Connexin36 knockout mice display increased sensitivity to pentylenetetrazol-induced seizure-like behaviors

Large-scale synchronous firing of neurons during seizures is modulated by electrotonic coupling between neurons via gap junctions. To explore roles for connexin36 (Cx36) gap junctions in seizures, we examined the seizure threshold of connexin36 knockout (Cx36KO) mice using a pentylenetetrazol (PTZ) model

Predictor-Based Model Reference Adaptive Control

This paper is devoted to robust, Predictor-based Model Reference Adaptive Control (PMRAC) design. The proposed adaptive system is compared with the now-classical Model Reference Adaptive Control (MRAC) architecture. Simulation examples are presented. Numerical evidence indicates that the proposed PMRAC tracking architecture has better than MRAC transient characteristics. In this paper, we presented a state-predictor based direct adaptive tracking design methodology for multi-input dynamical systems, with partially known dynamics. Efficiency of the design was demonstrated using short period dynamics of an aircraft. Formal proof of the reported PMRAC benefits constitute future research and will be reported elsewhere

Rapid Evolution of BRCA1 and BRCA2 in Humans and Other Primates

The maintenance of chromosomal integrity is an essential task of every living organism and cellular repair mechanisms exist to guard against insults to DNA. Given the importance of this process, it is expected that DNA repair proteins would be evolutionarily conserved, exhibiting very minimal sequence change over time. However, BRCA1, an essential gene involved in DNA repair, has been reported to be evolving rapidly despite the fact that many protein-altering mutations within this gene convey a significantly elevated risk for breast and ovarian cancers. Results: To obtain a deeper understanding of the evolutionary trajectory of BRCA1, we analyzed complete BRCA1 gene sequences from 23 primate species. We show that specific amino acid sites have experienced repeated selection for amino acid replacement over primate evolution. This selection has been focused specifically on humans and our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). After examining BRCA1 polymorphisms in 7 bonobo, 44 chimpanzee, and 44 rhesus macaque (Macaca mulatta) individuals, we find considerable variation within each of these species and evidence for recent selection in chimpanzee populations. Finally, we also sequenced and analyzed BRCA2 from 24 primate species and find that this gene has also evolved under positive selection. Conclusions: While mutations leading to truncated forms of BRCA1 are clearly linked to cancer phenotypes in humans, there is also an underlying selective pressure in favor of amino acid-altering substitutions in this gene. A hypothesis where viruses are the drivers of this natural selection is discussed.National Institutes of Health R01-GM-093086, 8U42OD011197-13National Science Foundation BCS-07115972Burroughs Wellcome FundMolecular Bioscience

Antiapoptotic Actions of Methyl Gallate on Neonatal Rat Cardiac Myocytes Exposed to H 2

Reactive oxygen species trigger cardiomyocyte cell death via increased oxidative stress and have been implicated in the pathogenesis of cardiovascular diseases. The prevention of cardiomyocyte apoptosis is a putative therapeutic target in cardioprotection. Polyphenol intake has been associated with reduced incidences of cardiovascular disease and better overall health. Polyphenols like epigallocatechin gallate (EGCG) can reduce apoptosis of cardiomyocytes, resulting in better health outcomes in animal models of cardiac disorders. Here, we analyzed whether the antioxidant N-acetyl cysteine (NAC) or polyphenols EGCG, gallic acid (GA) or methyl gallate (MG) can protect cardiomyocytes from cobalt or H2O2-induced stress. We demonstrate that MG can uphold viability of neonatal rat cardiomyocytes exposed to H2O2 by diminishing intracellular ROS, maintaining mitochondrial membrane potential, augmenting endogenous glutathione, and reducing apoptosis as evidenced by impaired Annexin V/PI staining, prevention of DNA fragmentation, and cleaved caspase-9 accumulation. These findings suggest a therapeutic value for MG in cardioprotection

Instrumented mouthguards in elite-level men’s and women’s rugby union: characterising tackle-based head acceleration events

Objectives To examine the propensity of tackle height and the number of tacklers that result in head acceleration events (HAEs) in elite-level male and female rugby tackles.Methods Instrumented mouthguard data were collected from women (n=67) and men (n=72) elite-level rugby players from five elite and three international teams. Peak linear acceleration and peak angular acceleration were extracted from HAEs. Propensities for HAEs at a range of thresholds were calculated as the proportion of tackles/carries that resulted in an HAE exceeding a given magnitude for coded tackle height (low, medium, high) and number of tacklers. Propensity ratios with 952.7 (95.89 to 155.02) and 41.2 (95.22 to 184.58) propensity ratio to cause ball carrier HAEsgt;30 g compared with medium tackles for men and women, respectively. Low tackles had a 2.6 (95.91 to 3.42) and 5.3 (95.28 to 8.53) propensity ratio to cause tackler HAEsgt;30 g compared with medium tackles for men and women, respectively. In men, multiple tacklers had a higher propensity ratio (6.1; 95.71 to 9.93) than singular tacklers to cause ball carrier HAEsgt;30 g but a lower propensity ratio (0.4; 95.29 to 0.56) to cause tackler HAEsgt;30 g. No significant differences were observed in female tacklers or carriers for singular or multiple tacklers.Conclusion To limit HAE exposure, rule changes and coaching interventions that promote tacklers aiming for the torso (medium tackle) could be explored, along with changes to multiple tackler events in the male game.Data are available upon reasonable request. Anonymous data are available at a reasonable request to the corresponding author

