Highly pathogenic avian influenza H5N1 virus infections in pinnipeds and seabirds in Uruguay: Implications for bird-mammal transmission in South America.

The highly pathogenic avian influenza viruses of clade 2.3.4.4b have caused unprecedented deaths in South American wild birds, poultry, and marine mammals. In September 2023, pinnipeds and seabirds appeared dead on the Uruguayan Atlantic coast. Sixteen influenza virus strains were characterized by real-time reverse transcription PCR and genome sequencing in samples from sea lions (Otaria flavescens), fur seals (Arctocephalus australis), and terns (Sterna hirundinacea). Phylogenetic and ancestral reconstruction analysis showed that these strains have pinnipeds most likely as the ancestral host, representing a recent introduction of clade 2.3.4.4b in Uruguay. The Uruguayan and closely related strains from Peru (sea lions) and Chile (sea lions and a human case) carry mammalian adaptative residues 591K and 701N in the viral polymerase basic protein 2 (PB2). Our findings suggest that clade 2.3.4.4b strains in South America may have spread from mammals to mammals and seabirds, revealing a new transmission route.

Revisiting the role of octahedral symmetry in the interpretation of spectroscopic properties of [OsF6]2- and PtF6 complexes.

The electronic structure of [OsF6]2- and PtF6 complexes was studied by means of CASSCF/NEVPT2 multiconfigurational calculations, including spin-orbital coupling, which is very relevant in the case of these metals. From these calculations, it is possible to establish that in the octahedral symmetry (Oh), the ground state is non-magnetic (Jeff = 0) because of the strong ligand field, and the interaction with paramagnetic excited states is almost negligible, resulting in a non-magnetic behavior, which is in agreement with the experimental evidence.

Sustainable Zeolite-Silver Nanocomposites via Green Methods for Water Contaminant Mitigation and Modeling Approaches.

This study explores cutting-edge and sustainable green methodologies and technologies for the synthesis of functional nanomaterials, with a specific focus on the removal of water contaminants and the application of kinetic adsorption models. Our research adopts a conscientious approach to environmental stewardship by synergistically employing eco-friendly silver nanoparticles, synthesized using Justicia spicigera extract as a biogenic reducing agent, in conjunction with Mexican zeolite to enhance contaminant remediation, particularly targeting Cu2+ ions. Structural analysis, utilizing X-ray diffraction (XRD) and high-resolution scanning and transmission electron microscopy (TEM and SEM), yields crucial insights into nanocomposite structure and morphology. Rigorous linear and non-linear kinetic models, encompassing pseudo-first order, pseudo-second order, Freundlich, and Langmuir, are employed to elucidate the kinetics and equilibrium behaviors of adsorption. The results underscore the remarkable efficiency of the Zeolite-Ag composite in Cu2+ ion removal, surpassing traditional materials and achieving an impressive adsorption rate of 98% for Cu. Furthermore, the Zeolite-Ag composite exhibits maximum adsorption times of 480 min. In the computational analysis, an initial mechanism for Cu2+ adsorption on zeolites is identified. The process involves rapid adsorption onto the surface of the Zeolite-Ag NP composite, followed by a gradual diffusion of ions into the cavities within the zeolite structure. Upon reaching equilibrium, a substantial reduction in copper ion concentration in the solution signifies successful removal. This research represents a noteworthy stride in sustainable contaminant removal, aligning with eco-friendly practices and supporting the potential integration of this technology into environmental applications. Consequently, it presents a promising solution for eco-conscious contaminant remediation, emphasizing the utilization of green methodologies and sustainable technologies in the development of functional nanomaterials.

Spreading of the High-Pathogenicity Avian Influenza (H5N1) Virus of Clade 2.3.4.4b into Uruguay.

BACKGROUND: Avian influenza viruses (genus Alphainfluenzavirus, family Orthomyxoviridae) infect avian and mammal hosts. In 2022, the high pathogenicity avian influenza virus (H5N1) spread to South America, resulting in the loss of thousands of wild birds, including endangered species, and severely impacting the global poultry industry. OBJECTIVES: We analyzed the complete genomes of influenza viruses obtained from wild birds and backyard poultry in Uruguay between February and May 2023. METHODS: Twelve complete genomes were obtained in 2023 from cloacal swabs using Illumina sequencing. Genomes were phylogenetically analyzed with regional and global strains. FINDINGS: The identified strains have multiple basic amino acids at the hemagglutinin cleavage sites, which is typical for highly pathogenic strains. The Uruguayan viruses belonged to hemagglutinin clade 2.3.4.4b of the H5N1 subtype. A reassortment in North America has resulted in some segments of South American strains being of Eurasian or North American origins. The Uruguayan viruses shared a common ancestor with South American strains from Argentina and Chile. The influenza viruses displayed a spatiotemporal divergence pattern rather than being host-specific. MAIN CONCLUSIONS: The arrival of the 2.3.4.4b clade in Uruguay may have been mediated by birds that acquired the virus from Argentine and Chilean waterfowl migrating in the Pacific Flyway.

Anti-Inflammatory Chilean Endemic Plants.

