bluuebunny/crossref_metadata_2025 huggingface dataset:
Ice core drilling on a high-elevation accumulation zone of Trambau Glacier in the Nepal Himalaya
Authors: Tsushima Akane , Miyahara Morihiro , Yamasaki Tetsuhide , Esashi Nao , Sato Yota , Kayastha Rijan B. , Sherpa Ang J. B. Lama , Sano Masaki , Fujita Koji
Published: September 2021

We drilled an 81.2-m-long ice core in the accumulation area (5860 m a.s.l.) of Trambau Glacier in the Rolwaling region during October–November 2019. The drilling operation was conducted with a lightweight electro-mechanical drill system after two reconnaissance fieldworks in 2017 and 2018, during which two shallow firn cores were drilled with a hand auger. The drill system and ice core samples were transported by helicopters at a high elevation of 6000 m a.s.l. A further challenging issue was the ice core transportation between Nepal and Japan, as no regular commercial flight was available for the frozen samples. The addition of dry ice imported from India immediately prior to leaving Nepal allowed the ice core samples to be successfully transported to a cold room in Japan, and remain in a frozen state. Stratigraphic observations during the drilling operation suggest the drill site has been affected by melting and refreezing.
Brauer groups of moduli of hyperelliptic curves via cohomological invariants
Authors: Di Lorenzo Andrea , Pirisi Roberto
Published: September 2021

Using the theory of cohomological invariants for algebraic stacks, we compute the Brauer group of the moduli stack of hyperelliptic curves${\mathcal {H}}_g$over any field of characteristic$0$. In positive characteristic, we compute the part of the Brauer group whose order is prime to the characteristic of the base field.
Rural–urban dimensions of the perception of malaria severity and practice of malaria preventive measures: insight from the 2018 Nigeria Demographic and Health Survey
Authors: Duodu Precious Adade , Dzomeku Veronica Millicent , Emerole Chiagoziem Ogazirilem , Agbadi Pascal , Arthur-Holmes Francis , Nutor Jerry John
Published: September 2021

Morbidities and mortalities caused by malaria are still a serious issue in Nigeria, with the country accounting for 25% of malaria morbidities and 24% of malaria mortalities globally in 2018. Treated bed nets reduce the incidence of malaria, but not all Nigerians use them. This study aimed to examine the factors associated with treated bed net usage, including perceived severity of malaria, and the rural–urban differences in the relationship between socio-demographic factors and use of treated bed nets in Nigeria. The analytic sample size comprised 40,693 women aged 15–49 years. Poisson regression and bivariable and multivariable analyses were used to test the study hypothesis that women who agreed that malaria could potentially lead to death would be more likely to adopt malaria preventive measures, including treated bed net use. About 48% of the women slept under a treated mosquito net the night before the survey. Those who perceived that malaria could lead to death had a higher likelihood of using a treated bed net in the urban, rural and combined samples. However, in the multivariable model, the association between perceived malaria severity and use of a treated bed net was only significant for rural women (APR=0.964, 95% CI: 0.933, 0.996). The results unexpectedly suggest that rural Nigerian women who perceive malaria to be severe have a lower likelihood of using treated bed nets. Also, rural–urban variations in the relationship between the socio-demographic variables and use of treated bed nets were observed. Policies should consider the observed rural–urban dichotomy in the influence of perceived severity of malaria and other socio-demographic factors on women’s use of treated bed nets in Nigeria.
A structure-preserving finite element method for compressible ideal and resistive magnetohydrodynamics
Authors: Gawlik Evan S. , Gay-Balmaz François
Published: September 2021

We construct a structure-preserving finite element method and time-stepping scheme for compressible barotropic magnetohydrodynamics both in the ideal and resistive cases, and in the presence of viscosity. The method is deduced from the geometric variational formulation of the equations. It preserves the balance laws governing the evolution of total energy and magnetic helicity, and preserves mass and the constraint$\text {div}B = 0$to machine precision, both at the spatially and temporally discrete levels. In particular, conservation of energy and magnetic helicity hold at the discrete levels in the ideal case. It is observed that cross-helicity is well conserved in our simulation in the ideal case.
Identifying functional cognitive disorder: a proposed diagnostic risk model
Authors: McWhirter Laura , Ritchie Craig , Stone Jon , Carson Alan
Published: September 2021

Background

Functional cognitive disorders (FCD) are an important differential diagnosis of neurodegenerative disease. The utility of suggested diagnostic features has not been prospectively explored in “real world” clinical populations. This study aimed to identify positive clinical markers of FCD.

Methods

Adults with cognitive complaints but not dementia were recruited from memory, neurology, and neuropsychiatry clinics. Participants underwent structured interview, Mini International Neuropsychiatric Interview, Montreal Cognitive Assessment, Luria 3-step, interlocking fingers, digit span and Medical Symptom Validity Test, Patient Health Questionnaire 15, Hospital Anxiety and Depression Scale, Multifactorial Memory Questionnaire, and Pittsburgh Sleep Quality Inventory. Potential diagnostic variables were tested against expert consensus diagnosis using logistic regression.

Results

FCD were identified in 31/49 participants. Participants with FCD were younger, spoke for longer when prompted “Tell me about the problems you’ve been having,” and had more anxiety and depression symptoms and psychiatric diagnoses than those without FCD. There were no significant differences in sex, education, or cognitive scores. Younger age and longer spoken response predicted FCD diagnosis in a model which explained 74% of diagnostic variability and had an area under the curve (AUC) of 94%.

