bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of Ocean Model Predictions of Mean Dynamic Topography in Shallow, Tidally Dominated Regions Using Observations of Overtides
Authors: Renkl C. , Thompson K. R. 
Published: February 2022

AbstractIn shallow, tidally dominated regions, overtides and the mean state of the ocean are coupled through their simultaneous generation by nonlinear processes. We present a new method that uses observed overtides (e.g., M4) and mean currents to independently assess the accuracy of mean dynamic topography (MDT) predicted by ocean models. This is useful in regions where no sufficiently long, geodetically referenced sea level records are available for validation of the predicted MDT. We apply the new method to a regional model of the Gulf of Maine/Scotian Shelf region (GoMSS) and a barotropic, higher resolution model focused on the upper Bay of Fundy (UBoF). We first show that the tides and mean circulation predicted by UBoF are in good agreement with observations and a significant improvement over GoMSS. Next, we use UBoF to demonstrate that observed overtides are useful in selecting the optimal bathymetry and constraining parameters of an ocean model. An accurate bathymetry is critical for capturing the dominant nonlinear processes that generate overtides and control the form of MDT in shallow, tidally dominated regions. Finally, we use the observed overtides to argue that the MDT predicted by UBoF is more realistic than the prediction by GoMSS. In the vicinity of headlands, both horizontal advection and bottom friction in UBoF generate harmonics of the tidal flow and local setdowns of coastal MDT of (10 cm). The prediction of such features, validated by observed overtides, can provide guidance in future deployments of tide gauges in support of geoid and ocean model validation.
Characterizing the Response of Vegetation Cover to Water Limitation in Africa Using Geostationary Satellites
Authors: Küçük Çağlar , Koirala Sujan , Carvalhais Nuno , Miralles Diego G. , Reichstein Markus , Jung Martin 
Published: February 2022

AbstractHydrological interactions between vegetation, soil, and topography are complex, and heterogeneous in semi‐arid landscapes. This along with data scarcity poses challenges for large‐scale modeling of vegetation‐water interactions. Here, we exploit metrics derived from daily Meteosat data over Africa at ca. 5 km spatial resolution for ecohydrological analysis. Their spatial patterns are based on Fractional Vegetation Cover (FVC) time series and emphasize limiting conditions of the seasonal wet to dry transition: the minimum and maximum FVC of temporal record, the FVC decay rate and the FVC integral over the decay period. We investigate the relevance of these metrics for large scale ecohydrological studies by assessing their co‐variation with soil moisture, and with topographic, soil, and vegetation factors. Consistent with our initial hypothesis, FVC minimum and maximum increase with soil moisture, while the FVC integral and decay rate peak at intermediate soil moisture. We find evidence for the relevance of topographic moisture variations in arid regions, which, counter‐intuitively, is detectable in the maximum but not in the minimum FVC. We find no clear evidence for wide‐spread occurrence of the “inverse texture effect” on FVC. The FVC integral over the decay period correlates with independent data sets of plant water storage capacity or rooting depth while correlations increase with aridity. In arid regions, the FVC decay rate decreases with canopy height and tree cover fraction as expected for ecosystems with a more conservative water‐use strategy. Thus, our observation‐based products have large potential for better understanding complex vegetation‐water interactions from regional to continental scales.
Sowing Storms: How Model Timestep Can Control Tropical Cyclone Frequency in a GCM
Authors: Zarzycki Colin M. 
Published: February 2022

AbstractWith general circulation models (GCMs) being increasingly used to explore extreme events over short temporal and small spatial scales, understanding how design choices in model configuration impact simulation results is critical. This research shows that the number of spontaneously generated tropical cyclones (TCs) in a version of the Community Atmosphere Model can be controlled by changing the coupling frequency between the dynamical core and physical parameterizations. More frequent coupling (i.e., shorter physics timesteps), even in the presence of an otherwise identical model, leads to large increases in TC activity. It is suggested that this arises due to competition within moist physics subroutines. Simulations with reduced physics timesteps preferentially eliminate instantaneous atmospheric instability via grid‐scale motions, even while producing mean climates similar to those with longer timesteps. These small‐scale variability increases lead to more tropical “seeds,” which are converted to full‐fledged TCs. This behavior is confirmed through a set of sensitivity experiments and highlights the caution needed in studying and generalizing phenomena that depend on both resolved and sub‐grid scales in GCMs and the need for targeting physics‐dynamics coupling as a model improvement strategy.
Reduced expression of TAZ inhibits primary cilium formation in renal glomeruli
Authors: Jun Jae Hee , Lee Eun Ji , Park Minah , Ko Je Yeong , Park Jong Hoon 
Published: February 2022

