Accelerating solid-phase synthesis is crucial for accessing a large number of peptides in a short time. Since standard peptide synthesis is usually done under poor diffusion conditions with slow or no mixing of the solid support, acceleration of the process is achieved by applying a large excess of reagents. In this work, overhead stirring and heating were combined to provide accelerated solid-phase peptide synthesis without using an excess of reagent. A new setup that allows both heating and fast stirring was designed specifically for research laboratory-scale peptide synthesis. By increasing the diffusion of both reagents and beads in a narrow dimension reactor, solid-phase reactions were done in seconds and medium-size peptides were synthesized in minutes.
We review a suite of stochastic vector computational approaches for studying the electronic structure of extended condensed matter systems. These techniques help reduce algorithmic complexity, facilitate efficient parallelization, simplify computational tasks, accelerate calculations, and diminish memory requirements. While their scope is vast, we limit our study to ground-state and finite temperature density functional theory (DFT) and second-order perturbation theory. More advanced topics, such as quasiparticle (charge) and optical (neutral) excitations and higher-order processes, are covered elsewhere. We start by explaining how to use stochastic vectors in computations, characterizing the associated statistical errors. Next, we show how to estimate the electron density in DFT and discuss highly effective techniques to reduce statistical errors. Finally, we review the use of stochastic vector techniques for calculating correlation energies within the secondorder Møller-Plesset perturbation theory and its finite temperature variational form. Example calculation results are presented and used to demonstrate the efficacy of the methods.
In the 1920s, during his émigré life in interbellum Berlin, Vladimir Nabokov wrote a number of Christmas stories. These stories—“Christmas,” “The Christmas Story,” and “A Reunion”—were all composed and published at Christmastime and set on the eve of Russian Christmas (first week of January). While involving the traditional motifs of the Christmas-story genre, such as the combination of joy and sorrow as well as the motifs of epiphany, gift, care, and forgiveness, these narratives expand the scope of the genre to represent not communal religious values but a private ethical stance. The purity of commitments emerges as a criterion for successful inner life. The gifts are usually the gifts of the memory, cherished in “Christmas” and “A Reunion,” and forfeited in “The Christmas Story,” as well as in a counter-story, “A Matter of Chance,” which was also written at Christmas time but set August and published with half a year’s delay.
Cytokines such as interleukin-8 activate the immune system during infection and interact with sulfated glycosaminoglycans with specific sulfation patterns. In some cases, these interactions are mediated by metal ion binding which can be used to tune surface-based glycan-protein interactions. We evaluated the effect of both hyaluronan sulfation pattern and Fe3+ on interleukin-8 binding by electrochemical impedance spectroscopy and surface characterizations. Our results show that sulfation pattern and metal ion interactions have a synergistic effect in tuning the electrochemical response of the glycated surfaces to the cytokine.
[4 + 4] and [2 + 2] cycloadditions are unique reactions since they form and deform cycloadducts under irradiation due to their inherent reversible nature. Whereas promising for the field of recycling, these reactions usually suffer from two major shortcomings: long reaction durations (hours) and the requirement of high-intensity light (∼100 W/cm2), typically at a short wavelength (<330 nm). We demonstrate several tetra-dentate catalysts that can overcome these fundamental limitations. Among them is a tin complex that enables 76% conversion within only 2 min of irradiation at 395 nm, much faster than the known ruthenium-based catalyst, under irradiation with light intensity two orders of magnitude lower than that reported in the literature. Due to the short photopolymerization time, low intensity (27 mW/cm2), and long UV light (395 nm), this unique complex opens new avenues for recycling three-dimensional printing products based on photopolymerization of cycloaddition reactions.
Tungsten, an essential refractory metal material, has the characteristics of high melting and boiling points, high hardness, low expansion coefficient, and low vapor pressure. An indirect strategy to print three-dimensional (3D) refractory metal materials via digital light processing (DLP) followed by a post-treatment process was proposed. To analyze this strategy, a transparent ink with tungsten salts was developed, printed into a 3D precursor via DLP, and subsequently transited into 3D porous tungsten. The ultraviolet rheological properties and stability of the ink, transition process from the precursor to a 3D article, and the properties of the obtained 3D porous tungsten were investigated. This ink was preferable for DLP 3D printing, possessing consistency, stability and favorable absorbance at the wavelength of 385 nm. With increasing temperature, the weight of the tungsten salt in the 3D precursor decreased by 8.97% and was transited to tungsten oxide below 460 °C, reduced to pure nano-sized tungsten at approximately 700 °C, and finally sintered into porous articles. The organics initially contributed to polymerization during printing as well as reduction as a carbon reducer after pyrolysis. The pore size distribution of porous tungsten is nonlinear or multimodal, depending on the final sintering temperature. At 1200 °C, two distinct peaks are observed in the pore distribution curves of the products. At 1400 °C, the small pore as a whole decreases from approximately 100-1000 nm. Correspondingly, the relative density of the samples increased with temperature.