Conclusions

A detailed description of cognitive failure is a sensitive and specific positive feature of FCD, demonstrating internal inconsistency between experienced and observed function. Cognitive and performance validity tests appear less helpful in FCD diagnosis. People with FCD are not “worried well” but often perform poorly on tests, and have more anxiety, depression, and physical symptoms than people with other cognitive disorders. Identifying diagnostic profiles is an important step toward parity of esteem for FCDs, as differential diagnoses of neurodegenerative disease and an independent target for clinical trials.
Introduction: special issue on weather and climate impacts in developing countries
Authors: Creti Anna , Delacote Philippe , Leblois Antoine
Published: September 2021

Shocks related to weather variations have strong effects on developing countries’ economies. Climate change is expected to increase the occurrence and magnitude of extreme weather events such as droughts, floods or hurricanes that strongly affect agriculture and other activities. This special issue gathers literature reviews and case studies that aim to better understand heterogeneous impacts and their transmission channels, as well as to evaluate the impact of such weather shocks on developing economies, including Sub-Saharan African countries, India and Brazil.
Occupational exoskeletons: A roadmap toward large-scale adoption. Methodology and challenges of bringing exoskeletons to workplaces
Authors: Crea Simona , Beckerle Philipp , De Looze Michiel , De Pauw Kevin , Grazi Lorenzo , Kermavnar Tjaša , Masood Jawad , O’Sullivan Leonard W. , Pacifico Ilaria , Rodriguez-Guerrero Carlos , Vitiello Nicola , Ristić-Durrant Danijela , Veneman Jan
Published: September 2021

The large-scale adoption of occupational exoskeletons (OEs) will only happen if clear evidence of effectiveness of the devices is available. Performing product-specific field validation studies would allow the stakeholders and decision-makers (e.g., employers, ergonomists, health, and safety departments) to assess OEs’ effectiveness in their specific work contexts and with experienced workers, who could further provide useful insights on practical issues related to exoskeleton daily use. This paper reviews present-day scientific methods for assessing the effectiveness of OEs in laboratory and field studies, and presents the vision of the authors on a roadmap that could lead to large-scale adoption of this technology. The analysis of the state-of-the-art shows methodological differences between laboratory and field studies. While the former are more extensively reported in scientific papers, they exhibit limited generalizability of the findings to real-world scenarios. On the contrary, field studies are limited in sample sizes and frequently focused only on subjective metrics. We propose a roadmap to promote large-scale knowledge-based adoption of OEs. It details that the analysis of the costs and benefits of this technology should be communicated to all stakeholders to facilitate informed decision making, so that each stakeholder can develop their specific role regarding this innovation. Large-scale field studies can help identify and monitor the possible side-effects related to exoskeleton use in real work situations, as well as provide a comprehensive scientific knowledge base to support the revision of ergonomics risk-assessment methods, safety standards and regulations, and the definition of guidelines and practices for the selection and use of OEs.
Simultaneous Pulsating Aurora and Microburst Observations With Ground‐Based Fast Auroral Imagers and CubeSat FIREBIRD‐II
Authors: Kawamura Miki , Sakanoi Takeshi , Fukizawa Mizuki , Miyoshi Yoshizumi , Hosokawa Keisuke , Tsuchiya Fuminori , Katoh Yuto , Ogawa Yasunobu , Asamura Kazushi , Saito Shinji , Spence Harlan , Johnson Arlo , Oyama Shin'ichiro , Brändström Urban
Published: September 2021

We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground‐based fast auroral imagers with the FIREBIRD‐Ⅱ CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD's CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the pulsating aurora and the microburst occur simultaneously due to the chorus waves at different latitudes along the same field‐line as predicted by Miyoshi et al. (2020, https://doi.org/10.1029/2020gl090360).
Millimeter‐ to Decimeter‐Scale Surface Roughness of the Moon at the Chang'e‐4 Exploration Region
Authors: Guo Dijun , Fa Wenzhe , Wu Bo , Li Yuan , Liu Yang
Published: September 2021

The surface slope and roughness of the Moon have been investigated extensively over a wide baseline range except millimeter to decimeter scales. In this study, we present for the first time millimeter‐to decimeter‐scale surface slope and roughness of the Moon at China's Chang'e‐4 landing regions (∼20 m across) using the Digital Terrain Model (DTM) with a resolution of 5 mm/pixel. The bidirectional slope at the 7 mm scale can be larger than 40° with a median value of ∼10°. The root‐mean‐square (RMS) height within a window size of 125 mm varies from ∼1 mm to ∼18 mm with a median value of ∼4 mm. Both the bidirectional slope and RMS height show scale‐dependent behaviors and the parameter of scale dependence, the Hurst exponent, is ∼0.6–0.85. We also synthesized the bidirectional slope at baseline from micrometer to kilometer, showing that bidirectional slope decreases from ∼60° at micrometer to ∼1° at a kilometer. At millimeter‐scale, surface roughness is mainly controlled by small impact craters, rocks, and regolith properties. Our roughness results not only bridge the gap in understanding surface roughness from traditional topographic data sets to radar and thermal observations, but also provide valuable information about lunar regolith characteristics, and small‐scale geological processes.
Observations and Validation of Plasma Density, Temperature, and Abundance From a Langmuir Probe Onboard the International Space Station
Authors: Debchoudhury Shantanab , Barjatya Aroh , Minow Joseph I. , Coffey Victoria N. , Chandler Michael O.
Published: September 2021

