How children and adults keep track of real information when thinking counterfactually.

Thinking about counterfactual conditionals such as "if she had not painted the sheet of paper, it would have been blank" requires us to consider what is conjectured (She did not paint and the sheet was blank) and what actually happened (She painted and the sheet was not blank). In two experiments with adults (Study 1) and schoolchildren from 7 to 13 years (Study 2), we tested three potential sources of difficulty with counterfactuals: inferring, distinguishing what is real vs conjectured (epistemic status) and comprehending linguistic conditional expressions ("if" vs "even if"). The results showed that neither adults nor schoolchildren had difficulty in the comprehension of counterfactual expressions such as "even if" with respect to "if then". The ability to infer with both of these develops during school years, with adults showing great ability. However, the third source factor is critical: we found that the key to young children's difficulty with counterfactual thinking was their inability to differentiate real and conjectured information, while adults showed little difficulty with this.

Chemical Composition and Preliminary Antimicrobial Activity of the Hydroxylated Sesquiterpenes in the Essential Oil from Piper barbatum Kunth Leaves.

This study evaluates the antimicrobial and antifungal potential of the essential oil extracted from a species located in the Andes of Ecuador, Piper barbatum Kunth, known as "cordoncillo" or "allupa", used by the Quichua people as an antibacterial plant for washing female genitalia in cases of infection. The most abundant molecules in the essential oil were: α- phellandrene (43.16%), limonene (7.04%); some oxygenated sesquiterpenes such as: trans-sesquisabinene hydrate (8.23%), elemol (7.21%) and others. The evaluation of antimicrobial activity showed activity in all the strains analyzed; however, those in which MIC values are considered to be very strong (less than 500 µg/mL) are: Staphylococcus aureus 264 µg/mL, Streptococcus mutans 132 µg/mL, Candida albicans 132 µg/mL and Candida tropicalis 264 µg/mL. Antimicrobial bioautography defines which molecules are responsible for the activity; thus, it was possible to establish the chromatographic regions of = 0.02 and Rf = 0.04, as those with active molecules. It was established that 4 hydroxylated sesquiterpene molecules are involved: elemol (7.21%), trans-sesquisabinene hydrate (8.23%), ß-eudesmol (3.49%) and 10-epi-γ-eudesmol (1.07%); the last two being the most active. The aim of this manuscript is to analyze both the ancestral knowledge of the Quichua people of Ecuador, and the chemical-biodiversity of the Andean forest ecosystem, in order to provide new raw materials of pharmaceutical interest.

Extracellular Monomeric Tau Is Internalized by Astrocytes.

Tau is a microtubule-associated protein that is expressed in neurons. However, in a group of neurodegenerative diseases named tauopathies - characterized by an increase in aggregated and/or hyperphosphorylated Tau - the protein accumulates inside other cells, such as astrocytes and microglia. Given that these glial cells do not produce Tau, its presence can be explained by internalization from the extracellular medium and consequent formation of Tau aggregates. Among internalization mechanisms, heparan sulfate proteoglycans (HSPGs) have been proposed to be responsible for fibrillary Tau uptake in various cell types. Here we studied whether monomeric Tau, which has been observed to be internalized by glial cells such as microglia, was also taken up by astrocytes. Although this Tau form was internalized from the extracellular medium by these cells, the mechanism of uptake was found to be independent of HSPGs.

Rediscovering Medicinal Amazonian Aromatic Plants: Piper carpunya (Piperaceae) Essential Oil as Paradigmatic Study.

Piper carpunya Ruiz & Pav. (Piperaceae) is a perennial aromatic shrub of Amazonian area of Ecuador and Peru, belonging to the ethnomedicine of these countries. The traditional preparations of the crude drug (fresh leaves used topically as is, and dried leaves in infusions or decoctions) are known for anti-inflammatory, antiulcer, antidiarrheal, antiparasitic effects, and wound healing properties. In light of this traditional evidence, chemical composition (GC-MS) and biological activity, i.e., antioxidant, antifungal (yeast) capacities, and genotoxicity, of Amazonian P. carpunya leaf essential oil (EO) have been investigated in order to valorize some of the putative ethnomedical effects. The EO was obtained through steam distillation of fresh leaves (yield: 7.6 g/kg [0.76%]; refractive index at 20°C: 1.49; density: 0.928 g/mL). Chemical characterization performed through GC-MS evidenced the presence of 21 compounds (96.2% of the total). The most abundant constituents were piperitone (26.2%), limonene (9.5%), elemicin (7.2%), and ß-phellandrene (5.6%). In vitro DPPH antioxidant assay showed a weak radical scavenging ability (IC50) if compared to positive control. Low bioactivity of the EO was also demonstrated against yeast, but it showed an interesting synergistic activity (FIC index of EO+fluconazole) against Candida sp. strains. Ames test evidenced the safety of the EO concerning genotoxicity.

