bluuebunny/crossref_metadata_2025 huggingface dataset:
Intense exercise at high altitude causes platelet loss across the brain in humans
Authors: Gibbons Travis Dylan , Caldwell Hannah G. , Islam Hashim , Duffy Jennifer , MacLeod David B. , Ainslie Philip N.
Published: January 2024

Platelets are known primarily for their role in blood clotting; however, it is becoming clear that they play diverse roles beyond that of haemostasis. Exercise has been shown to activate platelets and stimulate neurogenesis, neuroplasticity and improve cognitive function, highlighting a potentially powerful link between platelet function and brain health. Despite this clear link between platelets and the brain, very little is known about the behaviour of platelets through the cerebral circulation in humans. We examined platelet concentration across the brain in exercising humans at sea level (340 m) and high altitude (6–8 days at 3800 m; a stimulus known to modify platelet function). During intense exercise at sea level, platelet concentration increased similarly by 27 ± 17% in the arterial and internal jugular venous circulations (exercise: P < 0.001, interaction: P = 0.262), indicating no uptake or release of platelets into/from the brain. At high altitude, resting platelet concentrations were similar to sea level values in both the arterial and jugular venous circulations (P = 0.590); however, intense exercise at high altitude caused a 31 ± 35% decrease in platelet concentration across the brain (P = 0.016). This divergent response across the brain was not observed in any other haematological or metabolic variables. These data highlight a unique situation where the combination of intense exercise and high altitude hypoxia cause a decrease in platelet concentration across the cerebral circulation. The physiological implications and mechanisms that might influence platelet function across the brain during exercise at high altitude remain to be established.

image

Key points

Platelets are known primarily for their role in blood clotting; however, it is becoming clear that they play diverse roles beyond that of haemostasis.

Exercise has been shown to activate platelets, which in turn stimulate neurogenesis, neuroplasticity and improve cognitive function, highlighting a powerful link between platelet function and brain health.

At sea level, platelet concentration in blood going into and out of the brain was similar at rest, during maximal exercise and in recovery from exercise.

During maximal exercise at high altitude, platelet concentration was 31% lower in the blood exiting the brain; the final destination of these platelets is unknown.

The physiological implications and mechanisms that might influence platelet function across the cerebral circulation during exercise at high altitude remain to be established.
Theoretical Investigation of Low Global Warming Potential Blends Replacing R404A: The Simple Refrigeration Cycle and Its Modifications
Authors: Belman-Flores J. M. , Román-Aguilar R. , Valle-Hernández J. , Serrano-Arellano J.
Published: January 2024

R404A refrigerant is one of the most widely used hydrofluorocarbons in the commercial refrigeration industry for low and medium temperatures. However, this refrigerant contributes negatively to the environment due to its high global warming potential (GWP = 3943), and for several years, it has been labeled as one of the refrigerants that should be phased out. The present study theoretically evaluates low-GWP refrigerants as a replacement alternative to R404A, including R407H, R442A, R449A, R454A, R454C, R455A, R459B, and R465A. The analysis focuses on the comparison between relative differences in the volumetric flow in the compressor suction and the coefficient of performance for four configurations of the vapor compression cycle, such as the basic cycle, the cycle with an internal heat exchanger, the cycle with direct injection, and the cycle with a sub-cooler. According to the proposed operating conditions of evaporation temperature (−10 °C and −40 °C) and condensation temperature (40 °C and 55 °C), R454A could be the best long-term replacement option for its low GWP, energy performance, and direct fit for any configuration. R459B could also be considered a viable option, but with certain design modifications. On the contrary, the refrigerants R465A, R455A, and R454C would be discarded because they present a greater non-adaptation to the compressor in each configuration analyzed.
Film Cooling Effectiveness and Flow Structures of Butterfly-Shaped Film Cooling Hole Configuration
Authors: Jeong Jin Young , Jo Ye Rim , Kang Min Seok , Kang Young Jun , Kwak Jae Su
Published: January 2024

Film cooling is applied to various high-temperature components of a gas turbine and greatly affected by the shape of the injection hole. Numerous studies have been conducted to investigate various film cooling structures to increase the film cooling effectiveness by inducing coolants toward the surface. In this study, a butterfly-shaped film cooling hole configuration is proposed, which consists of a pair of asymmetric fan-shaped holes installed adjacently. This novel structure enhances film cooling effectiveness by utilizing the interaction between coolant jets from the asymmetrical film cooling holes. In this study, the film cooling effectiveness of the butterfly-shaped hole configuration was experimentally characterized under low-speed conditions on a flat plate, and was compared with that of widely used fan-shaped holes. Also, a numerical study was conducted to understand and visualize the flow structures generated by the butterfly-shaped film cooling configuration. As a result, an anti-vortex structure was observed near the hole exit. The film cooling effectiveness of the butterfly-shaped hole configuration was also compared with that of the fan-shaped hole. The film cooling effectiveness of the butterfly-shaped hole configuration was 1.9% higher than that of the optimized fan-shaped film cooling hole at its optimized condition. It was also found that the film cooling effectiveness increased with the blowing ratio for the butterfly-shaped hole configuration. It is expected that the film cooling effectiveness can be further improved by adjusting the shape parameters of the butterfly-shaped hole.
Aerothermal Optimization of Film Cooling Hole Locations on the Squealer Tip of an HP Turbine Blade
Authors: Yıldız F. , Alpman E. , Kavurmacıoğlu L. , Camci C.
Published: January 2024