The Floating Potential Measurement Unit (FPMU) has been operational on board the International Space Station (ISS) since 2006. One of the instruments in the FPMU suite is a spherical wide‐sweeping Langmuir probe, referred to as the WLP, which is sampled at a temporal cadence of 1 s giving in‐situ measurements of the plasma density and electron temperature. In this study we present our refinements to the Langmuir probe analysis algorithm that address the uncertainties associated with photoelectron emission current from the metal probe. We also derive the fraction of ions as a secondary data product, which shows decrease in abundance in the post‐midnight sector during solar minimum. The derived plasma parameters are compared and validated with an independent in‐situ measurement technique, overlapping ground‐based incoherent scatter radar measurements, as well as International Reference Ionosphere model output. The reduced data set spans the entire solar cycle 24 and shows the F‐region ionosphere variance at ISS altitudes.
Ion Kappa Distribution Parameters in the Magnetosphere of the Earth at Geocentric Distances Smaller Than 20 RE During Quiet Geomagnetic Conditions
Authors: Kirpichev I. P. , Antonova E. E. , Stepanova M. , Eyelade A. V. , Espinoza C. M. , Ovchinnikov I. L. , Vorobjev V. G. , Yagodkina O. I.
Published: September 2021

The Earth's magnetosphere is mainly a collisionless plasma system with non‐Maxwellian particle distributions, which are often fitted by the kappa function. While the Maxwell distribution function is described by two parameters (density and temperature), the kappa distribution function has three parameters: density, core energy, and the kappa index that characterizes the slope at high energies. In this study, we fitted an ion flux measured by the five Time History of Events and Macroscale Interactions during Substorms satellites in the Earth's magnetosphere during quiet geomagnetic conditions by a single kappa distribution function. The data were constrained to the following regions: from seven Earth Radii (7 ) to the Earth's magnetopause at the dayside, and up to 20 for other magnetic local time sectors. The two‐dimensional spatial distribution of the fitted parameters and their radial dependencies were analyzed. Regions of high and low ‐parameter are selected and their formation is discussed.
Black Carbon Involved Photochemistry Enhances the Formation of Sulfate in the Ambient Atmosphere: Evidence From In Situ Individual Particle Investigation
Authors: Zhang Guohua , Fu Yuzhen , Peng Xiaocong , Sun Wei , Shi Zongbo , Song Wei , Hu Weiwei , Chen Duohong , Lian Xiufeng , Li Lei , Tang Mingjin , Wang Xinming , Bi Xinhui
Published: September 2021

Mixing state of black carbon (BC) with secondary species has been highlighted as a major uncertainty in assessing its radiative forcing. While recent laboratory simulation has demonstrated that BC could serve as a catalyst to enhance the formation of sulfate, its role in the formation and evolution of secondary aerosols in the real atmosphere remains poorly understood. In the present study, the mixing of BC with sulfate/nitrate in the atmosphere of Guangzhou (China) was directly investigated with a single particle aerosol mass spectrometer (SPAMS). The peak area ratios of sulfate to nitrate (SNRs) for the BC‐containing particles are constantly higher than those of the BC‐free particles (defined as particles with negligible BC signals). Furthermore, the seasonal SNR peak is observed in summer and autumn, and the diurnal peak is found in the afternoon, consistent with the trends of radiation‐related parameters (i.e., solar radiation and temperature), pointing to the BC‐induced photochemical production of sulfate. Such hypothesis is further supported by the multilinear regression and random forest analysis, showing that the variation of SNRs associated with the BC‐containing particles could be well explained (R2 = ∼0.7–0.8) by the radiation‐related parameters (>30% of the variance) and the relative BC content (∼20%) in individual particles, but with limited influence of precursors (SO2/NOx: <5%). Differently, the radiation‐related factors only explain <10% of the SNR variation for the BC‐free particles. These results provide ambient observational evidence pointing to a unique role of BC on the photochemical formation and evolution of sulfate, which merits further quantitative evaluations.
Scaling Laws for Mixed‐Heated Stagnant‐Lid Convection and Application to Europa
Authors: Deschamps Frédéric , Vilella Kenny
Published: September 2021

Because rocks and ices viscosities strongly depend on temperature, planetary mantles and ice shells are often thought to be animated by stagnant‐lid convection. Their dynamics is further impacted by the release of internal heat, either through radioactive isotopes decay or tidal dissipation. Here, we quantify the impact of internal heating on stagnant‐lid convection. We perform numerical simulations of convection combining strongly temperature‐dependent viscosity and mixed (basal and internal) heating in 3D‐Cartesian and spherical geometries, and use these simulations to build scaling laws relating surface heat flux, Φsurf, interior temperature, Tm, and stagnant lid thickness, dlid, to the Rayleigh number, heating rate, H, and top‐to‐bottom viscosity ratio, Δη. These relationships show that Tm increases with H but decreases with Δη, while Φsurf increases with H and Δη. Importantly, they also describe heterogeneously heated systems well, provided that the maximum dissipation occurs in hottest regions. For H larger than a value Hcrit, the bottom heat flux turns negative and the system cools down both at its top and bottom. Two additional interesting results are that (a) while the rigid lid stiffens (its mobility decreases) with increasing H, it also thins; and (b) Hcrit increases with increasing Δη. We then use our scaling laws to assess the impact of tidal heating on Europa's ice shell properties and evolution. Our calculations suggest a shell thickness in the range 20–80 km, depending on viscosity and dissipated power, and show that internal heating has a stronger influence than the presence of impurities in the sub‐surface ocean.
Calibrating Trilobatus sacculifer Na/Ca Ratios From Atlantic Core‐Tops as a Proxy for Sea Surface Salinity
Authors: Watkins Colton S. , Schmidt Matthew W. , Hertzberg Jennifer E.
Published: September 2021

