bluuebunny/crossref_metadata_2025 huggingface dataset:
Information-theoretic measures of superconductivity in a two-dimensional doped Mott insulator
Authors: Walsh Caitlin , Charlebois Maxime , Sémon Patrick , Sordi Giovanni , Tremblay André-Marie S.
Published: June 2021

Significance

Quantum information can provide an overarching perspective on phases of matter in interacting quantum systems. We use tools of quantum information to characterize the entanglement-related properties of unconventional superconductivity in a doped Mott insulator—a phase of matter realized in cuprates and one that could soon be emulated with ultracold atoms. Using the canonical model of interacting quantum particles, we predict how key measures of correlations—thermodynamic entropy, local entropy, and total mutual information—detect the superconducting phase in a 2D doped Mott insulator. The local entropy reflects the source of condensation energy. In the superconducting phase, the thermodynamic entropy is suppressed, and the total mutual information is amplified. Our work provides a route to studying superconductivity with information-theoretic measures.
Long‐term evolution of cartilage abnormalities and osteophytes in the fingers of elite sport climbers: A cross‐sectional 10‐year follow‐up study
Authors: Pastor Torsten , Schweizer Andreas , Reissner Lisa , Pastor Tatjana , Spörri Jörg , Fröhlich Stefan
Published: June 2021

The sequelae of high mechanical stress to the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the fingers in elite sport climbers and its contribution to the development of osteoarthritis are still relatively unknown. The purpose of this study was to investigate the evolution of cartilage abnormalities of the PIP and DIP joints, as well as the progress of osteophytes, in the fingers of elite sport climbers with a minimum of 25 years of climbing history over the time period of the last 10 years. Moreover, their actual cartilage abnormalities and osteophyte occurrence were compared to non‐climbing age‐matched controls. Thirty‐one elite male sport climbers and 15 male non‐climbers underwent a sonographic examination of the PIP and DIP joint cartilage and osteophyte thickness in the frontal and sagittal plane of digits II–V of both hands. The same cohort had already been measured with an identical protocol 10 years earlier (follow‐up rate of 100%). Compared to the baseline assessment 10 years earlier, the cartilage thickness of sport climbers has significantly decreased; however, it was still greater than in age‐matched controls. Moreover, sport climbers showed significantly higher relative frequencies of osteophyte occurrence than non‐climbers (all fingers and joints). Nevertheless, despite a substantial (and compared to baseline a further increased) occurrence of osteophytes in elite sport climbers, there was no association between the radiological signs of osteoarthritis and pain within the last six months prior the follow‐up investigation.
The circumstellar matter of type II intermediate luminosity optical transients (ILOTs)
Authors: Soker Noam
Published: June 2021

I find that a ≃ 0.1 − 1 M
⊙ outflowing equatorial dusty disk (torus) that the binary system progenitor of an intermediate luminosity optical transient (ILOT) ejects several years to several months before and during the outburst can reduce the total emission to an equatorial observer by two orders of magnitude and shifts the emission to wavelengths of mainly λ ≳ 10 μm. This is termed a type II ILOT (ILOT II). To reach this conclusion, I use calculations of type II active galactic nuclei and apply them to the equatorial ejecta (disk/torus) of ILOTs II. This reduction in emission can last for tens of years after outburst. Most of the radiation escapes along the polar directions. The attenuation of the emission for wavelengths of λ < 5 μm can be more than three orders of magnitude, and the emission at λ ≲ 2 μ m is negligible. Jets that the binary system launches during the outburst can collide with polar CSM and emit radiation above the equatorial plane and dust in the polar outflow can reflect emission from the central source. Therefore, during the event itself the equatorial observer might detect an ILOT. I strengthen the previously suggested ILOT II scenario to the event N6946-BH1, where a red giant star disappeared in the visible.
The stellar system HIP 101227: is it a binary, a triple or a quadruple system?
Authors: Yousef Zahra Talal , Annuar Adlyka , Hussein Abdallah Mohammad , Al-Naimiy Hamid , Al-Wardat Mashhoor , Hamid Nurul Shazana Abdul , Talafha Mohammed Fadil
Published: June 2021

In this paper, we present the analysis of the stellar system HIP 101227 to determine the actual number of components in the system, and their properties. We use dynamical modeling and complex spectrophotometric (involving atmospheric modeling) techniques with recent data, to determine the physical properties and orbital solution for the system, respectively, with better accuracy than past studies. Based on our analysis, we found that the system is more consistent with being a quadruple rather than a binary or a triple system as suggested by previous studies. The total mass of the system determined from our SED analysis is 3.42 ± 0.20 M
⊙, which is distributed almost equally between the four stars. The stars are found to be zero-age main sequence stars; i.e., at the last stage of pre-main sequence, with age less than 200 Myr and spectral types K0. All four stars have very similar physical characteristics, suggesting that the fragmentation process is the most likely theory for the formation and evolution of the system.
Ground experiments and performance evaluation of the Low-Frequency Radio Spectrometer onboard the lander of Chang’e-4 mission
Authors: Zhu Xin-Ying , Su Yan , Ji Yi-Cai , Zhang Hong-Bo , Zhao Bo , Li Jun-duo , Dai Shun , Xue Xi-Ping , Li Chun-Lai
Published: June 2021

