Microbial Alkalinity Production and Silicate Alteration in Methane Charged Marine Sediments: Implications for Porewater Chemistry and Diagenetic Carbonate Formation

A numerical reaction-transport model was developed to simulate the effects of microbial activity and mineral reactions on the composition of porewater in a 230-m-thick Pleistocene interval drilled in the Peru-Chile Trench (Ocean Drilling Program, Site 1230). This site has porewater profiles similar to those along many continental margins, where intense methanogenesis occurs and alkalinity surpasses 100 mmol/L. Simulations show that microbial sulphate reduction, anaerobic oxidation of methane, and ammonium release from organic matter degradation only account for parts of total alkalinity, and excess CO2 produced during methanogenesis leads to acidification of porewater. Additional alkalinity is produced by slow alteration of primary aluminosilicate minerals to kaolinite and SiO2. Overall, alkalinity production in the methanogenic zone is sufficient to prevent dissolution of carbonate minerals; indeed, it contributes to the formation of cemented carbonate layers at a supersaturation front near the sulphate-methane transition zone. Within the methanogenic zone, carbonate formation is largely inhibited by cation diffusion but occurs rapidly if cations are transported into the zone via fluid conduits, such as faults. The simulation presented here provides fundamental insight into the diagenetic effects of the deep biosphere and may also be applicable for the long-term prediction of the stability and safety of deep CO2 storage reservoirs.

Quantum Dots: An Emerging Approach for Cancer Therapy

Nanotechnology is indisputably a scientific technique that offers the prospect of new therapies, and hope, for the treatment of malignant illnesses. It is a novel technology that offers new approaches for the diagnosis and management of diverse diseases. Although the discovery of Quantum dots (QD) nano-transporters has already led to a few positive developments, QD nano-transporters are still at their initial stage, though have yet proven valuable to society. The excertion of QD indicates conversion in natural imaging along with photograph have established incredible suitability in bio-imaging, new drug development, targeted gene deliverance, biosensing, photodynamic treatment as well as diagnosis. The present review aimed to confer the significance of QD in diagnosis as well as in management of cancer. This review aims to impart fundamental insight as well as conception of QD its merits, properties, utilization as well as mode of action. This review highlight of different designing schemes of QD like hydrothermal, drop-casting, ultrasonic, solvothermal, spin-coating, atomic layer desorption, layer by layer, polymethylmethacrylate aided-transfer, electrochemical, ion beam sputtering deposition. Moreover, we have elaborated on the diverse researches related to cytotoxic examination to reveal that QDs are harmless. Concisely, the present review summarizes the fabrication schemes, current research and utilization of QD in cancer treatment.

Improving force field accuracy by training against condensed phase mixture properties

Developing a sufficiently accurate classical force field representation of molecules is key to realizing the full potential of molecular simulation as a route to gaining fundamental insight into a broad spectrum of chemical and biological phenomena. This is only possible, however, if the many complex interactions between molecules of different species in the system are accurately captured by the model. Historically, the intermolecular van der Waals (vdW) interactions have primarily been trained against densities and enthalpies of vaporization of pure (single-component) systems, with occasional usage of hydration free energies. In this study, we demonstrate how including physical property data of binary mixtures can better inform these parameters, encoding more information about the underlying physics of the system in complex chemical mixtures. To demonstrate this, we re-train a select number of the Lennard-Jones parameters describing the vdW interactions of the OpenFF 1.0.0 (Parsley) fixed charge force field against training sets composed of densities and enthalpies of mixing for binary liquid mixtures as well as densities and enthalpies of vaporization of pure liquid systems, and assess the performance of each of these combinations. We show that retraining against the mixture data almost universally improves the force field's ability to reproduce both pure and mixture properties, reducing some systematic errors that exist when training vdW interactions against properties of pure systems only.