Recent studies found a positive correlation between seawater salinity and Na/Ca ratios in foraminiferal calcite, suggesting a potential new paleosalinity proxy (Bertlich et al., 2018, https://doi.org/10.5194/bg-15-5991-2018; Hauzer et al., 2021, https://doi.org/10.1029/2021pa004218; Mezger et al., 2016, https://doi.org/10.1002/2016pa003052; Wit et al., 2013). To test this new proxy in an open‐ocean setting, Na/Ca ratios from the surface‐dwelling planktic foraminifera Trilobatus sacculifer were measured from a suite of nine sediment core‐tops spanning from the North Atlantic subtropical gyre to the South Atlantic subtropical gyre across a salinity range of 1.6. Results show a positive correlation between habitat salinity (HS) and T. sacculifer Na/Ca (Na/Ca (mmol/mol) = 0.516 (HS (±0.17)) – 12.934; R2 = 0.81, p < 0.005). We also find no relationship between T. sacculifer Na/Ca and sample size or habitat temperature, indicating Na/Ca is predominantly controlled by salinity. Additionally, we generate the first downcore record of sea surface salinity (SSS) in the Florida Straits over the last deglaciation based on T. sacculifer Na/Ca variability. Results show agreement between our Na/Ca record and a previously published deglacial δ18Osw record that is also thought to reflect SSS variability from the same core (Schmidt & Lynch‐Stieglitz, 2011, https://doi.org/10.1029/2011PA002157). Both records indicate an abrupt increase in SSS during the Younger Dryas (11.7–12.9 kyr). Converting the Florida Straits T. sacculifer Na/Ca ratios to SSS using our new Atlantic core‐top calibration indicates a maximum salinity change of ∼2.2 across the last deglaciation, in agreement with modeling study estimates of salinity change across this period.
Peripheral inflammation is associated with micro-structural and functional connectivity changes in depression-related brain networks
Authors: Kitzbichler Manfred G. , Aruldass Athina R. , Barker Gareth J. , Wood Tobias C. , Dowell Nicholas G. , Hurley Samuel A. , McLean John , Correia Marta , Clarke Charlotte , Pointon Linda , Cavanagh Jonathan , Cowen Phil , Pariante Carmine , Cercignani Mara ,   Neuroimmunology of Mood Disorders and Alzheimer’s Disease (NIMA) Consortium, Bullmore Edward T. , Harrison Neil A.
Published: September 2021

Inflammation is associated with depressive symptoms and innate immune mechanisms are likely causal in some cases of major depression. Systemic inflammation also perturbs brain function and microstructure, though how these are related remains unclear. We recruited N = 46 healthy controls, and N = 83 depressed cases stratified by CRP (> 3 mg/L: N = 33; < 3 mg/L: N = 50). All completed clinical assessment, venous blood sampling for C-reactive protein (CRP) assay, and brain magnetic resonance imaging (MRI). Micro-structural MRI parameters including proton density (PD), a measure of tissue water content, were measured at 360 cortical and 16 subcortical regions. Resting-state fMRI time series were correlated to estimate functional connectivity between individual regions, as well as the sum of connectivity (weighted degree) of each region. Multiple tests for regional analysis were controlled by the false discovery rate (FDR = 5%). We found that CRP was significantly associated with PD in precuneus, posterior cingulate cortex (pC/pCC) and medial prefrontal cortex (mPFC); and with functional connectivity between pC/pCC, mPFC and hippocampus. Depression was associated with reduced weighted degree of pC/pCC, mPFC, and other nodes of the default mode network (DMN). Thus CRP-related increases in proton density—a plausible marker of extracellular oedema—and changes in functional connectivity were anatomically co-localised with DMN nodes that also demonstrated significantly reduced hubness in depression. We suggest that effects of peripheral inflammation on DMN node micro-structure and connectivity may mediate inflammatory effects on depression.
A dismantling study on imaginal retraining in overweight or obese women
Authors: Wirtz Janina , Ascone Leonie , Gehlenborg Josefine , Moritz Steffen , Kühn Simone
Published: September 2021