AbstractRenal primary cilia are antenna-like organelles that maintain cellular homeostasis via multiple receptors clustered along their membranes. Recent studies have revealed that YAP/TAZ, key paralogous effectors of the Hippo pathway, are involved in ciliogenesis; however, their independent roles need to be further investigated. Here, we analyzed the renal phenotypes of kidney-specific TAZ knockout mice and observed ciliary defects only in glomeruli where mild cysts were formed. This finding prompted us to verify the role of TAZ specifically in renal tubule ciliary regulation. Therefore, we investigated the effects of TAZ silencing and compared them to those of YAP knockdown using three different types of renal tubular cells. We found that the absence of TAZ prevented proper cilia formation in glomerular cells, whereas it had a negligible effect in collecting duct and proximal tubule cells. IFT and NPHP protein levels were altered because of TAZ deficiency, accompanied by ciliary defects in glomerular cells, and ciliary recovery was identified by regulating some NPHP proteins. Although our study focused on TAZ, ciliogenesis, and other ciliary genes, the results suggest the very distinct roles of YAP and TAZ in kidneys, specifically in terms of ciliary regulation.
Wearable multimode sensor with a seamless integrated structure for recognition of different joint motion states with the assistance of a deep learning algorithm
Authors: Wen Lei , Nie Meng , Chen Pengfan , Zhao Yu-na , Shen Jingcheng , Wang Chongqing , Xiong Yuwei , Yin Kuibo , Sun Litao 
Published: February 2022

AbstractAccurate motion feature extraction and recognition provide critical information for many scientific problems. Herein, a new paradigm for a wearable seamless multimode sensor with the ability to decouple pressure and strain stimuli and recognize the different joint motion states is reported. This wearable sensor is integrated into a unique seamless structure consisting of two main parts (a resistive component and a capacitive component) to decouple the different stimuli by an independent resistance-capacitance sensing mechanism. The sensor exhibits both high strain sensitivity (GF = 7.62, 0–140% strain) under the resistance mechanism and high linear pressure sensitivity (S = 3.4 kPa−1, 0–14 kPa) under the capacitive mechanism. The sensor can differentiate the motion characteristics of the positions and states of different joints with precise recognition (97.13%) with the assistance of machine learning algorithms. The unique integrated seamless structure is achieved by developing a layer-by-layer casting process that is suitable for large-scale manufacturing. The proposed wearable seamless multimode sensor and the convenient process are expected to contribute significantly to developing essential components in various emerging research fields, including soft robotics, electronic skin, health care, and innovative sports systems applications.
Nanog mediated by FAO/ACLY signaling induces cellular dormancy in colorectal cancer cells
Authors: Zhang Meng , Peng Ruyi , Wang Haizhou , Yang Zhenwei , Zhang Hailin , Zhang Yangyang , Wang Meng , Wang Hongling , Lin Jun , Zhao Qiu , Liu Jing 
Published: February 2022

