Testing the physiological capacity of the mussel Mytilus chilensis to establish into the Southern Ocean.

The Southern Ocean and the Antarctic Circumpolar Current create environmental conditions that serve as an efficient barrier to prevent the colonization of non-native species (NNS) in the marine ecosystems of Antarctica. However, warming of the Southern Ocean and the increasing number of transport opportunities are reducing the physiological and physical barriers, increasing the chances of NNS arriving. The aim of this study was to determine the limits of survival of the juvenile mussels, M. chilensis, under current Antarctic conditions and those projected under climate change. These assessments were used to define the mussels potential for establishment in the Antarctic region. Experimental mussels were exposed to four treatments: -1.5 °C (Antarctic winter), 2 °C (Antarctic summer), 4 °C (Antarctic projected) and 8 °C (control) for 80 days and a combination of physiological and transcriptomics approaches were used to investigate mussel response. The molecular responses of mussels were congruent with the physiological results, revealing tolerance to Antarctic winter temperatures. However, a higher number of regulated differentially expressed gene (DEGs) were reported in mussels exposed to Antarctic winter temperatures (-1.5 °C). This tolerance was associated with the activation of the biological processes associated with apoptosis (up regulated) and both cell division and cilium assembly (down regulated). The reduced feeding rate and the negative scope for growth, for a large part of the exposure period at -1.5 °C, suggests that Antarctic winter temperatures represents an environmental barrier to M. chilensis from the Magellanic region settling in the Antarctic. Although M. chilensis are not robust to current Antarctica thermal conditions, future warming scenarios are likely to weaken these physiological barriers. These results strongly suggest that the West Antarctic Peninsula could become part of Mytilus distributional range, especially with dispersal aided by increasing maritime transport activity across the Southern Ocean.

Morphology Determines an Efficient Coherent Electron Transport for Push-Pull Organic Semiconductors Based on Triphenylamine and Dicyanovinyl Groups.

The morphology of the active layer in organic solar cells is fundamental for achieving high power conversion efficiency. However, the morphological characteristics for optimal performance are still being investigated. An atomistic computational approach is required to determine the relationship between active layer morphology and performance. Since the organic solar cell has multiple phases and interfaces, the computational modeling of charge generation and transport is challenging. We then used a set of push-pull semiconductors to illustrate how the electronic transmission spectrum, derived from the Landauer-Büttiker formalism, can be used to investigate the efficiency of coherent charge transport across anisotropic organic solids. The electronic transmission spectrum was calculated from the electronic band structure obtained using the density-functional-based tight-binding method. We found that coherent charge transport was more efficient along the direction parallel with the interface between the electron-acceptor and electron-donor moieties for a herringbone morphology.

A factorial experiment grounded in the multiphase optimization strategy to promote viral suppression among people who inject drugs on the Texas-Mexico border: a study protocol.

BACKGROUND: People who inject drugs living with HIV (PWIDLH) suffer the lowest rates of HIV viral suppression due to episodic injection drug use and poor mental health coupled with poor retention in HIV care. Approximately 44% of PWIDLH along the US-Mexico border are retained in care and only 24% are virally suppressed. This underserved region faces a potential explosion of transmission of HIV due to highly prevalent injection drug use. This protocol describes an optimization trial to promote sustained viral suppression among Spanish-speaking Latinx PWIDLH. METHODS: The multiphase optimization strategy (MOST) is an engineering-inspired framework for designing and building optimized interventions and guides this intervention. The primary aim is to conduct a 24 factorial experiment in which participants are randomized to one of 16 intervention conditions, with each condition comprising a different combination of four behavioral intervention components. The components are peer support for methadone uptake and persistence; behavioral activation therapy for depression; Life-Steps medication adherence counseling; and patient navigation for HIV care. Participants will complete a baseline survey, undergo intervention, and then return for 3-,6-,9-, and 12-month follow-up assessments. The primary outcome is sustained viral suppression, defined as viral loads of < 40 copies per mL at 6-,9-, and 12-month follow-up assessments. Results will yield effect sizes for each component and each additive and interactive combination of components. The research team and partners will make decisions about what constitutes the optimized multi-component intervention by judging the observed effect sizes, interactions, and statistical significance against real-world implementation constraints. The secondary aims are to test mediators and moderators of the component-to-outcome relationship at the 6-month follow-up assessment. DISCUSSION: We are testing well-studied and available intervention components to support PWIDLH to reduce drug use and improve their mental health and engagement in HIV care. The intervention design will allow for a better understanding of how these components work in combination and can be optimized for the setting. TRIAL REGISTRATION: This project was registered at clinicaltrials.gov (NCT05377463) on May 17th, 2022.