Two-dimensional (2D) porous carbon-based composite nanosheets loaded with metal oxide nanoclusters are expected to be promising electrocatalysts for high-performance electrochemical sensors. However, for this complicated composite material, strict reaction conditions and complex synthesis steps limit its general application in electrochemical detection. Here we present a facile method to fabricate 2D mesoporous nitrogen-rich carbon nanosheets loaded with CeO2 nanoclusters (2D-mNC@CeO2), for fabricating superoxide anions (O2•−) electrochemical sensor. The method is based on block copolymers self-assembly and the affinity of polydopamine to metal ions to obtain organic-inorganic hybrid, which can be directly converted into 2D-mNC@CeO2 through carbonization strategy without structural deterioration. Characterizations demonstrate that the 2D-mNC@CeO2 owned the 2D N-doped carbon structure with an interlinked hierarchical mesoporous and the uniformly dispersed CeO2 nanoclusters on the surface. Benefitted from the unique structure, the 2D-mNC@CeO2 shortens electron transfer distance, enhances mass transfer efficiency, exposes numerous active sites, and obtain a high Ce3+/Ce4+ ratio for improving electrocatalytic performance. The 2D-mNC@CeO2/SPCEs sensors for O2•− detection has a detection limit of 0.179 μM (S/N = 3) and sensitivity of 401.4 μA cm-2 mM-1. The sensors can be applied to capture electrochemical signals of O2•− released from HepG2 cells, demonstrating the application potential of the sensors to monitor O2•− in biological fields.
End of century projections from Coupled Model Intercomparison Project (CMIP) models show a decrease in precipitation over subtropical oceans that often extends into surrounding land areas, but with...
Amey Nimkar, Munseok S. Chae, Shianlin Wee, Gil Bergman, Bar Gavriel, Meital Turgeman, Fyodor Malchik, Mikhael D. Levi, Daniel Sharon, Maria R. Lukatskaya, Netanel Shpigel, and Daniel Mandler. 2022. “What About Manganese? Toward Rocking Chair Aqueous Mn-Ion Batteries.” ACS ENERGY LETTERS, 7, 12, Pp. 4161-4167.
For voters, estimating beforehand which candidates will receive many or few votes in an upcoming election is valuable information. Probabilistic election forecasts help voters brace themselves for adverse outcomes or mobilize themselves to bring about favored ones, and constitute a critical prerequisite for strategic voting: By estimating which candidates stand a chance, voters can adjust their vote choices between multiple acceptable options, trying to maximize the impact of their vote. Especially in two-round voting systems such as the French presidential elections, tactical estimations of candidates’ chances are critical for making one’s vote count (Plutowski et al., 2020).
While strategic voting has been widely studied (e.g., Meffert et al., 2011), we know little about how voters rely on the news and other sources of information to gauge candidates’ differential chances at receiving a sufficient share of votes. In this study, we draw upon a four-wave panel survey coupled with a large-scale news content analysis to examine how French voters in the 2022 presidential elections predict candidates’ respective chances and adjust them over time to accommodate new developments. Using a longitudinal linkage-study design, which links voters’ expectations to the media contents that they are exposed to, we distinguish two main mechanisms that may explain voters’ differential probability estimates (Blais & Bodet, 2006): On the one hand, ongoing news coverage informs voters’ expectations, as journalists, pollsters, pundits and other commentators give visibility to those candidates deemed most relevant and expressly discuss their respective chances. On the other hand, voters have relatively stable, intrinsic reasons for believing in the viability of candidates’ bids based on their political party preference, para-social sympathies and other forms of motivated reasoning. Expanding the ongoing scholarly debate about the electoral effects of public opinion polling (e.g., Daoust et al., 2020), we investigate how both wishful thinking and different forms of current information inform the formation and updating of voters’ probabilistic estimates, eroding or reinforcing confidence in their intended vote choice.
Does an ongoing stalemate in a peace process affect the international agenda toward the conflict and international perceptions about policies that should be adopted to resolve it? We provide a tentative answer to this question by drawing insight from analysis of developments and trends in international media attention to key terms and concepts in the context of the Israeli-Palestinian conflict during cycles of violence, as well as periods of rapprochement and peace negotiations, in the last two and half decades (1996-2021). We find that although attention to the Israeli-Palestinian peace process have been declining over the years, much of the international discussion continues to be devoted to relaunching a negotiation process leading to a two state solution. The ongoing stalemate in such “process,” we show, provide ample opportunities for alternative approaches to emerge advocating alternative endgames (e.g. one-state), international pressure (e.g. BDS), or unilateral steps (e.g. annexation). Each of this approaches promotes an alternative vision and provides a different path, employs its own terminology and vision of the future. The Israeli-Palestinian case study helps illustrate what may happen to peace when the process is stalled, and how a stalemate can produce change in the international debate on the conflict and push for the emergence of new policy directions and agendas.