Beyond Contagion of Violence: Passionate Love and Empathy in the Thought of René Girard and Max Scheler

In his last book René Girard depicts apocalypse as disclosure of mimetic violence that is world-ending. He claims that in times of violent pandemic we are not called to fight for this world, but follow Christ in his withdrawal from the world. However, such an assertion creates serious theoretical and practical issues for the effort to heal interhuman relations from the virus of mimetic hostility. I argue for the importance of restoring a foundational distinction between passionate love and acquisitive mimetic desire from the forgotten regions of Girard’s oeuvre. With Max Scheler’s interpretation of Stendhal’s concept of l’amour passion, I explore in each thinker a fundamental insight about possibilities of transforming violent contagion through empathy and loving commitment to the world. I conclude that respective “passive” and “active” approaches to the contagion of mimetic rivalry and violence are necessary and equally valuable.

Risso's dolphins perform spin dives to target deep-dwelling prey

Foraging decisions of deep-diving cetaceans can provide fundamental insight into food web dynamics of the deep pelagic ocean. Cetacean optimal foraging entails a tight balance between oxygen-conserving dive strategies and access to deep-dwelling prey of sufficient energetic reward. Risso's dolphins ( Grampus griseus ) displayed a thus far unknown dive strategy, which we termed the spin dive. Dives started with intense stroking and right-sided lateral rotation. This remarkable behaviour resulted in a rapid descent. By tracking the fine-scale foraging behaviour of seven tagged individuals, matched with prey layer recordings, we tested the hypothesis that spin dives are foraging dives targeting deep-dwelling prey. Hunting depth traced the diel movement of the deep scattering layer, a dense aggregation of prey, that resides deep during the day and near-surface at night. Individuals shifted their foraging strategy from deep spin dives to shallow non-spin dives around dusk. Spin dives were significantly faster, steeper and deeper than non-spin dives, effectively minimizing transit time to bountiful mesopelagic prey, and were focused on periods when the migratory prey might be easier to catch. Hence, whereas Risso's dolphins were mostly shallow, nocturnal foragers, their spin dives enabled extended and rewarding diurnal foraging on deep-dwelling prey.

Improving force field accuracy by training against condensed phase mixture properties

Developing a sufficiently accurate classical force field representation of molecules is key to realizing the full potential of molecular simulation as a route to gaining fundamental insight into a broad spectrum of chemical and biological phenomena. This is only possible, however, if the many complex interactions between molecules of different species in the system are accurately captured by the model. Historically, the intermolecular van der Waals (vdW) interactions have primarily been trained against densities and enthalpies of vaporization of pure (single-component) systems, with occasional usage of hydration free energies. In this study, we demonstrate how including physical property data of binary mixtures can better inform these parameters, encoding more information about the underlying physics of the system in complex chemical mixtures. To demonstrate this, we re-train a select number of the Lennard-Jones parameters describing the vdW interactions of the OpenFF 1.0.0 (Parsley) fixed charge force field against training sets composed of densities and enthalpies of mixing for binary liquid mixtures as well as densities and enthalpies of vaporization of pure liquid systems, and assess the performance of each of these combinations. We show that retraining against the mixture data almost universally improves the force field's ability to reproduce both pure and mixture properties, reducing some systematic errors that exist when training vdW interactions against properties of pure systems only.

Fundamental insight into redox enzyme-based bioelectrocatalysis

Redox enzymes can work as efficient electrocatalysts. The coupling of redox enzymatic reactions with electrode reactions is called enzymatic bioelectrocatalysis, which imparts high reaction-specificity to electrode reactions with non-specific characteristics. The key factors required for bioelectrocatalysis are hydride ion/electron transfer characteristics and low specificity for either substrate in redox enzymes. Several theoretical features of steady-state responses are introduced to understand bioelectrocatalysis and to extend the performance of bioelectrocatalytic systems. Applications of the coupling concept to bioelectrochemical devices are also summarized with emphasis on the achievements recorded in the research group of the author.