Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors

Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects

Novel method for aroma recovery from the bioconversion of lutein to beta-ionone by Trichosporon asahii using a mesoporous silicate material

In this work, we report on the synthesis and ability of the mesoporous material MCM-41 to adsorb the norisoprenoid beta-ionone. This compound, with a violet aroma note, can be produced from lutein by the yeast Trichosporon asahii through a bioconversion process. We found that beta-ionone inhibited the yeast growth and constrained aroma formation. Growth inhibition was overcome using silicate MCM-41 as sorbent device in a fermentation system that allowed product removal from the culture medium by headspace manipulation. Compared to a commercial silica gel, the mesoporous material exhibited a 4.5-fold higher beta-ionone adsorption. Contrasting to cultures without the sorbent device, the presence of MCM-41 allowed a marked increase (14-fold) in beta-ionone production. Our results suggested that confinement of the norisoprenoid into the sorbent material bypassed its toxicity which allowed a better beta-ionone production. This study represents the first report on the use of MCM-41 to recover an aroma produced by fermentation and therefore, a novel application for a mesoporous material

Alternative to Nitric Acid Passivation of 15-5 and 17-4PH Stainless Steel Using Electrochemical Techniques

Increasingly stringent environmental regulations in different sectors of industry, especially the aeronautical sector, suggest the need for more investigations regarding the effect of environmentally friendly corrosion protective processes. Passivation is a finishing process that makes stainless steels more rust resistant, removing free iron from the steel surface resulting from machining operations. This results in the formation of a protective oxide layer that is less likely to react with the environment and cause corrosion. The most commonly used passivating agent is nitric acid. However, it is know that high levels of toxicity can be generated by using this agent. In this work, a study has been carried out into the electrochemical behavior of 15-5PH (precipitation hardening) and 17-4PH stainless steels passivated with (a) citric and (b) nitric acid solutions for 60 and 90 min at 49 °C, and subsequently exposed to an environment with chlorides. Two electrochemical techniques were used: electrochemical noise (EN) and potentiodynamic polarization curves (PPC) according to ASTM G199-09 and ASTM G5-13, respectively. The results obtained indicated that, for both types of steel, the passive layer formed in citric acid as passivating solution had very similar characteristics to that formed with nitric acid. Furthermore, after exposure to the chloride-containing solution and according with the localization index (LI) values obtained, the stainless steels passivated in citric acid showed a mixed type of corrosion, whereas the steels passivated in nitric acid showed localized corrosion. Overall, the results of the R n values derived show very low and similar corrosion rates for the stainless steels passivated with both citric and nitric acid solutions

Correction: Lara-Banda, M., et al. Alternative to Nitric Acid Passivation of 15-5 and 17-4PH Stainless Steel Using Electrochemical Techniques. Materials 2020, 13, 2836

The author wishes to make the following correction to this paper [...

Corrosion Behavior of AA2055 Aluminum-Lithium Alloys Anodized in the Presence of Sulfuric Acid Solution

The aim of this work was to evaluate the corrosion behavior of the AA2055 Aluminum-lithium alloy anodized in a sulfuric acid (H2SO4) bath, varying the current density of 0.19 and 1 A·cm−2 and why the sealing solution was water (H2O) and sodium dichromate (Na2Cr2O7). Anodized samples were exposed to a 10 vol.% H2SO4 solution and the electrochemical technique used was electrochemical impedance spectroscopy. Scanning electron microscopy and X-ray photoelectron spectroscopy were employed to characterization of the anodizing layer, determinate morphology and thickness of coatings. The Na2Cr2O7 sealing solution tends to increase the charge transfer resistance and produces a more homogeneous and compact passive oxide layer, and imparts a corrosion inhibition protection to the AA2055. SEM observations indicated that the morphology and thickness of the anodic films formed on AA2055 aluminum-lithium alloy anodized have the best results for both current densities