AbstractDormant cancer cells drive recurrence and drug resistance, which lead to poor prognosis in colorectal cancer (CRC). The mechanisms that regulate the entry of cancer cells into dormancy remain to be extensively studied. Nanog is a master transcription factor to maintain the self-renewal and pluripotency of stem cells. Since dormant cancer cells are similar to quiescent cancer stem cells, the correlation between dormant state and Nanog in CRC is worth to be explored. Serum deprivation is a common method to establish experimental cellular dormancy model. Here, we verified that serum deprivation-induced CRC cells to enter a cellular dormancy state, characterized by no proliferation, no death, no senescence, resistance to chemotherapy, high expression of dormant markers, metabolic suppression, and recovery to active status. Interestingly, we further identified that Nanog was upregulated in dormant CRC cells. Nanog knockdown could destroy the dormant state of serum-deprived CRC cells while Nanog overexpression could induce dormancy in CRC cells. Mechanistically, Nanog was regulated through a fatty acid oxidation (FAO)/ATP citrate lyase (ACLY)-dependent pathway. FAO increased ACLY expression to promote the synthesis of acetyl-CoA, which was transferred by P300 to accelerate H3K27 acetylation of Nanog promoter. Then, Nanog upregulation increased the transcription of P21 and P27, which promoted the dormancy of CRC cells. Our findings revealed that Nanog could induce cellular dormancy in CRC cells and unlocked a specific mechanism to govern the process.
Oxeiptosis: a novel pathway of melanocytes death in response to oxidative stress in vitiligo
Authors: Kang Pan , Chen Jianru , Zhang Weigang , Guo Ningning , Yi Xiuli , Cui Tingting , Chen Jiaxi , Yang Yuqi , Wang Yinghan , Du Pengran , Ye Zhubiao , Li Baizhang , Li Chunying , Li Shuli 
Published: February 2022

AbstractVitiligo is a cutaneous depigmenting autoimmune disease caused by the extensive destruction of epidermal melanocytes. Convincing data has defined a critical role for oxidative stress in the pathogenesis of vitiligo. Oxeiptosis is a caspase-independent cell death modality that was reportedly triggered by oxidative stress and operative in pathogen clearance. However, whether oxeiptosis exists in oxidative stress-induced melanocytes demise in vitiligo remains undetermined. In the present study, we initially found that other cell death modalities might exist in addition to the well-recognized apoptosis and necroptosis in H2O2-treated melanocytes. Furthermore, AIFM1 was found to be dephosphorylated at Ser116 in oxidative stress-induced melanocytes death, which was specific to oxeiptosis. Moreover, KEAP1 and PGAM5, upstream of the AIFM1 in oxeiptosis, were found to operate in melanocytic death. Subsequently, the KEAP1-PGAM5-AIFM1 signaling pathway was proved to be involved in oxidative stress-triggered melanocytes demise through the depletion of KEAP1 and PGAM5. Altogether, our study indicated that oxeiptosis might occur in melanocytes death under oxidative stress and contribute to the pathogenesis of vitiligo.
Mitochondrial homeostasis regulates definitive endoderm differentiation of human pluripotent stem cells
Authors: Lv Jing , Yi Ying , Qi Yan , Yan Chenchao , Jin Wenwen , Meng Liming , Zhang Donghui , Jiang Wei 
Published: February 2022

AbstractCellular organelles play fundamental roles in almost all cell behaviors. Mitochondria have been reported to be functionally linked to various biological processes, including reprogramming and pluripotency maintenance. However, very little about the role of mitochondria has been revealed in human early development and lineage specification. Here, we reported the characteristics and function of mitochondria during human definitive endoderm differentiation. Using a well-established differentiation system, we first investigated the change of mitochondrial morphology by comparing undifferentiated pluripotent stem cells, the intermediate mesendoderm cells, and differentiated endoderm cells, and found that mitochondria were gradually elongated and matured along differentiation. We further analyzed the expression pattern of mitochondria-related genes by RNA-seq, indicating that mitochondria became active during differentiation. Supporting this notion, the production of adenosine triphosphate (ATP) and reactive oxygen species (ROS) was increased as well. Functionally, we utilized chemicals and genome editing techniques, which could interfere with mitochondrial homeostasis, to determine the role of mitochondria in human endoderm differentiation. Treatment with mitochondrial inhibitors, or genetic depletion of mitochondrial transcription factor A (TFAM), significantly reduced the differentiation efficiency of definitive endoderm. In addition, the defect in endoderm differentiation due to dysfunctional mitochondria could be restored to some extent by the addition of ATP. Moreover, the clearance of excessive ROS due to dysfunctional mitochondria by N-acetylcysteine (NAC) improved the differentiation as well. We further found that ATP and NAC could partially replace the growth factor activin A for definitive endoderm differentiation. Our study illustrates the essential role of mitochondria during human endoderm differentiation through providing ATP and regulating ROS levels, which may provide new insight for metabolic regulation of cell fate determination.
Nanoscale rules governing the organization of glutamate receptors in spine synapses are subunit specific
Authors: Hruska Martin , Cain Rachel E. , Dalva Matthew B. 
Published: February 2022

