Polyelectrolyte substrate coating for controlling biofilm growth at solid–air interface

Because bacteria–surface interactions play a decisive role in bacteria adhesion and biofilm spreading, it is essential to understand how biofilms respond to surface properties to develop effective strategies to combat them. Polyelectrolyte coating is a simple and efficient way of controlling surface charge and energy. Using polyelectrolytes of various types, with different molecular weights and polyelectrolyte solutions of various pH provides a unique approach to investigate the interactions between biofilms and their substrate. Here, the formation of Escherichia coli biofilms at a solid–air interface is explored, whereby charge and interfacial energy are tuned using polyelectrolyte coatings on the surface. Cationic coatings are observed to limit biofilm spreading, which remain more confined when using high molecular weight polycations. Interestingly, biofilm surface densities are higher on polycationic surfaces despite their well-studied bactericidal properties. Furthermore, the degree of polyelectrolyte protonation also appears to have an influence on biofilm spreading on polycation-coated substrates. Finally, altering the interplay between biomass production and surface forces with polyelectrolyte coatings is shown to affect biofilm 3D architecture. Thereby, it is demonstrated that biofilm growth and spreading on a hydrogel substrate can be tuned from confined to expanded, simply by coating the surface using available polyelectrolytes

Melamine Barbiturate Crystal Twinning as a Function of Temperature

This work is supported by the Ministry of Science and Higher Education of the Russian Federation, goszadanie no. 2019-1075

The use of ultrasonic cavitation for near-surface structuring of robust and low-cost AlNi catalysts for hydrogen production

Ultrasonically induced shock waves stimulate intensive interparticle collisions in suspensions and create large local temperature gradients in AlNi particles. These trigger phase transformations at the surface rather than in the particle interior. We show that ultrasonic processing is an effective approach for developing the desired compositional gradients in nm-thick interfacial regions of metal alloys and formation of effective catalysts toward the hydrogen evolution reaction

Evolution of Cavitation Activity During Ultrasonic Nanostructuring of Magnesium

In this paper we focus on the investigation of the transient cavitation activity evolution during the sonochemical treatment of magnesium aqueous suspensions. We investigated the nonlinear behavior of cavitation activity that can be related with the influence of hydrogen gas released in the reaction of magnesium with water. Ultrasound causes the modification of the magnesium particles leading to the formation of the nanostructured Mg(OH)2 phase (brucite) resulting from both chemical and sonochemical impacts on the magnesium

Semi-contact AFM for surface characterisation in case of holographic PDADMAC films and functionalised paper

The research was carried out using equipment of the Ural Center for Shared Use "Modern Nanotechnologies" Ural Federal University. A. Vinogradov acknowledges the scholarship of the President of the Russian Federation (SP-1158.2019.1): S. Vasilev acknowledges the mobility programs of the Institute of Natural Sciences and Mathematics for the Young scientists in the 2018 year

Создание рН-чувствительных антикоррозионных контейнерных систем на основе частиц интеркалированного азолом оксида молибдена с олигооксометаллатной оболочкой

The container structures consisting of the core made of layered molybdenum oxide intercalated with 3-amono-1,2,4-triazole (it behaves as the corrosion inhibitor) capped with the shell made of polymerized tungsten oxide were synthesized employing the polycondensation of oxocompounds. It is shown that in the acid (pH < 5.5) and alkali (pH > 8.5) media, the coating continuity appears to be broken reversibly, which facilitates the emission of the encapsulated compounds from the containers. The intrinsic redox activity inherent into the oligooxometalate shell permits one to immobilize the synthesized containers by co-precipitation with galvanic nickel, whereas the possibility to open the container as a result of local pH value variations accompanying the corrosion process ensures the autonomic corrosion protection of the resultant metal-matrix coatings.С использованием процессов поликонденсации оксосоединений синтезированы контейнерные структуры в виде ядра из слоистого триоксида молибдена, интеркалированного 3-амино-1,2,4-триазолом (ингибитор коррозии), на поверхность которого нанесена оболочка из полимеризованной вольфрамовой кислоты. Показано, что в кислой (pH < 5,5) и щелочной (pH > 8,5) среде сплошность оболочки обратимо нарушается, что позволяет инкапсулированному содержимому выделяться в окружающую среду. Наличие у оксометаллатной оболочки собственной редокс-активности позволяет иммобилизовать содержащие ингибитор контейнерные структуры за счет электрохимического соосаждения с никелем, а возможность открытия контейнеров в результате изменения локальных значений рН при протекании коррозионного процесса обеспечивает автономную антикоррозионную защиту полученных металл-матричных покрытий

