Direct‐Write Formation and Dissolution of Silver Nanofilaments in Ionic Liquid‐Polymer Electrolyte Composites

Materials with reconfigurable optical properties are candidates for applications such as optical cloaking and wearable sensors. One approach to fabricate these materials is to use external fields to form and dissolve nanoscale conductive channels in well‐defined locations within a polymer. In this study, conductive atomic force microscopy is used to electrochemically form and dissolve nanoscale conductive filaments at spatially distinct points in a polyethylene glycol diacrylate (PEGDA)‐based electrolyte blended with varying amounts of ionic liquid (IL) and silver salt. The fastest filament formation and dissolution times are detected in a PEGDA/IL composite that has the largest modulus (several GPa) and the highest polymer crystal fraction. This is unexpected because filament formation and dissolution events are controlled by ion transport, which is typically faster within amorphous regions where polymer mobility is high. Filament kinetics in primarily amorphous and crystalline regions are measured, and two different mechanisms are observed. The formation time distributions show a power‐law dependence in the crystalline regions, attributable to hopping‐based ion transport, while amorphous regions show a normal distribution. The results indicate that the timescale of filament formation/dissolution is determined by local structure, and suggest that structure could be used to tune the optical properties of the film.     

Attomole voltammetric determination of metallothionein

Number of authors have concerned with electrochemical analysis of metallothionein. Recently new electroanalytical techniques enabling determination of MT at picomole level has been suggested. The aim of the presented work was to show advantages and disadvantages of the different electrochemical procedures, which are commonly used for the detection of MT—(i) cyclic voltammetry, (ii) differential pulse voltammetry, and (iii) Brdicka reaction. Primarily we aimed on improvement of the mentioned techniques. Using of reducing agent (tris(2-carboxyethyl)phosphine) and combination of the mentioned method with adsorptive transfer stripping technique (AdTS) were the main improvements of the voltammetric method. The detection limits of metallothionein measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and DPV Brdicka reaction were 0.5 pmol, 4 fmol and 10 amol, respectively. In addition AdTS DPV Brdicka reaction was used for the determination of metallothionein in human blood serum of 11-year-old girl, which were lead poisoned.     

Effect of localizing fruit and vegetable consumption on greenhouse gas emissions and nutrition, Santa Barbara County

The US agrifood system is very productive, but highly centralized and resource intensive with very weak links between production and consumption. This contributes to high levels of malnutrition and greenhouse gas emissions (GHGE). A popular approach to improvement is localization-reducing direct transport (farm to retail distance, or "food miles"). We examined Santa Barbara County (SBC) California, which mirrors the high production, nutritional and environmental problems, and growing localization movement of California. SBC ranks in the top 1% of US counties in value of agricultural products, and >80% of this value is produce (fruits and vegetables). We calculated the amount of produce grown in and consumed in SBC and estimated that >99% of produce grown in SBC is exported from the county, and >95% of produce consumed in SBC is imported. If all produce consumed in SBC was grown in the county (100% localization), it would reduce GHGE from the agrifood system <1%, and not necessarily affect nutrition. While food miles capture only a portion of the environmental impact of agrifood systems, localization could be done in ways that promote synergies between improving nutrition and reducing GHGE, and many such efforts exist in SBC.     

Modeling dependence of growth inhibition of Salmonella Typhimurium and Listeria monocytogenes by oregano or thyme essential oils on the chemical composition of minced pork

The aim of this study was to compare the antimicrobial effect of selected essential oils (EOs) at concentration of 1% in minced pork from five different meat cuts (loin, ham, shoulder, neck, and belly) and to assess the influence of the chemical parameters of meat on EO efficiency, determined by the decrease of pathogens in comparison to a control in samples after storage at 3°C/7 d in a vacuum. The inhibition was significant (p < .05) only in minced pork from meat cuts with a fat content lower than 5% (leg, loin and shoulder). Salmonella enterica serovar Typhimurium was more sensitive than Listeria monocytogenes and oregano was more effective than thyme (p < .001). The inhibition of S. Typhimurium depended mainly on the fat content (logarithmic dependence) and to a lesser degree on the pH, whereas pH was not found to be a significant predictor in the case of L. monocytogenes. The results of this study show that only lean minced meat (with a fat content max. 5%) is a suitable matrix for pathogen control by EOs.     

Electrophoretic deposition of ethanol steam-reforming catalysts on metal plates for the development of catalytic-wall reactors

A procedure based on electrophoretic deposition (EPD) was developed to coat metal plates with powder catalysts. The method was tested on stainless-steel plates with three Ni-based catalysts for the steam reforming of ethanol. The catalysts (Ni/La₂O₃/γ-Al₂O₃) contained 15% Ni and 8% La, and were prepared using three types of γ-alumina with different textural properties. The powder catalysts were suspended in isopropanol, and EPD deposition was performed with a voltage of 100 V and a distance between electrodes of 2 cm. Deposition time was varied between 3 and 7 min, which gave a thickness of the catalyst layer from around 30 to 100 μm. The morphology of the catalyst layer was dependent on the textural characteristics of the γ-Al₂O₃ used to prepare the catalyst. The activity of the catalyst plates was tested at 773 K using a steam to carbon molar ratio of 4. Significant differences in the selectivity towards ethanol dehydrogenation, reforming, and dehydration to ethylene could be observed between the three catalysts. Carbon deposition on the surface of the plates could be easily determined by SEM/ESEM.     