Structure of Supported and Unsupported Catalytic Rh Nanoparticles: Effects on Nucleation of Single-Walled Carbon Nanotubes.

Achieving a better control of the nucleation and growth of single-walled carbon nanotubes requires understanding of the changes in the catalyst structure and the interfacial phenomena occurring at the solid surface and the gaseous phase from the early stages of the synthesis process. Carbon nanotubes produced by chemical vapor deposition typically use carbon-philic metal catalysts such as Fe, Ni, and Co, in which both surface C and dissolved C atoms contribute to the nanotube formation. We use density functional theory to investigate the interactions of Rh, a noble metal, with carbon both as individual atoms gradually deposited on the catalyst surface from the precursor gas decomposition and as a nucleating seed adhered to the catalyst. Adsorption and limited dissolution of carbon atoms in the subsurface are found to be favorable in unsupported clusters of various sizes (Rh38, Rh55, and Rh68) and in Rh32 clusters supported on MgO(100) and MgO(111) surfaces. Changes in solubility, electron density transfer, and interactions of the Rh clusters with the support and the nascent nanotube are explored for increasing contents of carbon adsorbed on or dissolved inside the particles. The adhesion energy of small Rh38 clusters on the different MgO surfaces studied can differ by as much as 1 eV compared with the same-sized Rh2C particles. Also, the adhesion of graphene differs on the Rh particles by as much as 5.7 eV with respect to Rh2C supported nanoparticles. This demonstrates the influence that the presence of dissolved carbon can have on the catalyst interactions with the support and nucleating nanotube. A discussion on how such factors affect the lattice and electronic structure of the catalyst particles is presented in the interest of obtaining insight that will allow the design of improved catalysts for controlled nanotube synthesis.

Direct evidence of atomic-scale structural fluctuations in catalyst nanoparticles.

Rational catalyst design requires an atomic scale mechanistic understanding of the chemical pathways involved in the catalytic process. A heterogeneous catalyst typically works by adsorbing reactants onto its surface, where the energies for specific bonds to dissociate and/or combine with other species (to form desired intermediate or final products) are lower. Here, using the catalytic growth of single-walled carbon nanotubes (SWCNTs) as a prototype reaction, we show that the chemical pathway may in-fact involve the entire catalyst particle, and can proceed via the fluctuations in the formation and decomposition of metastable phases in the particle interior. We record in situ and at atomic resolution, the dynamic phase transformations occurring in a Cobalt catalyst nanoparticle during SWCNT growth, using a state-of-the-art environmental transmission electron microscope (ETEM). The fluctuations in catalyst carbon content are quantified by the automated, atomic-scale structural analysis of the time-resolved ETEM images and correlated with the SWCNT growth rate. We find the fluctuations in the carbon concentration in the catalyst nanoparticle and the fluctuations in nanotube growth rates to be of complementary character. These findings are successfully explained by reactive molecular dynamics (RMD) simulations that track the spatial and temporal evolution of the distribution of carbon atoms within and on the surface of the catalyst particle. We anticipate that our approach combining real-time, atomic-resolution image analysis and molecular dynamics simulations will facilitate catalyst design, improving reaction efficiencies and selectivity towards the growth of desired structure.

Reduction of Electrolyte Components on a Coated Si Anode of Lithium-Ion Batteries.

Surface modification of Si anodes in Li-ion batteries by deposition of a thin alucone coating has demonstrated an effective way to help maintain a stable anode/electrolyte interface and good battery performance. In this work, we investigate the interactions and reactivity of the film with electrolyte components using ab initio molecular dynamics simulations. Adsorption of solvent molecules (ethylene carbonate, EC) and salt (LiPF6) and reduction by two mechanisms depending on the Li content of the film (yielding open EC adsorbed on the film or C2H4 + CO32-) take place near the film/electrolyte and film/anode interfaces. Reaction products incorporate into the structure of the film and create a new kind of solid-electrolyte interphase layer.

Myrcia splendens (Sw.) DC. (syn. M. fallax (Rich.) DC.) (Myrtaceae) Essential Oil from Amazonian Ecuador: A Chemical Characterization and Bioactivity Profile.