The Low-Frequency Radio Spectrometer (LFRS) is a scientific payload onboard the Chang’e-4 lunar lander launched in December 2018. The LFRS provides in-situ measurements of the low-frequency radio phenomena on the far-side of theMoon for the first time in human history. To evaluate the performance of the LFRS, a series of ground experiments are conducted using an engineering model of the LFRS. It is not easy to perform the experiments because the Electro Magnetic Interference (EMI) from the Chang’e- 4 lunar lander itself and the environment is very intense. The results after EMI mitigation show that the sensitivity of the LFRS may be 10−18 W m−2 Hz−1.
Evolutionary and Hereditary Traits of an Albatross and its Aerodynamic Optimality
Authors: Mathew Bilji C , Lal Jeyan J V Muruga , Dutta Prantik , Savale Rushikesh R.
Published: June 2021

The aerodynamic efficiency of the albatross has always fascinated researchers and the designing of drones mimicking the albatross’s aerodynamic traits have been a major area of interest for the aerospace industry. This review sheds light on the traits behind an albatross’s aerodynamic efficiency such as dynamic soaring, bell shaped lift distribution and provides insights into its hereditary posed encodings and evolutions. The soaring techniques have been introduced and discussed along with the albatross’s morphology and structure which is responsible for its efficiency. In addition, the albatross’s navigational and foraging strategies are briefly discussed to provide a better understanding of the effects of atmospheric conditions on the albatross’s flight characteristics and the limitations.
A microclimatic study of urban neighbourhood parks
Authors: Nawani Akhil , Kaur Harsimran
Published: June 2021

Green spaces are considered important natural and human-centric spaces in a city. They are considered essential to allow the proper functioning of the natural ecosystem in an urban environment. The study aims to determine the thermal impact of a neighbourhood park upon its residential surroundings in a rapidly urbanising city. The city of Gurugram, India, was chosen for a study as it has seen unprecedented growth, increasing the need to develop green spaces. A traverse survey is conducted in some chosen neighbourhood parks of Gurugram, and microclimatic variables are recorded. Three sites in different wards are surveyed multiple times to record on-site climatic data, building typology, building heights, survey points, and characteristics. These are then denoted graphically, and specific trends are generated and explained. The study also provides a path towards the study’s future scope, further enhancing the research topic’s overall understanding.
Natural Microalgae Biofilm As A Tool To Clean-Up Mining Wastewater
Authors: Anbu Kumar S. , Gupta Shivam , Kumar Shubham , Meena Pawan Kumar
Published: June 2021

Pollutants in amphibian conditions will in general change the network arrangement and exercises of biofilm cells. The making of excessive reactive oxygen species (ROS) which is caused due to the stress induced out of these pollutants play a major role in debasement of pollutants in oceanic conditions. This smaller than expected audit is pointed toward anticipating the proficiency of the utilisation of regular biofilm in water treatment coming about because of mining exercises. Additionally, it sums up the idea of mining by briefly expressing the stages engaged with mining and how the toxins delivered during mining can make harmful impacts on amphibian vegetation. Discussion on how the advancement of biodiversity is impacted by the ecological issues resulting from activities of mining was done. Microalgae assume a significant part in the alleviation of the effect of contamination coming about because of mining exercises. The cycle of toxins expulsion in freshwater by miniature green growth biofilm is by debasement and biosorption. Biosorption of hefty metals in mining wastewater was caused because of the extracellular polymeric substances (EPS). The kinetic model should be understood properly which explains the biosorption of hefty metals through physical and chemical reactions.
An equivariant basis for the cohomology of Springer fibers
Authors: Precup Martha , Richmond Edward
Published: June 2021

Springer fibers are subvarieties of the flag variety that play an important role in combinatorics and geometric representation theory. In this paper, we analyze the equivariant cohomology of Springer fibers for

G

L
n

(

C

)

GL_n(\mathbb {C})

using results of Kumar and Procesi that describe this equivariant cohomology as a quotient ring. We define a basis for the equivariant cohomology of a Springer fiber, generalizing a monomial basis of the ordinary cohomology defined by De Concini and Procesi and studied by Garsia and Procesi. Our construction yields a combinatorial framework with which to study the equivariant and ordinary cohomology rings of Springer fibers. As an application, we identify an explicit collection of (equivariant) Schubert classes whose images in the (equivariant) cohomology ring of a given Springer fiber form a basis.
Implementation of telehealth antimicrobial stewardship through partnership of an academic medical center and a community hospital
Authors: Klatt Megan E , Schulz Lucas T , Fleischman Dan , Fox Barry C , Burke Stuart , Grinder Dave , Rose Warren E , Lepak Alexander J , Andes David R
Published: June 2021

Purpose

Small community hospitals often lack the human, financial, and technological resources necessary to implement and maintain successful antimicrobial stewardship programs now required by national regulatory and accrediting bodies. Creative solutions are needed to address this problem.