This article presents a time-efficient method to optimize the positions of film cooling holes on a gas turbine blade's squealer tip for cooling and aerodynamic performance. A computational approach is employed for the optimization, including validations against experiments. Five discrete film cooling holes are considered, and two different blowing ratios of 0.4 and 1.0 are studied. The positions of cooling holes on the tip along the tangential direction are varied as the input parameters of optimization. The multi-objective optimization uses an algorithm with an artificial neural network for fast fitness function predictions. The best cooling configuration found by the optimization achieves a 13.43% reduction in total heat flux and a 0.4% increase in aerodynamic loss when the blowing rate is 1.0. Including the casing relative motion in the computations results in a total pressure loss coefficient increase of about 8% for both blowing ratios. For M = 1.0, imposing the casing's motion results in a 10.2% reduction in total heat transfer to the tip compared to the stationary casing. For the lower blowing rate of 0.4, the total heat flux reduction to the tip is 12.0% because of the imposed casing motion. Hence, the cooling effectiveness can be improved by employing the particular position optimization method presented in this study. The results suggest that experimental and computational heat transfer studies on cooled turbine blade tips, especially in cascade arrangements, need to consider the relative motion of the blade tip.
Soft Computing Model for Inverse Prediction of Surface Heat Flux From Temperature Responses in Short-Duration Heat Transfer Experiments
Authors: Nayak Sima , Sahoo Niranjan , Komiyama Masaharu
Published: January 2024

Aerodynamic experiments in the high-speed flow domain mainly rely on precise measurement of transient surface temperatures and subsequent quantification of heat flux. These experiments are primarily simulated in high-enthalpy short-duration facilities for which test flow durations are in the order of a few milliseconds, and the thermal loads resemble the nature of step/impulse. This study focuses on a specially designed fast-response coaxial surface junction thermal probe (CSTP) with the capability of capturing transient temperature signals. The CSTP, with a 3.25 mm diameter and 13 mm length, incorporates a precisely examined sensing junction (20 µm thickness) and EDX, FESEM verified surface characterization. The short-duration calibration experiments are realized to mimic the simulated flow conditions of high-enthalpy test facilities. The classical one-dimensional heat conduction modeling has been used to deduce surface heat flux from the acquired temperature responses. It demonstrates a commendable accuracy of ±2.5% when compared with known heat loads of calibration experiments. Departing from traditional heat conduction models, an advanced soft-computing technique, the Adaptive Neuro-Fuzzy Inference System (ANFIS), is introduced for short-duration heat flux predictions. This methodology successfully recovers known (step or ramp) heat loads within a specific experimental time frame (0.2 s). The results exhibit excellent agreement in the prediction of trend and magnitude, carrying uncertainties of ±3% for radiative and ±5% for convective experiments. Consequently, the CSTP appears as a rapidly responsive transient heat flux sensor for real-time short-duration experiments. The soft-computing approach (ANFIS) offers an alternative means of heat flux estimation from temperature history irrespective of the mode of heat transfer and nature of heat load, marked by its prediction accuracy, diminished mathematical intricacies, and reduced numerical requisites.
Beatriz Moncó Rebollo: Antropóloga y catedrática. In memoriam
Authors:   Universiad de Cantabria, Gómez Pellón Eloy
Published: January 2024

Tuve la fortuna de conocer a Beatriz Moncó Rebollo (1955-2023) mediados los años ochenta, cuando acababa de concluir su tesis doctoral y luchaba denodadamente por conquistar un espacio en la antropología española. También era el momento en el que comenzaba a soñar con un futuro gracias a que la vida familiar y la social le sonreían. Inquieta y apasionada, avanzaba sin parar en la conquista de un mundo intelectual que recogía muchas de las preocupaciones académicas de la época, en una España que oteaba tiempos mejores que los que había vivido. Beatriz Moncó pertenecía a una generación que ingresa en la universidad en los estertores del franquismo y concluye sus estudios cuando aun estaba muy presente el espíritu de la Transición en la vida del Estado. Por lo tanto, tuvo la fortuna de conocer una España en la cual se distinguía cada vez más nítidamente, en medio de las sombras de aquel largo amanecer, un horizonte de anhelos y esperanzas.
Adios, Beatriz
Authors:   State University of New York at Potsdam, López Sergio
Published: January 2024

En una mesita de noche de una casa cualquiera de Nueva York, descansa un libro en español que una niña de siete años lee en voz alta poco antes de dormir. El libro es un volumen de cuentos con las rimas de Gloria Fuertes. Fue un preciado tesoro que Beatriz Moncó regaló a la hija de uno de sus miles de estudiantes. Aunque con un océano de por medio, la relación entre ellos seguía más viva que nunca sin importar el tiempo ni la distancia.  (...)
Beatriz Moncó In Memoriam
Authors:   Universidad Complutense de Madrid, Pichardo Galán José Ingnacio
Published: January 2024

