Model charged cylindrical nanopore in a colloidal dispersion: charge reversal, overcharging and double overcharging

Using the hypernetted-chain/mean spherical approximation (HNC/MSA) integral equations we study the electrical double layer inside and outside a model charged cylindrical vesicle (nanopore) immersed into a primitive model macroions solution, so that the macroions are only present outside the nanopore, i.e., the vesicle wall is impermeable only to the external macroions. We calculate the ionic and local linear charge density profiles inside and outside the vesicle, and find that the correlation between the inside and outside ionic distributions causes the phenomena of overcharging (also referred to as surface charge amplification) and/or charge reversal. This is the first time overcharging is predicted in an electrical double layer of cylindrical geometry. We also report the new phenomenon of double overcharging. The present results can be of consequence for relevant systems in physical-chemistry, energy storage and biology, e.g., nanofilters, capacitors and cell membranes.Comment: 10 pages, 4 figure

The (Possibly) Injured Consumer: Standing in Data Breach Litigation

(Excerpt) This Note will address the question of what factors a prospective plaintiff must display to “push [a] threatened injury of future identity theft beyond the speculative to the sufficiently imminent.” Part I will delve into relevant statistics to identify the characteristics of a data breach that most often lead to eventual identity theft. Part II will explore recent data breach standing cases and analyze the factual differences and legal perspectives that have led to disparate results among the federal circuits. Lastly, Part III will recommend a method for evaluating future data breach standing issues

Overcharging: The Crucial Role of Excluded Volume

In this Letter we investigate the mechanism for overcharging of a single spherical colloid in the presence of aqueous salts within the framework of the primitive model by molecular dynamics (MD) simulations as well as integral-equation theory. We find that the occurrence and strength of overcharging strongly depends on the salt-ion size, and the available volume in the fluid. To understand the role of the excluded volume of the microions, we first consider an uncharged system. For a fixed bulk concentration we find that upon increasing the fluid particle size one strongly increases the local concentration nearby the colloidal surface and that the particles become laterally ordered. For a charged system the first surface layer is built up predominantly by strongly correlated counterions. We argue that this a key mechanism to produce overcharging with a low electrostatic coupling, and as a more practical consequence, to account for charge inversion with monovalent aqueous salt ions.Comment: 7 pages, 3 figs (4 EPS files). To appear in Europhysics Letter

Entropy driven key-lock assembly

The effective interaction between a sphere with an open cavity (lock) and a spherical macroparticle (key), both immersed in a hard sphere fluid, is studied by means of Monte Carlo simulations. As a result, a 2d map of the key-lock effective interaction potential is constructed, which leads to the proposal of a self-assembling mechanism: there exists trajectories through which the key-lock pair could assemble avoiding trespassing potential barriers. Hence, solely the entropic contribution can induce their self-assembling even in the absence of attractive forces. This study points out the solvent contribution within the underlying mechanisms of substrate-protein assembly/disassembly processes, which are important steps of the enzyme catalysis and protein mediated transport

May I Hold on to My God as I Die?: An Analysis on a Death Row Inmate\u27s Right to Spiritual Advisors Inside the Execution Chamber

This article analyzes the first amendment right of condemned prisoners to have their spiritual advisor with them up to the point of execution. It dives into a brief yet relevant historical background of the death penalty in the United States. Then it analyzes the specific protections awarded to death penalty inmates up to the point of their executions through R.L.U.I.P.A. At its core, it compares and contrasts two recent decisions by the U.S. Supreme Court: Dunn v. Ray, 139 S. Ct. 661 (2019) and Murphy v. Collier, 139 S. Ct. 1111 (2019), in which the Court reached two different conclusions regarding the matter of a prisoner\u27s right to a spiritual advisor during execution. The comparison is made in the light of the Establishment Clause and Free exercise of religion, as established in the First Amendment of the Constitution. It concludes that denying condemned prisoners a right to have their spiritual advisor with them up to the point of execution is a violation of their First Amendment rights, as guaranteed by the Constitution

Cognitive Plasticity in Foraging Vespula germanica Wasps

Vespula germanica (F.) (Hymenoptera: Vespidae) is a highly invasive social wasp that exhibits a rich behavioral repertoire in which learning and memory play a fundamental role in foraging. The learning abilities of these wasps were analyzed while relocating a food source and whether V. germanica foragers are capable of discriminating between different orientation patterns and generalizing their choice to a new pattern. Foraging wasps were trained to associate two different stripe orientation patterns with their respective food locations. Their response to a novel configuration that maintained the orientation of one of the learned patterns but differed in other aspects (e.g. width of stripes) was then evaluated. The results support the hypothesis that V. germanica wasps are able to associate a particular oriented pattern with the location of a feeder and to generalize their choice to a new pattern, which differed in quality, but presented the same orientation

The electrical double layer for a fully asymmetric electrolyte around a spherical colloid: an integral equation study

The hypernetted chain/mean spherical approximation (HNC/MSA) integral equation is obtained and solved numerically for a totally asymmetric primitive model electrolyte around a spherical macroparticle. The ensuing radial distribution functions show a very good agreement when compared to our Monte Carlo and molecular dynamics simulations for spherical geometry and with respect to previous anisotropic reference HNC calculations in the planar limit. We report an analysis of the potential vs charge relationship, radial distribution functions, mean electrostatic potential and cumulative reduced charge for representative cases of 1:1 and 2:2 salts with a size asymmetry ratio of 2. Our results are collated with those of the Modified Gouy-Chapman (MGC) and unequal radius Modified Gouy-Chapman (URMGC) theories and with those of HNC/MSA in the restricted primitive model (RPM) to assess the importance of size asymmetry effects. One of the most striking characteristics found is that,\textit{contrary to the general belief}, away from the point of zero charge the properties of an asymmetric electrical double layer (EDL) are not those corresponding to a symmetric electrolyte with the size and charge of the counterion, i.e. \textit{counterions do not always dominate}. This behavior suggests the existence of a new phenomenology in the EDL that genuinely belongs to a more realistic size-asymmetric model where steric correlations are taken into account consistently. Such novel features can not be described by traditional mean field theories like MGC, URMGC or even by enhanced formalisms, like HNC/MSA, if they are based on the RPM.Comment: 29 pages, 13 figure

Acceptability of yacon flakes (Smallanthus sonchifolia) for dietary use with inulin

"This study aimed to elaborate on yacon flakes and determine the proximal composition of fresh yacon and final flakes, made at different temperatures (120°C, 150°C and 180°C) for 20 mins. We measured the acceptability of the sensory attributes: taste, texture, odour and colour and the global acceptability at the laboratory level, using semi-trained panellists and an unstructured hedonic scale. The acceptability of the flakes was measured at different temperatures. Our results indicate that the flakes made at 180°C had the highest acceptance (87%), and the flakes made at 120°C had 80% of unacceptability. Our data were analysed according to the analysis of variance (ANOVA) and Tukey's test. We found significant differences between the averages of the taste scores (T0:7.1; T1:7.6; T2:6.7; T3:4.6), p<0.05; texture (T0:7.1; T1:7.2; T2:5.7; T3:4.5), p<0.05; and odour (T0:7.2; T1:7.6; T2:5.1; T3:3.3), p<0.05. The amount of fructooligosaccharides on a fresh basis was Ⱦ±SD (31.60±0.650) and on a dry basis (37.44±1DS). Microbiological analysis shows that the flakes are fit for human consumption. It is concluded that yacon flakes contain significant amounts of inulin, being a good substitute alternative for the preparation of snack-type dietetic products