Electrical Coupling Between Cells and Graphene Transistors

In this work, both experimental data and a model are presented on the coupling between living cells and graphene solution‐gated field‐effect transistors. Modified HEK 293 cells are successfully cultured on graphene transistor arrays and electrically accessed by the patch clamp method. Transistor recordings are presented, showing the opening and closing of voltage‐gated potassium ion channels in the cell membrane. The experimental data is compared with the broadly used standard point‐contact model. The ion dynamics in the cell–transistor cleft are analyzed to account for the differences between the model and the experimental data revealing a significant increase in the total ionic strength in the cleft. In order to describe the influence of the ion concentration resulting from the cell activity, the ion‐sensitivity of graphene solution‐gated field‐effect transistors is investigated experimentally and modelled by considering the screening effect of the ions on the surface potential at the graphene/electrolyte interface. Finally, the model of the cell–transistor coupling is extended to include the effect of ion accumulation and ion sensitivity. The experimental data shows a very good agreement with this extended model, emphasizing the importance of considering the ion concentration in the cleft to properly understand the cell‐transistor coupling.     

Phylogenetic distribution of fungal mycosporines within the Pucciniomycotina (Basidiomycota)

The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution of the ability to produce MYCs appeared to be related to the yeast taxonomic affiliation. In view of the potential significance of MYCs in yeast taxonomy, we here studied the distribution of this trait among dimorphic basidiomycetes of the Pucciniomycotina. Of the 94 fungal species (377 strains and 33 genera) tested, almost half were MYC-positive and MGG was the main compound produced. MGG synthesis was observed for representatives of five of seven Pucciniomycotina classes, indicating that this trait is widely distributed in this group. MGG detection proved useful for the differentiation of species of the polyphyletic genera, such as Rhodotorula and Sporobolomyces, that are phylogenetically separated. MGG quantification and UV tolerance studies in Cystobasidiomycetes supported the idea that the habitat of origin of each strains is important in the level of MGG synthesis and that MYCs have a photoprotective function in yeasts. The taxonomic value of this trait in fungal systematics is discussed.     

Degradation of pharmaceutical beta-blockers by electrochemical advanced oxidation processes using a flow plant with a solar compound parabolic collector

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L⁻¹ of total organic carbon of each drug in 0.1 M Na₂SO₄ with 0.5 mM Fe²⁺ of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single Pt/carbon felt (CF) and boron-doped diamond (BDD)/air-diffusion electrode (ADE) cells and combined Pt/ADE-Pt/CF and BDD/ADE-Pt/CF cells were used. SPEF treatments were more potent with the latter cell, yielding 95-97% mineralization with 100% of maximum current efficiency and energy consumptions of about 0.250 kWh g TOC⁻¹. However, the Pt/ADE-Pt/CF cell gave much lower energy consumptions of about 0.080 kWh g TOC⁻¹ with slightly lower mineralization of 88-93%, then being more useful for its possible application at industrial level. The EF method led to a poorer mineralization and was more potent using the combined cells by the additional production of hydroxyl radicals (^•OH) from Fenton’s reaction from the fast Fe²⁺ regeneration at the CF cathode. Organics were also more rapidly destroyed at BDD than at Pt anode. The decay kinetics of beta-blockers always followed a pseudo first-order reaction, although in SPEF, it was accelerated by the additional production of ^•OH from the action of UV light of solar irradiation. Aromatic intermediates were also destroyed by hydroxyl radicals. Ultimate carboxylic acids like oxalic and oxamic remained in the treated solutions by EF, but their Fe(III) complexes were photolyzed by solar irradiation in SPEF, thus explaining its higher oxidation power. NO₃⁻ was the predominant inorganic ion lost in EF, whereas the SPEF process favored the production of NH₄⁺ ion and volatile N-derivatives.     

Recent Advances in Ni-Catalyzed 1,1-Difunctionalization of Unactivated Olefins

Unactivated olefins rank amongst the most important feedstocks in organic synthesis. Their availability makes them particularly useful synthons for subsequent functionalization, particularly in a catalytic manner. Driven by the popularity ascribed by nickel catalysis as a new tool to rapidly forge molecular architectures via one-or two-electron manifolds, the recent years have witnessed significant advances in Ni-catalyzed olefin difunctionalization. While 1,2-difunctionalization or remote functionalization via “chain-walk” have become mature disciplines for repurposing the potential of olefins as building blocks, it was only recently that extensions of this chemistry to 1,1-difunctionalization have been possible. This review summarizes the recent advances in Ni-catalyzed olefin 1,1-difunctionalization, holding considerable promise as a new powerful strategy for our ever-growing synthetic repertoire.     