A 3-stage, quasi-experimental study including patients receiving antibiotics for pneumonia, skin and soft tissue infections, and urinary tract infections at a community hospital in Wisconsin from June 2013 to December 2015 was conducted. Remote telehealth prospective audit and feedback, guideline and order set management, and staff education targeting pharmacists, nurses, and physicians were provided during the 7-month intervention phase; these services were then removed for the postintervention period. Antimicrobial utilization (days of therapy [DOT] per 1,000 patient-days), hospital length of stay, and readmission and 30-day mortality rates were assessed to determine the impact of telehealth services on these outcomes. During the preintervention (baseline), intervention, and postintervention periods, 1,037 patients received antibiotics for the targeted infectious disease conditions. Patient demographics and rates of infectious disease conditions were similar among the different periods. Telehealth antimicrobial stewardship reduced broad-spectrum antibiotic use, including use of imipenem (from 83 to 31 DOT, P < 0.001), levofloxacin (from 123 to 99 DOT, P < 0.001), and vancomycin (from 104 to 85 DOT, P < 0.001), compared to utilization during the baseline period; mean (SD) length of stay also decreased (from 4.6 [2.8] days to 4.2 [2.6] days, P = 0.02). After nonrenewal of telehealth stewardship, vancomycin and piperacillin/tazobactam usage returned to or exceeded baseline levels.

Conclusion

The partnership between an academic medical center and a small community hospital improved antimicrobial utilization and clinical outcomes. Successful telehealth antimicrobial stewardship models should be explored further as a means to provide optimal patient care.
A triangle for the French translation of General Theory: Keynes, Sraffa, and Largentaye
Authors: Deleplace Ghislain
Published: June 2021

The paper studies the correspondence exchanged in 1938–1939 between Keynes and the French translator of General Theory, Jean de Largentaye, and between Keynes and Sraffa on this translation. The focus is on some analytical difficulties raised in this correspondence. After having described the circumstances of Sraffa’s involvement, the paper evokes a disagreement between Keynes and Largentaye about the kind of language that should be used in a book like General Theory. A section deals with clarifications and improvements brought about by the correspondence, particularly on the treatment of entrepreneurs’ profits and on the behaviour of lenders and borrowers in a financial crisis. Another section studies an important amendment to Chapter 17 on the concept of own-rate of interest. This amendment was suggested by Largentaye and accepted by Keynes in the context of various critiques expressed elsewhere by Pigou, Hicks, and Sraffa.
The EP300/TP53 pathway, a suppressor of the Hippo and canonical WNT pathways, is activated in human hearts with arrhythmogenic cardiomyopathy in the absence of overt heart failure
Authors: Rouhi Leila , Fan Siyang , Cheedipudi Sirisha M , Braza-Boïls Aitana , Molina Maria Sabater , Yao Yan , Robertson Matthew J , Coarfa Cristian , Gimeno Juan R , Molina Pilar , Gurha Priyatansh , Zorio Esther , Marian Ali J
Published: June 2021

Aims 

Arrhythmogenic cardiomyopathy (ACM) is a primary myocardial disease that typically manifests with cardiac arrhythmias, progressive heart failure, and sudden cardiac death (SCD). ACM is mainly caused by mutations in genes encoding desmosome proteins. Desmosomes are cell–cell adhesion structures and hubs for mechanosensing and mechanotransduction. The objective was to identify the dysregulated molecular and biological pathways in human ACM in the absence of overt heart failure.

Methods and results

Transcriptomes in the right ventricular endomyocardial biopsy samples from three independent individuals carrying truncating mutations in the DSP gene and five control samples were analysed by RNA-Seq (discovery group). These cases presented with cardiac arrhythmias and had a normal right ventricular function. The RNA-Seq analysis identified ∼5000 differentially expressed genes (DEGs), which predicted suppression of the Hippo and canonical WNT pathways, among others. Dysregulated genes and pathways, identified by RNA-Seq, were tested for validation in the right and left ventricular tissues from five independent autopsy-confirmed ACM cases with defined mutations (validation group), who were victims of SCD and had no history of heart failure. Protein levels and nuclear localization of the cWNT and Hippo pathway transcriptional regulators were reduced in the right and left ventricular validation samples. In contrast, levels of acetyltransferase EP300, known to suppress the Hippo and canonical WNT pathways, were increased and its bona fide target TP53 was acetylated. RNA-Seq data identified apical junction, reflective of cell–cell attachment, as the most disrupted biological pathway, which were corroborated by disrupted desmosomes and intermediate filament structures. Moreover, the DEGs also predicted dysregulation of over a dozen canonical signal transduction pathways, including the Tec kinase and integrin signalling pathways. The changes were associated with increased apoptosis and fibro-adipogenesis in the ACM hearts.