In this study, we performed the chemical characterization of Myrcia splendens (Sw.) DC. (Myrtaceae) essential oil from Amazonian Ecuador and the assessment of its bioactivity in terms of cytotoxic, antibacterial, and antioxidant activity as starting point for possible applicative uses. M. splendens essential oil, obtained by hydro-distillation, was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Flame Ionization Detector (GC-FID): the major components were found to be trans-nerolidol (67.81%) and α-bisabolol (17.51%). Furthermore, we assessed the cytotoxic activity against MCF-7 (breast), A549 (lung) human tumor cell lines, and HaCaT (human keratinocytes) non-tumor cell line through 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test: promising results in terms of selectivity and efficacy against the MCF-7 cell line (IC50 of 5.59 ± 0.13 µg/mL at 48 h) were obtained, mainly due to α-bisabolol. Furthermore, antibacterial activity against Gram positive and negative bacteria were performed through High Performance Thin Layer Chromatography (HPTLC) bioautographic assay and microdilution method: trans-nerolidol and ß-cedren-9-one were the main molecules responsible for the low antibacterial effects against human pathogens. Nevertheless, interesting values of Minimum Inhibitory Concentration (MIC) were noticeable against phytopathogen strains. Radical scavenging activity performed by HPTLC bioautographic and spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) approaches were negligible. In conclusion, the essential oil revealed a good potential for plant defense and anti-cancer applications.

Concessive and semifactual interpretations during reasoning with multiple conditionals.

The present research evaluates how people integrate factual 'if then' and semifactual 'even if' conditional premises in an inference task. The theory of mental models establishes that semifactual statements are represented by two mental models with different epistemic status: 'A & B' is conjectured and 'not-A & B' is presupposed. However, following the principle of cognitive economy in tasks with a high working memory load such as reasoning with multiple conditionals, people could simplify the deduction process in two ways, by discarding: (a) the presupposed case and/or (b) the epistemic status information. In Experiment 1 and Experiment 2, we evaluated each of these hypotheses. In Experiment 1, participants make inferences from two conditionals: two factual conditionals or one factual and one semifactual, with different representations. In Experiment 2, participants make inferences with a factual conditional followed by two different semifactual conditionals that share the same representations but differ in their epistemic status. Accuracy and latency data suggest that people think of both the conjectured and the presupposed situations, but do not codify the epistemic status of either when the task does not require it. The results are discussed through theoretical predictions about how people make inferences from different connected conditionals.

Ethnobotanical Research at the Kutukú Scientific Station, Morona-Santiago, Ecuador.

This work features the results of an ethnobotanical study on the uses of medicinal plants by the inhabitants of the region near to the Kutukú Scientific Station of Universidad Politécnica Salesiana, located in the Morona-Santiago province, southeast of Ecuador. In the surroundings of the station, one ethnic group, the Shuar, has been identified. The survey hereafter reports a total of 131 plant species, with 73 different therapeutic uses.

Structure and dynamics of metallic and carburized catalytic Ni nanoparticles: effects on growth of single-walled carbon nanotubes.

Understanding the evolution of the catalyst structure and interactions with the nascent nanotube under typical chemical vapor deposition (CVD) conditions for the synthesis of single-walled carbon nanotubes is an essential step to discover a way to guide growth toward desired chiralities. We use density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations on model metallic and carburized Ni clusters to explore changes in the fundamental features of the nanocatalyst: geometric and electronic structure, dynamics and stability of the carburized nanocatalyst, and interactions with nascent nanotube caps at two different temperatures (750 and 1000 K) and different carbon composition ratios. This allows us to gain insight about the evolution of these aspects during the pre-growth and growth stages of CVD synthesis of single-walled carbon nanotubes and their implications for reactivity and control of the nanotube structure.

Nanocatalyst shape and composition during nucleation of single-walled carbon nanotubes.

The dynamic evolution of nanocatalyst particle shape and carbon composition during the initial stages of single-walled carbon nanotube growth by chemical vapor deposition synthesis is investigated. Classical reactive and ab initio molecular dynamics simulations are used, along with environmental transmission electron microscope video imaging analyses. A clear migration of carbon is detected from the nanocatalyst/substrate interface, leading to a carbon gradient showing enrichment of the nanocatalyst layers in the immediate vicinity of the contact layer. However, as the metal nanocatalyst particle becomes saturated with carbon, a dynamic equilibrium is established, with carbon precipitating on the surface and nucleating a carbon cap that is the precursor of nanotube growth. A carbon composition profile decreasing towards the nanoparticle top is clearly revealed by the computational and experimental results that show a negligible amount of carbon in the nanoparticle region in contact with the nucleating cap. The carbon composition profile inside the nanoparticle is accompanied by a well-defined shape evolution of the nanocatalyst driven by the various opposing forces acting upon it both from the substrate and from the nascent carbon nanostructure. This new understanding suggests that tuning the nanoparticle/substrate interaction would provide unique ways of controlling the nanotube synthesis.

