2 yr−1 and 35 ± 0.3 g CH4‐C m−2 yr−1, respectively. While considering the traditional and sustained global warming potentials of CH4 over the 100‐year timescale, the peatland acted as a net CO2‐eq source (1,059 ± 30 and 1,853 ± 31 g CO2‐eq m−2 yr−1, respectively). The net CO2‐eq emissions during the non‐growing seasons contributed to over 40% of the annual CO2‐eq budgets. We further found that net CO2‐eq flux was primarily influenced by global radiation and soil temperature variations. This study was the first assessment to quantify the net CO2‐eq flux of the alpine peatland in the QTP region using EC measurements. Our study highlights that CH4 emissions from the alpine peatlands can largely offset the net cooling effect of CO2 uptake and future climate changes such as global warming might further enhance their potential warming effect.
Single-cell transcriptome analysis reveals cellular heterogeneity in the ascending aortas of normal and high-fat diet-fed mice
Authors: Kan Hao , Zhang Ka , Mao Aiqin , Geng Li , Gao Mengru , Feng Lei , You Qingjun , Ma Xin
Published: September 2021

The aorta contains numerous cell types that contribute to vascular inflammation and thus the progression of aortic diseases. However, the heterogeneity and cellular composition of the ascending aorta in the setting of a high-fat diet (HFD) have not been fully assessed. We performed single-cell RNA sequencing on ascending aortas from mice fed a normal diet and mice fed a HFD. Unsupervised cluster analysis of the transcriptional profiles from 24,001 aortic cells identified 27 clusters representing 10 cell types: endothelial cells (ECs), fibroblasts, vascular smooth muscle cells (SMCs), immune cells (B cells, T cells, macrophages, and dendritic cells), mesothelial cells, pericytes, and neural cells. After HFD intake, subpopulations of endothelial cells with lipid transport and angiogenesis capacity and extensive expression of contractile genes were defined. In the HFD group, three major SMC subpopulations showed increased expression of extracellular matrix-degradation genes, and a synthetic SMC subcluster was proportionally increased. This increase was accompanied by upregulation of proinflammatory genes. Under HFD conditions, aortic-resident macrophage numbers were increased, and blood-derived macrophages showed the strongest expression of proinflammatory cytokines. Our study elucidates the nature and range of the cellular composition of the ascending aorta and increases understanding of the development and progression of aortic inflammatory disease.
Bromodomain proteins: protectors against endogenous DNA damage and facilitators of genome integrity
Authors: Lee Seo Yun , Kim Jae Jin , Miller Kyle M.
Published: September 2021

Endogenous DNA damage is a major contributor to mutations, which are drivers of cancer development. Bromodomain (BRD) proteins are well-established participants in chromatin-based DNA damage response (DDR) pathways, which maintain genome integrity from cell-intrinsic and extrinsic DNA-damaging sources. BRD proteins are most well-studied as regulators of transcription, but emerging evidence has revealed their importance in other DNA-templated processes, including DNA repair and replication. How BRD proteins mechanistically protect cells from endogenous DNA damage through their participation in these pathways remains an active area of investigation. Here, we review several recent studies establishing BRD proteins as key influencers of endogenous DNA damage, including DNA–RNA hybrid (R-loops) formation during transcription and participation in replication stress responses. As endogenous DNA damage is known to contribute to several human diseases, including neurodegeneration, immunodeficiencies, cancer, and aging, the ability of BRD proteins to suppress DNA damage and mutations is likely to provide new insights into the involvement of BRD proteins in these diseases. Although many studies have focused on BRD proteins in transcription, evidence indicates that BRD proteins have emergent functions in DNA repair and genome stability and are participants in the etiology and treatment of diseases involving endogenous DNA damage.
Suppression of 4.1R enhances the potency of NKG2D-CAR T cells against pancreatic carcinoma via activating ERK signaling pathway
Authors: Gao Yaoxin , Lin Haizhen , Guo Dandan , Cheng Sijia , Zhou Ying , Zhang Li , Yao Jie , Farooq Muhammad Asad , Ajmal Iqra , Duan Yixin , He Cong , Tao Lei , Wu Shijia , Liu Mingyao , Jiang Wenzheng
Published: September 2021

Pancreatic carcinoma (PC) is one of the most common malignancies. Chimeric antigen receptor (CAR)-modified T cells has achieved remarkable efficacy in the treatment of hematological malignancies. However, lack of tumor-specific targets and the existence of inhibitory factors limit the function of CAR T cells when treating solid tumors. 4.1R has been reported to suppress the anti-tumor activity of T cell responses. In this study, we investigated the anti-tumor activity of 4.1R deletion in natural killer group 2D (NKG2D)-CAR T cells against PC. The CAR T cells were obtained by transfecting T cells with lentiviral vector carrying NKG2D-CAR, NC-NKG2D-CAR, or KD2-NKG2D-CAR. In vitro, NKG2D-CAR T cells showed higher cytotoxicity than Mock T cells. However, compared to NKG2D-CAR T cells, furtherly higher cytotoxicity against PC cells in a dose-dependent manner was found in KD2-NKG2D-CAR T cells. In addition, the proliferation rate and cytotoxic activity of KD2-NKG2D-CAR T cells were significantly higher than those of NKG2D-CAR T cells. Besides, the inhibitory receptors PD-1 and TIM-3 were expressed in lower level on KD2-NKG2D-CAR T cells. In vivo, KD2-NKG2D-CAR T cells suppressed tumor growth more effectively in a xenograft model compared to NKG2D-CAR T cells. Mechanistically, 4.1R regulated CAR T cell function via activating ERK signaling pathway. Therefore, the study provides a new idea to enhance the anti-tumor efficiency of CAR T therapy.
Machine-learning-based diagnosis of drug-naive adult patients with attention-deficit hyperactivity disorder using mismatch negativity
Authors: Kim Sungkean , Baek Ji Hyun , Kwon Young Joon , Lee Hwa Young , Yoo Jae Hyun , Shim Se-hoon , Kim Ji Sun
Published: September 2021

Relatively little is investigated regarding the neurophysiology of adult attention-deficit/hyperactivity disorder (ADHD). Mismatch negativity (MMN) is an event-related potential component representing pre-attentive auditory processing, which is closely associated with cognitive status. We investigated MMN features as biomarkers to classify drug-naive adult patients with ADHD and healthy controls (HCs). Sensor-level features (amplitude and latency) and source-level features (source activation) of MMN were investigated and compared between the electroencephalograms of 34 patients with ADHD and 45 HCs using a passive auditory oddball paradigm. Correlations between MMN features and ADHD symptoms were analyzed. Finally, we applied machine learning to differentiate the two groups using sensor- and source-level features of MMN. Adult patients with ADHD showed significantly lower MMN amplitudes at the frontocentral electrodes and reduced MMN source activation in the frontal, temporal, and limbic lobes, which were closely associated with MMN generators and ADHD pathophysiology. Source activities were significantly correlated with ADHD symptoms. The best classification performance for adult ADHD patients and HCs showed an 81.01% accuracy, 82.35% sensitivity, and 80.00% specificity based on MMN source activity features. Our results suggest that abnormal MMN reflects the adult ADHD patients’ pathophysiological characteristics and might serve clinically as a neuromarker of adult ADHD.