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Floquet Non-Bloch formalism for a Non-Hermitian ladder: from theoretical framework to topolectrical circuits
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An assessment of the CO2 storage potential of the Indian subcontinent
No full textCurrent annual CO2 emissions from large industrial point sources in India, Pakistan, Bangladesh and Sri Lanka are estimated to be 721, 45, 17 and 3 million tonnes (Mt) CO2 respectively. Rapid growth in annual CO2 emissions is likely: in India, the nine planned ultramega power plants alone could add some 257 Mt CO2 to annual emissions. The main potential CO2 storage sites in India are located in the saline aquifers and oil and gas fields around the margins of the peninsula, especially offshore, but also onshore in the states of Gujarat and Rajasthan. There is also thought to be considerable saline aquifer CO2 storage potential in NE India, but this is distant from the main emission sources. CO2 sources in the centre of the peninsula appear to be poorly placed with respect to potential CO2 storage sites. There is estimated to be about 5Gt CO2 storage potential in India's major coalfields and oil and gas fields. It is important that India's saline aquifer storage capacity is quantified, as this will determine whether there is significant potential for the application of CCS. Pakistan will have significant CO2 storage potential (c. 1.6 Gt CO2) in its gas fields when they become depleted. It is also thought to have good potential for saline aquifer CO2 storage in the Lower Indus and Potwar Basins and there is a good match between the locations of sources and potential storage sites. Bangladesh's annual CO2 emissions from large point sources are approximately 17 Mt CO2. It is thought to have significant CO2 storage potential in its gas fields (c. 1.1 Gt CO2) which will become available gradually as the individual fields are depleted. Bangladesh also probably has significant CO2 storage potential in saline aquifers in most of the eastern half of the country, both onshore and offshore. Sri Lanka's total annual emissions of CO2 from large point sources are estimated to be approximately 3 Mt. These will be increased by the operation of new coal-fired power plant. There may be some saline aquifer CO2 storage capacity offshore to the north of the island, in Palk Bay and the Gulf of Mannar, but at present this requires further investigation. (C) 2008 Elsevier Environment Research Council. Published by Elsevier Ltd. All reserved
An integrated multimethod approach for size-specific assessment of potentially toxic element adsorption onto micro- and nanoplastics: implications for environmental risk
No full textMicro- and nanoscale plastics (MnPs), arising from the environmental degradation of plastic waste, pose significant environmental and health risks as carriers for potentially toxic element (PTE) metals. This study employs asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) to provide a size-resolved assessment of chromium (Cr), arsenic (As), and selenium (Se) adsorption onto carboxylated polystyrene nanoparticles (COOH-PSNPs) of 100 nm, 500 nm, and 1000 nm. Cr exhibited the highest adsorption, with adsorption per particle surface area increasing from 9.45 × 10−15 μg nm−2 for 100 nm particles to 6.87 × 10−14 μg nm−2 for 1000 nm particles, driven by chemisorptive interactions with carboxyl groups. In contrast, As and Se exhibited slower adsorption rates and significantly weaker interactions, attributed to outer-sphere complexation and electrostatic repulsion. Smaller particles exhibited enhanced adsorption efficiency per unit mass due to their larger surface area-to-volume ratios and higher carboxyl group density (18.5 μEq g−1 for 100 nm compared to 7.9 μEq g−1 for 1000 nm particles). Se adsorption remained negligible across all sizes, near detection limits, highlighting its low affinity for carboxylated surfaces. Our study demonstrates the superior resolution of AF4-MALS-ICP-MS compared to that of bulk ICP-MS, which lacks the ability to discern particle-specific adsorption trends. Unlike bulk ICP-MS, which provides average adsorption values, AF4-MALS-ICP-MS reveals the size-dependent mechanisms influencing metal binding, offering critical insights into the role of MnPs as PTE vectors. The findings highlight the environmental implications of MnPs in facilitating PTE transport and highlights the need for size-specific mitigation strategies. This work sets a foundation for developing more precise risk assessment frameworks and advanced remediation approaches for MnP-contaminated environments
Room-Temperature Deuterium Separation in van Der Waals Gap Engineered Vermiculite Quantum Sieves
No full textAs the demand for nuclear energy grows, enriching deuterium from hydrogen mixtures has become more important. However, traditional methods are either very energy-intensive because they require extremely cold temperatures, or they don't separate deuterium (D2) from regular hydrogen (H2) very well, with a D2/H2 selectivity of ≈0.71. To achieve efficient deuterium separation at room temperature, materials with very tiny spaces, on an atomic scale are needed. For the first time, a material with spaces just ≈2.1 Å (angstroms) wide is successfully created, which is similar in size to the wavelength of hydrogen isotopes at room temperature. This allows for efficient deuterium separation, with a much higher D2/H2 selectivity of ≈2.20, meaning the material can separate deuterium from hydrogen much more effectively at room temperature. The smaller deuterium molecules are more likely to pass through these tiny spaces, showing that quantum effects play a key role in this process. In contrast, a material like graphene oxide, with larger spaces (≈4.0 Å), only shows a lower D2/H2 selectivity of ≈1.17, indicating weaker quantum effects. This discovery suggests that materials with very small, atomic-scale spaces can be key to efficient separation of hydrogen isotopes at room temperature