Hace tiempo escuché que la idea de AIBR había nacido de la mano de varios estudiantes en el despacho que Beatriz Moncó tenía en la Universidad Complutense de Madrid. Por eso siempre ha sido una especie de madrina de la asociación y la única socia de honor que hemos tenido hasta hoy. Yo no fui testigo de ese momento seminal, pero mi relación con Beatriz se inició ligada a nuestra asociación. Nada más unirme al que entonces era un proyecto incipiente, Sergio López me invitó a una pequeña cena en la que participaba Beatriz, una referencia obligada en la antropología española y de la que me sorprendió esa mezcla de erudición y cercanía que regalaba. Allí pude comenzar a conocerla más allá de sus textos y acercarme a una mujer que siempre me apoyó y me trató con una sonrisa. En varias ocasiones, tuve la fortuna de participar en tribunales de tesis dirigidas por ella y siempre fueron auténticas oportunidades de aprendizaje que reflejaban su meticulosa guía teórica y metodológica.
Hollow-cathode plasma deposited vanadium oxide films: Metal precursor influence on growth and material properties
Authors: Mohammad Adnan , Joshi Krishna D. , Rana Dhan , Ilhom Saidjafarzoda , Wells Barrett , Sinkovic Boris , Okyay Ali K. , Biyikli Necmi
Published: January 2024

Due to its different polymorphs, including vanadium pentoxide (V2O5) and vanadium dioxide (VO2), the vanadium oxide (VOX) compound is an immensely interesting material with many important applications. While atomic layer deposition (ALD) is among the possible VOX film synthesis methods, literature reports have majorly utilized thermal-ALD, which reveals as-grown amorphous VOX films. Further post-deposition annealing process is needed to crystallize these films. High-temperature crystallization indeed limits the use of low-temperature compatible materials, processes, and substrates. In this work, we report on the low-temperature crystalline VOX film growth in a hollow-cathode plasma-enhanced atomic layer deposition reactor using two different vanadium precursors, tetrakis(ethylmethylamino)vanadium and vanadium(V) oxytriisopropoxide. Oxygen plasmas were used as co-reactants at a substrate temperature of 150 °C. Along with the purpose of investing in the impact of metal precursors on VOX film growth, we also studied Ar-plasma in situ and thermal ex situ annealing to investigate possible structural enhancement and phase transformation. In situ Ar-plasma annealing was performed with 20 s, 20 SCCM Ar-plasma, while post-deposition ex situ annealing was carried out at 500 °C and 0.5 mTorr O2 pressure. In situ ellipsometry was performed to record instant film thickness variation and several ex situ characterizations were performed to extract the optical, structural, and electrical properties of the films. The outcomes of the study confirm that both metal precursors result in as-grown crystalline V2O5 films at 150 °C. On the other hand, post-deposition annealing converted the as-grown crystalline V2O5 film to VO2 film. Finally, we have also successfully confirmed the metal-to-insulator transition property of the annealed VO2 films via temperature-dependent structural and electrical measurements.
Suppression of phase segregations in Ge–Fe–Co–Ni–Mn films by high-entropy effect
Authors: Sun Sen , Jiang Wenyu , Liu Qinxin , Jiang Yueyong , Zhu Tianyi , Hu Jie , Song Honglian , Yang Zheng , Hui Xinfeng , Lao Yuanxia
Published: January 2024

Fe–Co–Ni–Mn films doped with different concentrations of Ge were prepared on the Si substrates by using radio frequency magnetron sputtering. Transmission electron microscopy (with an energy dispersive x-ray spectrometer) and an x-ray diffractometer were used to systematically study the microstructure evolution of the Fe–Co–Ni–Mn–Ge films. The results indicate that the Fe–Co–Ni–Mn films doped with a large amount of Ge show significant element segregation after rapid high-temperature annealing. However, with the decrease in the doping amount of Ge to approximately equal molar ratio with magnetic elements, Ge and magnetic elements achieve perfect mutual dissolution at the same annealing conditions, forming single-phase solid solution. Electrical transport tests suggest that its electrical property is close to semiconductors. The mechanism of enhanced mutual solubility between semiconductor elements and magnetic elements is discussed in detail.
Rehabilitation exercise–driven symbiotic electrical stimulation system accelerating bone regeneration
Authors: Wang Tianlong , Ouyang Han , Luo Yiping , Xue Jiangtao , Wang Engui , Zhang Lei , Zhou Zifei , Liu Zhiqing , Li Xifan , Tan Shuo , Chen Yixing , Nan Liping , Cao Wentao , Li Zhou , Chen Feng , Zheng Longpo
Published: January 2024

Electrical stimulation can effectively accelerate bone healing. However, the substantial size and weight of electrical stimulation devices result in reduced patient benefits and compliance. It remains a challenge to establish a flexible and lightweight implantable microelectronic stimulator for bone regeneration. Here, we use self-powered technology to develop an electric pulse stimulator without circuits and batteries, which removes the problems of weight, volume, and necessary rigid packaging. The fully implantable bone defect electrical stimulation (BD-ES) system combines a hybrid tribo/piezoelectric nanogenerator to provide biphasic electric pulses in response to rehabilitation exercise with a conductive bioactive hydrogel. BD-ES can enhance multiple osteogenesis-related biological processes, including calcium ion import and osteogenic differentiation. In a rat model of critical-sized femoral defects, the bone defect was reversed by electrical stimulation therapy with BD-ES and subsequent bone mineralization, and the femur completely healed within 6 weeks. This work is expected to advance the development of symbiotic electrical stimulation therapy devices without batteries and circuits.
A multimodal magnetoelastic artificial skin for underwater haptic sensing
Authors: Zhou Yihao , Zhao Xun , Xu Jing , Chen Guorui , Tat Trinny , Li Justin , Chen Jun
Published: January 2024

