A finite strain model of stress, diffusion, plastic flow, and electrochemical reactions in a lithium-ion half-cell

We formulate the continuum field equations and constitutive equations that govern deformation, stress, and electric current flow in a Li-ion half-cell. The model considers mass transport through the system, deformation and stress in the anode and cathode, electrostatic fields, as well as the electrochemical reactions at the electrode/electrolyte interfaces. It extends existing analyses by accounting for the effects of finite strains and plastic flow in the electrodes, and by exploring in detail the role of stress in the electrochemical reactions at the electrode-electrolyte interfaces. In particular, we find that that stress directly influences the rest potential at the interface, so that a term involving stress must be added to the Nernst equation if the stress in the solid is significant. The model is used to predict the variation of stress and electric potential in a model 1-D half-cell, consisting of a thin film of Si on a rigid substrate, a fluid electrolyte layer, and a solid Li cathode. The predicted cycles of stress and potential are shown to be in good agreement with experimental observations.     

On Collisions Times of ‘Self-Sorting’ Interacting Particles in One-Dimension with Random Initial Positions and Velocities

We investigate a one-dimensional system of N particles, initially distributed with random positions and velocities, interacting through binary collisions. The collision rule is such that there is a time after which the N particles do not interact and become sorted according to their velocities. When the collisions are elastic, we derive asymptotic distributions for the final collision time of a single particle and the final collision time of the system as the number of particles approaches infinity, under different assumptions for the initial distributions of the particles’ positions and velocities. For comparison, a numerical investigation is carried out to determine how a non-elastic collision rule, which conserves neither momentum nor energy, affects the median collision time of a particle and the median final collision time of the system.     

Observation of inverse a.c. Josephson effect in bulk Y-Ba-Cu-O possessing highT c

Microwave-induced d.c. voltage due to inverse a.c. Josephson effect has been observed across bulk samples of Y-Ba-Cu-O. Variation of the d.c. voltage with small external magnetic field and temperature has been investigated. Our results indicate that weakly coupled superconducting grains exist up to 230 K.     

Substitutional effect on superconducting transition of Y-Ba-Cu-O

Superconducting Y-Ba-Cu-O system has been studied. The effect of changing compositions as well as the constituents on the superconducting transition temperature is reported.     

6,6′-Dihydroxythiobinupharidine (DTBN) Purified from Nuphar lutea Leaves Is an Inhibitor of Protein Kinase C Catalytic Activity

Water lily (Nuphar) bioactive extracts have been widely used in traditional medicine owing to their multiple applications against human ailments. Phyto-active Nuphar extracts and their purified and synthetic derivatives have attracted the attention of ethnobotanists and biochemists. Here, we report that 6,6′-dihydroxythiobinupharidine (DTBN), purified from extracts of Nuphar lutea (L.) Sm. leaves, is an effective inhibitor of the kinase activity of members of the protein kinase C (PKC) family using in vitro and in silico approaches. We demonstrate that members of the conventional subfamily of PKCs, PKCα and PKCγ, were more sensitive to DTBN inhibition as compared to novel or atypical PKCs. Molecular docking analysis demonstrated the interaction of DTBN, with the kinase domain of PKCs depicting the best affinity towards conventional PKCs, in accordance with our in vitro kinase activity data. The current study reveals novel targets for DTBN activity, functioning as an inhibitor for PKCs kinase activity. Thus, this and other data indicate that DTBN modulates key cellular signal transduction pathways relevant to disease biology, including cancer.     

Microwave‐assisted Synthesis of 6‐{(5‐Aryl‐1,3,4‐oxadiazol‐2‐yl)methyl}‐6H‐indolo[2,3‐b]quinoxalines

An efficient and convenient synthesis of a new series of 2‐{(6H‐indolo[2,3‐b]quinoxalin‐6‐yl)methyl}‐5‐aryl‐1,3,4‐oxadiazoles from readily available 1,2‐diaminobenzene and isatins under microwave irradiation conditions was disclosed. The 6‐{(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)methyl}‐6H‐indolo[2,3‐b]quinoxalines were also prepared by the thermal cyclo‐condensation reaction of 2‐(6H‐indolo[2,3‐b]quinoxalin‐6‐yl)acetohydrazides with carboxylic acids in refluxing POCl₃. The microwave‐assisted synthesis was rapid and resulted in higher yield of the products at lower operating temperature with reduced waste generation in comparison with the thermal reaction protocol.     

Effective Amyloid Defibrillation by Polyhydroxyl‐Substituted Squaraine Dyes

With an objective to develop β‐amyloid destabilizing agents, we have investigated the interactions of a few water‐soluble near‐infrared (NIR)‐absorbing squaraine dyes 1 – 3 with lysozyme and its amyloid aggregates through photophysical and biophysical techniques. These dyes exhibited strong interactions with lysozyme and β‐amyloids in addition to serum albumins as evidenced by the absorption and emission changes. The interactions were found to be spontaneous with association constant values in the range of approximately 10⁴–10⁵ m ^?1, as confirmed through half‐reciprocal analysis and isothermal calorimetric measurements. Uniquely, such effective interactions of the dyes have led to the complete disassembly of the β‐amyloid fibrillar structures to form spherical particles approximately 350 nm in size, as confirmed through photophysical, thioflavin assay, circular dichroism (CD), atomic force microscopy (AFM), TEM, and selected‐area electron diffraction (SAED) techniques. These results demonstrate that the squaraine dyes 1 – 3 under investigation act as effective protein‐labelling and destabilizing agents of the protein amyloidogenesis.     

A general contact mechanical formulation of multilayered structures and its application to deconvolute thickness/mechanical properties of glue used in surface force apparatus

Currently data obtained from surface force apparatus experiments are convoluted with the mechanical response of glue of unknown thickness, used to bond mica sheets to the substrates. This paper describes a formulation to precisely deconvolute out the forces between the mica sheets by determining the thickness of glue, knowing the mechanical properties of the glue. The formulation consists of a general solution based on the noniterative Hankel transform of the Laplace equation. The generality is achieved by treating all the layers except the one in contact as an effective lumped system consisting of a set of springs in series, where each spring represents a layer. The solution is validated by nanoindentation of trilayer systems consisting of layers with widely diverse mechanical properties, some differing from each other by three orders of magnitude. SFA experiments are done with carefully metered slabs of glue. The proposed method is validated by comparing the actual glue thicknesses with those determined using the present analysis.     

Synthesis and structures of cross-conjugated bis-dehydroannulenes with a Y-enediyne motif and different pi topologies

A synthesis of cross-conjugated bis-dehydroannulenes with different topologies of the pi electrons by Cu(II)-mediated oxidative coupling of the corresponding terminal acetylenic precursors is reported. In general, of the two possible modes of cyclization, which would yield either a [13]annulene or an [18]annulene, the precursors yielded exclusively the bis-dehydro[13]annulenes. However, one example of the formation of a bis-dehydro[18]annulene is also reported. The mode of cyclization to form either the [13]annulene or the [18]annulene is explained on the basis of the conformational preference of the core unit bearing the Y-enediyne moieties. The structures of the two types of bis-annulenes have been unequivocally established by means of single-crystal X-ray crystallographic analysis.