Controlling Capture and Release of Guests from Cross-Linked Supramolecular Polymers

Formation of a cross-linked, porous supramolecular polymer leads to instant entrapment of organic guest species. These can be stored and then released upon changing solvent polarity, temperature, pH, and concentration

The Roles of Citrate and Defects in the Anisotropic Growth of Ag Nanostructures

Synthetic control of nanocrystal shape is often achieved by controlling the crystal structure of the seed crystals as well as through the use of additives that are thought to block atomic addition to certain facets. However, the effect of the crystal structure or additives on the rate of atomic addition to a specific facet is not usually quantified, making it difficult to understand and design nanocrystal syntheses. This article combines single-crystal electrochemistry measurements with measurements of anisotropic nanocrystal growth to quantify the roles of citrate and planar defects in anisotropic atomic addition. Citrate lowers the rate of atomic addition to Ag(100) and Ag(111) single crystals by 3.2 and 15 times, respectively. Citrate decreases the rate of ascorbic acid oxidation in a facet-selective manner, but citrate decreases the rate of silver ion reduction to roughly the same extent on Ag(100) and Ag(111) single crystals. The degree to which citrate passivates single-crystal electrodes at different citrate concentrations closely matches the facet-dependent growth rates for single-crystal seeds. In contrast, seeds with planar defects exhibit anisotropic growth that is 30–100 times greater than can be explained by the facet-selective passivation by citrate. Without citrate, more silver deposits on the edges of seeds with planar defects than in the middle, but the seeds do not exhibit anisotropic growth. Evidence suggests that citrate improves the stability of nanoplates bounded by large {111} facets by preventing diffusion to {111} facets

Adaptive Endpoints Selection with Application in Rare Disease

In rare diseases, there are many unanswered questions that are critical to clinical development. Among them, one important question is how to choose primary endpoints that translate into meaningful improvement of health outcomes for patients while maximizing trial probability of success at the same time. A natural history study is often recommended by regulatory agencies. Following this traditional approach has dampened enthusiasm for many drug developers because it entails much higher cost and longer timeline. We propose to use an innovative design that allows adaptation on primary endpoint(s) so that learning about disease endpoints can be done within the pivotal trial itself through a subset of patients (i.e., informational cohort). The overall Family Wise Error Rate (FWER) will be controlled through the use of combination test following partition testing principle. A case example in patients with Pompe disease is used to show that the proposed innovative design maintains robust power across treatment effect scenarios while traditional fixed design bears the high risk of failure due to incorrect endpoint selection. Even if multiple endpoints can be included as primary, the proposed innovative design can still improve power over traditional designs by optimizing alpha allocations in cases with differential treatment effects.</p

Optimal Designs for the Two-Dimensional Interference Model

Recently, there have been some major advances in the theory of optimal designs for interference models when the block is arranged in one-dimensional layout. Relatively speaking, the study for two-dimensional interference model is quite limited partly due to technical difficulties. This article tries to fill this gap. Specifically, we set the tone by characterizing all possible universally optimal designs simultaneously through one linear equations system (LES) with respect to the proportions of block arrays. However, such a LES is not readily solvable due to the extremely large number of block arrays. This computational issue could be resolved by identifying a small subset of block arrays with the theoretical guarantee that any optimal design is supported by this subset. The nature of two-dimensional layout of the block has made this task very technically challenging, and we have theoretically derived such subset for any size of the treatment array and any number of treatments under comparison. This facilitates the development of the algorithm for deriving either approximate or exact designs. Supplementary materials for this article are available online.</p

Anisotropic Growth of Silver Nanocubes: The Role of Bromide Adsorption and Hydrophilic Polymers

The application of capping agents to modulate the colloidal synthesis of metal nanocrystals offers an effective avenue for shape control, but the roles of such agents are not yet completely understood. This study uses seed-mediated growth, single-crystal electrochemistry, and surface-enhanced Raman spectroscopy (SERS) to illuminate the roles of polyvinyl­pyrrolidone (PVP) and bromide (Br–) in the anisotropic growth of Ag nanocubes. Synthetic results show that Ag nanocubes only form in the presence of both PVP and sufficiently high concentrations of Br–. Truncated octahedra form in the presence of PVP, and truncated cubes form in the presence of Br– alone. Electrochemical measurements indicate that elevated concentrations of Br– consistently passivate Ag(100) facets more than Ag(111) facets regardless of the presence of PVP. The critical condition for the growth of cubes, however, materializes only when both PVP and Br– are present, which sufficiently suppresses atomic deposition to Ag(100) relative to Ag(111). SERS measurements show that high concentrations of Br– displace PVP from Ag(100) and Ag(111), but electrochemical measurements suggest PVP acts as a strong passivator under such conditions. We propose that the chemisorption of Br– beneath a physisorbed layer of PVP creates a unique condition for the growth of Ag nanocubes. Furthermore, our investigation points to a generalizable adsorption structure for the synthesis of {100}-faceted Ag nanocrystals, where Br– adsorption under other hydrophilic polymers can similarly guide the formation of Ag nanocubes. This study enhances our understanding of the synergistic roles of Br– and hydrophilic polymers in the controlled morphogenesis of Ag nanocrystals