Conclusion 

Altered apical junction structures are associated with activation of the EP300-TP53 and suppression of the Hippo/cWNT pathways in human ACM caused by defined mutations in the absence of an overt heart failure. The findings implicate altered mechanotransduction in the pathogenesis of ACM.
Comparing clinical performance of current implantable cardioverter-defibrillator implantation recommendations in arrhythmogenic right ventricular cardiomyopathy
Authors: Bosman Laurens P , Nielsen Gerlach Claire L , Cadrin-Tourigny Julia , Orgeron Gabriela , Tichnell Crystal , Murray Brittney , Bourfiss Mimount , van der Heijden Jeroen F , Yap Sing-Chien , Zeppenfeld Katja , van den Berg Maarten P , Wilde Arthur A M , Asselbergs Folkert W , Tandri Hariskrishna , Calkins Hugh , van Tintelen J Peter , James Cynthia A , te Riele Anneline S J M
Published: June 2021

Aims

Arrhythmogenic right ventricular cardiomyopathy (ARVC) patients have an increased risk of ventricular arrhythmias (VA). Four implantable cardioverter-defibrillator (ICD) recommendation algorithms are available The International Task Force Consensus (‘ITFC’), an ITFC modification by Orgeron et al. (‘mITFC’), the AHA/HRS/ACC guideline for VA management (‘AHA’), and the HRS expert consensus statement (‘HRS’). This study aims to validate and compare the performance of these algorithms in ARVC.

Methods and results

We classified 617 definite ARVC patients (38.5 ± 15.1 years, 52.4% male, 39.2% prior sustained VA) according to four algorithms. Clinical performance was evaluated by sensitivity, specificity, ROC-analysis, and decision curve analysis for any sustained VA and for fast VA (>250 b.p.m.). During 6.4 [2.8–11.5] years follow-up, 282 (45.7%) patients experienced any sustained VA, and 63 (10.2%) fast VA. For any sustained VA, ITFC and mITFC provide higher sensitivity than AHA and HRS (94.0–97.8% vs. 76.7–83.5%), but lower specificity (15.9–32.0% vs. 42.7%-60.1%). Similarly, for fast VA, ITFC and mITFC provide higher sensitivity than AHA and HRS (95.2–97.1% vs. 76.7–78.4%) but lower specificity (42.7–43.1 vs. 76.7–78.4%). Decision curve analysis showed ITFC and mITFC to be superior for a 5-year sustained VA risk ICD indication threshold between 5–25% or 2–9% for fast VA.

Conclusion

The ITFC and mITFC provide the highest protection rates, whereas AHA and HRS decrease unnecessary ICD placements. ITFC or mITFC should be used if we consider the 5-year threshold for ICD indication to lie within 5–25% for sustained VA or 2–9% for fast VA. These data will inform decision-making for ICD placement in ARVC.
Glutamine supplementation affected the gut bacterial community and fermentation leading to improved nutrient digestibility in growth-retarded yaks
Authors: Ma Jian , Zhu Yixiao , Wang Zhisheng , Yu Xiong , Hu Rui , Wang Xueying , Cao Guang , Zou Huawei , Shah Ali Mujtaba , Peng Quanhui , Xue Bai , Wang Lizhi , Zhao Suonan , Kong Xiangying
Published: June 2021

This study evaluated the effects of glutamine supplementation on nutrient digestibility, immunity, digestive enzyme activity, gut bacterial community and fermentation of growth-retarded yaks. A total of 16 growth-retarded yaks were randomly allocated to two groups: negative control (GRY) and glutamine supplementation group (GLN). Another eight growth-normal yaks were used as a positive control (GNY). Compared with GRY group, the crude protein digestibility was higher in GLN and GNY animals and the neutral detergent fiber digestibility was increased in GLN yaks. The concentrations of serum IgA, IgG, IgM and IL-10, as well as butyrate concentration and cellulase activity in the rumen and cecum were higher in GLN yaks compared to those in GRY animals. Supplementation with glutamine enhanced the chymotrypsin activity and increased the relative abundances of unclassified Peptostreptococcaceae and Romboutsia while decreased the relative abundances of unclassified Chitinophagaceae and Bacteroides in the jejunum and ileum of growth-retarded yaks. In the cecum, the relative abundance of unclassified Muribaculaceae was higher in GLN group than that in GRY group. The findings in this study suggest that the improved nutrient digestibility and immunity of growth-retarded yaks with glutamine supplementation may be through its potential impact on the lower gut host and microbial functions.
Plant phenology influences rhizosphere microbial community and is accelerated by serpentine microorganisms inPlantago erecta
Authors: Igwe Alexandria N , Quasem Bibi , Liu Naomi , Vannette Rachel L
Published: June 2021

Serpentine soils are drought-prone and rich in heavy metals, and plants growing on serpentine soils host distinct microbial communities that may affect plant survival and phenotype. However, whether the rhizosphere communities of plants from different soil chemistries are initially distinct or diverge over time may help us understand drivers of microbial community structure and function in stressful soils. Here, we test the hypothesis that rhizosphere microbial communities will converge over time (plant development), independent of soil chemistry and microbial source. We grew Plantago erecta in serpentine or nonserpentine soil, with serpentine or nonserpentine microbes and tracked plant growth and root phenotypes. We used 16S rRNA gene barcoding to compare bacterial species composition at seedling, vegetative, early- and late-flowering phases. Plant phenotype and rhizosphere bacterial communities were mainly structured by soil type, with minor contributions by plant development, microbe source and their interactions. Serpentine microorganisms promoted early flowering in plants on nonserpentine soils. Despite strong effects of soil chemistry, the convergence in bacterial community composition across development demonstrates the importance of the plant–microbe interactions in shaping microbial assembly processes across soil types.
Intersectoral partnerships and competencies for mental health promotion: a Delphi-based qualitative study in Finland
Authors: Tamminen Nina , Solin Pia , Barry Margaret M , Kannas Lasse , Kettunen Tarja
Published: June 2021