Nucleation of graphene and its conversion to single-walled carbon nanotubes.

We use an environmental transmission electron microscope to record atomic-scale movies showing how carbon atoms assemble together on a catalyst nanoparticle to form a graphene sheet that progressively lifts-off to convert into a nanotube. Time-resolved observations combined with theoretical calculations confirm that some nanoparticle facets act like a vice-grip for graphene, offering anchoring sites, while other facets allow the graphene to lift-off, which is the essential step to convert into a nanotube.

Necrotic mature ovarian teratoma associated with anti-N-methyl-D-aspartate receptor encephalitis.

A 20-year-old female with a diagnosis of autoimmune encephalitis against N-methyl-D-aspartate receptor was found to have a 13 mm teratoma in the left ovary. The tumor had undergone massive coagulative necrosis within a normal ovary, a previously unreported feature. Necrosis of a mature cystic teratoma is very rare in the absence of ovarian torsion. It is proposed that necrosis may have induced a massive liberation of neuronal antigens. The vast majority of the tumors associated with this newly described condition are ovarian teratomas containing neural tissues. In this paper, we review their different histopathological aspects that may explain the relative incidence of various tumor types associated to this form of encephalitis. Anti N-methyl-D-aspartate receptor encephalitis has now become the most frequent autoimmune disorder associated with ovarian teratoma.

Mouse mutants for the nicotinic acetylcholine receptor ß2 subunit display changes in cell adhesion and neurodegeneration response genes.

Mice lacking expression of the ß2 subunit of the neuronal nicotinic acetylcholine receptor (CHRNB2) display abnormal retinal waves and a dispersed projection of retinal ganglion cell (RGC) axons to their dorsal lateral geniculate nuclei (dLGNs). Transcriptomes of LGN tissue from two independently generated Chrnb2-/- mutants and from wildtype mice were obtained at postnatal day 4 (P4), during the normal period of segregation of eye-specific afferents to the LGN. Microarray analysis reveals reduced expression of genes located on the cell membrane or in extracellular space, and of genes active in cell adhesion and calcium signaling. In particular, mRNA for cadherin 1 (Cdh1), a known axon growth regulator, is reduced to nearly undetectable levels in the LGN of P4 mutant mice and Lypd2 mRNA is similarly suppressed. Similar analysis of retinal tissue shows increased expression of crumbs 1 (Crb1) and chemokine (C-C motif) ligand 21 (Ccl21) mRNAs in Chrnb2-/- mutant animals. Mutations in these genes are associated with retinal neuronal degeneration. The retinas of Chrnb2-/- mutants are normal in appearance, but the increased expression of these genes may also be involved in the abnormal projection patterns of RGC to the LGN. These data may provide the tools to distinguish the interplay between neural activity and molecular expression. Finally, comparison of the transcriptomes of the two different Chrnb2-/- mutant strains reveals the effects of genetic background upon gene expression.

Prophylactic effect of clarithromycin in skin flap complications in cochlear implants surgery.

OBJECTIVES/HYPOTHESIS: To assess the usefulness of postoperative clarithromycin versus classical postoperative prophylaxis with occlusive dressing to prevent cochlear implant skin flap complications. STUDY DESIGN: Cohort study. METHODS: Surgical site infections were compared in four groups: 1) ceramic/classical postoperative cares (21 patients), 2) titanium-silicon/classical postoperative cares (75), 3) ceramic/clarithromycin (24), and 4) titanium-silicon/clarithromycin (76). Preoperative ceftriaxone was systematically used in all patients in all four groups. Patients were followed up for at least 4 months. Attributable risk and number needed to treat were calculated. RESULTS: All infections appeared in titanium-silicon covered implants, and the risk of surgical site infection was 8.1 times higher in patients treated only with ceftriaxone and classical postoperative prophylaxis compared to those also given clarithromycin. Eleven patients needed to receive clarithromycin to avoid surgical infection. CONCLUSIONS: Long-term treatment with low-dose clarithromycin may reduce the incidence of surgical site infections.

[Surgical options for hearing loss in patients with osteogenesis imperfecta]. / Posibilidades de tratamiento quirúrgico de la hipoacusia en pacientes afectados de osteogénesis imperfecta.

