bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss of regulation of protein synthesis and turnover underpins an attenuated stress response in senescent human mesenchymal stem cells
Authors: Llewellyn Jack , Mallikarjun Venkatesh , Appleton Ellen , Osipova Maria , Gilbert Hamish T. J. , Richardson Stephen M. , Hubbard Simon J. , Swift Joe 
Published: March 2023

Cells respond to stress by synthesizing chaperone proteins that seek to correct protein misfolding and maintain function. However, abrogation of protein homeostasis is a hallmark of aging, leading to loss of function and the formation of proteotoxic aggregates characteristic of pathology. Consequently, discovering the underlying molecular causes of this deterioration in proteostasis is key to designing effective interventions to disease or to maintaining cell health in regenerative medicine strategies. Here, we examined primary human mesenchymal stem cells, cultured to a point of replicative senescence and subjected to heat shock, as an in vitro model of the aging stress response. Multi -omics analysis showed how homeostasis components were reduced in senescent cells, caused by dysregulation of a functional network of chaperones, thereby limiting proteostatic competence. Time-resolved analysis of the primary response factors, including those regulating heat shock protein 70 kDa (HSPA1A), revealed that regulatory control is essentially translational. Senescent cells have a reduced capacity for chaperone protein translation and misfolded protein (MFP) turnover, driven by downregulation of ribosomal proteins and loss of the E3 ubiquitin ligase CHIP (C-terminus of HSP70 interacting protein) which marks MFPs for degradation. This limits the cell’s stress response and subsequent recovery. A kinetic model recapitulated these reduced capacities and predicted an accumulation of MFP, a hypothesis supported by evidence of systematic changes to the proteomic fold state. These results thus establish a specific loss of regulatory capacity at the protein, rather than transcript, level and uncover underlying systematic links between aging and loss of protein homeostasis.
Cholinergic regulation of vascular endothelial function by human ChAT
+
T cells
Authors: Tarnawski Laura , Shavva Vladimir S. , Kort Eric J. , Zhuge Zhengbing , Nilsson Ingrid , Gallina Alessandro L. , Martínez-Enguita David , Heller Sahlgren Benjamin , Weiland Matthew , Caravaca April S. , Schmidt Staffan , Chen Ping , Abbas Katarina , Wang Fu-Hua , Ahmed Osman , Eberhardson Michael , Färnert Anna , Weitzberg Eddie , Gustafsson Mika , Kehr Jan , Malin Stephen G. , Hult Henrik , Carlström Mattias , Jovinge Stefan , Olofsson Peder S. 
Published: March 2023

Endothelial dysfunction and impaired vasodilation are linked with adverse cardiovascular events. T lymphocytes expressing choline acetyltransferase (ChAT), the enzyme catalyzing biosynthesis of the vasorelaxant acetylcholine (ACh), regulate vasodilation and are integral to the cholinergic antiinflammatory pathway in an inflammatory reflex in mice. Here, we found that human T cell ChAT mRNA expression was induced by T cell activation involving the PI3K signaling cascade. Mechanistically, we identified that ChAT mRNA expression was induced following the attenuation of RE-1 Silencing Transcription factor REST-mediated methylation of the ChAT promoter, and that ChAT mRNA expression levels were up-regulated by GATA3 in human T cells. In functional experiments, T cell-derived ACh increased endothelial nitric oxide-synthase activity, promoted vasorelaxation, and reduced vascular endothelial activation and promoted barrier integrity by a cholinergic mechanism. Further, we observed that survival in a cohort of patients with severe circulatory failure correlated with their relative frequency of
ChAT
+
CD4
+
T cells in blood. These findings on ChAT
+
human T cells provide a mechanism for cholinergic immune regulation of vascular endothelial function in human inflammation.
Identification of a broadly conserved family of enzymes that hydrolyze (p)ppApp
Authors: Ahmad Shehryar , Gordon Isis J. , Tsang Kara K. , Alexei Andrea G. , Sychantha David , Colautti Jake , Trilesky Sarah L. , Kim Youngchang , Wang Boyuan , Whitney John C. 
Published: March 2023