Pyrolysis Kinetics of Byrsonima crassifolia Stone as Agro-Industrial Waste through Isoconversional Models.

This study is aimed at the analysis of the pyrolysis kinetics of Nanche stone BSC (Byrsonima crassifolia) as an agro-industrial waste using non-isothermal thermogravimetric experiments by determination of triplet kinetics; apparent activation energy, pre-exponential factor, and reaction model, as well as thermodynamic parameters to gather the required fundamental information for the design, construction, and operation of a pilot-scale reactor for the pyrolysis this lignocellulosic residue. Results indicate a biomass of low moisture and ash content and a high volatile matter content (≥70%), making BCS a potential candidate for obtaining various bioenergy products. Average apparent activation energies obtained from different methods (KAS, FWO and SK) were consistent in value (~123.8 kJ/mol). The pre-exponential factor from the Kissinger method ranged from 105 to 1014 min-1 for the highest pyrolytic activity stage, indicating a high-temperature reactive system. The thermodynamic parameters revealed a small difference between EA and ∆H (5.2 kJ/mol), which favors the pyrolysis reaction and indicates the feasibility of the energetic process. According to the analysis of the reaction models (master plot method), the pyrolytic degradation was dominated by a decreasing reaction order as a function of the degree of conversion. Moreover, BCS has a relatively high calorific value (14.9 MJ/kg) and a relatively low average apparent activation energy (122.7 kJ/mol) from the Starink method, which makes this biomass very suitable to be exploited for value-added energy production.

Neuralgia del glosofaríngeo izquierdo: una patología poco frecuente. Un reporte de caso

La neuralgia del glosofaríngeo es una patología rara donde hay dolor agudo y punzante en la fosa amigdalina, ángulo de la mandíbula y base de la lengua. Su principal causa es la compresión neurovascular la cual se puede diagnosticar con una resonancia cerebral. Su manejo es médico, principalmente; con fármacos, especialmente, carbamazepina y oxcarbazepina; y si no hay respuesta, va a cirugía mediante descompresión microvascular e interposición de material blando (politetrafluoroetileno), con o sin transección del IX par craneal. Se presenta el caso de una mujer de 64 años, hipertensa controlada, con dolor característico, que con 5 fármacos antineuropáticos y 1 derivado de opioides no cedía el dolor. La resonancia cerebral con secuencia FIESTA muestra una compresión neurovascular del IX PC con la PICA izquierda. Se le realiza descompresión microvascular del IX PC, con resolución de la sintomatología y sin recurrencia, saliendo de alta pronto. Se concluye que el manejo quirúrgico de esta patología en casos refractarios al tratamiento médico es una opción con buenas tasas de éxito y baja morbilidad.

Glossopharyngeal neuralgia is a rare pathology, with a sharp and stabbing pain in the tonsillar fossa, angle of the jaw and base of the tongue. Its main etiology is neurovascular compression, which can be diagnosed with a brain MRI. Its management is mainly medical with drug, especially carbamazepine and oxcarbazepine, and if there is no response, surgery is performed through microvascular decompression and interposition of soft material (polytetrafluoroethylene) with or without transection of IX cranial nerve. We present the case of a 64-year-old woman, with controlled hypertension, with classic pain, who did not relieve pain with 5 antineuropathic drugs and 1 opioid derivative. Brain MRI with FIESTA sequence shows a neurovascular compression of the glossopharyngeal nerve with the left PICA. Microvascular decompression of the glossopharyngeal nerve was performed, with resolution of the symptoms and without recurrence, and she was discharged soon. We concluded that the surgical management of this pathology in refractory cases to medical treatment is an option with good success rates and low morbidity.