Imaginal retraining is a variant of approach bias modification and transfers the method into one’s own mind. As the technique contains multiple elements, this pilot study aimed to dismantle which of its components is most efficient in reducing craving for high-calorie food. A total of 113 women were randomly allocated to one out of six conditions containing a short intervention to mentally manipulate a picture displaying high-calorie foods. Four of the interventions involved different combinations of elements of the imaginal retraining technique, while the remaining two conditions comprised thought suppression or merely observing a picture. Participants rated their level of craving, as well as three pictures containing healthy and unhealthy foods regarding their pleasantness before and after the interventions took place. Within-group changes were assessed with paired t-tests (in case of non-normal data Wilcoxon paired t-tests) and between-group differences with one-way ANOVAs (non-parametric Kruskal–Wallis tests). A trend level reduction in craving was found in the imaginal retraining condition with and without a movement. A post hoc analysis of both conditions joint together showed a statistically significant reduction in craving. In addition, positive picture appraisal for unhealthy foods was significantly reduced in both imaginal retraining conditions (with and without movement) with medium to large effect sizes. This study demonstrated that imaginal retraining with an arm movement can reduce craving and picture appraisal for high-calorie foods significantly in a one-time application. It is a promising technique to reduce appraisal for unhealthy high-calorie foods. Future studies should repeat the experiment in situations of high craving and allow for a personalized selection of stimuli.
Alpha-Synuclein defects autophagy by impairing SNAP29-mediated autophagosome-lysosome fusion
Authors: Tang Qilin , Gao Pan , Arzberger Thomas , Höllerhage Matthias , Herms Jochen , Höglinger Günter , Koeglsperger Thomas
Published: September 2021

Dopaminergic (DA) cell death in Parkinson’s disease (PD) is associated with the gradual appearance of neuronal protein aggregates termed Lewy bodies (LBs) that are comprised of vesicular membrane structures and dysmorphic organelles in conjunction with the protein alpha-Synuclein (α-Syn). Although the exact mechanism of neuronal aggregate formation and death remains elusive, recent research suggests α-Syn-mediated alterations in the lysosomal degradation of aggregated proteins and organelles – a process termed autophagy. Here, we used a combination of molecular biology and immunochemistry to investigate the effect of α-Syn on autophagy turnover in cultured human DA neurons and in human post-mortem brain tissue. We found α-Syn overexpression to reduce autophagy turnover by compromising the fusion of autophagosomes with lysosomes, thus leading to a decrease in the formation of autolysosomes. In accord with a compensatory increase in the plasma membrane fusion of autophagosomes, α-Syn enhanced the number of extracellular vesicles (EV) and the abundance of autophagy-associated proteins in these EVs. Mechanistically, α-Syn decreased the abundance of the v-SNARE protein SNAP29, a member of the SNARE complex mediating autophagolysosome fusion. In line, SNAP29 knockdown mimicked the effect of α-Syn on autophagy whereas SNAP29 co-expression reversed the α-Syn-induced changes on autophagy turnover and EV release and ameliorated DA neuronal cell death. In accord with our results from cultured neurons, we found a stage-dependent reduction of SNAP29 in SNc DA neurons from human post-mortem brain tissue of Lewy body pathology (LBP) cases. In summary, our results thus demonstrate a previously unknown effect of α-Syn on intracellular autophagy-associated SNARE proteins and, as a consequence, a reduced autolysosome fusion. As such, our findings will therefore support the investigation of autophagy-associated pathological changes in PD
TKT maintains intestinal ATP production and inhibits apoptosis-induced colitis
Authors: Tian Na , Hu Lei , Lu Ying , Tong Lingfeng , Feng Ming , Liu Qi , Li Yakui , Zhu Yemin , Wu Lifang , Ji Yingning , Zhang Ping , Xu Tianle , Tong Xuemei
Published: September 2021

Inflammatory bowel disease (IBD) has a close association with transketolase (TKT) that links glycolysis and the pentose phosphate pathway (PPP). However, how TKT functions in the intestinal epithelium remains to be elucidated. To address this question, we specifically delete TKT in intestinal epithelial cells (IECs). IEC TKT-deficient mice are growth retarded and suffer from spontaneous colitis. TKT ablation brings about striking alterations of the intestine, including extensive mucosal erosion, aberrant tight junctions, impaired barrier function, and increased inflammatory cell infiltration. Mechanistically, TKT deficiency significantly accumulates PPP metabolites and decreases glycolytic metabolites, thereby reducing ATP production, which results in excessive apoptosis and defective intestinal barrier. Therefore, our data demonstrate that TKT serves as an essential guardian of intestinal integrity and barrier function as well as a potential therapeutic target for intestinal disorders.
The Arabidopsis MIK2 receptor elicits immunity by sensing a conserved signature from phytocytokines and microbes
Authors: Hou Shuguo , Liu Derui , Huang Shijia , Luo Dexian , Liu Zunyong , Xiang Qingyuan , Wang Ping , Mu Ruimin , Han Zhifu , Chen Sixue , Chai Jijie , Shan Libo , He Ping
Published: September 2021

Sessile plants encode a large number of small peptides and cell surface-resident receptor kinases, most of which have unknown functions. Here, we report that the Arabidopsis receptor kinase MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) recognizes the conserved signature motif of SERINE-RICH ENDOGENOUS PEPTIDEs (SCOOPs) from Brassicaceae plants as well as proteins present in fungal Fusarium spp. and bacterial Comamonadaceae, and elicits various immune responses. SCOOP signature peptides trigger immune responses and altered root development in a MIK2-dependent manner with a sub-nanomolar sensitivity. SCOOP12 directly binds to the extracellular leucine-rich repeat domain of MIK2 in vivo and in vitro, indicating that MIK2 is the receptor of SCOOP peptides. Perception of SCOOP peptides induces the association of MIK2 and the coreceptors SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (SERK3) and SERK4 and relays the signaling through the cytosolic receptor-like kinases BOTRYTIS-INDUCED KINASE 1 (BIK1) and AVRPPHB SUSCEPTIBLE1 (PBS1)-LIKE 1 (PBL1). Our study identifies a plant receptor that bears a dual role in sensing the conserved peptide motif from phytocytokines and microbial proteins via a convergent signaling relay to ensure a robust immune response.
Structural basis of RNA polymerase inhibition by viral and host factors
Authors: Pilotto Simona , Fouqueau Thomas , Lukoyanova Natalya , Sheppard Carol , Lucas-Staat Soizick , Díaz-Santín Luis Miguel , Matelska Dorota , Prangishvili David , Cheung Alan C. M. , Werner Finn
Published: September 2021