The importance of intersectoral collaboration and partnership working in mental health promotion, together with the requisite competencies for effective collaboration, is widely acknowledged. This Delphi-based qualitative study examined how intersectoral collaboration and partnership work are constructed and adopted in mental health promotion practice. Descriptive data from a Delphi panel of mental health promotion practitioners working in the health sector (n = 32) were used as a data source. Thematic analysis was used to analyze the data. Applying the theory of collaborative advantage, eight themes of collaboration advantage and the related competencies were identified: management structure, leadership, communication and language, common aims, working processes, resources, trust, and commitment and determination. The themes capture the competencies required to influence and work with others to improve the mental health and wellbeing of individuals and communities. The identified theme areas can be used to inform education and training and capacity building for professional practice in mental health promotion. Future research is needed to explore other possible collaborative advantage themes in mental health promotion practice and the competencies required to facilitate effective partnerships across sectors. Further investigations are also needed on the identified theme areas in order to develop and guide capacity building and training in mental health promotion.
A qualitative meta-synthesis on how autonomy promotes vaccine rejection or delay among health care providers
Authors: Akande Adebisi , Ahmad Mobeen , Majid Umair
Published: June 2021

In spite of the overwhelming evidence that highlights the effectiveness of routine vaccination, an increasing number of people are refusing to follow recommended vaccination schedules. While the majority of research in this area has focussed on vaccine hesitancy in parents, there is little research on the factors that promote vaccine hesitancy in health care providers (HCPs). Identifying factors that promote vaccine hesitancy in HCPs is essential because it may help broaden our understanding of vaccine hesitancy in patients. Therefore, the goal of this investigation was to review 21 studies and examine how professional autonomy and risk perception may promote vaccine acceptance, rejection and delay in physicians and nurses. We found that vaccine hesitant nurses and physicians shared similar views towards vaccines; both groups believed that their decision to vaccinate was separate from their role as an HCP. This belief comprised of three themes: decisional autonomy, personal risk perception and alternatives to vaccination. Both groups believed that mandatory vaccine policies reduced their ability to decide whether vaccination was in their best interests. We argue that decisional autonomy may weaken risk perception of disease, which in turn may encourage beliefs and behaviours that reinforce a ‘hero persona’ that reduces appropriate preventive and hygiene measures. We employ the Health Belief Model to discuss the crucial role that risk perceptions may play in reinforcing autonomy in vaccine hesitant physician and nurses. We conclude this paper by providing a set of recommendations that aim to improve the decision-making process surrounding mandatory vaccinations for HCPs.
The winds of young Solar-type stars in the Hyades
Authors: Evensberget D , Carter B D , Marsden S C , Brookshaw L , Folsom C P
Published: June 2021

Stellar winds govern the spin-down of Solar-type stars as they age, and play an important role in determining planetary habitability, as powerful winds can lead to atmospheric erosion. We calculate 3D stellar wind models for five young Solar-type stars in the Hyades cluster, using TOUPIES survey stellar magnetograms and state-of-the-art Alfvén wave-driven wind modelling. The stars have the same 0.6 Gyr age and similar fundamental parameters, and we account for the uncertainty in and underestimation of absolute field strength inherent in Zeeman–Doppler imaging by adopting both unscaled and scaled (by a factor of five) field strengths. For the unscaled fields, the resulting stellar wind mass-loss is 2–4 times greater and the angular momentum loss 2–10 times greater than for the Sun today, with the scaled results correspondingly greater. We compare our results with a range published of wind models and for the Alfvén wave-driven modelling see evidence of mass-loss saturation at ${\sim 10} \dot{M}_{\odot }$.
Cytotoxic function of xylanase VdXyn4 in the plant vascular wilt pathogen Verticillium dahliae
Authors: Wang Dan , Chen Jie-Yin , Song Jian , Li Jun-Jiao , Klosterman Steven J. , Li Ran , Kong Zhi-Qiang , Subbarao Krishna V. , Dai Xiao-Feng , Zhang Dan-Dan
Published: June 2021