Bacteria produce a variety of nucleotide second messengers to adapt to their surroundings. Although chemically similar, the nucleotides guanosine penta- and tetraphosphate [(p)ppGpp] and adenosine penta- and tetraphosphate [(p)ppApp] have distinct functions in bacteria. (p)ppGpp mediates survival under nutrient-limiting conditions and its intracellular levels are regulated by synthetases and hydrolases belonging to the RelA-SpoT homolog (RSH) family of enzymes. By contrast, (p)ppApp is not known to be involved in nutrient stress responses and is synthesized by RSH-resembling toxins that inhibit the growth of bacterial cells. However, it remains unclear whether there exists a family of hydrolases that specifically act on (p)ppApp to reverse its toxic effects. Here, we present the structure and biochemical characterization of adenosine 3′-pyrophosphohydrolase 1 (Aph1), the founding member of a monofunctional (p)ppApp hydrolase family of enzymes. Our work reveals that Aph1 adopts a histidine-aspartate (HD)-domain fold characteristic of phosphohydrolase metalloenzymes and its activity mitigates the growth inhibitory effects of (p)ppApp-synthesizing toxins. Using an informatic approach, we identify over 2,000 putative (p)ppApp hydrolases that are widely distributed across bacterial phyla and found in diverse genomic contexts, and we demonstrate that 12 representative members hydrolyze ppApp. In addition, our in silico analyses reveal a unique molecular signature that is specific to (p)ppApp hydrolases, and we show that mutation of two residues within this signature broadens the specificity of Aph1 to promiscuously hydrolyze (p)ppGpp in vitro. Overall, our findings indicate that like (p)ppGpp hydrolases, (p)ppApp hydrolases are widespread in bacteria and may play important and underappreciated role(s) in bacterial physiology.
Digital practice as discriminatory discourse
Authors: Peng Altman Yuzhu 
Published: March 2023

Abstract
This chapter incorporates and draws on the concept of affect to examine how users’ discursive practices are reshaped by the design of interactive digital platforms. An affective critical discourse analysis approach is developed to analyse the affective-discursive loop by using Internet users’ practice of regional discriminatory discourses against Henan people as a case study. Through a comparison between users’ differing practices on two major Chinese news portals – Tencent and NetEase – this chapter reveals the extent to which regional discrimination is amplified by the locative IP-address function of NetEase news portal’s user commentary system. This chapter makes a methodological contribution in response to the CDS notion of discursive power in the digital realm.
Towards an ethnographic approach to social media discourses
Authors: Boukala Salomi , Serafis Dimitris 
Published: March 2023

Abstract
This chapter intends to show how the arena of political debate has relocated from Parliament to Facebook in contemporary Greece and explore the parameters and impact of such relocation in discourses of contemporary political polemics. It explores the way social media spaces combine bottom-up and top-down discourses and their repercussions for discourses of national identity. We assume that social media dominate current politics not only as a source of official announcements but, quite contrarily, that platforms such as Facebook enable communication between civilians and politicians and shape a new public sphere with a new discursive dynamic. In line with studies on the Self and the Other in digital discourses of identity (e.g., KhosraviNik and Sarkhoh 2018), the chapter particularly focuses on the dispute over the name ‘Macedonia’ in Greek digital discourses. The chapter considers the research on the impact of social media on current politics and proposes an ethnographic approach for the analysis of social media discourse by integrating traditions in discourse studies, anthropology, and digital ethnography (Androutsopoulos 2008; Horst and Miller 2012; Hine 2015; KhosraviNik and Unger 2016).
Online counterspeech and the targeting of digital discourses of racism in New Zealand
Authors: Smith Philippa 
Published: March 2023

Abstract
This chapter seeks to locate online counterspeech in the relatively new framework of Social Media Critical Discourse Studies (SM-CDS) by examining the discursive strategies used to counter the racist discourse beneath a YouTube video. I argue that online counterspeech – a phenomenon whereby the Internet is used as a platform to challenge another person’s speech or ideology whether race, religion, or political beliefs – is worthy of critical examination as its associated discourses are inherent in the many-to-many dynamic of bottom-up online social interaction. Innovative ways of investigation such as SM-CDS are called for on top of the traditions in CDS where existing frameworks may fall short in accounting for the techno-discursive dynamic of digital discourse and the way new environments may produce new dynamics of power and influence in discourse formation and consumption.
Bayesian inversion of log-normal eikonal equations
Authors: Yeo Zhan Fei , Hoang Viet Ha 
Published: March 2023