RNA polymerase inhibition plays an important role in the regulation of transcription in response to environmental changes and in the virus-host relationship. Here we present the high-resolution structures of two such RNAP-inhibitor complexes that provide the structural bases underlying RNAP inhibition in archaea. The Acidianus two-tailed virus encodes the RIP factor that binds inside the DNA-binding channel of RNAP, inhibiting transcription by occlusion of binding sites for nucleic acid and the transcription initiation factor TFB. Infection with the Sulfolobus Turreted Icosahedral Virus induces the expression of the host factor TFS4, which binds in the RNAP funnel similarly to eukaryotic transcript cleavage factors. However, TFS4 allosterically induces a widening of the DNA-binding channel which disrupts trigger loop and bridge helix motifs. Importantly, the conformational changes induced by TFS4 are closely related to inactivated states of RNAP in other domains of life indicating a deep evolutionary conservation of allosteric RNAP inhibition.
Demonstration of valley anisotropy utilized to enhance the thermoelectric power factor
Authors: Li Airan , Hu Chaoliang , He Bin , Yao Mengyu , Fu Chenguang , Wang Yuechu , Zhao Xinbing , Felser Claudia , Zhu Tiejun
Published: September 2021

Valley anisotropy is a favorable electronic structure feature that could be utilized for good thermoelectric performance. Here, taking advantage of the single anisotropic Fermi pocket in p-type Mg3Sb2, a feasible strategy utilizing the valley anisotropy to enhance the thermoelectric power factor is demonstrated by synergistic studies on both single crystals and textured polycrystalline samples. Compared to the heavy-band direction, a higher carrier mobility by a factor of 3 is observed along the light-band direction, while the Seebeck coefficient remains similar. Together with lower lattice thermal conductivity, an increased room-temperature zT by a factor of 3.6 is found. Moreover, the first-principles calculations of 66 isostructural Zintl phase compounds are conducted and 9 of them are screened out displaying a pz-orbital-dominated valence band, similar to Mg3Sb2. In this work, we experimentally demonstrate that valley anisotropy is an effective strategy for the enhancement of thermoelectric performance in materials with anisotropic Fermi pockets.
Reactive wear protection through strong and deformable oxide nanocomposite surfaces
Authors: Liu Chang , Li Zhiming , Lu Wenjun , Bao Yan , Xia Wenzhen , Wu Xiaoxiang , Zhao Huan , Gault Baptiste , Liu Chenglong , Herbig Michael , Fischer Alfons , Dehm Gerhard , Wu Ge , Raabe Dierk
Published: September 2021

Wear-related energy and material loss cost over 2500 Billion Euro per year. Traditional wisdom suggests that high-strength materials reveal low wear rates, yet, their plastic deformation mechanisms also influence their wear performance. High strength and homogeneous deformation behavior, which allow accommodating plastic strain without cracking or localized brittle fracture, are crucial for developing wear-resistant metals. Here, we present an approach to achieve superior wear resistance via in-situ formation of a strong and deformable oxide nanocomposite surface during wear, by reaction of the metal surface with its oxidative environment, a principle that we refer to as ‘reactive wear protection’. We design a TiNbZr-Ag alloy that forms an amorphous-crystalline oxidic nanocomposite surface layer upon dry sliding. The strong (2.4 GPa yield strength) and deformable (homogeneous deformation to 20% strain) nanocomposite surface reduces the wear rate of the TiNbZr-Ag alloy by an order of magnitude. The reactive wear protection strategy offers a pathway for designing ultra-wear resistant alloys, where otherwise brittle oxides are turned to be strong and deformable for improving wear resistance.
Two-dimensional molybdenum carbide 2D-Mo2C as a superior catalyst for CO2 hydrogenation
Authors: Zhou Hui , Chen Zixuan , Kountoupi Evgenia , Tsoukalou Athanasia , Abdala Paula M. , Florian Pierre , Fedorov Alexey , Müller Christoph R.
Published: September 2021

Early transitional metal carbides are promising catalysts for hydrogenation of CO2. Here, a two-dimensional (2D) multilayered 2D-Mo2C material is prepared from Mo2CTx of the MXene family. Surface termination groups Tx (O, OH, and F) are reductively de-functionalized in Mo2CTx (500 °C, pure H2) avoiding the formation of a 3D carbide structure. CO2 hydrogenation studies show that the activity and product selectivity (CO, CH4, C2–C5 alkanes, methanol, and dimethyl ether) of Mo2CTx and 2D-Mo2C are controlled by the surface coverage of Tx groups that are tunable by the H2 pretreatment conditions. 2D-Mo2C contains no Tx groups and outperforms Mo2CTx, β-Mo2C, or the industrial Cu-ZnO-Al2O3 catalyst in CO2 hydrogenation (evaluated by CO weight time yield at 430 °C and 1 bar). We show that the lack of surface termination groups drives the selectivity and activity of Mo-terminated carbidic surfaces in CO2 hydrogenation.
Generating circularly polarized luminescence from clusterization‐triggered emission using solid phase molecular self-assembly
Authors: Liao Peilong , Zang Shihao , Wu Tongyue , Jin Hongjun , Wang Wenkai , Huang Jianbin , Tang Ben Zhong , Yan Yun
Published: September 2021