Velocidad al comer en personas con normopeso y sobrepeso-obesidad: un análisis experimental / Eating speed in people with normal-weight and overweight-obese: An experimental analysis

Resumen La obesidad se ha posicionado como uno de los principales problemas de salud pública en México. Su estudio involucra el análisis de la conducta alimentaria (CA) y de algunos de sus parámetros, como la velocidad al comer (VC). El objetivo de este trabajo fue comparar la VC, tamaño y número de mordiscos, número y patrón de masticaciones que realizan personas con normopeso (n = 5) y sobrepeso-obesidad (n = 4). Mediante un diseño cuasiexperimental de una sola evaluación, los participantes fueron video-grabados mientras comían una rebana de pizza (90 gramos). Se encontraron diferencias significativas en el tamaño del mordisco (Z = 2.357, p = 0.016) y el número de mordiscos (Z = -2.357, p = 0.016), con un tamaño del efecto pequeño en ambos parámetros (r = 0.29), lo que indica que las personas con sobrepeso-obesidad tienen un mordisco de mayor tamaño y realizan un menor número de mordiscos. México posee un ambiente obesogénico y una prevalencia alta en enfermedades crónico-degenerativas, que comparten a la CA como una de las principales causas de su génesis, continuar con el estudio de la VC y parámetros asociados permitirá sentar las bases para el diseño de intervenciones para la prevención de sobrepeso-obesidad.

Abstract Obesity has become one of the main public health problems in Mexico. Its study involves the analysis of eating behavior (EB) and some of its parameters, such as eating speed (ES). The objective of this study was to compare the ES, size and number of bites, number and pattern of chewing performed by normal-weight (n = 5) and overweight-obese (n = 4) individuals. Using a single-assessment quasi-experimental design, participants were videotaped while eating a slice of pizza (90 grams). Significant differences were found in bite size (Z = 2.357, p = 0.016) and number of bites (Z = -2.357, p = 0.016), with a small effect size in both parameters (r = 0.29), indicating that overweight-obese individuals have a larger bite size and take a smaller number of bites. Mexico has an obesogenic environment and a high prevalence of chronic degenerative diseases, which share EB as one of the main causes of their genesis; continuing with the study of ES and associated parameters will allow us to lay the foundations for the design of interventions for the prevention of overweight-obesity.

Photophysical Properties of BODIPY Derivatives for the Implementation of Organic Solar Cells: A Computational Approach.

Solar cells based on organic compounds are a proven emergent alternative to conventional electrical energy generation. Here, we provide a computational study of power conversion efficiency optimization of boron dipyrromethene (BODIPY) derivatives by means of their associated open-circuit voltage, short-circuit density, and fill factor. In doing so, we compute for the derivatives' geometrical structures, energy levels of frontier molecular orbitals, absorption spectra, light collection efficiencies, and exciton binding energies via density functional theory (DFT) and time-dependent (TD)-DFT calculations. We fully characterize four D-π-A (BODIPY) molecular systems of high efficiency and improved J sc that are well suited for integration into bulk heterojunction (BHJ) organic solar cells as electron-donor materials in the active layer. Our results are twofold: we found that molecular complexes with a structural isoxazoline ring exhibit a higher power conversion efficiency (PCE), a useful result for improving the BHJ current, and, on the other hand, by considering the molecular systems as electron-acceptor materials, with P3HT as the electron donor in the active layer, we found a high PCE compound favorability with a pyrrolidine ring in its structure, in contrast to the molecular systems built with an isoxazoline ring. The theoretical characterization of the electronic properties of the BODIPY derivatives provided here, computed with a combination of ab initio methods and quantum models, can be readily applied to other sets of molecular complexes to hierarchize optimal power conversion efficiency.