MDMA attenuates THC withdrawal syndrome in mice

3, 4-Methylenedioxymethamphetamine (MDMA) and cannabis are widely abused illicit drugs that are frequently consumed in combination. Interactions between these two drugs have been reported in several pharmacological responses observed in animals, such as body temperature, anxiety, cognition and reward. However, the interaction between MDMA and cannabis in addictive processes such as physical dependence has not been elucidated yet. In this study, the effects of acute and chronic MDMA were evaluated on the behavioral manifestations of Δ9-tetrahydrocannabinol (THC) abstinence in mice. THC withdrawal syndrome was precipitated by injecting the cannabinoid antagonist rimonabant (10 mg/kg, i.p.) in mice chronically treated with THC, and receiving MDMA (2.5, 5 and 10 mg/kg i.p.) or saline just before the withdrawal induction or chronically after the THC administration. Both, chronic and acute MDMA decreased in a dose-dependent manner the severity of THC withdrawal. In vivo microdialysis experiments showed that acute MDMA (5 mg/kg, i.p.) administration increased extracellular serotonin levels in the prefrontal cortex, but not dopamine levels in the nucleus accumbens. Our results also indicate that the attenuation of THC abstinence symptoms was not due to a direct interaction between rimonabant and MDMA nor to the result of the locomotor stimulating effects of MDMA. The modulation of the cannabinoid withdrawal syndrome by acute or chronic MDMA suggests a possible mechanism to explain the associated consumption of these two drugs in humans.This study was supported by grants from Spanish MCYT (SAF 2004/568; BFU 2004/920BFI), Generalitat de Catalunya (2005SGR00131), European Communities (GENADDICT LSHM–CT–2004–005166) and NIH (Extra-mural research project #DA016768). CT has a fellowship supported by the Department of Education and Universities from Generalitat de Catalunya and by the Social European Fund. Ms Dulce Real in this work is kindly acknowledged for her excellent technical assistance in the in vivo microdialysis experiments

Corrosion Resistance of Hard Coat Anodized AA 6061 in Citric–Sulfuric Solutions

Aluminum is a material widely used in aeronautical and transport industries due to its excellent mechanical and corrosion resistance properties. Unfortunately, aluminum alloys are susceptible to corrosion, which limits their use in some corrosive environments. The aim of this work is to characterize hard coat film fabricated by anodizing in a citric–sulfuric acid system using electrochemical techniques. The anodization process was carried out using an aluminum alloy AA 6061 anodization bath: a mix of citric and sulfuric acid solutions were used. For the anodizing process, two current densities were used, 1 and 7.2 A·cm−2. Anodized specimens obtained under different conditions were exposed to a 3.5 wt.% NaCl solution, and their electrochemical behavior was studied by electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) according to ASTM G106-15 and ASTM G5-13, respectively. Scanning electron microscopy (SEM) was employed to determinate the morphology and thickness of coatings. The results showed improved corrosion resistance in 6061 aluminum anodized in citric–sulfuric acid electrolyte compared to those anodized in sulfuric acid solution

Alternative to Nitric Acid Passivation of 15-5 and 17-4PH Stainless Steel Using Electrochemical Techniques

Increasingly stringent environmental regulations in different sectors of industry, especially the aeronautical sector, suggest the need for more investigations regarding the effect of environmentally friendly corrosion protective processes. Passivation is a finishing process that makes stainless steels more rust resistant, removing free iron from the steel surface resulting from machining operations. This results in the formation of a protective oxide layer that is less likely to react with the environment and cause corrosion. The most commonly used passivating agent is nitric acid. However, it is know that high levels of toxicity can be generated by using this agent. In this work, a study has been carried out into the electrochemical behavior of 15-5PH (precipitation hardening) and 17-4PH stainless steels passivated with (a) citric and (b) nitric acid solutions for 60 and 90 min at 49 °C, and subsequently exposed to an environment with chlorides. Two electrochemical techniques were used: electrochemical noise (EN) and potentiodynamic polarization curves (PPC) according to ASTM G199-09 and ASTM G5-13, respectively. The results obtained indicated that, for both types of steel, the passive layer formed in citric acid as passivating solution had very similar characteristics to that formed with nitric acid. Furthermore, after exposure to the chloride-containing solution and according with the localization index (LI) values obtained, the stainless steels passivated in citric acid showed a mixed type of corrosion, whereas the steels passivated in nitric acid showed localized corrosion. Overall, the results of the Rn values derived show very low and similar corrosion rates for the stainless steels passivated with both citric and nitric acid solutions