Future exploitation of marine resources in a sustainable and eco-friendly way requires autonomous underwater robotics with human-like perception. However, the development of such intelligent robots is now impeded by the lack of adequate underwater haptic sensing technology. Inspired by the populational coding strategy of the human tactile system, we harness the giant magnetoelasticity in soft polymer systems as an innovative platform technology to construct a multimodal underwater robotic skin for marine object recognition with intrinsic waterproofness and a simple configuration. The bioinspired magnetoelastic artificial skin enables multiplexed tactile modality in each single taxel and obtains an impressive classification rate of 95% in identifying seven types of marine creatures and marine litter. By introducing another degree of freedom in underwater haptic sensing, this work represents a milestone toward sustainable marine resource exploitation.
Regulatory T cells in skin mediate immune privilege of the hair follicle stem cell niche
Authors: Cohen Jarish N. , Gouirand Victoire , Macon Courtney E. , Lowe Margaret M. , Boothby Ian C. , Moreau Joshua M. , Gratz Iris K. , Stoecklinger Angelika , Weaver Casey T. , Sharpe Arlene H. , Ricardo-Gonzalez Roberto R. , Rosenblum Michael D.
Published: January 2024

Immune tolerance is maintained in lymphoid organs (LOs). Despite the presence of complex immune cell networks in non-LOs, it is unknown whether self-tolerance is maintained in these tissues. We developed a technique to restrict genetic recombination to regulatory T cells (T
regs
) only in skin. Selective depletion of skin T
regs
resulted in T cell–mediated inflammation of hair follicles (HFs). Suppression did not rely on CTLA-4, but instead on high-affinity interleukin-2 (IL-2) receptor expression by skin T
regs
, functioning exclusively in a cell-extrinsic manner. In a novel model of HF stem cell (HFSC)–driven autoimmunity, we reveal that skin T
regs
immunologically protect the HFSC niche. Finally, we used spatial transcriptomics to identify aberrant IL-2 signaling at stromal-HF interfaces in a rare form of human alopecia characterized by HFSC destruction and alopecia areata. Collectively, these results reveal the fundamental biology of T
regs
in skin uncoupled from the systemic pool and elucidate a mechanism of self-tolerance.
Microbial associates of the elm leaf beetle: uncovering the absence of resident bacteria and the influence of fungi on insect performance
Authors: Schott Johanna , Rakei Juliette , Remus-Emsermann Mitja , Johnston Paul , Mbedi Susan , Sparmann Sarah , Hilker Monika , Paniagua Voirol Luis R.
Published: January 2024

Microbial symbionts play crucial roles in the biology of many insects. While bacteria have been the primary focus of research on insect-microbe symbiosis, recent studies suggest that fungal symbionts may be just as important. The elm leaf beetle (ELB,
Xanthogaleruca luteola
) is a serious pest species of field elm (
Ulmus minor
). Using culture-dependent and independent methods, we investigated the abundance and species richness of bacteria and fungi throughout various ELB life stages and generations, while concurrently analyzing microbial communities on elm leaves. No persistent bacterial community was found to be associated with the ELB or elm leaves. By contrast, fungi were persistently present in the beetle’s feeding life stages and on elm leaves. Fungal community sequencing revealed a predominance of the genera
Penicillium
and
Aspergillus
in insects and on leaves. Culture-dependent surveys showed a high prevalence of two fungal colony morphotypes closely related to
Penicillium lanosocoeruleum
and
Aspergillus flavus
. Among these, the
Penicillium
morphotype was significantly more abundant on feeding-damaged compared with intact leaves, suggesting that the fungus thrives in the presence of the ELB. We assessed whether the detected prevalent fungal morphotypes influenced ELB’s performance by rearing insects on (i) surface-sterilized leaves, (ii) leaves inoculated with
Penicillium
spores, and (iii) leaves inoculated with
Aspergillus
spores. Insects feeding on
Penicillium
-inoculated leaves gained more biomass and tended to lay larger egg clutches than those consuming surface-sterilized leaves or
Aspergillus
-inoculated leaves. Our results demonstrate that the ELB does not harbor resident bacteria and that it might benefit from associating with
Penicillium
fungi.

IMPORTANCE

Our study provides insights into the still understudied role of microbial symbionts in the biology of the elm leaf beetle (ELB), a major pest of elms. Contrary to expectations, we found no persistent bacterial symbionts associated with the ELB or elm leaves. Our research thus contributes to the growing body of knowledge that not all insects rely on bacterial symbionts. While no persistent bacterial symbionts were detectable in the ELB and elm leaf samples, our analyses revealed the persistent presence of fungi, particularly
Penicillium
and
Aspergillus
on both elm leaves and in the feeding ELB stages. Moreover, when ELB were fed with fungus-treated elm leaves, we detected a potentially beneficial effect of
Penicillium
on the ELB’s development and fecundity. Our results highlight the significance of fungal symbionts in the biology of this insect.
Polysaccharide utilization loci from Bacteroidota encode CE15 enzymes with possible roles in cleaving pectin-lignin bonds
Authors: Seveso Andrea , Mazurkewich Scott , Banerjee Sanchari , Poulsen Jens-Christian Navarro , Lo Leggio Leila , Larsbrink Johan
Published: January 2024

