Volcanic eruptions and the global subsea telecommunications network

When the first transoceanic telegraph cables were laid in the mid-1800s, rapid communication between continents became possible. The advent of fibre-optic submarine cables in the 1990s catalyzed a global digital revolution. Today, a network of > 1.7 million kilometres of fibre-optic cables crosses the oceans, carrying more than 99% of all digital data traffic worldwide and trillions of dollars in financial transactions. These arteries of the global internet underpin many aspects of our daily lives, and are particularly important for remote island communities that rely on submarine cables for telemedicine, e-commerce, and online education. However, these same remote communities are often in seismically and volcanically active regions and can be prone to natural hazards that threaten their critical subsea communication infrastructure. This vulnerability was acutely exposed in January 2022, when the collapse of the eruption plume of Hunga Volcano triggered fast-moving density currents that damaged Tonga’s only international submarine cable, cutting off an entire nation from global communications in the midst of a volcanic crisis. Here, we present a new comprehensive analysis of damage to subsea communications cables by volcanic events from around the world, and document their diverse impacts. Examples include (i) severing of the telegraph cable crossing the Sunda Strait by a tsunami triggered by the 1883 Krakatau eruption, Indonesia; (ii) ocean-entering pyroclastic density currents, lahars, and landslides during the 1902 eruptions of Mount Pelée, Martinique, that damaged six telegraph cables; (iii) destruction of a cable landing station on Montserrat by a pyroclastic density current in 1997; (iv) submarine slope failure at Kick ‘em Jenny, Grenada, that damaged two fibre-optic cables; (v) complete loss of the telecommunications network due to power outages following the 2000 eruption of Miyake-jima, Japan; and (vi) disruption to subsea cables resulting from the 2021 eruption of La Soufrière, St. Vincent. We find that the causes of damage typically relate to secondary hazards that occur not only at the same time as the eruption climax, but also some time after. There does not appear to be an explosivity intensity threshold for cable-damaging events; however, the extent of damage may be related to the original volcano morphology (e.g. steep slopes), spatial location (e.g. near the coast or partially/totally submerged), the eruption size or explosivity, and/or volcanic depositional processes involved. Based on these diverse case studies, we present lessons learned for enhancing telecommunications resilience, and discuss how subsea cables themselves can be used as sensors to improve understanding and early warning of volcanic hazards, potentially filling a monitoring gap for remote island communities

High-Throughput Thermal Scanning for Protein Stability: Making a Good Technique More Robust

We present a high-throughput approach to help define experimental formulations that enhance protein stability, which is based on differential scanning fluorimetry (DSF). The method involves defining the thermal stability of a protein against a screen of 13 buffer systems, systematically sampling pH from 5.0 to 9.0 at high and low salt concentrations, using both redundancy and extensive controls to make the method robust. The screen allows rapid determination of a suitable base formulation for protein samples, and is particularly useful for difficult samples: those that are rapidly degraded or cannot be sufficiently concentrated for downstream analyses. Data obtained from three samples in this assay illustrate the vastly different values for thermal stability that can be obtained from different formulations. This approach is simple to interpret and reliable enough that it has been implemented as a service through the Collaborative Crystallisation Centre (C3)

Acrylate Based Anticorrosion Films Using Novel Bis-Phosphonic Methacrylates

International audienceTwo novel phosphonated methacrylate monomers were successfully synthesized and subsequently incorportated into adhesion/anticorrosive coatings. Specifically, they were propyl N,N-tetramethyl-bis(phosphonate)-2-hydroxyl-bis(methylene) amine methylmethacrylate (MAC3NP2) and 2-[2,2-bis(diisopropoxyphosphoryl) ethoxy]-methylmethacrylate, (MAC3P2). The phosphonic forms of each monomer were blended with 85% w.w acrylates (tripropyleneglycol-diacrylate and hexanediol-diacrylate) and 6% w.w of the photo sensitive initiator DarocurVVR. Along with a monophosphonic monomer synthesized in a previous publication (MAC3P), they were polymerized on Q-panels under ultraviolet light, and then subject to the salt spray test (ca. 0.5 mol/L NaCl at 35 C) for a duration of up to 50 days. The results indicate that acrylate blends with low concentration of the bisphosphonic compound MAC3P2 have excellent resistance to corrosion, thus excellent adhesive properties. Importantly, these coatings were formed without the use of a hydrophobic polymer matrix or solvents