A metamorphic inorganic framework that can be switched between eight single-crystalline states

The design of highly flexible framework materials requires organic linkers, whereas inorganic materials are more robust but inflexible. Here, by using linkable inorganic rings made up of tungsten oxide (P8W48O184) building blocks, we synthesized an inorganic single crystal material that can undergo at least eight different crystal-to-crystal transformations, with gigantic crystal volume contraction and expansion changes ranging from −2,170 to +1,720 Å3 with no reduction in crystallinity. Not only does this material undergo the largest single crystal-to-single crystal volume transformation thus far reported (to the best of our knowledge), the system also shows conformational flexibility while maintaining robustness over several cycles in the reversible uptake and release of guest molecules switching the crystal between different metamorphic states. This material combines the robustness of inorganic materials with the flexibility of organic frameworks, thereby challenging the notion that flexible materials with robustness are mutually exclusive

Extent and Volume of Lava Flows Erupted at 9°50′N, East Pacific Rise in 2005–2006 From Autonomous Underwater Vehicle Surveys

Seafloor volcanic eruptions are difficult to directly observe due to lengthy eruption cycles and the remote location of mid-ocean ridges. Volcanic eruptions in 2005–2006 at 9°50′N on the East Pacific Rise have been well documented, but the lava volume and flow extent remain uncertain because of the limited near-bottom bathymetric data. We present near-bottom data collected during 19 autonomous underwater vehicle (AUV) Sentry dives at 9°50′N in 2018, 2019, and 2021. The resulting 1 m-resolution bathymetric grid and 20 cm-resolution sidescan sonar images cover 115 km2, and span the entire area of the 2005–2006 eruptions, including an 8 km2 pre-eruption survey collected with AUV ABE in 2001. Pre- and post-eruption surveys, combined with sidescan sonar images and seismo-acoustic impulsive events recorded during the eruptions, are used to quantify the lava flow extent and to estimate changes in seafloor depth caused by lava emplacement. During the 2005–2006 eruptions, lava flowed up to ∼3 km away from the axial summit trough, covering an area of ∼20.8 km2; ∼50% larger than previously thought. Where pre- and post-eruption surveys overlap, individual flow lobes can be resolved, confirming that lava thickness varies from ∼1 to 10 m, and increases with distance from eruptive fissures. The resulting lava volume estimate indicates that ∼57% of the melt extracted from the axial melt lens probably remained in the subsurface as dikes. These observations provide insights into recharge cycles in the subsurface magma system, and are a baseline for studying future eruptions at the 9°50′N area.publishedVersio

Extent and volume of lava flows erupted at 9°50’N, East Pacific Rise in 2005–2006 from autonomous underwater vehicle surveys

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wu, J., Parnell‐Turner, R., Fornari, D., Kurras, G., Berrios‐Rivera, N., Barreyre, T., & McDermott, J. Extent and volume of lava flows erupted at 9°50’N, East Pacific Rise in 2005–2006 from autonomous underwater vehicle surveys. Geochemistry Geophysics Geosystems, 23, (2022): e2021GC010213, https://doi.org/10.1029/2021gc010213.Seafloor volcanic eruptions are difficult to directly observe due to lengthy eruption cycles and the remote location of mid-ocean ridges. Volcanic eruptions in 2005–2006 at 9°50′N on the East Pacific Rise have been well documented, but the lava volume and flow extent remain uncertain because of the limited near-bottom bathymetric data. We present near-bottom data collected during 19 autonomous underwater vehicle (AUV) Sentry dives at 9°50′N in 2018, 2019, and 2021. The resulting 1 m-resolution bathymetric grid and 20 cm-resolution sidescan sonar images cover 115 km2, and span the entire area of the 2005–2006 eruptions, including an 8 km2 pre-eruption survey collected with AUV ABE in 2001. Pre- and post-eruption surveys, combined with sidescan sonar images and seismo-acoustic impulsive events recorded during the eruptions, are used to quantify the lava flow extent and to estimate changes in seafloor depth caused by lava emplacement. During the 2005–2006 eruptions, lava flowed up to ∼3 km away from the axial summit trough, covering an area of ∼20.8 km2; ∼50% larger than previously thought. Where pre- and post-eruption surveys overlap, individual flow lobes can be resolved, confirming that lava thickness varies from ∼1 to 10 m, and increases with distance from eruptive fissures. The resulting lava volume estimate indicates that ∼57% of the melt extracted from the axial melt lens probably remained in the subsurface as dikes. These observations provide insights into recharge cycles in the subsurface magma system, and are a baseline for studying future eruptions at the 9°50′N area.This project is supported by National Science Foundation grants OCE-1834797, OCE-1949485, OCE-194893, OCE-1949938, and by Scripps Institution of Oceanography's David DeLaCour Endowment Fund

Stability of the non-extremal enhancon solution I: perturbation equations

We consider the stability of the two branches of non-extremal enhancon solutions. We argue that one would expect a transition between the two branches at some value of the non-extremality, which should manifest itself in some instability. We study small perturbations of these solutions, constructing a sufficiently general ansatz for linearised perturbations of the non-extremal solutions, and show that the linearised equations are consistent. We show that the simplest kind of perturbation does not lead to any instability. We reduce the problem of studying the more general spherically symmetric perturbation to solving a set of three coupled second-order differential equations.Comment: 20 pages, 1 figure, references added, typos fixed, version to appear in PR