Lignocellulose is a renewable but complex material exhibiting high recalcitrance to enzymatic hydrolysis, which is attributed, in part, to the presence of covalent linkages between lignin and polysaccharides in the plant cell wall. Glucuronoyl esterases from carbohydrate esterase family 15 (CE15) have been proposed as an aid in reducing this recalcitrance by cleaving ester bonds found between lignin and glucuronoxylan. In the Bacteroidota phylum, some species organize genes related to carbohydrate metabolism in polysaccharide utilization loci (PULs) which encode all necessary proteins to bind, deconstruct, and respond to a target glycan. Bioinformatic analyses identified CE15 members in some PULs that appear to not target the expected glucuronoxylan. Here, five CE15 members from such PULs were investigated with the aim of gaining insights on their biological roles. The selected targets were characterized using glucuronoyl esterase model substrates and with a new synthetic molecule mimicking a putative ester linkage between pectin and lignin. The CE15 enzyme from
Phocaeicola vulgatus
was structurally determined by X-ray crystallography both with and without carbohydrate ligands with galacturonate binding in a distinct conformation than that of glucuronate. We further explored whether these CE15 enzymes could act akin to pectin methylesterases on pectin-rich biomass but did not find evidence to support the proposed activity. Based on the evidence gathered, the CE15 enzymes in the PULs expected to degrade pectin could be involved in cleavage of uronic acid esters in rhamnogalacturonans.

IMPORTANCE

The plant cell wall is a highly complex matrix, and while most of its polymers interact non-covalently, there are also covalent bonds between lignin and carbohydrates. Bonds between xylan and lignin are known, such as the glucuronoyl ester bonds that are cleavable by CE15 enzymes. Our work here indicates that enzymes from CE15 may also have other activities, as we have discovered enzymes in PULs proposed to target other polysaccharides, including pectin. Our study represents the first investigation of such enzymes. Our first hypothesis that the enzymes would act as pectin methylesterases was shown to be false, and we instead propose that they may cleave other esters on complex pectins such as rhamnogalacturonan II. The work presents both the characterization of five novel enzymes and can also provide indirect information about the components of the cell wall itself, which is a highly challenging material to chemically analyze in fine detail.
Ten-eleven translocation (Tet) methylcytosine dioxygenase-dependent viral DNA demethylation mediates
in vivo
hepatitis B virus (HBV) biosynthesis
Authors: Matrenec Rachel , Oropeza Claudia E. , Dekoven Eddie , Tarnow Grant , Maienschein-Cline Mark , Chau Cecilia S. , Green Stefan J. , McLachlan Alan
Published: January 2024

Chronic hepatitis B virus (HBV) infection causes significant worldwide morbidity and mortality. There are no curative therapies available to resolve chronic HBV infections, and the small viral genome limits molecular targets for drug development. An alternative approach to drug development is to target cellular genes essential for HBV biosynthesis. In the liver, ten-eleven translocation (Tet) genes encode cellular enzymes that are not essential for postnatal mouse development but represent essential activities for viral DNA demethylation and transcription. Consequently, Tet inhibitors may potentially be developed into therapeutic agents capable of inducing and/or maintaining HBV covalently closed circular DNA methylation, resulting in transcriptional silencing and the resolution of chronic viral infection.
Diet composition drives tissue-specific intensity of murine enteric infections
Authors: Israelson Helene , Vedsted-Jakobsen Amalie , Zhu Ling , Gagnaire Aurelie , von Münchow Alexandra , Polakovicova Nina , Valente Angela H. , Raza Ali , Andersen-Civil Audrey I. S. , Olsen John E. , Myhill Laura J. , Geldhof Peter , Williams Andrew R.
Published: January 2024

Enteric infections induce dysbiosis and inflammation and are a major public health burden. As the gut environment is strongly shaped by diet, the role of different dietary components in promoting resistance to infection is of interest. While diets rich in fiber or whole grain are normally associated with improved gut health, we show here that these components predispose the host to higher levels of pathogen infection. Thus, our results have significance for interpreting how different dietary interventions may impact on gastrointestinal infections. Moreover, our results may shed light on our understanding of how gut flora and mucosal immune function is influenced by the food that we eat.
Intestinal
Bacteroides
modulates inflammation, systemic cytokines, and microbial ecology via propionate in a mouse model of cystic fibrosis
Authors: Price Courtney E. , Valls Rebecca A. , Ramsey Alexis R. , Loeven Nicole A. , Jones Jane T. , Barrack Kaitlyn E. , Schwartzman Joseph D. , Royce Darlene B. , Cramer Robert A. , Madan Juliette C. , Ross Benjamin D. , Bliska James , O'Toole George A.
Published: January 2024

The composition of the gut microbiome in persons with CF is correlated with lung health outcomes, a phenomenon referred to as the gut-lung axis. Here, we demonstrate that the intestinal microbe
Bacteroides
decreases inflammation through the production of the short-chain fatty acid propionate. Supplementing the levels of
Bacteroides
in an animal model of CF is associated with reduced systemic inflammation and reduction in the relative abundance of the opportunistically pathogenic group
Escherichia
/
Shigella
in the gut. Taken together, these data demonstrate a key role for
Bacteroides
and microbially produced propionate in modulating inflammation, gut microbial ecology, and the gut-lung axis in cystic fibrosis. These data support the role of
Bacteroides
as a potential probiotic in CF.
Substrate specificity and ecological significance of PstS homologs in phosphorus uptake in marine
Synechococcus
sp. WH8102
Authors: Ranjit Pramita , Varkey Deepa , Shah Bhumika S. , Paulsen Ian T.
Published: January 2024

