Hierarchical Mo2C@CNT Hybrid Structure Formation for the Improved Lithium-Ion Battery Storage Performance

2-D transition metal carbides (TMCs)-based anode materials offer competitive performance in lithium-ion batteries (LIBs) owing to its excellent conductivity; cheaper, flexible uses; and superior mechanical stability. However, the electrochemical energy storage of TMCs is still the major obstacle due to their modest capacity and the trends of restacking/aggregation. In this report, the Mo2C nanosheets were attached on conductive CNT network to form a hierarchical 2D hybrid structure, which not only alleviated the aggregation of the Mo2C nanoparticle and facilitated the rapid transference of ion/electron, but also adapted effectually to the hefty volume expansion of Mo2C nanosheets and prevented restacking/collapse of Mo2C structure. Benefitting from the layered Mo2@CNT hybrid structure, the charge/discharge profile produced a 200 mAh g−1 discharge-specific capacity (second cycle) and 132 mAh g−1 reversible-discharge discharge-specific capacity (after 100 cycles) at 50 mA g−1 current density, with high-speed competency and superior cycle stability. The improved storage kinetics for Mo2@CNT hybrid structure are credited to the creation of numerous active catalytic facets and association reaction between the CNT and Mo2C, promoting the efficient electron transfer and enhancing the cycling stability.

Single-molecule determination of chemical equilibrium of DNA intercalation by electrical conductance

We investigated a single-molecule reaction of DNA intercalation as an example of a bimolecular association reaction. Single-molecule conductance values of the product and reactant molecules adsorbed on an Au surface...

Allosteric regulation in CRISPR/Cas1-Cas2 protospacer acquisition mediated by DNA in association with Cas2

ABSTRACTCas1 and Cas2 are highly conserved proteins across CRISPR-Cas systems and play a significant role in protospacer acquisition. Here we study the protospacer (or ps) DNA binding, recognition, and response to cleavage on the protospacer-adjacent-motif complementary sequence or PAMc by Cas1-Cas2, implementing all-atom molecular dynamics simulations. First, we noticed that two active sites of Cas1&1’ bind asymmetrically to two identical PAMc in the simulation. For psDNA containing only one PAMc to be recognized, it is then found that the non-PAMc association site remains destabilized until after the bound PAMc being cleaved. Thus, correlation appears to exist between the two active sites, which can be allosterically mediated by psDNA and Cas2&2’ in bridging. To substantiate such findings, we further simulated Cas1-Cas2 in complex with synthesized psDNA sequences psL and psH, which have been measured with low and high efficiency in acquisition, respectively. Notably, such inter-site correlation becomes largely enhanced for Cas1-Cas2 in complex with psH, and remains low with psL. Hence, our studies demonstrate that PAMc recognition and cleavage in one active site of Cas1-Cas2 allosterically regulates non-PAMc association/reaction in the other site, and such allosteric regulation is mediated by non-catalytic Cas 2 and DNA protospacer in acquisition.

Correction and Validation of Time-Critical Behavioral Measurements over the Internet in the Stage Twin Cohort with More Than 7000 Participants

Behavioral data are increasingly collected over the Internet. This is particularly useful when participants’ own computers can be used as they are, without any modification that relies on their technical skills. However, the temporal accuracy in these settings is generally poor, unknown, and varies substantially across different hard- and software components. This makes it dubious to administer time-critical behavioral tests such as implicit association, reaction time, or various forms of temporal judgment/perception and production. Here, we describe the online collection and subsequent data quality control and adjustment of reaction time and time interval production data from 7127 twins sourced from the Swedish Twin Registry. The purposes are to (1) validate the data that are already and will continue to be reported in forthcoming publications (due to their utility, such as the large sample size and the twin design) and to (2) provide examples of how one might engage in post-hoc analyses of such data, and (3) explore how one might control for systematic influences from specific components in the functional chain. These possible influences include the type and version of the operating system, browser, and multimedia plug-in type

Marketing Plan Design for Classified Website Based on Big Data

With the background of big data, it is getting better and better for the marketing environment of classified information websites. Meanwhile, society is progressing, and the traditional marketing model is bound to develop and change, ranging from the beginning of 4P marketing theory (product, price, channel, publicity) to the 4C marketing theory (customer, cost, convenience, communication) to the current 4R marketing theory (association, reaction, relationship, remuneration), with different focus on the specific marketing theory. Therefore, this paper presents an active exploration of big data as the core marketing model for classified information websites.

Molecular-physics aspects of cold chemistry

Molecular-physics aspects of cold chemistry are introduced with the example of few-electron molecules. After a brief overview of general aspects of molecular physics, the solution of the molecular Schrödinger equation is presented based on the Born-Oppenheimer approximation and the subsequent evaluation of adiabatic, nonadiabatic, relativistic and radiative (QED) corrections. Low-temperature chemical phenomena are introduced with the example of ion-molecule reactions, using the classical Langevin model for barrier-free exothermic reactions as reference. Then, methods to generate cold few-electron molecules by supersonic-beam-deceleration methods such as Stark, Zeeman, and Rydberg-Stark decelerations are presented. Two astrophysically important reactions, the reaction between H2 and H2+ forming H3+ and H, a very fast reaction following Langevin-capture going over to quantum-Langevin capture at low temperature, and the radiative association reaction H+ + H forming H2+, a very slow reaction in which quantum effects (shape resonances) become important at low temperatures, are used to illustrate the concepts introduced.

Interplay of self-association and conformational flexibility in regulating protein function

Many functional roles have been attributed to homodimers, the most common mode of protein self-association, notably in the regulation of enzymes, ion channels, transporters and transcription factors. Here we review findings that offer new insights into the different roles conformational flexibility plays in regulating homodimer function. Intertwined homodimers of two-domain proteins and their related family members display significant conformational flexibility, which translates into concerted motion between structural domains. This flexibility enables the corresponding proteins to regulate function across family members by modulating the spatial positions of key recognition surfaces of individual domains, to either maintain subunit interfaces, alter them or break them altogether, leading to a variety of functional consequences. Many proteins may exist as monomers but carry out their biological function as homodimers or higher-order oligomers. We present early evidence that in such systems homodimer formation primes the protein for its functional role. It does so by inducing elevated mobility in protein regions corresponding to the binding epitopes of functionally important ligands. In some systems this process acts as an allosteric response elicited by the self-association reaction itself. Our analysis furthermore suggests that the induced extra mobility likely facilitates ligand binding through the mechanism of conformational selection. This article is part of a discussion meeting issue ‘Allostery and molecular machines’.