Knowledge about COVID-19, coping and resilience in Mexican women: comparison by stress levels / Conocimiento de la COVID- 19, afrontamiento y resiliencia en mujeres mexicanas: comparación por niveles de estrés

ABSTRACT Background: The psychosocial effects derived from the COVID-19 pandemic have represented a challenge for the population worldwide. Stress is a frequent problem reported by women, impacting the strategies they use to deal with problems in daily life and their ability to recover from this critical phenomenon. Objective: The objective of this study was to evaluate the relationship between stress levels, knowledge about COVID -19, ways of coping, and resilience in women. Method: A non-experimental, cross-sectional, and correlational study was carried out in a group of 386 Mexican women through a format that was distributed on social networks. Results: The data suggest that the higher the level of knowledge about COVID-19, the greater the perceived stress. High stress is positively and statistically significantly related to coping style, denial (r = .245; q = .20) and cognitive-reflective analysis (r = .303; q= .21). Low levels of stress are negatively and statistically significantly associated with a weak effect size with factors like social competence (r= -.198; q= .11) and family support (r = -. 227; q = .16). Conclusion: Stress affects women considerably due to work overload and interpersonal factors. This study offers the possibility of knowing the emotional state of women in times of COVID-19.

RESUMEN Introducción: Las afectaciones psicosociales derivadas de la pandemia por COVID-19 han representado un reto para la población a nivel mundial. El estrés es uno de los problemas emocionales mayormente reportados en las mujeres, impactando en las estrategias que emplean para enfrentar los problemas de la vida cotidiana y su capacidad de recuperarse ante este fenómeno crítico. Objetivo: El objetivo de este estudio fue evaluar la relación entre los niveles de estrés, el conocimiento sobre la COVID -19, los estilos de afrontamiento y la resiliencia en mujeres. Método: Se realizó un estudio no experimental, transversal y correlacional en el que participaron 386 mujeres mexicanas las cuales respondieron un formato que se diseminó en redes sociales. Resultados: Los datos sugieren que a mayor nivel de conocimientos sobre la COVID-19 mayor estrés percibido. El estrés elevado se relaciona de manera positiva y estadísticamente significativa con el estilo de afrontamiento, negación (r=.245; q=.20) y análisis cognitivo-reflexivo (r=.303; q=.21). Niveles bajos de estrés se asocian de forma negativa, estadísticamente significativa y con un tamaño del efecto débil con las variables competencia social (r=-.198; q=.11) y apoyo familiar (r=-.227; q=.16). Conclusiones: El estrés afecta considerablemente a las mujeres debido a la sobrecarga de trabajo y a factores interpersonales. Este estudio ofrece la posibilidad de conocer el estado emocional de las mujeres en tiempos de la COVID-19.

Terapia Cognitivo-Conductual sobre la adherencia terapéutica y conducta alimentaria en personas adultas mayores: una revisión sistemática / Cognitive-Behavioral Therapy on therapeutic adherence and eating behavior in elderly: a systematic review

Resumen La diabetes mellitus (DM) es uno de los principales padecimientos en población adulta. Se dice que en México el 47.7% de personas adultas mayores (PAM) viven con este padecimiento, razón por la cual resulta indispensable conocer las investigaciones psicológicas centradas en mejorar el estado de salud y la adherencia al tratamiento médico en este grupo etario que va en aumento debido a la transición demográfica. El objetivo de esta revisión sistemática fue reunir los estudios que den cuenta de la eficacia de la Terapia Cognitivo-Conductual sobre la adherencia terapéutica y la conducta alimentaria en PAM con DM tipo 2. La búsqueda se realizó por medio de la estrategia PIO en siete bases de datos (Pubmed, PsycINFO, Scopus, PsycArticles, SciELO, Dialnet y Redalyc). Se encontraron 4,088 estudios, de los cuales sólo 11 cumplieron los criterios de inclusión. Los resultados revelan que este tipo de intervenciones son eficaces para favorecer conductas de adherencia al tratamiento, produciendo cambios significativos en la dieta, HbA1C y colesterol HDL, a pesar de que originalmente no fueron diseñadas para PAM y aun cuando las muestras de participantes fueron heterogéneas. Resulta evidente la carencia de tratamientos diseñados exclusivamente para PAM con DM, además de no considerar en el tratamiento variables como años con el diagnóstico, conducta alimentaria, funcionalidad, comorbilidades, escolaridad, apoyo social y nivel socioeconómico.