The aim of the study is to present the severe, extensive lesions in the temporal bone appearing in the mildest forms of osteogenesis imperfecta, correlate these with audiometric results and discuss the possible surgical treatments available. We present three patients suffering hearing loss due to osteogenesis imperfecta type 1 to various functional degrees. All patients underwent an audiological, medical and radiological evaluation and were then treated with different surgical procedures. The patients presented mild, severe and profound mixed hearing losses and the radiological images showed extensive areas of demineralization affecting the ossicular chain and removal of protection for the vital structures inside the temporal bone. Also, the cochlea showed otic capsule demineralization, dehiscence, distortions and even destructions. The various surgical treatments, indicated under current international criteria, obtained limited functional results. This study reviews the need to evaluate the current surgical criteria for this specific condition.

Complications and pitfalls of cochlear implantation in otosclerosis: a 6-year follow-up cohort study.

OBJECTIVE: To describe and discuss the midterm complications and pitfalls reported in patients with otosclerosis who received a cochlear implant. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Fifteen patients who received a cochlear implant for otosclerosis, followed up for a minimum of 6 years. Onset of hearing loss occurred at a mean age (+/-standard deviation [SD]) of 32.6 +/- 8.6 years. Mean duration (+/-SD) of hearing loss was 26.8 +/- 7.9 years, and mean age (+/-SD) at implant surgery was 58.7 +/- 9.5 years. INTERVENTIONS: Before cochlear implantation, hearing thresholds were tested, and temporal bone anatomy and otosclerotic lesions were documented by high-resolution computed tomography and magnetic resonance imaging. All patients were implanted with a Med-El Combi 40 + device and a Standard Electrode Array. MAIN OUTCOME MEASURES: The number of inserted electrodes was checked by x-ray. After cochlear implantation, hearing skills were tested, fitting parameters were recorded, and complications were noted. RESULTS: As the disease progressed, the number of electrodes decreased, and the electrical thresholds, maximum comfort levels, and electric charge increased; these changes were more evident in the middle electrodes. Although facial nerve stimulation rate was lower than previously reported (13.3%), it increased during follow-up. Two patients (13.3%) had untreatable tinnitus. Nevertheless, all speech discrimination parameters improved significantly in all patients. CONCLUSION: Despite the need for special fitting strategies and the appearance of complications, facial nerve stimulation, and tinnitus, improvements in speech discrimination tests support the use of cochlear implantation for patients with otosclerosis.

Posibilidades de tratamiento quirúrgico de la hipoacusia en pacientes afectados de osteogénesis imperfecta / Surgical options for hearing loss in patients with osteogenesis imperfecta

El objetivo del estudio es presentar las extensas y severas lesiones óticas que acontecen en la forma más leve de osteogénesis imperfecta, correlacionarlas con las alteraciones audiométricas y discutir las posibilidades quirúrgicas disponibles. Se presenta a 3 pacientes afectados de osteogénesis imperfecta tipo 1 con hipoacusia en distintos estadios funcionales. Se realizó a cada paciente estudio audiológico, médico y radiológico, y se sometieron a distintos tratamientos quirúrgicos. Los pacientes presentaron hipoacusias mixtas de carácter moderado, severo y profundo, imágenes radiológicas con extensas áreas de desmineralización que afectaban la cadena osicular y con desprotección de las estructuras vitales alojadas en el peñasco temporal, desmineralización de la cápsula ótica, dehiscencias, distorsiones y destrucciones cocleares. Los tratamientos quirúrgicos realizados, e indicados según los criterios actualmente aceptados, obtuvieron escasos resultados funcionales. El presente estudio plantea la necesidad de evaluar los criterios quirúrgicos específicos para esta enfermedad(AU)

The aim of the study is to present the severe, extensive lesions in the temporal bone appearing in the mildest forms of osteogenesis imperfecta, correlate these with audiometric results and discuss the possible surgical treatments available. We present three patients suffering hearing loss due to osteogenesis imperfecta type 1 to various functional degrees. All patients underwent an audiological, medical and radiological evaluation and were then treated with different surgical procedures. The patients presented mild, severe and profound mixed hearing losses and the radiological images showed extensive areas of demineralization affecting the ossicular chain and removal of protection for the vital structures inside the temporal bone. Also, the cochlea showed otic capsule demineralization, dehiscence, distortions and even destructions. The various surgical treatments, indicated under current international criteria, obtained limited functional results. This study reviews the need to evaluate the current surgical criteria for this specific condition(AU)