Phytopathogen xylanases play critical roles in pathogenesis, likely due to their ability to degrade plant structural barriers and manipulate host immunity. As an invader of plant xylem vessels, the fungus Verticillium dahliae is thought to deploy complex cell wall degrading enzymes. Comparative genomics analyses revealed that the V. dahliae genome encodes a family of six xylanases, each possessing a glycosyl hydrolase 11 domain, but the functions of these enzymes are undetermined. Characterizing gene deletion mutants revealed that only V. dahliae xylanase 4 (VdXyn4) degraded the plant cell wall and contributed to the virulence of V. dahliae. VdXyn4 displayed cytotoxic activity and induced a necrosis phenotype during the late stages of infection, leading to vein and petiole collapse that depended on the enzyme simultaneously localizing to nuclei and chloroplasts. The internalization of VdXyn4 was in conjunction with that of the plasma membrane complexLeucine-rich repeat (LRR)-receptor-like kinase suppressor of BIR1-1 (SOBIR1)/LRR-RLK BRI1-associated kinase-1 (BAK1), but we could not rule out the possibility that VdXyn4 may also act as an apoplastic effector. Immune signaling (in the SA–JA pathways) induced by VdXyn4 relative to that induced by known immunity effectors was substantially delayed. While cytotoxic activity could be partially suppressed by known effectors, they failed to impede necrosis in Nicotiana benthamiana. Thus, unlike typical effectors, cytotoxicity of VdXyn4 plays a crucial intracellular role at the late stages of V. dahliae infection and colonization, especially following pathogen entry into the xylem; this cytotoxic activity is likely conserved in the corresponding enzyme families in plant vascular pathogens.
Oscillating 4-Polytopal Universe in Regge Calculus
Authors: Tsuda Ren , Fujiwara Takanori
Published: June 2021

The discretized closed Friedmann–Lemaître–Robertson–Walker (FLRW) universe with positive cosmological constant is investigated by Regge calculus. According to the Collins–Williams formalism, a hyperspherical Cauchy surface is replaced with regular 4-polytopes. Numerical solutions to the Regge equations approximate well to the continuum solution during the era of small edge length. Unlike the expanding polyhedral universe in three dimensions, the 4-polytopal universes repeat expansions and contractions. To go beyond the approximation using regular 4-polytopes we introduce pseudo-regular 4-polytopes by averaging the dihedral angles of the tessellated regular 600-cell. The degree of precision of the tessellation is called the frequency. Regge equations for the pseudo-regular 4-polytope have simple and unique expressions for any frequency. In the infinite frequency limit, the pseudo-regular 4-polytope model approaches the continuum FLRW universe.
ASSESSMENT OF NORM LEVELS AND RADIOLOGICAL HAZARDS FROM PETROLEUM EXTRACTION IN THE ONSHORE OIL FIELDS, EGYPT
Authors: Salahel Din Khaled , Rashed Wafaa
Published: June 2021

Forty-nine different samples (crude oil, surface soil, produced water and sludge) from onshore oil fields in the Western Desert of Egypt were assessed for naturally occurring radioactive material (NORM) levels using HPGe gamma-ray spectrometer. The average activity concentrations of 226Ra, 232Th and 40K were 25 ± 1.3, 26 ± 1.0 and 21 ± 1.5; 9.8 ± 0.50, 11 ± 0.40 and 94 ± 6.9; 130 ± 6.6, 91 ± 3.4 and 41 ± 3.0; and 180 ± 16, 70 ± 6.9 and 1300 ± 110 Bq kg−1 for crude oil, surface soil, produced water and sludge, respectively. The obtained NORM levels are much below the International Atomic Energy Agency NORM clearance levels. Radiological parameters (radium equivalent activity, absorbed dose rate and annual effective dose) were calculated and compared with the international acceptable limits. The annual effective doses are below 1 and 20 mSv, the ICRP safety limits for the public and workers, respectively. Consequently, insignificant radiological hazards could present for the workers and surrounding environment from petroleum extraction activities in the studied area.
Connecting chemistry to biology to understand why O‐GlcNAc transferase is essential
Authors: Walker Suzanne
Published: June 2021

O‐GlcNAc transferase (OGT) is an essential mammalian enzyme that catalyzes two fundamentally different, physiologically relevant chemical reactions using the same active site. One reaction is the transfer of N‐acetyl glucosamine to Ser/Thr side chains of nuclear and cytoplasmic proteins. OGT uniquely O‐GlcNAcylates myriad intracellular proteins involved in cell growth and division in a nutrient‐ and stress‐responsive manner, attracting comparisons between it and mTOR. The second reaction is polypeptide backbone cleavage. OGT is required for the proteolytic maturation of another essential mammalian protein, Host Cell Factor 1, a transcriptional co‐regulator found in a number of chromatin‐associated complexes. Understanding OGT's complex biology requires first understanding its chemistry well enough to separate its functions and then developing genetic approaches to replace wildtype OGT with well‐characterized variants. We will talk about our published structural and mechanistic work to understand how OGT catalyzes glycosylation and peptide backbone cleavage, and will also describe recent results that reveal how it chooses many of its substrates. We will then describe how we have combined this knowledge with a genetic system to replace OGT in cells in order to begin to address a key question: why is OGT essential in all dividing mammalian cells?