Abstract Diabetes mellitus (DM) is one of the primary diseases in the adult population. It is said that in Mexico 47.7% of older adults (OA) live with this condition, which is why it is essential to know psychological research focused on improving health status and adherence to medical treatment in this age group that is increasing due to the demographic transition. The aim of this systematic review was to gather the studies that account for the efficacy of Cognitive-Behavioral Therapy on therapeutic adherence and eating behavior in PAM with type 2 DM. The search was carried out using the PIO strategy in seven databases. data (Pubmed, PsycINFO, Scopus, PsycArticles, SciELO, Dialnet and Redalyc). 4,088 studies were found, of which only 11 met the inclusion criteria. The results reveal that this type of intervention is effective in favoring treatment adherence behaviors, producing significant changes in diet, HbA1C and HDL cholesterol, even though they were not initially designed for PAM and even when the participant samples were heterogeneous. The lack of treatments created exclusively for PAM with DM is evident, in addition to not considering treatment variables such as years since diagnosis, eating behavior, functionality, comorbidities, education, social support and socioeconomic level.

A theoretical chemistry-based strategy for the rational design of new luminescent lanthanide complexes: an approach from a multireference SOC-NEVPT2 method.

Theoretical methods of the SOC-NEVPT2 type combined with a molecular fragmentation scheme have been proven to be a powerful tool that allows explaining the luminescence sensitization mechanism in Ln(III) coordination compounds through the antenna effect. In this work, we have used this strategy to predict luminescence in a family of compounds of the Eu(R-phen)(BTA)3 type where R-phen = 5-methyl-1,10-phenanthroline (Me-phen), 5-nitro-1,10-71 phenanthroline (Nitro-phen), 4,5-diazafluoren-9-one (One-phen), or 5,6-epoxy-5,6-dihydro-1,10-72 phenanthroline (Epoxy-phen); and BTA = fluorinated ß-diketone. Possible sensitization pathways were elucidated from the energy difference between the ligand-centered triplet (3T) states and the emissive excited states of the Eu(III) fragments (Latva rules). Calculations show that the most probable mechanism occurs through the triplet state of the BTA which should be enriched by several parallel energy transfer pathways from R-phen substituents. The complexes were synthesized and structurally characterized by X-ray crystallography and various other physicochemical and spectroscopic methods to realize their optical properties and energy transfer pathways from dual antennae. Experimental results were in good agreement with the theoretical predictions, which reinforces the predictive power of the used theoretical methodology.

Whole Genome Sequencing Links Mycobacterium bovis From Cattle, Cheese and Humans in Baja California, Mexico.

Mycobacterium bovis causes tuberculosis (TB) in cattle, which in turn can transmit the pathogen to humans. Tuberculosis in dairy cattle is of particular concern where the consumption of raw milk and dairy products is customary. Baja California (BCA), Mexico, presents high prevalence of TB in both cattle and humans, making it important to investigate the molecular epidemiology of the disease in the region. A long-term study was undertaken to fully characterize the diversity of M. bovis genotypes circulating in dairy cattle, cheese and humans in BCA by whole-genome sequencing (WGS). During a 2-year period, 412 granulomatous tissue samples were collected from local abattoirs and 314 cheese samples were purchased from local stores and vendors in BCA and sent to the laboratory for mycobacterial culture, histology, direct PCR and WGS. For tissue samples M. bovis was recovered from 86.8%, direct PCR detected 90% and histology confirmed 85.9% as mycobacteriosis-compatible. For cheese, M. bovis was recovered from 2.5% and direct PCR detected 6% of the samples. There was good agreement between diagnostic tests. Subsequently, a total of 345 whole-genome SNP sequences were obtained. Phylogenetic analysis grouped these isolates into 10 major clades. SNP analysis revealed putative transmission clusters where the pairwise SNP distance between isolates from different dairies was ≤3 SNP. Also, human and/or cheese isolates were within 8.45 (range 0-17) and 5.8 SNP (range 0-15), respectively, from cattle isolates. Finally, a comparison between the genotypes obtained in this study and those reported previously suggests that the genetic diversity of M. bovis in BCA is well-characterized, and can be used to determine if BCA is the likely source of M. bovis in humans and cattle in routine epidemiologic investigations and future studies. In conclusion, WGS provided evidence of ongoing local transmission of M. bovis among the dairies in this high-TB burden region of BCA, as well as show close relationships between isolates recovered from humans, cheese, and cattle. This confirms the need for a coordinated One Health approach in addressing the elimination of TB in animals and humans. Overall, the study contributes to the knowledge of the molecular epidemiology of M. bovis in BCA, providing insight into the pathogen's dynamics in a high prevalence setting.