sj-docx-1-ijlew-10.1177_15347346221082776 - Supplemental material for Role of Dipeptidyl Dipeptidase 4 Inhibitors in the Management of Diabetic Foot

Supplemental material, sj-docx-1-ijlew-10.1177_15347346221082776 for Role of Dipeptidyl Dipeptidase 4 Inhibitors in the Management of Diabetic Foot by Wen-hui Yu, Tong Zhang and Heng Xu in The International Journal of Lower Extremity Wounds</p

Model and simulation platform.

A: Model schematic and probe parameterization (gold: probe coverage, P3: 3’-most edge of the probe, P5: 5′-most edge of the probe) B: Time-dependent molecule-level visualizations available through the GUI. Trajectory generated using kini = 100 min-1, kon = 3 min-1, koff = 10 min-1, kdeg = 0.5 min-1, vel = 41.5 nt s-1, Tend = 10 min, L = 5300 nt, 241 steps of elongation to complete transcription (dark line: intact RNA stretches, light line: degraded RNA stretches, pink circle: RNase molecule). C: Single-cell trajectory with simulated nascent and mature fluorescent signals. Parameters same as in B (red: total signal, blue: nascent signal, green: mature signal, shaded regions: times displayed in B).</p

Selective Gram-Scale C–H Carbenoid Functionalization of <i>N</i>‑Sulfonylarylamides with a Rhodium Catalyst

This work describes an effective Cp*RhIII-catalyzed C–H carbenoid functionalization of N-sulfonylarylamides. Compared to the previous late-stage C–H modification methods of N-sulfonylarylamide analogues, this method efficiently achieves the gram-scale transformation with 2.5 mol % Rh-catalyst loading at 0 °C or with a 0.1 mol % Rh-catalyst loading at room temperature. The reaction medium has a great influence on the reaction rate. Methanol is optimal, and adding a nonpolar solvent (such as toluene or 1,2-dichloroethane) causes the rate to decrease. Experiments and density functional theory calculations were performed to rationalize the mechanism of rate control by a polar medium

A pH Switch in Supramolecular Polymeric Capsules

A switchable, supramolecular polymer is introduced which is held together through hydrogen bonding and reversibly precipitates−redissolves upon subtle pH control. Precipitating, it entraps and stores guest molecules within the self-assembling capsules incorporated within the polymeric chain

Parameter estimation process and performance.

A: Parallelized calculation of the search objective function for a set of trial parameters (ΔMean: mean squared error, ΔCDF: Wasserstein distance, Objective: error function value). B: Convergence of the genetic algorithm at the end of each stage of the search (red: ground truth target, gray: population of parameter estimates). C: Final trial parameter population from B (red: ground truth target, histogram: estimate population, gray line: mean estimate, gray region: one-sigma region of estimates). D: Evolution of parameter estimates throughout the search process (red: ground truth target, gray line: mean estimate, gray region: one-sigma region of estimates). E: Comparison of mean probe signal between target and fit (circles: target data, dotted line: mean parameter estimate, shaded region around dotted line: signal spanned by fifty estimates sampled from the one-sigma region). Colors as in Fig 1. F: Comparison of copy-number distributions between target and fit (shaded gray regions: target histogram, colored lines: histogram generated from mean parameter estimate, top row/blue: nascent mRNA distribution, bottom row/red: total mRNA distribution). G: Comparison of mean probe signal between target and fit in turn-off cross-validation experiment. Convention as given for E. H: Estimation of modulated parameters. Top trial modulates kon, bottom trial modulates koff. All other parameters are constant but unknown to the search algorithm and are fit independently (red: ground truth target, gray dots and error bars: mean estimate and one-sigma region of three replicates).</p