Purely-organic clusterization‐triggered emission (CTE) has displayed promising abilities in bioimaging, chemical sensing, and multicolor luminescence. However, it remains absent in the field of circularly polarized luminescence (CPL) due to the difficulties in well-aligning the nonconventional luminogens. We report a case of CPL generated with CTE using the solid phase molecular self-assembly (SPMSA) of poly-L-lysine (PLL) and oleate ion (OL), that is, the macroscopic CPL supramolecular film self-assembled by the electrostatic complex of PLL/OL under mechanical pressure. Well-defined interface charge distribution, given by lamellar mesophases of OL ions, forces the PLL chains to fold regularly as a requirement of optimal electrostatic interactions. Further facilitated by hydrogen bonding, the through-space conjugation (TSC) of orderly aligned electron-rich O and N atoms leads to CTE-based CPL, which is capable of transferring energy to an acceptor via a Förster resonance energy transfer (FRET) process, making it possible to develop environmentally friendly and economic CPL from sustainable and renewable materials.
Distinct functions of POT1 proteins contribute to the regulation of telomerase recruitment to telomeres
Authors: Gu Peili , Jia Shuting , Takasugi Taylor , Tesmer Valerie M. , Nandakumar Jayakrishnan , Chen Yong , Chang Sandy
Published: September 2021

Human shelterin components POT1 and TPP1 form a stable heterodimer that protects telomere ends from ATR-dependent DNA damage responses and regulates telomerase-dependent telomere extension. Mice possess two functionally distinct POT1 proteins. POT1a represses ATR/CHK1 DNA damage responses and the alternative non-homologous end-joining DNA repair pathway while POT1b regulates C-strand resection and recruits the CTC1-STN1-TEN1 (CST) complex to telomeres to mediate C-strand fill-in synthesis. Whether POT1a and POT1b are involved in regulating the length of the telomeric G-strand is unclear. Here we demonstrate that POT1b, independent of its CST function, enhances recruitment of telomerase to telomeres through three amino acids in its TPP1 interacting C-terminus. POT1b thus coordinates the synthesis of both telomeric G- and C-strands. In contrast, POT1a negatively regulates telomere length by inhibiting telomerase recruitment to telomeres. The identification of unique amino acids between POT1a and POT1b helps us understand mechanistically how human POT1 switches between end protective functions and promoting telomerase recruitment.
Development of a new biocathode for a single enzyme biofuel cell fuelled by glucose
Authors: Kausaite-Minkstimiene Asta , Kaminskas Algimantas , Popov Anton , Ramanavicius Arunas , Ramanaviciene Almira
Published: September 2021

In this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid) (PPCA), and glucose oxidase (GOx) biocomposite modified graphite rod (GR) electrode as a potential biocathode for single enzyme biofuel cell fuelled by glucose. In order to design the biocathode, the GR electrode was coated with a composite of PB particles embedded in the PPCA shell and an additional layer of PPCA by cyclic voltammetry. Meanwhile, GOx molecules were covalently attached to the carboxyl groups of PPCA by an amide bond. The optimal conditions for the biocathode preparation were elaborated experimentally. After optimization, the developed biocathode showed excellent electrocatalytic activity toward the reduction of H2O2 formed during GOx catalyzed glucose oxidation at a low potential of 0.1 V vs Ag/AgCl, as well as good electrochemical performance. An electrocatalytic current density of 31.68 ± 2.70 μA/cm2 and open-circuit potential (OCP) of 293.34 ± 15.70 mV in O2-saturated 10 mM glucose solution at pH 6.0 were recorded. A maximal OCP of 430.15 ± 15.10 mV was recorded at 98.86 mM of glucose. In addition, the biocathode showed good operational stability, maintaining 95.53 ± 0.15% of the initial response after 14 days. These results suggest that this simply designed biocathode can be applied to the construction of a glucose-powered single enzyme biofuel cell.
Dietary tomato inhibits angiogenesis in TRAMP prostate cancer but is not protective with a Western-style diet in this pilot study
Authors: Applegate Catherine C. , Lowerison Matthew R. , Hambley Emma , Song Pengfei , Wallig Matthew A. , Erdman John W.
Published: September 2021

Prostate cancer (PCa) remains the second most diagnosed cancer worldwide. Higher body weight is associated with chronic inflammation, increased angiogenesis, and treatment-resistant tumor phenotypes. Dietary tomato reduces PCa risk, which may be due to tomato inhibition of angiogenesis and disruption of androgen signaling. This pilot study investigated the interplay between tomato powder (TP), incorporated into control (CON) and obesogenic (OB) diets, and PCa tumor growth and blood perfusion over time in a transgenic model of PCa (TRAMP). Ultrasound microvessel imaging (UMI) results showed good agreement with gold-standard immunohistochemistry quantification of endothelial cell density, indicating that this technique can be applied to non-invasively monitor tumor blood perfusion in vivo. Greater body weight was positively associated with tumor growth. We also found that TP significantly inhibited prostate tumor angiogenesis but that this inhibition differentially affected measured outcomes depending on CON or OB diets. TP led to reduced tumor growth, intratumoral inflammation, and intratumoral androgen-regulated gene expression (srd5a1, srd5a2) when incorporated with the CON diet but greater tumor growth and intratumoral gene expression when incorporated with the OB diet. Results from this study show that protective benefits from dietary tomato are lost, or may become deleterious, when combined with a Western-style diet.
Synthesis of nanocellulose aerogels and Cu-BTC/nanocellulose aerogel composites for adsorption of organic dyes and heavy metal ions
Authors: Shaheed Nuhaa , Javanshir Shahrzad , Esmkhani Maryam , Dekamin Mohammad G. , Naimi-Jamal Mohammad Reza
Published: September 2021

