Mo3S132− Intercalated Layered Double Hydroxide: Highly Selective Removal of Heavy Metals and Simultaneous Reduction of Ag+ Ions to Metallic Ag0 Ribbons

We demonstrate a new material by intercalating Mo₃S₁₃^2? into Mg/Al layered double hydroxide (abbr. Mo₃S₁₃-LDH), exhibiting excellent capture capability for toxic Hg²⁺ and noble metal silver (Ag). The as-prepared Mo₃S₁₃-LDH displays ultra-high selectivity of Ag⁺, Hg²⁺ and Cu²⁺ in the presence of various competitive ions, with the order of Ag⁺>Hg²⁺>Cu²⁺>Pb²⁺≥Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺. For Ag⁺ and Hg²⁺, extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag⁺ and Cu²⁺, especially for trace amounts of Ag⁺ (≈1 ppm), achieving a large separation factor (SF_Ag/Cu) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag⁺ (q_m^Ag=1073 mg g^?1) and Hg²⁺ (q_m^Hg=594 mg g^?1) place the Mo₃S₁₃-LDH at the top of performing sorbent materials. Most importantly, Mo₃S₁₃-LDH captures Ag⁺ via two paths: a) formation of Ag₂S due to Ag-S complexation and precipitation, and b) reduction of Ag⁺ to metallic silver (Ag⁰). The Mo₃S₁₃-LDH is a promising material to extract low-grade silver from copper-rich minerals and trap highly toxic Hg²⁺ from polluted water.     

Extraction of configurational entropy from molecular simulations via an expansion approximation

A method is presented for extracting the configurational entropy of solute molecules from molecular dynamics simulations, in which the entropy is computed as an expansion of multidimensional mutual information terms, which account for correlated motions among the various internal degrees of freedom of the molecule. The mutual information expansion is demonstrated to be equivalent to estimating the full-dimensional configurational probability density function (PDF) using the generalized Kirkwood superposition approximation (GKSA). While the mutual information expansion is derived to the full dimensionality of the molecule, the current application uses a truncated form of the expansion in which all fourth- and higher-order mutual information terms are neglected. Truncation of the mutual information expansion at the nth order is shown to be equivalent to approximating the full-dimensional PDF using joint PDFs with dimensionality of n or smaller by successive application of the GKSA. The expansion method is used to compute the absolute (classical) configurational entropy in a basis of bond-angle-torsion internal coordinates for several small molecules as well as the change in entropy upon binding for a small host-guest system. Convergence properties of the computed entropy values as a function of simulation time are investigated and comparisons are made with entropy values from the second generation Mining Minima software. These comparisons demonstrate a deviation in -TS of no more than about 2 kcal/mol for all cases in which convergence has been obtained.     

Refining the Two-Dimensional Signed Small Ball Inequality

Journal of Fourier Analysis and Applications - The two-dimensional signed small ball inequality states that for all possible choices of signs, $$\begin{aligned} \left\| \sum _{|R| = 2^{-n}}{...     

Approach to formation of multifunctional polyester particles in controlled nanoscopic dimensions

We present the synthesis of discrete functionalized polyester nanoparticles in selected nanoscale size dimensions via a controlled intermolecular chain cross-linking process. The novel technique involves the controlled coupling of epoxide functionalized polyesters with 2,2'-(ethylenedioxy)bis(ethylamine) to give well-defined nanoparticles with narrow size distribution and selected nanoscopic size dimensions. Diverse functionalized polyesters, synthesized with pendant functionalities via ring-opening copolymerization of delta-valerolactone with alpha-allyl-delta-valerolactone, alpha-propargyl-delta-valerolactone and 2-oxepane-1,5-dione, were prepared as linear precursors which facilitated 3-D nanoparticles with functionalities such as amines, keto groups, and alkynes for post modification reactions. We found that the nanoparticle formation and the control over the nanoscopic dimension is primarily influenced by the degree of the epoxide entity implemented in the precursor polymers and the amount of 2,2'-(ethylenedioxy)bis(ethylamine) as cross-linking reagent. The other functionalities in the linear polyester do not participate in the nanoparticle formation and particles with defined functionalities can be prepared from batches of identical linear polymers containing various functionalities or by mixing different polyester materials to achieve controlled amounts of specific functional groups. The utilization of integrated functionalities was demonstrated in one post-modification reaction with N-Boc-ethylenediamine via reductive amination. This work describes the development of a novel methodology to prepare functionalized well-defined 3-D nanoparticle polyester materials in targeted nanoscopic ranges with amorphous morphologies or tailored crystallinities that offer a multitude of utilizations as a result of their unique properties and control in preparation.     

Targeted therapy of the insulin-like growth factor-1 receptor in cancer

Recently, significant progress has been made towards understanding the pathogenesis of cancer from the molecular standpoint. To this end, a growing number of approaches are being exploited for the identification and validation of new therapeutic targets suitable for potent and specific intervention. The type 1 insulin-like growth factor receptor (IGF-1R) system has recently become the focus of major attention in the arena of cancer research. The involvement of the receptor and its downstream signaling cascades in the carcinogenesis process makes this system an excellent target for potential cancer therapy. Indeed, advances in the understanding of the molecular mechanisms behind IGF-1R activation have led to the discovery of agents designed selectively for targeting IGF-1R. The potential application of these inhibitors is currently under intense clinical investigation. This review describes the biology of IGF-1R particularly from a cancer perspective. The attempts to develop effective IGF-1R antagonists are discussed comprehensively with special emphasis on antibodies and small tyrosine kinase inhibitors.     

Rapid identification of bacteria with a disposable colorimetric sensing array

Rapid identification of both species and even specific strains of human pathogenic bacteria grown on standard agar has been achieved from the volatiles they produce using a disposable colorimetric sensor array in a Petri dish imaged with an inexpensive scanner. All 10 strains of bacteria tested, including Enterococcus faecalis and Staphylococcus aureus and their antibiotic-resistant forms, were identified with 98.8% accuracy within 10 h, a clinically important time frame. Furthermore, the colorimetric sensor arrays also proved useful as a simple research tool for the study of bacterial metabolism and as an easy method for the optimization of bacterial production of fine chemicals or other fermentation processes.