Organoids as host models for infection biology – a review of methods

Infectious diseases are a major threat worldwide. With the alarming rise of antimicrobial resistance and emergence of new potential pathogens, a better understanding of the infection process is urgently needed. Over the last century, the development of in vitro and in vivo models has led to remarkable contributions to the current knowledge in the field of infection biology. However, applying recent advances in organoid culture technology to research infectious diseases is now taking the field to a higher level of complexity. Here, we describe the current methods available for the study of infectious diseases using organoid cultures.Subject terms: Biological models, Adult stem cells     

A combined computational and experimental study of methane activation during oxidative coupling of methane (OCM) by surface metal oxide catalysts

The experimentally validated computational models developed herein, for the first time, show that Mn-promotion does not enhance the activity of the surface Na₂WO₄ catalytic active sites for CH₄ heterolytic dissociation during OCM. Contrary to previous understanding, it is demonstrated that Mn-promotion poisons the surface WO₄ catalytic active sites resulting in surface WO₅ sites with retarded kinetics for C–H scission. On the other hand, dimeric Mn₂O₅ surface sites, identified and studied via ab initio molecular dynamics and thermodynamics, were found to be more efficient in activating CH₄ than the poisoned surface WO₅ sites or the original WO₄ sites. However, the surface reaction intermediates formed from CH₄ activation over the Mn₂O₅ surface sites are more stable than those formed over the Na₂WO₄ surface sites. The higher stability of the surface intermediates makes their desorption unfavorable, increasing the likelihood of over-oxidation to CO_x, in agreement with the experimental findings in the literature on Mn-promoted catalysts. Consequently, the Mn-promoter does not appear to have an essential positive role in synergistically tuning the structure of the Na₂WO₄ surface sites towards CH₄ activation but can yield MnO_x surface sites that activate CH₄ faster than Na₂WO₄ surface sites, but unselectively.

The experimentally validated computational models developed herein, for the first time, show that Mn-promotion does not necessarily enhance the activity of the surface Na₂WO₄ catalytic active sites for CH₄ heterolytic dissociation during OCM.     

Self-Driving Platform for Metal Nanoparticle Synthesis: Combining Microfluidics and Machine Learning

Many applications of inorganic nanoparticles (NPs), including photocatalysis, photovoltaics, chemical and biochemical sensing, and theranostics, are governed by NP optical properties. Exploration and identification of reaction conditions for the synthesis of NPs with targeted spectroscopic characteristics is a time-, labor-, and resource-intensive task, as it involves the optimization of multiple interdependent reaction conditions. Integration of machine learning (ML) and microfluidics (MF) offers accelerated identification and optimization of reaction conditions for NP synthesis. Here, an autonomous ML-driven, oscillatory MF platform for the synthesis of NPs is reported. The platform utilized multiple recipes and reaction times for the synthesis of NPs with different dimensions, conducted spectroscopic NP characterization, and employed ML approaches to analyze multiple yet prioritized spectroscopic NP characteristics, and identified reaction conditions for the synthesis of NPs with targeted optical properties. The platform is also used to develop an understanding of the relationship between reaction conditions and NP properties. This study shows the strong potential of ML-driven oscillatory MF platforms in materials science and paves the way for automated NP development.     

Assessing the Efficiency of Sodium Ferrate Production by Solution Plasma Process

Plasma Chemistry and Plasma Processing - Application of sodium ferrate (Na2FeO4) is considered as the environmental friendly and cost-effective method for oxidation, coagulation and disinfection...     

Biosynthesis of Nano Nickel Oxide Powder Using Malva sylvestris; Evaluation of Electrocatalytic Activity for Determination of Cephalexin in Real Samples

Russian Journal of Electrochemistry - In the present study, Malva sylvestris leaf extracts was used as a reducing agent for the synthesis of NiO NPs. They were characterized by FT-IR, XRD, and SEM...     

AuBr3-Catalyzed Chemoselective Annulation of Isocyanates with 2H-Azirine

The chemoselective cyclization of isocyanates with 2H-azirine was achieved with AuBr₃ as catalyst. This transfer sets the stage for the synthesis of aromatic oxazole-ureas in a tandem process. The addition of a catalytic amount of phosphite enhances the process enormously. The reaction can also be performed in a one-pot process using benzoyl azide instead of isocyanate under the same conditions. A detailed study on the role of the phosphite that was applied as an additive revealed that only non-coordinated phosphite can reduce gold(III) and that gold(I) coordinated phosphite is not oxidized. Accompanied by the reduction of gold, HBr is generated in situ, which turned out to be the actual promotor in combination with the remaining AuBr₃. The positive effect of acid can be explained by a strong N–Au coordination, which tends to break more easily in the presence of small amount of protic acid in the reaction solution.     

Observation of Undamped 3D Brownian Motion of Nanoparticles Using Liquid-Cell Scanning Transmission Electron Microscopy

In theory, liquid-cell (scanning) transmission electron microscopy (LC(S)TEM) is the ideal method to measure 3D diffusion of nanoparticles (NPs) on a single particle level, beyond the capabilities of optical methods. However, particle diffusion experiments have been especially hard to explain in LC(S)TEM as the observed motion thus far has been slower than theoretical predictions by 3–8 orders of magnitude due to electron beam effects. Here, direct experimental evidence of undamped diffusion for two systems is shown; charge-neutral 77 nm gold nanoparticles in glycerol and negatively charged 350 nm titania particles in glycerol carbonate. The high viscosities of the used media and a low electron dose rate allow observation of Brownian motion that is not significantly altered by the electron beam. The resulting diffusion coefficient agrees excellently with a theoretical value assuming free diffusion. It is confirmed that the particles are also moving in the direction parallel to the electron beam by simulating STEM images using Monte Carlo simulations. Simulations and experiments show blurring of the particles when these move out of focus. These results make clear that direct observation of 3D diffusion of NPs is possible, which is of critical importance for the study of interparticle interactions or in situ colloidal self-assembly using LC(S)TEM.     

液相体系晶须生长机理:拓展的ACP机制

晶须生长机制一直备受关注,然而"晶须到底是怎样生长为条状的?"这一科学问题始终未能得到解决.传统晶须生长机制不适用于液相体系晶须生长.本文试图提出液相体系晶须生长机制应为拓展的ACP(Anion Coordination Polyhedron)机制.因为传统的晶须生长机制未能解释液相体系晶须的生长形态,也未能解释晶须的多样性以及指导人工可控晶须生长.拓展的ACP生长机制克服了这些问题,并有效地指导人工晶须生长.     

Commuting Graphs of Group Algebras

The commuting graph of a ring R, denoted by Γ(R), is a graph of all whose vertices are noncentral elements of R, and 2 distinct vertices x and y are adjacent if and only if xy = yx. In this article we investigate some graph-theoretic properties of Γ(kG), where G is a finite group, k is a field, and 0 ≠ |G| ∈k. Among other results it is shown that if G is a finite nonabelian group and k is an algebraically closed field, then Γ(kG) is not connected if and only if |G| = 6 or 8. For an arbitrary field k, we prove that Γ(kG) is connected if G is a nonabelian finite simple group or G′ ≠ G″ and G″ ≠ 1.