Piezo-Responsive Hydrogen-Bonded Frameworks Based on Vanillin-Barbiturate Conjugates

A concept of piezo-responsive hydrogen-bonded π-π-stacked organic frameworks made from Knoevenagel-condensed vanillin–barbiturate conjugates was proposed. Replacement of the substituent at the ether oxygen atom of the vanillin moiety from methyl (compound 3a) to ethyl (compound 3b) changed the appearance of the products from rigid rods to porous structures according to optical microscopy and scanning electron microscopy (SEM), and led to a decrease in the degree of crystallinity of corresponding powders according to X-ray diffractometry (XRD). Quantum chemical calculations of possible dimer models of vanillin–barbiturate conjugates using density functional theory (DFT) revealed that π-π stacking between aryl rings of the vanillin moiety stabilized the dimer to a greater extent than hydrogen bonding between carbonyl oxygen atoms and amide hydrogen atoms. According to piezoresponse force microscopy (PFM), there was a notable decrease in the vertical piezo-coefficient upon transition from rigid rods of compound 3a to irregular-shaped aggregates of compound 3b (average values of d33 coefficient corresponded to 2.74 ± 0.54 pm/V and 0.57 ± 0.11 pm/V), which is comparable to that of lithium niobate (d33 coefficient was 7 pm/V). © 2022 by the authors.2.1.06.03, 20211572; Russian Foundation for Basic Research, РФФИ: 20-53-00043-Bel_a; Ministry of Science and Technology, Taiwan, MOST: 19-52-06004 MNTI_a; Ural Federal University, UrFU: 2968; Ministry of Science and Higher Education of the Russian Federation: 075-15-2021-677The work was supported by the Russian Foundation for Basic Research (RFBR, project no. 20-53-00043-Bel_a) and the PFM measurements were done under RFBR and MOST project no. 19-52-06004 MNTI_a. The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg. No. 2968), which is supported by the Ministry of Science and Higher Education RF (project No. 075-15-2021-677), was used. T.V.S. acknowledges the support from the State Program of Scientific Researchers of Belarus (research issue 2.1.06.03, state registration number: 20211572)

Many Labs 5:Testing pre-data collection peer review as an intervention to increase replicability

Replication studies in psychological science sometimes fail to reproduce prior findings. If these studies use methods that are unfaithful to the original study or ineffective in eliciting the phenomenon of interest, then a failure to replicate may be a failure of the protocol rather than a challenge to the original finding. Formal pre-data-collection peer review by experts may address shortcomings and increase replicability rates. We selected 10 replication studies from the Reproducibility Project: Psychology (RP:P; Open Science Collaboration, 2015) for which the original authors had expressed concerns about the replication designs before data collection; only one of these studies had yielded a statistically significant effect (p < .05). Commenters suggested that lack of adherence to expert review and low-powered tests were the reasons that most of these RP:P studies failed to replicate the original effects. We revised the replication protocols and received formal peer review prior to conducting new replication studies. We administered the RP:P and revised protocols in multiple laboratories (median number of laboratories per original study = 6.5, range = 3?9; median total sample = 1,279.5, range = 276?3,512) for high-powered tests of each original finding with both protocols. Overall, following the preregistered analysis plan, we found that the revised protocols produced effect sizes similar to those of the RP:P protocols (?r = .002 or .014, depending on analytic approach). The median effect size for the revised protocols (r = .05) was similar to that of the RP:P protocols (r = .04) and the original RP:P replications (r = .11), and smaller than that of the original studies (r = .37). Analysis of the cumulative evidence across the original studies and the corresponding three replication attempts provided very precise estimates of the 10 tested effects and indicated that their effect sizes (median r = .07, range = .00?.15) were 78% smaller, on average, than the original effect sizes (median r = .37, range = .19?.50)