Selenophene-Based Hole-Transporting Materials for Perovskite Solar Cells.

Two novel and simple donor-π-bridge-donor (D-π-D) hole-transporting materials (HTMs) containing two units of the p-methoxytriphenylamine (TPA) electron donor group covalently bridged by means of the 3,4-dimethoxyselenophene spacer through single and triple bonds are reported. The optoelectronic and thermal properties of the new selenium-containing HTMs have been determined using standard experimental techniques and theoretical density functional theory (DFT) calculations. The selenium-based HTMs have been incorporated in mesoporous perovskite solar cells (PSCs) in combination with the triple-cation perovskite [(FAPbI3 )0.87 (MAPbBr3 )0.13 ]0.92 [CsPbI3 ]0.08 . Limited values of power conversion efficiencies, up to 13.4 %, in comparison with the archetype spiro-OMeTAD (17.8 %), were obtained. The reduced efficiencies showed by the new HTMs are attributed to their poor film-forming ability, which constrains their photovoltaic performance due to the appearance of structural defects (pinholes).

Chitosan performance during Paralytic Shellfish Toxins (PST) depuration of Mytilus chilensis exposed to Alexandrium catenella.

Blooms of the dinoflagellate Alexandrium catenella, which produces Paralytic Shellfish Toxins (PST), generate serious socio-economic consequences for mariculture in Chile, especially for the production of Mytilus chilensis and other bivalves. Palliative strategies, such as the depuration of mussels in enriched water with chitosan offer encouraging prospects against the advance of contaminated areas and toxin persistence. Adult mussels were fed with A. catenella for 20 days and then were allowed to depurate using chitosan as facilitator, for the same period. Intoxicated mussels showed a reduction in feeding activity and rapid PST accumulation in 20 days (C = 451.5t + 1,673.6, R2 = 0.55 p = 0.008). Not enough evidence was found to indicate a positive effect of chitosan in mussel depuration after 20 days (C = -311.1t + 8,462.4, R2 = 0.8 p = 0.001). At the end of the study, toxicity was higher than 800 µg STX eq kg-1. C2 and GTX4 analogues were the most abundant in the dinoflagellate strain, while C2 and C1 were the most accumulated in mussels. The presence of C1 was notorious during depuration, as the persistence of GTX2,3. GTX5 was only detected in A. catenella, while STX was only present in mussels. Mussel sensitivity to the presence of the toxic dinoflagellate was observed in the present study. The biotransformation, selective elimination and epimerization processes were deduced from intoxication and depuration experiments.

Azatruxene-Based, Dumbbell-Shaped, Donor-π-Bridge-Donor Hole-Transporting Materials for Perovskite Solar Cells.

Three novel donor-π-bridge-donor (D-π-D) hole-transporting materials (HTMs) featuring triazatruxene electron-donating units bridged by different 3,4-ethylenedioxythiophene (EDOT) π-conjugated linkers have been synthesized, characterized, and implemented in mesoporous perovskite solar cells (PSCs). The optoelectronic properties of the new dumbbell-shaped derivatives (DTTXs) are highly influenced by the chemical structure of the EDOT-based linker. Red-shifted absorption and emission and a stronger donor ability were observed in passing from DTTX-1 to DTTX-2 due to the extended π-conjugation. DTTX-3 featured an intramolecular charge transfer between the external triazatruxene units and the azomethine-EDOT central scaffold, resulting in a more pronounced redshift. The three new derivatives have been tested in combination with the state-of-the-art triple-cation perovskite [(FAPbI3 )0.87 (MAPbBr3 )0.13 ]0.92 [CsPbI3 ]0.08 in standard mesoporous PSCs. Remarkable power conversion efficiencies of 17.48 % and 18.30 % were measured for DTTX-1 and DTTX-2, respectively, close to that measured for the benchmarking HTM spiro-OMeTAD (18.92 %), under 100 mA cm-2 AM 1.5G solar illumination. PSCs with DTTX-3 reached a PCE value of 12.68 %, which is attributed to the poorer film formation in comparison to DTTX-1 and DTTX-2. These PCE values are in perfect agreement with the conductivity and hole mobility values determined for the new compounds and spiro-OMeTAD. Steady-state photoluminescence further confirmed the potential of DTTX-1 and DTTX-2 for hole-transport applications as an alternative to spiro-OMeTAD.