Classroom Seating and Functional Brain Asymmetry.

This study examined the relationship between functional brain asymmetry, as measured by the characteristic direction of eye movements in response to face-to-face questioning, and sitting on the left or the right side of a classroom: 74 undergraduate students, whose laterality had previously been ascertained, participated. As predicted, left movers preferred to sit on the right side, and right movers on the left. A significant proportion of the subjects who indicated a differential seating preference for hard compared to soft topics, placed themselves more to the left for the former. The results are congruent with other findings comparing right movers and left movers on a variety of personality measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antimicrobial materials based on poly(ethylene-co-vinyl alcohol) and silver acetate produced by reactive extrusion

The use of silver as an antimicrobial agent has exhibited great interest in recent years. In this research, poly(ethylene-co-vinyl alcohol) (EVOH)–silver acetate-based antimicrobial materials were prepared at high temperature by reactive extrusion. Silver acetates were used without pretreatment. The thermal reaction of silver acetates in the material and their effect on the thermal and mechanical properties of the polymer were investigated as a function of their concentration. The dispersed silver acetate salts within the EVOH matrix have displayed a significant thermal reaction. This reaction of metallic salts was partial when the extrusion temperature was fixed at 190 °C and completed at 230 °C. The antimicrobial agents also had significant effects on the properties of the matrix. Reductions of glass temperature and storage modulus were observed by the analyses. All the variations were dependent on both the concentration of silver acetate and the extrusion parameters. The antimicrobial activity was studied and demonstrated a promising potential to create an antimicrobial material in a one-step solvent free extrusion method. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47799.     

Computational Economics: Help for the Underestimated Undergraduate

Our concern in this paper is that the capability of economics undergraduates is substantially underestimated in the design of the present college curriculum and that our students are insufficiently challenged and motivated. Students enter our classrooms with substantial previous knowledge about computers and computation and we are not taking full advantage of this opportunity. We suggest a set of examples from computational economics which are challenging enough to motivate students and simple enough that they can master them within a few hours. By encouraging the students to modify the models in directions of their own interest, avenues for creative endeavor are opened which deeply involve the students in their own education.     

Decrease of the incidence of sepsis syndrome after early enteral nutrition of patients with severe burns

The objective of this study was to evaluate the effect of early enteral nutrition on the incidence of the septic syndrome as well as its tolerance, in patients with severe burns. We retrospectively studied 64 patients older than 15 years of age, with a greater than 20% burned body surface area. They were divided into 2 groups as a function of the time elapsed between the beginning of Enteral Nutrition and the time of the burning: 23 patients were given Enteral Nutrition within 24 hours after the burn, and in 41 patients the enteral nutrition was started later than 24 hours after sustaining the thermal injury. Both groups were similar with respect to age, sex, percentage of 2nd and 3rd degree burns, incidence of inhalation, and deaths. All patients received the Enteral Nutrition through a nasogastric tube, with administration of a polymeric, hyperprotein and hypocaloric formula through a continuous infusion pump. In our study we saw a reduction of the incidence of the septic syndrome in the patients who received early enteral Nutrition (26%; 6 patients of a total of 23), with respect to those who did non receive early Enteral Nutrition (54%; 22 patients of a total of 41), with a statistical significance of p > 0.05. There were no differences between both groups with respect to the digestive tolerance to Enteral Nutrition. From our study we can deduce that early Enteral Nutrition reduces the incidence of septic complications, without this increasing the digestive intolerance to the same.     

Superior vena cava syndrome as initial manifestation of acute aortic dissection: a case report and review of the literature

Aortic dissection usually presents with chest pain, abnormal pulses and a widened mediastinum on chest radiograph. It is rarely associated with the superior vena cava syndrome as the first manifestation. This paper presents a patient who had a superior vena cava syndrome as a result of a painless aortic dissection and compared with other previously reported cases.