AbstractHeterotetrameric glutamate receptors are essential for the development, function, and plasticity of spine synapses but how they are organized to achieve this is not known. Here we show that the nanoscale organization of glutamate receptors containing specific subunits define distinct subsynaptic features. Glutamate receptors containing GluA2 or GluN1 subunits establish nanomodular elements precisely positioned relative to Synaptotagmin-1 positive presynaptic release sites that scale with spine size. Glutamate receptors containing GluA1 or GluN2B specify features that exhibit flexibility: GluA1-subunit containing AMPARs are found in larger spines, while GluN2B-subunit containing NMDARs are enriched in the smallest spines with neither following a strict modular organization. Given that the precise positioning of distinct classes of glutamate receptors is linked to diverse events including cell death and synaptic plasticity, this unexpectedly robust synaptic nanoarchitecture provides a resilient system, where nanopositioned glutamate receptor heterotetramers define specific subsynaptic regions of individual spine synapses.
Observational evidence of ring current in the magnetosphere of Mercury
Authors: Zhao J.-T. , Zong Q.-G. , Yue C. , Sun W.-J. , Zhang H. , Zhou X.-Z. , Le G. , Rankin R. , Slavin J. A. , Raines J. M. , Liu Y. , Wei Y. 
Published: February 2022

AbstractThe magnetic gradient and curvature drift of energetic ions can form a longitudinal electric current around a planet known as the ring current, that has been observed in the intrinsic magnetospheres of Earth, Jupiter, and Saturn. However, there is still a lack of observational evidence of ring current in Mercury’s magnetosphere, which has a significantly weaker dipole magnetic field. Under such conditions, charged particles are thought to be efficiently lost through magnetopause shadowing and/or directly impact the planetary surface. Here, we present the observational evidence of Mercury’s ring current by analysing particle measurements from MErcury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft. The ring current is bifurcated because of the dayside off-equatorial magnetic minima. Test-particle simulation with Mercury’s dynamic magnetospheric magnetic field model (KT17 model) validates this morphology. The ring current energy exceeds $$5\times {10}^{10}$$
5
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10

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J during active times, indicating that magnetic storms may also occur on Mercury.
Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloids
Authors: Chen Wen , Ma Yonghui , He Wenyan , Wu Yinxia , Huang Yuancheng , Zhang Yipeng , Tian Hongchang , Wei Kai , Yang Xiaodong , Zhang Hongbin 
Published: February 2022

AbstractSarpagine-Ajmaline-Koumine type monoterpenoid indole alkaloids represent a fascinating class of natural products with polycyclic and cage-like structures, interesting biological activities, and related biosynthetic origins. Herein we report a unified approach towards the asymmetric synthesis of these three types of alkaloids, leading to a collective synthesis of 14 natural alkaloids. Among them, akuammidine, 19-Z-akuammidine, vincamedine, vincarine, quebrachidine, vincamajine, alstiphylianine J, and dihydrokoumine are accomplished for the first time. Features of our synthesis are a new Mannich-type cyclization to construct the key indole-fused azabicyclo[3.3.1]nonane common intermediate, a SmI2 mediated coupling to fuse the aza-bridged E-ring, stereoselective olefinations to install either the 19-E or 19-Z terminal alkenes presented in the natural alkaloids, and an efficient iodo-induced cyclization to establish the two vicinal all-carbon quaternary centers in the Koumine-type alkaloids.
Filling the gap between topological insulator nanomaterials and triboelectric nanogenerators
Authors: Li Mengjiao , Lu Hong-Wei , Wang Shu-Wei , Li Rei-Ping , Chen Jiann-Yeu , Chuang Wen-Shuo , Yang Feng-Shou , Lin Yen-Fu , Chen Chih-Yen , Lai Ying-Chih 
Published: February 2022