Abstract
We study the Bayesian inverse problem for inferring the log-normal slowness function of the eikonal equation, given noisy observation data on its solution at a set of spatial points. We contribute rigorous proofs on the existence and well-posedness of the problem. We then study approximation of the posterior probability measure by solving the truncated eikonal equation, which contains only a finite number of terms in the Karhunen–Loeve expansion of the slowness function, by the fast marching method (FMM). The error of this approximation in the Hellinger metric is deduced in terms of the truncation level of the slowness and the grid size in the FMM resolution. It is well known that the plain Markov chain Monte Carlo (MCMC) procedure for sampling the posterior probability is highly expensive. We develop and justify the convergence of a multilevel MCMC method. Using the heap sort procedure in solving the forward eikonal equation by the FMM, our multilevel MCMC method achieves a prescribed level of accuracy for approximating the posterior expectation of quantities of interest, requiring only an essentially optimal level of complexity. Numerical examples confirm the theoretical results.
A new nonconvex low-rank tensor approximation method with applications to hyperspectral images denoising
Authors: Tu Zhihui , Lu Jian , Zhu Hong , Pan Huan , Hu Wenyu , Jiang Qingtang , Lu Zhaosong 
Published: March 2023

Abstract
Hyperspectral images (HSIs) are frequently corrupted by mixing noise during their acquisition and transmission. Such complicated noise may reduce the quality of the obtained HSIs and limit the accuracy of the subsequent processing. By using the low-rank prior of the tensor formed by spatial and spectral information and further exploring the intrinsic structure of the underlying HSI from noisy observations, in this paper, we propose a new nonconvex low-rank tensor approximation method including optimization model and efficient iterative algorithm to eliminate multiple types of noise. The proposed mathematical model consists of a nonconvex low-rank regularization term using the γ nuclear norm, which is nonconvex surrogate to Tucker rank, and two data fidelity terms representing sparse and Gaussian noise components, which are regularized by the

ℓ

1

-norm and the Frobenius norm, respectively. To solve this model, we propose an efficient augmented Lagrange multiplier algorithm. We also study the convergence and parameter setting of the algorithm. Extensive experimental results show that the proposed method has better denoising performance than the state-of-the-art competing methods for low-rank tensor approximation and noise modeling.
An ionic pressure sensor array with digitizable sensitivity
Authors: Zou Qiang , Liu Chenyu , Su Qi , Xue Tao 
Published: March 2023

Abstract
Flexible pressure sensors play an indispensable role in electronic skin. A flexible pressure sensor array with a larger sensing area is an inevitable trend for further developing a single flexible pressure sensor. However, pressure sensor arrays suffer from a key challenge: each sensing unit in the array cannot be individually defined for its pressure sensing range and sensitivity. Here, we present an ionic pressure sensor array with digitizable sensitivity achieved through the synergistic cooperation of an ion gel shell interfacial capacitive sensing mechanism and a filler with digitally tunable mechanical stiffness. Through this design, the sensitivity of each sensing pixel unit in the array can be digitally defined in the range of 20 times, and the fabrication process is greatly simplified. We fabricated sensor arrays for object contour recognition and weight judgment, demonstrating their potential application in electronic skin. In addition, we proposed using a customized 3D printer of elastomer to simplify its fabrication process, which is beneficial for engineering applications.
Early crystallization of amorphous selenium under high pressure studied by synchrotron XRD method
Authors: Yuan Shuhua , Wang Luhong , Liu Fuyang , Bass Jay D , Li Yingzhe , Ginsberg Paul A , Zhang Dongzhou , Prakapenka Vitali B , Tkachev Sergey , Liu Haozhe 
Published: March 2023

