Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

The nervous and visual systems of onychophorans and tardigrades: learning about arthropod evolution from their closest relatives

Understanding the origin and evolution of arthropods requires examining their closest outgroups, the tardigrades (water bears) and onychophorans (velvet worms). Despite the rise of molecular techniques, the phylogenetic positions of tardigrades and onychophorans in the panarthropod tree (onychophorans + tardigrades + arthropods) remain unresolved. Hence, these methods alone are currently insufficient for clarifying the panarthropod topology. Therefore, the evolution of different morphological traits, such as one of the most intriguing features of panarthropods—their nervous system—becomes essential for shedding light on the origin and evolution of arthropods and their relatives within the Panarthropoda. In this review, we summarise current knowledge of the evolution of panarthropod nervous and visual systems. In particular, we focus on the evolution of segmental ganglia, the segmental identity of brain regions, and the visual system from morphological and developmental perspectives. In so doing, we address some of the many controversies surrounding these topics, such as the homology of the onychophoran eyes to those of arthropods as well as the segmentation of the tardigrade brain. Finally, we attempt to reconstruct the most likely state of these systems in the last common ancestors of arthropods and panarthropods based on what is currently known about tardigrades and onychophorans

Genetic models

Genetically altered rat and mouse models have been instrumental in the functional analysis of genes in a physiological context. In particular, studies on the renin-angiotensin system (RAS) have profited from this technology in the past. In this review, we summarize the existing animal models for the protective axis of the RAS consisting of angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7)(Ang-(1-7), and its receptor Mas. With the help of models with altered expression of the components of this axis in the brain and cardiovascular organs, its physiological and pathophysiological functions have been elucidated. Thus, novel opportunities for therapeutic interventions in cardiovascular diseases were revealed targeting ACE2 or Mas

Antibiofilm, Antifouling, and Anticorrosive Biomaterials and Nanomaterials for Marine Applications

Formation of biofilms is one of the most serious problems affecting the integrity of marine structures both onshore and offshore. These biofilms are the key reasons for fouling of marine structures. Biofilm and biofouling cause severe economic loss to the marine industry. It has been estimated that around 10% of fuel is additionally spent when the hull of ship is affected by fouling. However, the prevention and control treatments for biofilms and biofouling of marine structures often involve toxic materials which pose severe threat to the marine environment and are strictly regulated by international maritime conventions. In this context, biomaterials for the treatment of biofilms, fouling, and corrosion of marine structures assume much significance. In recent years, due to the technological advancements, various nanomaterials and nanostructures have revolutionized many of the biological applications including antibiofilm, antifouling, and anticorrosive applications in marine environment. Many of the biomaterials such as furanones and some polypeptides are found to have antibiofilm, antifouling, and anticorrosive potentials. Many of the nanomaterials such as metal (titanium, silver, zinc, copper, etc.) nanoparticles, nanocomposites, bioinspired nanomaterials, and metallic nanotubes were found to exhibit antifouling and anticorrosive applications in marine environment. Both biomaterials and nanomaterials have been used in the control and prevention of biofilms, biofouling, and corrosion in marine structures. In recent years, the biomaterials and nanomaterials were also characterized to have the ability to inhibit bacterial quorum sensing and thereby control biofilm formation, biofouling, and corrosion in marine structures. This chapter would provide an overview of the biomaterials from diverse sources and various category of nanomaterials for their use in antibiofilm, antifouling, and anticorrosion treatments with special reference to marine applications