Thyroid gland in dwarf mice: a stereological study

Stereological methods were used to compare thyroids of dwarf mice and of their heterozygote littermates. In the thyroid of dwarf mice unorganized cellular masses, adipous tissue and ultimobranchial cysts are abundant. Follicles are small and their distribution function is unimodal. The number of cells per follicle is considerably lowered if compared with the normal. In control mice the distribution function of thyroid follicles is bimodal. These data show that origin of the thyroid anomaly in dwarf mice is due to a drastic diminution of cell divisions, probably resulting from the lack of growth hormone.     

Focalization: A Numerical Test for Smoothing Effects of Collision Operators

This paper deals with the numerical analysis of the focalization of a beam of particles. In particular, this model can be useful to check whether or not the cut-off Boltzmann equation leads to some kind of smoothing effect as for the Fokker-Planck–Landau equation     

Effects of general anesthetics on intercellular communications mediated by gap junctions between astrocytes in primary culture

BACKGROUND: Astrocytes represent a major nonneuronal cell population in the central nervous system (CNS) and are actively involved in several brain functions. These cells are coupled by gap junctions (GJ) into a syncytial-like network resulting in cellular communication through ionic and metabolic exchange between adjacent astrocytes. Whether anesthetics affect astrocyte function is not known. In the present study, the effects of general anesthetics on GJ permeability were investigated in primary cultures of mouse striatal astrocytes. METHODS: Junctional permeability was determined by using the fluorescent probe Lucifer yellow and the scrape loading/dye transfer technique. Confluent cells were preincubated 5 min with various concentrations of anesthetic agents and GJ permeability was estimated by measuring the area occupied by the dye from digitalized images taken 8 min after cell loading. RESULTS: Of the intravenous anesthetics tested, only propofol (P: 10(-4) M, P < 0.01 and 10(-5) M, P < 0.05) and etomidate (ET: 10(-4) M, P < 0.05, but not 10(-5) M) induced a significant reduction of GJ permeability. In contrast, diazepam (10(-5) M), morphine (10(-4) M), ketamine (10(-4) M), thiopental (10(-4) M), and clonidine (10(-7) M) did not affect junctional permeability. In addition, the halogenated anesthetics halothane, enflurane, and isoflurane induced a dose-dependent closure of GJ. For halothane, enflurane, and isoflurane, the maximum effect was achieved with a 10(-4) M, 1.6 x 10(-3) M, and 10(-3) M anesthetic concentration, respectively. Removal of volatile anesthetics resulted in the restoration of the control fluorescence area between 15 and 45 min. The time course of recovery of GJ permeability was examined more precisely for shorter periods of halothane administration (5 min, 1 mM). Under these conditions, the rate of dye spread returned to control values following anesthetic washout, while, during the same period of time, complete uncoupling of GJ was still observed in the presence of a 1 mM halothane concentration. CONCLUSIONS: These results indicate that general anesthetics differentially affect GJ permeability in cultured astrocytes. This uncoupling effect (closure of gap junctions) may contribute to the mechanisms of action of some anesthetic agents (primarily volatile anesthetics) at the level of the CNS by altering astrocyte communication.     

Blast Furnace Injections

This paper describes methods of calculation, which give the conditions to be fulfilled in order to tap the same quality of iron and have a smooth running furnace when a new matericd is injected into the blast. These calculations also show the effects of the injection upon the regularity of the iron, the production of the furnace, the coke rate, and the quality of gas produced. Included in the paper are the results of two industrial campaigns: one with natural gas and the other with light fuel oil.     

Stability Is Not Everything: The Case of the Cyclisation of a Thrombin-Binding Aptamer

With the aim of developing a new approach to obtain improved aptamers, a cyclic thrombin-binding aptamer (TBA) analogue (cycTBA) has been prepared by exploiting a copper(I)-assisted azide–alkyne cycloaddition. The markedly increased serum resistance and exceptional thermal stability of the G-quadruplex versus TBA were associated with halved thrombin inhibition, which suggested that some flexibility in the TBA structure was necessary for protein recognition.     

Modified Galacto- or Fuco-Clusters Exploiting the Siderophore Pathway to Inhibit the LecA- or LecB-Associated Virulence of Pseudomonas aeruginosa

Galacto- and fuco-clusters conjugated with one to three catechol or hydroxamate motifs were synthesised to target LecA and LecB lectins of Pseudomonas aeruginosa (PA) localised in the outer membrane and inside the bacterium. The resulting glycocluster–pseudosiderophore conjugates were evaluated as Trojan horses to cross the outer membrane of PA by iron transport. The data suggest that glycoclusters with catechol moieties are able to hijack the iron transport, whereas those with hydroxamates showed strong nonspecific interactions. Mono- and tricatechol galactoclusters ( G1C and G3C ) were evaluated as inhibitors of infection by PA in comparison with the free galactocluster ( G0 ). All of them exhibited an inhibitory effect between 46 to 75 % at 100 μM, with a higher potency than G0 . This result shows that LecA localised in the outer membrane of PA is involved in the infection mechanism.     

Study of the Photocrosslinking of Ethylene Propylene Diene Monomer Terpolymer Under UV Irradiation

The photocrosslinking of thick samples of 5-ethylidene-2-norbornene–ethylene propylene diene monomer (ENB-EPDM) under air at room temperature was investigated. First, a model study was carried out on low-molecular weight oligomers: squalene, 1,2-polybutadiene, and 1,4-polybutadiene. Several crosslinking agents (meth(acrylics), bismaleimide, and thiol) combined with various photoinitiators were tested to improve the reactivity of these oligomers under UV irradiation. Gel contents, crosslinking densities, viscosities, and viscoelastic properties were measured in order to characterize the extent of crosslinking. Acrylate-based crosslinking agents appeared to be the most reactive species and these results were then applied to a low-molecular weight EPDM. Several photoinitiators were tested and benzophenone turned out to be the most efficient photoinitiator when combined with trimethylolpropane triacrylate. Finally, a commercial EPDM was subsequently photocrosslinked and high gel content and crosslinking density were obtained after only 2 min of irradiation. POLYM. ENG. SCI., 60:95–103, 2020. © 2019 Society of Plastics Engineers     

Highly efficient electrocatalysts fabricated via electrophoretic deposition for alcohol oxidation,oxygen reduction,hydrogen evolution,and oxygen evolution reactions

Electrophoretic deposition (EPD) is a versatile technique that has drawn attention due to its ease of use and performance in depositing high-quality layers at room temperature. This technique principle is based on the deposition of charged particles from a stable colloidal suspension on a conductive substrate using either a direct or alternating current. Using relatively simple and low-cost equipment, the EPD technique enables the deposition of layers with controlled microstructures at nanoscale. The EPD technique has been particularly successful in the fabrication of the electrocatalyst layers for low-temperature fuel cells, which are anchored on the top of the fuel cell electrodes. In comparison with other electrocatalyst layer deposition techniques such as drop-casting, the EPD technique offers clear advantages for the control of the thickness and packing density of the electrocatalyst layers. Owing to the dense packing density, electrocatalyst layers deposited by EPD could achieve enhanced conductivity and efficiency. The present review aims at comprehensively evaluating the recently published results on the electrocatalyst layers fabricated by EPD and applied in oxygen reduction reactions, alcohol electro-oxidation reactions, hydrogen evolution reactions, and oxygen evolution reactions.