Long term durability and corrosion resistance of hydrothermally etched slippery AA5083 surfaces under brine water up to 4 months
No full textAluminium alloys are widely used in the construction of marine vessels owing to their low density, high corrosion resistance, low cost, high weldability and ease of availability. Previously, superhydrophobic Al alloys were shown to improve anti-biofouling properties, corrosion resistance and reduced frictional drag. However, their long-term durability in underwater is limited. This research successfully showcases the slippery dewetting properties of silicone oil coated hydrothermally etched Al 5083 alloys under 3.5 wt. % NaCl brine solution for up to 122 days. The etched surfaces comprise of polygonal, spherical microfeatures and nano grass/flakes upon etching for 1 h, 5 h, 10 h, and 20 h using 1 vol. % NH4OH aqueous solution. The mean surface roughness (Ra) increased from 40 nm (polished) to 1.3–3.6 µm (etched) due to the formation of Al(OH)3 layer as revealed by X-ray diffraction analyses. Water droplets readily slide over specimens coated with 25 μm thick silicone oil (100,000 cSt), exhibiting contact angle hysteresis (CAH) of <5° and slide-off angles (SAs) of <15°. When submerged in stagnant 3.5 wt. % NaCl brine solution, ≥60 % of the oil thickness (i.e. ∼15 µm) was retained even after 122 days. Among all, the 10 h etched specimens consistently exhibited excellent retention of slippery properties up to 122 days of submersion. Additionally, oil coated 10 h etched AA 5083 showed excellent anticorrosion, with corrosion current densities reduced by 3 orders of magnitude compared to polished AA 5083 and oil coated AA 5083
Characterization of a Bioactive Chitosan Dressing: A Comprehensive Solution for Different Wound Healing Phases
No full textWound management has made significant advances over the past few decades, particularly with the development of advanced dressings that facilitate autolytic debridement, the absorption of wound exudate, and protection from external bacteria. However, finding a single dressing that effectively addresses all four phases of wound healing─hemostasis, inflammation, proliferation, and remodeling─remains a major challenge. Additionally, biofilms in chronic wounds pose a substantial obstacle by shielding microbes from topical antiseptics and antibiotics, thereby delaying the healing process. This study evaluates the wound-healing properties of a commercially available bioactive microfiber gelling (BMG) dressing made from chitosan alongside commercially available silver-loaded carboxymethyl cellulose (CMC-Ag) dressing, carboxymethyl cellulose dressing (CMC) and cotton gauze. In vitro testing demonstrated that the BMG dressing significantly exhibited superior fluid absorption and exudate-locking properties compared with the CMC-Ag dressing. Additionally, the BMG dressing effectively sequestered and eradicated wound-relevant pathogenic microorganisms, including drug-resistant bacteria. Its bioactive properties were further highlighted by its ability to enhance platelet-derived growth factor (PDGF) expression and sequester matrix metalloproteases (MMPs). Overall, this study highlights the effectiveness of the BMG dressing in wound management, particularly in exudate absorption and antimicrobial activity, demonstrating its relevance in wound care
In silico self-assembly and complexation dynamics of cationic lipids with DNA nanocages to enhance lipofection
No full textDNA nanostructures are promising materials for drug delivery due to their unique topology, shape, size control, biocompatibility, structural stability, and blood-brain-barrier penetration capability. However, their cellular permeability is hindered by strong electrostatic repulsion from negatively charged cellular membranes, posing a significant obstacle to the use of DNA nanostructures as a drug delivery vehicle. Recent experimental studies have shown enhanced cellular uptake for the conjugate binary mixtures of DNA Tetrahedron (TDN) with cationic lipid N -[1-(2,3-dioleyloxy)propyl]- N , N , N -trimethylammonium chloride (DOTMA) compared to TDN alone. However, the cationic DOTMA lipid binding mechanism with the TDN nucleotides is still elusive. Using fully atomistic MD simulations, we aim to understand the molecular interactions that drive the formation and stability of the TDN-DOTMA binary complexes in a physiological environment. Our results uncovered that lipid concentration plays a crucial role in the energetics of the TDN-DOTMA association. We also report that distinct time scales are associated with the self-assembly of cationic DOTMA lipids first, followed by the complexation of self-assembled DOTMA lipid clusters with the TDN nucleotides, where electrostatics, hydrophobicity, and hydrogen bonding are the key interactions that drive the formation and stability of these complexes. Our results provide molecular insights into TDN-DOTMA interactions, highlighting the lipid self-assembly dynamics, complex stability, and morphology, paving the way for the better rational design of cationic lipid-functionalized DNA nanostructures for efficient drug delivery and transfection