Abstract
The amorphous selenium (a-Se) was studied via x-ray diffraction (XRD) under pressures ranging from ambient pressure up to 30 GPa at room temperature to study its high-pressure behavior. Two compressional experiments on a-Se samples, with and without heat treatment, respectively, were conducted. Contrary to the previous reports that a-Se crystallized abruptly at around 12 GPa, in this work we report an early partially crystallized state at 4.9 GPa before completing the crystallization at around 9.5 GPa based on in-situ high pressure XRD measurements on the a-Se with 70 °C heat treatment. In comparison, crystallization pressure on another a-Se sample without thermal treatment history was observed to be 12.7 GPa, consistent with the previously reported crystallization pressure. Thus, it is proposed in this work that prior heat treatment of a-Se can result in an earlier crystallization under high pressure, which helps to understand the possible mechanism caused by the previous controversial reports on pressure induced crystallization behavior in a-Se.
EXAFS investigations on the pressure induced local structural changes of GeSe2 glass under different hydrostatic conditions
Authors: Mijit Emin , Elias F S Rodrigues João , Tchoudinov Georghii , Paparoni Francesco , Shinmei Toru , Irifune Tetsuo , Mathon Olivier , Dorothea Rosa Angelika , Di Cicco Andrea 
Published: March 2023

Abstract
Pressure-induced transformations in glassy GeSe2 have been studied using the x-ray absorption spectroscopy. Experiments have been carried out at the scanning-energy beamline BM23 (European Synchrotron Radiation Facility) providing a micrometric x-ray focal spot up to pressures of about 45 GPa in a diamond anvil cell. Both Se and Ge K-edge experiments were performed under different hydrostatic conditions identifying the metallization onsets by accurate determinations of the edge shifts. The semiconductor-metal transition was observed to be completed around 20 GPa when neon was used as a pressure transmitting medium (PTM), while this transition was slightly shifted to lower pressures when no PTM was used. Accurate double-edge extended x-ray absorption fine structure (EXAFS) refinements were carried out using advanced data-analysis methods. EXAFS data-analysis confirmed the trend shown by the edge shifts for this disordered material, showing that the transition from tetrahedral to octahedral coordination for Ge sites is not fully achieved at 45 GPa. Results of present high pressure EXAFS experiments have shown the absence of significant neon incorporation into the glass within the pressure range up to 45 GPa.
Two-dimensional half-metallicity and fully spin-polarized topological fermions in monolayer EuOBr
Authors: Li Chenyao , Li Minghang , Li Yefeng , He Tingli , Liu Ying , Zhang Xiaoming , Dai Xuefang , Liu Guodong 
Published: March 2023

Abstract
Two-dimensional (2D) half-metal and topological states have been the current research focus in condensed matter physics. Herein, we report a novel 2D material named EuOBr monolayer, which can simultaneously show 2D half-metal and topological fermions. This material shows a metallic state in the spin-up channel but a large insulating gap of 4.38 eV in the spin-down channel. In the conducting spin channel, the EuOBr monolayer shows the coexistence of Weyl points and nodal-lines near the Fermi level. These nodal-lines are classified by type-I, hybrid, closed, and open nodal-lines. The symmetry analysis suggests these nodal-lines are protected by the mirror symmetry, which cannot be broken even spin–orbit coupling is included because the ground magnetization direction in the material is out-of-plane [001]. The topological fermions in the EuOBr monolayer are fully spin-polarized, which can be meaningful for future applications in topological spintronic nano-devices.
A non-nuclear inline densitometer for multiphase flows
Authors: Ramakrishnan Vijay , Arsalan Muhammad , Deffenbaugh Max 
Published: March 2023

Abstract
Multiphase flowmeters are used in the oil-and-gas industry to measure real-time flow rates of oil, gas, and brine, flowing simultaneously as a non-homogeneous mixture, in a pipeline from wellhead to separator. Since these flow rates cannot be measured directly, they are inferred from other measurements including mixture density. Mixture density is commonly measured using nuclear densitometers which can be problematic in terms of safety and maintenance. This paper details the development—concept and experimental validation—of a non-nuclear inline densitometer that measures multiphase mixture density using pressure sensors. A comprehensive flow-loop test was conducted at a commercial facility to evaluate the technology under a wide range of flow conditions—flow rates 1000 to 10000 bpd, gas fractions 0% to 96%, water cuts 0% to 100%, with a synthetic oil as liquid hydrocarbon, methane as gas medium, two water salinities—totaling nearly 300 test points. The results from this experimental validation—specifically, the technology’s accuracy and operating envelope—point to a groundbreaking practical solution to a long-standing problem.
Degradation phenomena of quantum dot light-emitting diodes induced by high electric field
Authors: Cha Yunmi , Woo Hwi Je , Yoon Sang Hyun , Song Young Jae , Choi Young Jin , Kim Seong Heon 
Published: March 2023