Synthesis, photophysical properties and theoretical studies of new bis-quinolin curcuminoid BF2-complexes and their decomplexed derivatives.

This paper presents the synthesis and characterization of two series of new bis-quinolin curcuminoid BF2-complexes 11 and their respective decomplexed bis-quinolin curcuminoid derivatives 12, in an attempt to understand their optical properties. The synthesized compounds showed interesting fluorescent characteristics in both solution and in solid-state. The characteristic of the electronic transitions involved in these systems were measured via Uv-vis spectroscopy and fluorescence spectroscopy. Results revealed that the absorption and emission bands are dependent of the structure of compounds 11 and 12 but also of the type of substituent, even showing a push-pull behavior in those derivatives substituted with methyl group. These findings were also confirmed through computational calculations at DFT level via simulations of the Uv-vis spectra and determining the topology of the border orbitals responsible for light absorption.

Combined effects of warming and freshening on the physiological energetics of the edible whelk Trophon geversianus.

The interacting effects of climate change pressures and human use of natural resources are increasingly affecting marine biodiversity. Variations in key abiotic factors such as temperature and salinity may therefore negatively influence marine organisms that are already threatened by intensive fisheries. Herein, we tested the hypothesis that future ocean warming and freshening will affect the fitness and survival of the overexploited snail Trophon geversianus in Southern Patagonia. To test this hypothesis, we investigated the effect of a 50 day incubation period of five temperatures (1, 5, 9, 12 and 15 °C) and two salinities (25 and 30 psu), (which correspond to current and projected conditions for Antarctic and Sub-Antarctic regions), on the physiological energetics (ingestion rate, absorption efficiency, oxygen uptake and scope for growth (SFG)) of the edible whelk T. geversianus. Our results showed no significant effects for salinity or the combination of temperature and salinity on T. geversianus bioenergetics. On the contrary, incubation at low temperatures (1 and 5 °C) was shown to affect the ingestion rate, absorption efficiency, oxygen uptake and SFG for T. geversianus, whereas for specimens incubated at 12 and 15 °C, physiological rates remained similar to control. Our data suggests that T. geversianus might be robust to warming and future variations of salinity, but longer term experiments are needed to ensure that no reduction of performance will occur after an extended incubation time from an increase in temperature.

Trophic transfer of paralytic shellfish toxin (PST): Physiological and reproductive effects in the carnivorous gastropod Acanthina monodon (Pallas, 1774).

Harmful algal blooms can adversely affect different levels of the trophic chain, from primary consumers, such as bivalve molluscs, to higher links such as large fish, birds and mammals, including humans. Among secondary consumers, it has been described that carnivorous gastropods can accumulate these toxins when they prey on bivalves that have been exposed to toxic microalgae; these could also harm human health. In Chile, frequent events of harmful algal blooms caused by the dinoflagellate Alexandrium catenella have been described. This organism produces paralytic shellfish toxin (PST) which has been identified in some carnivorous gastropods. The objective of this research was to identify the physiological and reproductive response of the carnivorous gastropod Acanthina monodon fed on the Mytilid Perumytilus purpuratus, which had previously been maintained on a diet containing PST. Specimens of A. monodon showed a decrease in ingestion and absorption rate when they consumed PST indirectly through their diet. The oxygen consumption rate was also affected by the diet-time interaction. The variations of these parameters were reflected in the scope for growth, since the available energy was lower in gastropods exposed to toxic diet. Consumption of PST had a negative effect on the reproduction of A. monodon, since intoxicated adults presented lower egg-masses and delayed start of oviposition. We observed a delay in the development of the embryos inside the capsules, and a lower number of hatched juveniles, although these few juveniles from intoxicated parents accomplished higher growth rates during the next 6 months. We may therefore suggest that toxin transfer, from harmful microalgae through the trophic chain, can generate deleterious effects on the physiological energetics of the organisms that consume them, affecting their reproductive capacity and early ontogenetic development.