Phosphorus, a vital macronutrient, often limits primary productivity in marine environments. Marine
Synechococcus
strains, including WH8102, rely on high-affinity phosphate-binding proteins (PstS) to scavenge inorganic phosphate in oligotrophic oceans. However, WH8102 possesses three distinct PstS homologs whose substrate specificity and ecological roles are unclear. The three PstS homologs were heterologously expressed and purified to investigate their substrate specificity and binding kinetics. Our study revealed that all three PstS homologs exhibited a high degree of specificity for phosphate but differed in phosphate binding affinities. Notably, PstS1b displayed nearly 10-fold higher binding affinity (
K
D
= 0.44 µM) compared to PstS1a (
K
D =
3.3 μM) and PstS2 (
K
D =
4.3 μM). Structural modeling suggested a single amino acid variation in the binding pocket of PstS1b (threonine instead of serine in PstS1a and PstS2) likely contributed to its higher Pi affinity. Genome context data, together with the protein biophysical data, suggest distinct ecological roles for the three PstS homologs. We propose that PstS1b may be involved in scavenging inorganic phosphorus in oligotrophic conditions and that PstS1a may be involved in transporting recycled phosphate derived from organic phosphate cleavage. The role of PstS2 is less clear, but it may be involved in phosphate uptake when environmental phosphate concentrations are transiently higher. The conservation of three distinct PstS homologs in
Synechococcus
clade III strains likely reflects distinct adaptations for P acquisition under varying oligotrophic conditions.

IMPORTANCE

Phosphorus is an essential macronutrient that plays a key role in marine primary productivity and biogeochemistry. However, intense competition for bioavailable phosphorus in the marine environment limits growth and productivity of ecologically important cyanobacteria. In oligotrophic oceans, marine
Synechococcus
strains, like WH8102, utilize high-affinity phosphate-binding proteins (PstS) to scavenge inorganic phosphate. However, WH8102 possesses three distinct PstS homologs, with unclear substrate specificity and ecological roles, creating a knowledge gap in understanding phosphorus acquisition mechanisms in picocyanobacteria. Through genomic, functional, biophysical, and structural analysis, our study unravels the ecological functions of these homologs. Our findings enhance our understanding of cyanobacterial nutritional uptake strategies and shed light on the crucial role of these conserved nutrient uptake systems in adaptation to specific niches, which ultimately underpins the success of marine
Synechococcus
across a diverse array of marine ecosystems.
Methane-carbon budget of a ferruginous meromictic lake and implications for marine methane dynamics on early Earth
Authors: Akam Sajjad A. , Chuang Pei-Chuan , Katsev Sergei , Wittkop Chad , Chamberlain Michelle , Dale Andrew W. , Wallmann Klaus , Heathcote Adam J. , Swanner Elizabeth D.
Published: January 2024

The greenhouse gas methane (CH4) contributed to a warm climate that maintained liquid water and sustained Earth’s habitability in the Precambrian despite the faint young sun. The viability of methanogenesis (ME) in ferruginous environments, however, is debated, as iron reduction can potentially outcompete ME as a pathway of organic carbon remineralization (OCR). Here, we document that ME is a dominant OCR process in Brownie Lake, Minnesota (midwestern United States), which is a ferruginous (iron-rich, sulfate-poor) and meromictic (stratified with permanent anoxic bottom waters) system. We report ME accounting for ≥90% and >9% ± 7% of the anaerobic OCR in the water column and sediments, respectively, and an overall particulate organic carbon loading to CH4 conversion efficiency of ≥18% ± 7% in the anoxic zone of Brownie Lake. Our results, along with previous reports from ferruginous systems, suggest that even under low primary productivity in Precambrian oceans, the efficient conversion of organic carbon would have enabled marine CH4 to play a major role in early Earth’s biogeochemical evolution.
Effects of electromagnetic field on a radiating star
Authors: Jaryal Suresh C. , Chatterjee Ayan , Kumar Akshay
Published: January 2024

In this paper we study the shear free spherical symmetric gravitational collapse of a charged radiating star. All the physical quantities including pressure, density are regular. Energy conditions are satisfied throughout the interior of the matter configuration. The luminosity is time independent and mass is radiated linearly. The causal and non causal temperature remain greater than that of the uncharged collapsing scenario.
Isotropization and complexity shift of gravitationally decoupled charged anisotropic sources
Authors: Albalahi Abeer M. , Yousaf Z. , Ali Akbar , Khan S.
Published: January 2024

This article focuses on investigating the role of decoupling in isotropizing anisotropic, self-gravitational charged sources with spherical symmetry through a well-known gravitational technique, known as minimal geometric deformation (MGD). This technique separates the given system into two gravitational systems: the Einstein-Maxwell system and the gravitational system governed by additional source. We employ novel approaches, including the zero complexity factor and isotropization techniques, to construct various charged compact star models using the Tolman IV as the seed source within the framework of the MGD scheme. The term complexity factor emerges as one of the structure-defining scalar quantities resulting from the orthogonal splitting of the Riemann–Christoffel curvature tensor, as proposed by Herrera (Phys Rev D 97(4):044010, 2018). This scalar function, denoted as $$Y_{TF}$$