Interzeolite Conversion of FAU Type Zeolite into CHA and its Application in NH3-SCR

In this work we studied the potential feasibility to synthesize small pore zeolites, such as chabazite (CHA) via interzeolite conversion of FAU type zeolite. We have thereafter used CHA as the starting material to obtain Cu–CHA. When CHA in NH₄ ⁺ form was used to prepare Cu–CHA, the large size of the potassium cation present in the structure caused pore blockage in the chabazite framework, and diminished the adsorption and exchange capacity. However, Cu–CHA with comparable Selective Catalytic Reduction performance to the commercial catalyst was obtained via ion exchange if Cu-exchange was performed from H⁺–CHA form. Still, the main challenge was to fully eliminate K⁺ from the zeolite structure in order to further improve its catalytic performance and high temperature stability.     

Nanocarriers for Delivery of Oligonucleotides to the CNS

Nanoparticles with oligonucleotides bound to the outside or incorporated into the matrix can be used for gene editing or to modulate gene expression in the CNS. These nanocarriers are usually optimised for transfection of neurons or glia. They can also facilitate transcytosis across the brain endothelium to circumvent the blood-brain barrier. This review examines the different formulations of nanocarriers and their oligonucleotide cargoes, in relation to their ability to enter the brain and modulate gene expression or disease. The size of the nanocarrier is critical in determining the rate of clearance from the plasma as well as the intracellular routes of endothelial transcytosis. The surface charge is important in determining how it interacts with the endothelium and the target cell. The structure of the oligonucleotide affects its stability and rate of degradation, while the chemical formulation of the nanocarrier primarily controls the location and rate of cargo release. Due to the major anatomical differences between humans and animal models of disease, successful gene therapy with oligonucleotides in humans has required intrathecal injection. In animal models, some progress has been made with intraventricular or intravenous injection of oligonucleotides on nanocarriers. However, getting significant amounts of nanocarriers across the blood-brain barrier in humans will likely require targeting endothelial solute carriers or vesicular transport systems.     

Pesticide adsorption in relation to soil properties and soil type distribution in regional scale

Study was focused on the evaluation of pesticide adsorption in soils, as one of the parameters, which are necessary to know when assessing possible groundwater contamination caused by pesticides commonly used in agriculture. Batch sorption tests were performed for 11 selected pesticides and 13 representative soils. The Freundlich equations were used to describe adsorption isotherms. Multiple-linear regressions were used to predict the Freundlich adsorption coefficients from measured soil properties. Resulting functions and a soil map of the Czech Republic were used to generate maps of the coefficient distribution. The multiple linear regressions showed that the K(F) coefficient depended on: (a) combination of OM (organic matter content), pH(KCl) and CEC (cation exchange capacity), or OM, SCS (sorption complex saturation) and salinity (terbuthylazine), (b) combination of OM and pH(KCl), or OM, SCS and salinity (prometryne), (c) combination of OM and pH(KCl), or OM and ρ(z) (metribuzin), (d) combination of OM, CEC and clay content, or clay content, CEC and salinity (hexazinone), (e) combination of OM and pH(KCl), or OM and SCS (metolachlor), (f) OM or combination of OM and CaCO(3) (chlorotoluron), (g) OM (azoxystrobin), (h) combination of OM and pH(KCl) (trifluralin), (i) combination of OM and clay content (fipronil), (j) combination of OM and pH(KCl), or OM, pH(KCl) and CaCO(3) (thiacloprid), (k) combination of OM, pH(KCl) and CEC, or sand content, pH(KCl) and salinity (chlormequat chloride).     

Nonnegative matrix factorization for rapid recovery of constituent spectra in magnetic resonance chemical shift imaging of the brain

We present an algorithm for blindly recovering constituent source spectra from magnetic resonance (MR) chemical shift imaging (CSI) of the human brain. The algorithm, which we call constrained nonnegative matrix factorization (cNMF), does not enforce independence or sparsity, instead only requiring the source and mixing matrices to be nonnegative. It is based on the nonnegative matrix factorization (NMF) algorithm, extending it to include a constraint on the positivity of the amplitudes of the recovered spectra. This constraint enables recovery of physically meaningful spectra even in the presence of noise that causes a significant number of the observation amplitudes to be negative. We demonstrate and characterize the algorithm's performance using 31P volumetric brain data, comparing the results with two different blind source separation methods: Bayesian spectral decomposition (BSD) and nonnegative sparse coding (NNSC). We then incorporate the cNMF algorithm into a hierarchical decomposition framework, showing that it can be used to recover tissue-specific spectra given a processing hierarchy that proceeds coarse-to-fine. We demonstrate the hierarchical procedure on 1H brain data and conclude that the computational efficiency of the algorithm makes it well-suited for use in diagnostic work-up.     

Electrophoretic deposition of Co–Me/ZnO (Me = Mn,Fe) ethanol steam reforming catalysts on stainless steel plates

A procedure for coating metal plates with powder catalysts was developed based on electrophoretic deposition (EPD), and tested to deposit three different Co-based catalysts for the steam reforming of ethanol on stainless steel plates. The catalysts contained 10 wt% Co and 1 wt% of Mn or Fe supported on ZnO, and were prepared by co-precipitation (Co–Mn/ZnO–P and Co–Fe/ZnO–P) and impregnation (Co–Mn/ZnO–I). EPD was performed suspending the powder catalysts in isopropanol, using a voltage of 100 V and a distance between electrodes of 2 cm. Polyethyleneimine (PEI, 1 g/L) was used as binder. Deposition time was fixed at 5 min, which gave a thickness of the catalyst layer from around 30–45 μm, depending on the catalyst. The activity of the catalyst plates was tested at 773 K using steam to carbon ratios of 3 and 4, under incomplete conversion conditions. All catalysts favored ethanol dehydrogenation to acetaldehyde, and steam reforming. Ethanol dehydration to ethylene and acetaldehyde cracking to methane and carbon monoxide were not favored, and the selectivity towards those products was very low.