Support or Funding Information

Funding for this work was provided by a National Institutes of Health grant (R01 GM094263)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
tRNA Methylation Controls Bacterial Multi‐Drug Resistance
Authors: Masuda Isao , Matsubara Ryuma , Christian Thomas , Rojas Enrique R. , Yadavalli Srujana S. , Goulian Mark , Huang Kerwyn Casey , Hou Ya‐Ming
Published: June 2021

Bacterial multi‐drug resistance is a burgeoning crisis whose origin remains mechanistically opaque. Through altered permeability or efflux activity, the membrane prevents many antibiotics from reaching high enough intracellular concentrations to exert a therapeutic effect. We show here that protein synthesis of membrane‐associated genes involves translation of proline CC[C/U] codons, which require N1‐methylation of guanosine 37 (m1G37) on the 3′‐side of the tRNA anticodon. TrmD is the bacterial methyl transferase that catalyzes m1G37‐methylation. Removal of m1G37 by trmD inactivation reduces biosynthesis of membrane proteins, impairs membrane structure and mechanics, and sensitizes Gram‐negative bacteria to multiple classes of antibiotics and suppresses development of resistance and persistence. Codon engineering in the major efflux gene tolC removes the dependence on trmD for biosynthesis of membrane proteins. TrmD activity requires the conserved G37 in tRNAPro; replacement of G37 with C37 increases membrane permeability and accelerates cell death. These findings demonstrate the potential to diminish multi‐drug resistance by inaction of TrmD and its m1G37‐tRNA product.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sensing Changes in Cellular Iron Metabolism: Regulation of IRP1 by FBXL5 and Cytosolic Iron‐Sulfur Cluster Assembly
Authors: Johnson Nathan B.
Published: June 2021

Iron is a micronutrient essential for the viability of nearly all cells, but in excess, iron can overwhelm antioxidant defense mechanisms resulting in damage of cellular structures and cell death. Therefore, cellular iron levels must be maintained within narrow limits to prevent iron deficiency and iron toxicity. In order to maintain optimal iron levels, mammalian cells utilize Iron Regulatory Proteins (IRP). IRP1 and IRP2 are iron‐regulated RNA binding proteins that control the fate of mRNAs encoding proteins important for maintaining cellular iron homeostasis. For example, in iron replete cells IRP RNA binding is inactivated resulting in decreased iron uptake by transferrin receptor 1 and increased iron storage by ferritin. IRP1 RNA binding is inactivated primarily by the insertion of a [4Fe–4S] cluster by the cytosolic iron‐sulfur cluster assembly (CIA) system converting it into the cytosolic isoform of aconitase (c‐acon). IRP1 can also be inactivated by the iron‐dependent E3 ligase FBXL5 that also targets IRP2. Since, human diseases associated with impaired Fe‐S cluster assembly can disrupt cellular iron metabolism, we sought to understand the mechanism by which CIA and FBXL5 regulate IRP1. I will discuss a model for how CIA and FBXL5 collaborate to control the level of IRP1 RNA binding activity and optimize iron metabolism to meet cellular needs for proliferation.

Support or Funding Information

This work was supported by National Institutes of Health Grant RO1 DK66600, United States Department of Agriculture Hatch Project WIS01667, and the Iron Metabolism Research Fund.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Asymmetric Configurations in a Reengineered Homodimer Reveal Multiple Subunit Communication Pathways in Protein Allostery
Authors: Lanfranco Maria Fe , Garate Fernanda , Engdahl Ashton , Maillard Rodrigo
Published: June 2021

Many allosteric proteins form homo‐oligomeric complexes to regulate a biological function. In homo‐oligomers, subunits establish communication pathways that are modulated by external stimuli like ligand binding. A challenge for dissecting the communication mechanisms in homo‐oligomers is identifying intermediate liganded states, which are typically transiently populated. However, their identities provide the most mechanistic information on how ligand‐induced signals propagate from bound to empty subunits. Here, we dissected the directionality and magnitude of subunit communication in a reengineered, single‐chain version of the homodimeric transcription factor cAMP Receptor Protein (CRPSC). By combining wild‐type and mutant subunits in various asymmetric configurations, we revealed a linear relationship between the magnitude of cooperative effects and the number of mutant subunits. We found that a single mutation is sufficient to change the global allosteric behavior of the dimer even when one subunit remains wild‐type. Dimers harboring two mutations with opposite cooperative effects had different allosteric properties depending on the arrangement of the mutations. When the two mutations were placed in the same subunit, the resulting cooperativity was neutral. In contrast, when placed in different subunits, the observed cooperativity was dominated by the mutation with strongest effects over cAMP affinity relative to wild‐type. These results highlight the distinct roles of intrasubunit interactions and intersubunit communication in allostery. Finally, dimers bound to either one or two cAMP molecules had similar DNA affinities, indicating that both asymmetric and symmetric liganded states activate DNA interactions. These studies have revealed the multiple communication pathways that homo‐oligomers employ to transduce signals.