Y

TF

, is associated with the fundamental structural characteristics of self-gravitational compact configurations. Our approach is innovative in that it derives the deformation functions by imposing the requirement of $$Y_{TF}=0$$

Y

TF

=
0

and employs isotropization techniques for electrically charged anisotropic configurations.
Flat and bent branes in Born–Infeld-like scalar field models
Authors: Andrade I. , Marques M. A. , Menezes R.
Published: January 2024

In this work, we investigate the presence of thick branes modeled by a single scalar field with Born–Infeld-like dynamics. We consider the 4-dimensional metric being Minkowski, de Sitter or anti-de Sitter. We obtain the field equations and the conditions to get a first order formalism compatible with them. To illustrate our procedure, some specific models are presented. They support localized warp factor and have their properties controlled by the 4-dimensional cosmological constant. In particular, a hybrid brane may arise, with a thick or thin profile depending on the extra dimension being inside or outside a compact space.
CATALYZING URBAN AND RURAL FEMALE ENTREPRENEURIAL SUCCESS THROUGH HRM PRACTICES AND DIGITAL TECHNOLOGY USE: INSIGHTS FROM LEBANON
Authors: HADDAD GLORIA GHANTOUS , SOUBRA AMAL DABBOUS , BOUSTANI NADA MALLAH
Published: January 2024

This study investigates the influence of human resource management (HRM) practices and digital technology use (DTU) on women’s perceived venture growth. Further, it explores the mediating role of perceived venture growth and whether this factor contributes to the improvement of female entrepreneurs’ economic conditions. The analysis also assesses differences between urban and rural areas. Using a sample of 100 female entrepreneurs in Lebanon, the results indicate that HRM practices and DTU exert a positive, significant effect on female entrepreneurs’ perceived venture growth. The latter also has a positive influence on the economic conditions of these women and acts as a mediator in these relationships. The findings differ between urban and rural areas. For female entrepreneurs in urban areas, perceived venture growth is shown to mediate the relationship between DTU and women’s economic conditions while it mediates the relationship between HRM practices and women’s economic conditions for female entrepreneurs in rural areas. The findings emphasize the collectivistic nature of rural female entrepreneurs, underscoring their reliance on strategic people management for business growth. It also advocates for promoting digital literacy among rural female entrepreneurs to help them grow and expand their businesses.
BROAD-BASED BLACK ECONOMIC EMPOWERMENT POLICY AND ENTREPRENEURSHIP IN SOUTH AFRICA
Authors: NGWABA CHIGOZIE ANDY
Published: January 2024

This article examines the effects of the Broad-based Black Economic Empowerment (BBBEE) policy on black entrepreneurship in South Africa. The BBBEE policy is a legal framework aimed at addressing historical inequalities by promoting equal opportunities and encouraging the participation of black individuals in the economy. The policy highlights include increased access to funding for previously marginalized groups to start and grow their businesses, improved market access to encourage large businesses to partner with small businesses owned by previously marginalized groups, and increased skills and development. Using the policy as a quasi-natural experiment, the study adopts a difference-in-difference estimation technique contrasting periods before and after implementation and measuring its effectiveness on black entrepreneurial entry. Results from the analysis indicate that the policy was ineffective in improving black entrepreneurship in South Africa.
Institutional Quality, Trust, and Stock Market Participation: Learning to Forget
Authors: Asgharian Hossein , Liu Lu , Lundtofte Frederik
Published: January 2024

In this paper, we explore the relations among institutional quality, households’ level of trust, and stock market participation. We find that institutional quality has a significant impact on both trust and participation. The individual level of trust significantly affects participation, but trust plays a small role in the effect of institutional quality on participation. Further, we demonstrate that immigrants are affected by the institutional quality of both their country of residence and their home country, and that education emerges as an important learning factor in immigrants’ adaptation to new institutional environments.
A Case of Polyarteritis Nodosa and Antiphospholipid Antibody Positivity Presenting with Intramuscular Haematoma
Authors: Ng Cheryl Chun Man
Published: January 2024

Polyarteritis nodosa (PAN) is a medium-sized vessel vasculitis often presenting report as both stenotic and aneurysmal lesions. Association with antiphospholipid antibody (aPL) has also been described. Here, we reported a case of PAN with history of cutaneous vasculitis presenting as multiple territory ischemic stroke, mesenteric panniculitis, coronary artery stenosis on imaging; lupus anticoagulant (LA) was also identified, patient was treated with immunosuppressants and anticoagulation. Disease course was, however, complicated by development of thigh haematoma. Clinical manifestation of PAN and its association with aPL will be discussed.
Study on graphene grown on SiC substrate by heat-sublimation method applied for NO2 gas sensor fabrication
Authors: Huu Ly Truong , Tran Hoai Duy , Nguyen Phuong Thanh , Dao Tuan Minh , Dang Tuan Quoc , Tieu Doanh Tu , Nguyen Tham Thi Hong , Nguyen Anh Tuan , Tran-Thuy Tuyet-Mai , Ngo Thanh Vo Ke
Published: January 2024