Accumulation and biotransformation dynamics of the neurotoxic complex, saxitoxin, in different life stages of Ostrea chilensis.

The neurotoxic complex saxitoxin, is a group of marine toxins that historically has significantly impacted human health and the ability to utilize marine resources. A steady increase in the distribution and intensity of Alexandrium catenella blooms in Chile, and around the world, has caused major ecological and socioeconomic impacts, putting this type of dinoflagellate, and its toxicity, in the spotlight. Ostrea chilensis is a commercially and ecologically important resource harvested from wild populations and farmed in centers of southern Chile, where it is exposed to large harmful algal blooms of the type that can cause paralysis in humans. This study contributes to our understanding about the transfer of toxins from A. catenella cells to juvenile and adult Ostrea chilensis by tracking transformations of the neurotoxic complex until it reaches its most stable molecular form in the intracellular environment of O. chilensis tissues. These biotransformations are different in O. chilensis juveniles and adults, indicating a differentiated response for these two life stages of this bivalve species. These studies can be used for similar analyses in other ecologically and commercially important species of filter feeding organisms, providing greater understanding of the specific interactions of bivalves in scenarios of toxic dinoflagellate proliferations (e.g. A. catenella blooms).

Ocean acidification exacerbates the effects of paralytic shellfish toxins on the fitness of the edible mussel Mytilus chilensis.

High latitudes are considered particularly vulnerable to ocean acidification, since they are naturally low in carbonate ions. The edible mussel Mytilus chilensis is a common calcifier inhabiting marine ecosystems of the southern Chile, where culturing of this species is concentrated and where algal blooms produced by the toxic dinoflagellate A. catenella are becoming more frequent. Juvenile Mytilus chilensis were exposed to experimental conditions simulating two environmental phenomena: pCO2 increase and the presence of paralytic shellfish toxins (PST) produced by the dinoflagellate Alexandrium catenella. Individuals were exposed to two levels of pCO2: 380 µatm (control condition) and 1000 µatm (future conditions) over a period of 39 days (acclimation), followed by another period of 40 days exposure to a combination of pCO2 and PST. Both factors significantly affected most of the physiological variables measured (feeding, metabolism and scope for growth). However, these effects greatly varied over time, which can be explained by the high individual variability described for mussels exposed to different environmental conditions. Absorption efficiency was not affected by the independent effect of the toxic diet; however, the diet and pCO2 interaction affected it significantly. The inhibition of the physiological processes related with energy acquisition by diets containing PST, may negatively impact mussel fitness, which could have important consequences for both wild and cultured mussel populations, and thus, for socioeconomic development in southern Chile.

Optical and Electronic Properties of Molecular Systems Derived from Rhodanine.

Push-pull functional compounds consisting of dicyanorhodanine derivatives have attracted a lot of interest because their optical, electronic, and charge transport properties make them useful as building blocks for organic photovoltaic implementations. The analysis of the frontier molecular orbitals shows that the vertical transitions of electronic absorption are characterized as intramolecular charge transfer; furthermore, we show that the analyzed compounds exhibit bathochromic displacements when comparing the presence (or absence) of solvent as an interacting medium. In comparison with materials defined by their energy of reorganization of electrons (holes) as electron (hole) transporters, we find a transport hierarchy whereby the molecule ( Z)-2-(1,1-dicyanomethylene)-5-[(4-dimethylamino)benzylidene]-1,3-thiazol-4 is better at transporting holes than molecule ( Z)-2-(1,1-dicyanomethylene)-5-(tetrathiafulvalene-2-ylidene)-1,3-thiazol-4.