Termination rate coefficients for acrylamide in the aqueous phase at low conversion

The kinetics of acrylamide (AAm) free radical polymerization at low conversion of monomer to polymer in the aqueous phase was investigated at 50 degrees C using gamma-radiolysis relaxation, which is sensitive to radical-loss processes. The values of the termination rate coefficients for AAm ranged from 8 X 10(6) to 3 X 10(7) M-1 s(-1) as the weight fraction of polymer ranged from 0.002 to 0.0035, which is significantly lower than the low-conversion values for monomers such as styrene (2 X 10(8) M-1 s(-1)) and methyl methacrylate (4 X 10(7) M-1 s(-1)) in organic media. These can be quantitatively explained by applying a chain-length-dependent model of free-radical polymerization kinetics [Russell GT, Gilbert RG, Napper DH. Macromolecules 1992;25:2459. [19]] in which termination kinetics are expressed in terms of a diffusion-controlled encounter of radicals which ultimately yields an expression for the chain-length-averaged termination rate coefficient, .The lower for AAm arises due to a combination of the high k(p) value, promoting rapid formation of slower terminating long chains, and the slow diffusion of short propagating chains, relative to other common monomers. The chain transfer to monomer constant for AAm in water at 50 degrees C, Cm, was estimated using the chain-length-distribution method with correction for band-broadening [Castro JV, van Berkel KY, Russell GT, Gilbert RG. Aust J Chem 2005;58:178. [21]] and found to be 1.2 X 10(-4) (+/- 10%). The diffusion characteristics for AAm were adapted from those obtained for a similar aqueous system (hydroxyethyl methacrylate) together with a 0.5 exponent for the power law dependence on penetrant degree of polymerization at zero weight fraction polymer. This provides an adequate fit to the data. This is the first application of the chain-length-dependent model to describe experimental termination rate coefficients for an aqueous system at low conversion to polymer. The result that the experimental termination rate coefficients can be reproduced with an a priori model with physically reasonable parameters supports the physical assumptions underlying that model. (c) 2005 Elsevier Ltd. All rights reserved

Radical Telomerisation of Vinyl Phosphonic Acid with a Series of Chain Transfer Agents

The use of CTAs for the radical polymerisation of VPA has been successfully applied for the first time. Several CTAs were investigated, including thiol, disulfide and halogenated compounds. The use of mercaptoacetic acid led to the synthesis of the mercaptan VPA monoadduct, which was attributed to a high transfer constant (CT¼ktr/kp) of approximately 7. Transfer reactions with VPA appeared to be unsuccessful when using benzyldisulfide, 1,1,1-trichloroethane and trichloroacetic acid. Application of bromotrichloromethane as a transfer agent led to the oligomerisation of VPA, with final conversion being approximately 80%. The transfer events were characterised by 13C NMR, MALDI-TOF and elemental analysis. Molecular weights of the successful VPA polymerisations showed values ranging from 600 to 5 000 g mol1, which were in close agreement with the theoretically calculated values

Characterization of starch by size-exclusion chromatography: The limitations imposed by shear scission

Exosomes are a subset of extracellular vesicles (EVs) that have important roles in intercellular communication. They contain and carry bioactive molecules within their membranes which are delivered to target cells. Reproducible isolation and enrichment of these exosomes will aid in evaluation of cellular communication. We present an approach that involved the pre-processing of plasma, combined with ultracentrifugation (UC) and size exclusion chromatography (SEC) to isolate EVs and subsequently enrich exosomes. Four variations of this approach (denoted methods I to IV) were compared. Coupling an ultracentrifugation method with size exclusion chromatography (Method II) provided the best yield by nanoparticle tracking analyses (NTA), the presence of the exosomal markers CD63, Flotillin-1 and TSG-101 (immunoblotting) and showed exosome morphology using transmission electron microscopy (TEM). This method provides an efficient way to enrich the exosomes from blood (plasma), which could be potentially employed for clinical diagnostic assessment and therapeutic intervention