This article aimed to build a low-cost system and synthesized graphene on 4H-silicon carbide (4H-SiC) wafer by the thermal sublimation method toward the gas-sensing applications. The advantage of this epitaxy growth obtained the large-area graphene sheet on 4H-SiC substrate. The graphene layers were grown directly on a semiconductor material without the complicated transfer process as previous methods, making this method suitable to fabricate the electronic devices, MEMS, and sensors. The characterization of graphene on 4H-SiC (Graphene@SiC) was analyzed by various methods of surface morphology, structure, and spectroscopy. The low sheet resistance ([Formula: see text]) with large area of Graphene@SiC had the attention for application in gas sensor. While exposed to the nitrogen dioxide gas, the resistivity of Graphene@SiC sample also was changed. It is the hope of a designed gas sensor in future.
Degradation and protection of cut slopes in weathered gneiss; a 40 year case study
Authors: Martin R. P. , Howell J. H.
Published: January 2024

The retreat of two roadside cut slopes in weathered gneiss in the Middle Himalaya of east Nepal has been assessed by engineering geological mapping, sequential photography and slope profiling over a 40 year period, from 1979 to 2018, allowing approximate degradation rates to be calculated. The rate of removal of completely weathered gneiss and residual soil was about twice that of highly weathered material, primarily reflecting increased micro-cracking and breakdown of feldspars and micas in the weathered fabric. Surface water erosion by rilling and gullying in the summer monsoon wet season was the dominant process affecting the slopes, with landsliding (mainly by soil falls and debris slides) playing a secondary role. Drainage and bio-engineering protection measures applied to the slopes within the first 3–12 years after excavation were effective in reducing the degradation rate by between one and two orders of magnitude once the slopes had developed a moderate vegetation cover. The total volume of material removed from the slopes over four decades is equivalent to average rates of ground lowering in the range of 150–320 and 2–4 mm a
−1
before and after protection works, respectively. The latter range is similar to long-term denudation rates measured in drainage catchments in the region with similar settings.

Supplementary material:
One figure in three parts showing slope retreat over time for a complete set of 28 measured cross-sections and two tables giving details of calculated cross-sectional area losses and approximate intersectional volumetric losses of slope material are available at
https://doi.org/10.6084/m9.figshare.c.7005885
Completeness, Recall, and Negation in Open-world Knowledge Bases: A Survey
Authors: Razniewski Simon , Arnaout Hiba , Ghosh Shrestha , Suchanek Fabian
Published: January 2024

General-purpose knowledge bases (KBs) are a cornerstone of knowledge-centric AI. Many of them are constructed pragmatically from web sources and are thus far from complete. This poses challenges for the consumption as well as the curation of their content. While several surveys target the problem of completing incomplete KBs, the first problem is arguably to know whether and where the KB is incomplete in the first place, and to which degree.

In this survey, we discuss how knowledge about completeness, recall, and negation in KBs can be expressed, extracted, and inferred. We cover (i) the logical foundations of knowledge representation and querying under partial closed-world semantics; (ii) the estimation of this information via statistical patterns; (iii) the extraction of information about recall from KBs and text; (iv) the identification of interesting negative statements; and (v) relaxed notions of relative recall.

This survey is targeted at two types of audiences: (1) practitioners who are interested in tracking KB quality, focusing extraction efforts, and building quality-aware downstream applications; and (2) data management, knowledge base, and semantic web researchers who wish to understand the state-of-the-art of knowledge bases beyond the open-world assumption. Consequently, our survey presents both fundamental methodologies and the results that they have produced, and gives practice-oriented recommendations on how to choose between different approaches for a problem at hand.
Learning the Optimal Representation Dimension for Restricted Boltzmann Machines
Authors: Novaes de Oliveira Amanda Camacho
Published: January 2024

Hyperparameters refer to a set of parameters of a machine learning model that are fixed and not adjusted during training. A fundamental problem in this context is hyperparameter tuning which refers to the problem of identifying the best values for a set of model hyperparameters for a given task. In particular, model performance strongly depends on the choice of hyperparameters, and the right choice often determines the difference between average and stateof- the-art performance. This becomes especially important in models with many hyperparameters, as is common in deep learning models (DL) and automated machine learning (AutoML). However, finding the best set of hyperparameters for a model faced with a given task is very difficult in general, given the large state space and the high computational cost of assessing the quality of a given set of hyperparameters.
PEMA+: A Comprehensive Resource Manager for Microservices
Authors: Hossen Md Rajib
Published: January 2024

Motivation. Microservices architecture has become more prevalent in cloud-based applications where small, looselycoupled service components work together to handle user requests [1]. This architecture differs greatly from traditional monolithic deployments and provides advantages such as agile resource management, better fault tolerance, and platform compatibility [2, 3]. The figure 1 shows the difference between monolithic and microservice architecture. However, microservices come with their own set of challenges, particularly in the area of resource management. Resource management for microservices-based applications is more challenging than for monolithic applications due to the larger configuration space and complex communication topology [4, 5]. Additionally, existing resource management techniques for monolithic applications must manage microservices effectively. The resource management challenges for microservices must be addressed as more production cloud services adopt this architecture [6, 7].
Best Practices for Exoskeleton Evaluation Using DeepLabCut
Authors: Ahmed Nishat , Rahman Amaan , Rhode Lucia
Published: January 2024

Exoskeleton fit evaluation using pose estimation is necessary to ensure exoskeletons promote productivity in industrial settings. However, both marker-based and markerless vision based systems consist of uncertainties in tracking human joints while a person is wearing an exoskeleton because they have been trained on datasets consisting of only the human body [14].