Abstract
Quantum dots possess exceptional optoelectronic properties, such as narrow bandwidth, controllable wavelength, and compatibility with solution-based processing. However, for efficient and stable operation in electroluminescence mode, several issues require resolution. Particularly, as device dimensions decrease, a higher electric field may be applied through next-generation quantum dot light-emitting diode (QLED) devices, which could further degrade the device. In this study, we conduct a systematic analysis of the degradation phenomena of a QLED device induced by a high electric field, using scanning probe microscopy (SPM) and transmission electron microscopy (TEM). We apply a local high electric field to the surface of a QLED device using an atomic force microscopy (AFM) tip, and we investigate changes in morphology and work function in the Kelvin probe force microscopy mode. After the SPM experiments, we perform TEM measurements on the same degraded sample area affected by the electric field of the AFM tip. The results indicate that a QLED device could be mechanically degraded by a high electric field, and work function changes significantly in degraded areas. In addition, the TEM measurements reveal that In ions migrate from the indium tin oxide (ITO) bottom electrode to the top of the QLED device. The ITO bottom electrode also deforms significantly, which could induce work function variation. The systematic approach adopted in this study can provide a suitable methodology for investigating the degradation phenomena of various optoelectronic devices.
The first mobile photon-counting detector CT: the human images and technical performance study
Authors: Park Su-Jin , Park Junyoung , Kim Doil , Lee Duhgoon , Lee Chang-Lae , Bechwati Ibrahim , Wu Dufan , Gupta Rajiv , Jung Jinwook 
Published: March 2023

Abstract

Objective. The purpose of this study is to assess its human images and its unique capabilities such as the ‘on demand’ higher spatial resolution and multi-spectral imaging of photon-counting-detector (PCD)-CT. Approach. In this study, the FDA 510(k) cleared mobile PCD-CT (OmniTom Elite) was used. To this end, we imaged internationally certified CT phantoms and a human cadaver head to evaluate the feasibility of high resolution (HR) and multi-energy imaging. We also demonstrate the performance of PCD-CT via first-in-human imaging by scanning three human volunteers. Main results. At the 5 mm slice thickness, routinely used in diagnostic head CT, the first human PCD-CT images were diagnostically equivalent to the EID-CT scanner. The HR acquisition mode of PCD-CT achieved a resolution of 11 line-pairs (lp)/cm as compared to 7 lp cm−1 using the same kernel (posterior fossa-kernel) in the standard acquisition mode of EID-CT. For the quantitative multi-energy CT performance, the measured CT numbers in virtual mono-energetic images (VMI) of iodine inserts in the Gammex Multi-Energy CT phantom (model 1492, Sun Nuclear Corporation, USA) matched the manufacturer reference values with mean percent error of 3.25%. Multi-energy decomposition with PCD-CT demonstrated the separation and quantification of iodine, calcium, and water. Significance. PCD-CT can achieve multi-resolution acquisition modes without physically changing the CT detector. It can provide superior spatial resolution compared with the standard acquisition mode the conventional mobile EID-CT. Quantitative spectral capability of PCD-CT can provide accurate, simultaneous multi-energy images for material decomposition and VMI generation using a single exposure.
Wetting ridges on slippery liquid-infused porous surfaces
Authors: Tran Hong-Huy , Lee Daeyeon , Riassetto David 
Published: March 2023

Abstract
Slippery liquid-infused porous surfaces (SLIPS) show remarkable liquid repellency, making them useful for many coating applications. The outstanding repellency of SLIPS comes from a lubricant layer stabilized within and at the surface of a porous template. The stability of this lubricant layer is key for SLIPS to exhibit their unique functionality. The lubricant layer, however, is depleted over time, causing degradation of liquid repellency. The formation of wetting ridges surrounding liquid droplets on the surface of SLIPS is one of the primary sources of lubricant depletion. Here, we present the fundamental understanding and characteristics of wetting ridges and highlight the latest developments that enable the detailed investigation and suppression of wetting ridge formation on SLIPS. In addition, we offer our perspectives on new and exciting directions for SLIPS.