MOFs compounds with open metal sites, particularly Cu-BTC, have great potential for adsorption and catalysis applications. However, the powdery morphology limits their applications. One of the almost new ways to overcome this problem is to trap them in a standing and flexible aerogel matrix to form a hierarchical porous composite. In this work, Cu-BTC/CNC (crystalline nanocellulose) and Cu-BTC/NFC (nanofibrillated cellulose) aerogel composites were synthesized using a direct mixing method by the addition of Cu-BTC powder to the liquid precursor solution followed by gelation and freeze-drying. Also, pure nanocellulose aerogels (CNC and NFC aerogels) have been synthesized from cellulose isolated from peanut shells. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra, and X-ray diffraction (XRD) were utilized to evaluate the structure and morphology of the prepared materials. The adsorption ability of pure CNC aerogel and Cu-BTC/NFC aerogel composite for organic dye (Congo Red) and heavy metal ion (Mn7+) was studied and determined by the UV–Vis spectrophotometry and inductively-coupled plasma optical emission spectrometry (ICP-OES), respectively. It was concluded that Cu-BTC/NFC aerogel composite shows excellent adsorption capacity for Congo Red. The adsorption process of this composite is better described by the pseudo-second-order kinetic model and Langmuir isotherm, with a maximum monolayer adsorption capacity of 39 mg/g for Congo Red. Nevertheless, CNC aerogel shows no adsorption for Congo Red. Both CNC aerogel and Cu-BTC/NFC aerogel composite act as a monolith standing solid reducer, which means they could remove permanganate ions from water by reducing it into manganese dioxide without releasing any secondary product in the solution.
Application of LDH assay for therapeutic efficacy evaluation of ex vivo tumor models
Authors: Cox Megan C. , Mendes Rita , Silva Fernanda , Mendes Teresa F. , Zelaya-Lazo Adelyn , Halwachs Kathleen , Purkal Julie J. , Isidro Inês A. , Félix Ana , Boghaert Erwin R. , Brito Catarina
Published: September 2021

The current standard preclinical oncology models are not able to fully recapitulate therapeutic targets and clinically relevant disease biology, evidenced by the 90% attrition rate of new therapies in clinical trials. Three-dimensional (3D) culture systems have the potential to enhance the relevance of preclinical models. However, the limitations of currently available cellular assays to accurately evaluate therapeutic efficacy in these models are hindering their widespread adoption. We assessed the compatibility of the lactate dehydrogenase (LDH) assay in 3D spheroid cultures against other commercially available readout methods. We developed a standardized protocol to apply the LDH assay to ex vivo cultures, considering the impact of culture growth dynamics. We show that accounting for growth rates and background release levels of LDH are sufficient to make the LDH assay a suitable methodology for longitudinal monitoring and endpoint assessment of therapeutic efficacy in both cell line-derived xenografts (xenospheres) and patient-derived explant cultures. This method has the added value of being non-destructive and not dependent on reagent penetration or manipulation of the parent material. The establishment of reliable readout methods for complex 3D culture systems will further the utility of these tumor models in preclinical and co-clinical drug development studies.
Larger muscle fibers and fiber bundles manifest smaller elastic modulus in paraspinal muscles of rats and humans
Authors: Malakoutian Masoud , Theret Marine , Yamamoto Shun , Dehghan-Hamani Iraj , Lee Michael , Street John , Rossi Fabio , Brown Stephen H. M. , Oxland Thomas R.
Published: September 2021

The passive elastic modulus of muscle fiber appears to be size-dependent. The objectives of this study were to determine whether this size effect was evident in the mechanical testing of muscle fiber bundles and to examine whether the muscle fiber bundle cross-section is circular. Muscle fibers and fiber bundles were extracted from lumbar spine multifidus and longissimus of three cohorts: group one (G1) and two (G2) included 13 (330 ± 14 g) and 6 (452 ± 28 g) rats, while Group 3 (G3) comprised 9 degenerative spine patients. A minimum of six muscle fibers and six muscle fiber bundles from each muscle underwent cumulative stretches, each of 10% strain followed by 4 minutes relaxation. For all specimens, top and side diameters were measured. Elastic modulus was calculated as tangent at 30% strain from the stress–strain curve. Linear correlations between the sample cross sectional area (CSA) and elastic moduli in each group were performed. The correlations showed that increasing specimen CSA resulted in lower elastic modulus for both rats and humans, muscle fibers and fiber bundles. The median ratio of major to minor axis exceeded 1.0 for all groups, ranging between 1.15–1.29 for fibers and 1.27–1.44 for bundles. The lower elastic moduli with increasing size can be explained by relatively less collagenous extracellular matrix in the large fiber bundles. Future studies of passive property measurement should aim for consistent bundle sizes and measuring diameters of two orthogonal axes of the muscle specimens.