Support or Funding Information

This work was supported with startup funds from Georgetown University.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Natural product bioactive peptide discovery using PepSAVI‐MS
Authors: Hicks Leslie
Published: June 2021

As current methods for antibiotic drug discovery are being outpaced by the rise of antimicrobial resistance, new methods and innovative technologies are crucial to replenish our dwindling arsenal of antimicrobial therapeutics. While natural products are a well‐studied source of biologically active small molecules, peptidyl factors contributing to their medicinal properties remain largely unexplored. To this end, we have developed the PepSAVI‐MS (Statistically‐guided bioactive peptides prioritized via mass spectrometry) pipeline1 to identify bioactive peptide targets from complex biological samples. MS/MS techniques such as CID, ETD, UVPD are implemented for de novo characterization. To validate this pipeline, we have demonstrated successful detection and identification of a known antimicrobial peptide, cycloviolacin O2 (cyO2), from the botanical species Viola odorata. Additionally, we have widened the known antimicrobial spectrum for V. odorata cyclotides, including antibacterial activity of cyO2 against A. baumannii and novel anticancer activities for cycloviolacins by their cytotoxicity against ovarian, breast and prostate cancer cell lines. The developed platform is highly versatile as it is adaptable to any natural product source of peptides and can test against diverse physiological targets, including bacteria, fungi, viruses, protozoans, and cancer cells for which there is a developed bioassay. As such, we demonstrate extension of this pipeline to fungal and bacterially‐sourced AMPs through the identification of the killer toxin KP4 from Ustilago maydis2 and the bacteriocin bac‐21 from Enterococcus faecalis harboring pPD13. Bac‐21 is identical in nucleotide sequence to another enterococcal bacteriocin, AS‐484, but herein we have experimentally validated the protein sequence of bac‐21 for the first time. Additionally, we begin to probe the vast array of botanical natural product sources to prioritize highly active species for downstream analysis.

Support or Funding Information

University of North Carolina Chapel Hill

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Small Molecule Differentiation of RNA Structures Using Pattern Recognition
Authors: Hargrove Amanda E.
Published: June 2021

The critical importance of RNA elements in gene regulation and the potential of targeting RNA with small molecules are increasingly appreciated, yet many questions remain unanswered in small molecule:RNA recognition. These questions include which RNA structures can best be differentiated by small molecules and how small molecules can be used as tools to probe RNA structure and function. We developed a method termed Pattern Recognition of RNA with Small Molecules (PRRSM) that evaluates the ability of small molecules to classify RNA structures under a variety of conditions and in turn uses these small molecule “receptors” to identify site‐specific RNA structural changes. Insights gained from the assay, the current scope of the method, and future directions will be discussed.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Optical Imaging Tools for Elucidating the Roles of Anions in Cellular Signaling
Authors: Dodani Sheel
Published: June 2021

Living systems have evolved finely tuned mechanisms to coordinate transporters, chaperones, and non‐proteinaceous ligands to spatially and temporally position ions for normal physiology. In this context, freely diffusing and protein‐bound anions link to signal transduction, regulation of intracellular pH, and even detoxification. However, a breakdown in cellular homeostasis can lead to anion dysregulation in a wide range of diseases including neuropathic pain, cancer, and cystic fibrosis suggesting that anions could be signals of cellular status. Despite this biological significance, chemical biology approaches to identify the cellular stores, protein targets, and signaling roles of biologically relevant anions, are still underdeveloped, but could provide new insights for the role of anions in human health and disease. To this end, in this presentation I will describe the development and applications of turn‐on fluorescent biosensors for the real‐time imaging of anions in biological systems.

Support or Funding Information

Acknowledgment is made to the Welch Foundation (Grant No. AT‐1918‐20170325).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Promotion Of Muscle Satellite Cell Proliferation By cAMP‐Induced Transcription
Authors: Berdeaux Rebecca , Akhmedov Dmitry
Published: June 2021

The cAMP‐activated transcription factor CREB stimulates proliferation of myogenic progenitor cells during embryonic development, and genetic activation of CREB stimulates proliferation during muscle regeneration. Proliferation of muscle progenitor cells, known as satellite cells, declines during aging. We hypothesized that pharmacologic activation of the cAMP‐CREB pathway would promote satellite cell proliferation after injury and that cAMP‐regulated CREB co‐activators (CRTCs) contribute to CREB‐regulated target gene expression during satellite cell proliferation. To test this, we created ROSA26‐GsDREADD knock‐in mice for tissue‐specific expression of a Gs‐coupled DREADD (Designer Receptor Exclusively Activated by Designer Drugs, “GsD”). After tamoxifen‐induced expression of GsD in muscle satellite cells in young adult mice, activation of the receptor by the GsD ligand CNO (clozapine N‐oxide) increased proliferation after muscle injury. Consistent with our hypothesis, myoblasts over‐expressing constitutively active CRTC2 had increased cell proliferation in vitro, and Crtc2 knockout mice had reduced proliferation after muscle injury. Our results indicate that cAMP signaling enhances satellite cell proliferation in vivo and cAMP regulated CREB coactivator 2 (CRTC2) contributes to the proliferative response after muscle injury. ROSA26‐GsDREADD mice can therefore be used to stimulate cAMP signaling in specific cell populations in vivo to study the effects of pharmacologic activation of cAMP signaling without using ligands that have pleiotropic effects in other cell types.

Support or Funding Information

Research reported in this abstract was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number R01‐AR059847. DA was supported by a Postdoctoral Fellowship from the American Heart Association (15POST25090134). The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.