AbstractReliable energy modules and higher-sensitivity, higher-density, lower-powered sensing systems are constantly required to develop wearable electronics and the Internet of Things technology. As an emerging technology, triboelectric nanogenerators have been potentially guiding the landscape of sustainable power units and energy-efficient sensors. However, the existing triboelectric series is primarily populated by polymers and rubbers, limiting triboelectric sensing plasticity to some extent owing to their stiff surface electronic structures. To enrich the current triboelectric group, we explore the triboelectric properties of the topological insulator nanofilm by Kelvin probe force microscopy and reveal its relatively positive electrification charging performance. Both the larger surface potential difference and the conductive surface states of the nanofilms synergistically improve the charge transfer behavior between the selected triboelectric media, endowing the topological insulator-based triboelectric nanogenerator with considerable output performance. Besides serving as a wearable power source, the ultra-compact device array demonstrates innovative system-level sensing capabilities, including precise monitoring of dynamic objects and real-time signal control at the human-machine interface. This work fills the blank between topological quantum matters and triboelectric nanogenerators and, more importantly, exploits the significant potential of topological insulator nanofilms for self-powered flexible/wearable electronics and scalable sensing technologies.
ASPP2 maintains the integrity of mechanically stressed pseudostratified epithelia during morphogenesis
Authors: Royer Christophe , Sandham Elizabeth , Slee Elizabeth , Schneider Falk , Lagerholm Christoffer B. , Godwin Jonathan , Veits Nisha , Hathrell Holly , Zhou Felix , Leonavicius Karolis , Garratt Jemma , Narendra Tanaya , Vincent Anna , Jones Celine , Child Tim , Coward Kevin , Graham Chris , Fritzsche Marco , Lu Xin , Srinivas Shankar 
Published: February 2022

AbstractDuring development, pseudostratified epithelia undergo large scale morphogenetic events associated with increased mechanical stress. Using a variety of genetic and imaging approaches, we uncover that in the mouse E6.5 epiblast, where apical tension is highest, ASPP2 safeguards tissue integrity. It achieves this by preventing the most apical daughter cells from delaminating apically following division events. In this context, ASPP2 maintains the integrity and organisation of the filamentous actin cytoskeleton at apical junctions. ASPP2 is also essential during gastrulation in the primitive streak, in somites and in the head fold region, suggesting that it is required across a wide range of pseudostratified epithelia during morphogenetic events that are accompanied by intense tissue remodelling. Finally, our study also suggests that the interaction between ASPP2 and PP1 is essential to the tumour suppressor function of ASPP2, which may be particularly relevant in the context of tissues that are subject to increased mechanical stress.
Hypoxia-induced macropinocytosis represents a metabolic route for liver cancer
Authors: Zhang Misty Shuo , Cui Jane Di , Lee Derek , Yuen Vincent Wai-Hin , Chiu David Kung-Chun , Goh Chi Ching , Cheu Jacinth Wing-Sum , Tse Aki Pui-Wah , Bao Macus Hao-Ran , Wong Bowie Po Yee , Chen Carrie Yiling , Wong Chun-Ming , Ng Irene Oi-Lin , Wong Carmen Chak-Lui 
Published: February 2022

AbstractHepatocellular carcinoma (HCC) invariably exhibits inadequate O2 (hypoxia) and nutrient supply. Hypoxia-inducible factor (HIF) mediates cascades of molecular events that enable cancer cells to adapt and propagate. Macropinocytosis is an endocytic process initiated by membrane ruffling, causing the engulfment of extracellular fluids (proteins), protein digestion and subsequent incorporation into the biomass. We show that macropinocytosis occurs universally in HCC under hypoxia. HIF-1 activates the transcription of a membrane ruffling protein, EH domain-containing protein 2 (EHD2), to initiate macropinocytosis. Knockout of HIF-1 or EHD2 represses hypoxia-induced macropinocytosis and prevents hypoxic HCC cells from scavenging protein that support cell growth. Germline or somatic deletion of Ehd2 suppresses macropinocytosis and HCC development in mice. Intriguingly, EHD2 is overexpressed in HCC. Consistently, HIF-1 or macropinocytosis inhibitor suppresses macropinocytosis and HCC development. Thus, we show that hypoxia induces macropinocytosis through the HIF/EHD2 pathway in HCC cells, harnessing extracellular protein as a nutrient to survive.