Medicinal plants have been used since prehistoric times and continue to treat several diseases as a fundamental part of the healing process. Inflammation is a condition characterized by redness, pain, and swelling. This process is a hard response by living tissue to any injury. Furthermore, inflammation is produced by various diseases such as rheumatic and immune-mediated conditions, cancer, cardiovascular diseases, obesity, and diabetes. Hence, anti-inflammatory-based treatments could emerge as a novel and exciting approach to treating these diseases. Medicinal plants and their secondary metabolites are known for their anti-inflammatory properties, and this review introduces various native Chilean plants whose anti-inflammatory effects have been evaluated in experimental studies. Fragaria chiloensis, Ugni molinae, Buddleja globosa, Aristotelia chilensis, Berberis microphylla, and Quillaja saponaria are some native species analyzed in this review. Since inflammation treatment is not a one-dimensional solution, this review seeks a multidimensional therapeutic approach to inflammation with plant extracts based on scientific and ancestral knowledge.

Continuing professional development challenges in a rural setting: A mixed-methods study.

INTRODUCTION: Health professionals in rural settings encounter a wide range of medical conditions requiring broad knowledge for their clinical practice. This creates the need for ongoing continuing professional development (CPD). In this study, we explored the barriers that health professionals in a rural healthcare context faced participating in CPD activities and their preferences regarding educational strategies to overcome these challenges. METHODS: This mixed-methods (exploratory sequential) study in a community hospital in rural Mexico includes 22 interviews, 3 focus groups, 40 observational hours, and a questionnaire of healthcare staff. RESULTS: Despite low engagement with CPD activities (67% not motivated), all participants expressed interest and acknowledged the importance of learning for their practice. Barriers to participating include a disparity between strategies used (lecture-based) and their desire for practical learning, institutional barriers (poor leadership engagement, procedural flaws, and lack of resources), and collaboration barriers (adverse interprofessional education environment, ineffective teamwork, and poor communication). Additional barriers identified were inconvenient scheduling of sessions (75%), inadequate classrooms (65%), high workload (60%), ineffective speakers (60%), and boring sessions (55%). Participants' preferred learning strategies highlighted activities relevant to their daily clinical activities (practical workshops, simulations, and case analysis). The questionnaire had an 18% response rate. DISCUSSION: The barriers to CPD in this rural setting are multifactorial and diverse. A strong interest to engage in context-specific active learning strategies highlighted the need for leadership to prioritize interprofessional education, teamwork, and communication to enhance CPD and patient care. These results could inform efforts to strengthen CPD in other rural contexts.

Effects of resistance exercise and dance in the functionality of lower limbs in the older adult of INAPAM´s senior clubs / Efectos del ejercicio de resistencia y baile en la funcionalidad de miembros inferiores en el adulto mayor de clubes de ancianos INAPAM / Efeitos do exercício físico e da dança a funcionalidade dos membros inferiores em idosos dos clubes seniores do INAPAM / Effets de la résistance et exercice de danse dans la fonctionnalité des membres inférieurs chez les personnes âgées,des clubs seniors de l'INAPAM

Abstract Objective To determine the effect of resistance exercise routine and dancing in the lower limbs of no institutionalized elderly, cognitively intact, functional for basic activities of daily living without falling risks. Material and Methods A quasi-experimental study, the effect of an intervention on a single group, consisting of 26 persons aged 60 AM considering criteria of inclusion and non-inclusion was determined. The Short Portable Mental Status Questionnaire was used; Katz Scale and the Scale of Tinetti. The information obtained was analyzed in two stages, descriptive and inferential. In the first phase, frequency distribution tables and measures of central tendency and dispersion for all variables were obtained, as discussed in qualitative or quantitative variables, respectively. In the second phase, the effect of the intervention trophism comparing averages, muscle strength and arcs of movement group and individual pre- and post-intervention was evaluated. Results There was a trend for improvement in the flexibility of the hip, knee and ankle mostly knee extension remained the same, 84.61% and 80.76% right left. Left hip extension remains the same at 50% and 53.84%, the right side. Muscle strength increased overall in all muscle groups of both lower extremities. Trophism increased in diameter thighs, calves by 46% and over 50% were similar diameters, some of the older adults lost weight so their diameter decreased. Conclusions This program showed significant changes in muscle strength and range of motion in the study participants could see the significant association between dancing Zumba Gold and resistance exercises to increase muscle strength, flexibility lower extremities and increased level of activity in older adults. Exercise and physical activity are important for the positive effects that cause health and improvements in the diameter of the thighs and increased functionality of the elderly.

Resumen Objetivo Determinar el efecto de una rutina de ejercicios de resistencia y baile en miembros inferiores de adultos mayores no institucionalizados, cognitivamente íntegros, funcionales para actividades básicas de la vida diaria, sin riesgo de caídas. Material y métodos Estudio cuasi-experimental, se determinó el efecto de una intervención sobre un grupo único, constituido por 26 personas AM de 60 años considerando criterios de inclusión y de no inclusión. Se utilizó el Short Portable Mental Status Questionnaire; la Escala de Katz y la Escala de Tinetti. La información obtenida fue analizada en dos fases, descriptiva e inferencial. En la primera fase, se obtuvieron tablas de distribución de frecuencias así como medidas de tendencia central y de dispersión para todas las variables, según se trató de variables cualitativas o cuantitativas, respectivamente. En la segunda fase, se evaluó el efecto de la intervención comparando los promedios de trofismo, fuerza muscular y de arcos de movimientos, individuales y grupales pre- y post intervención. Resultados Hubo tendencia a la mejoría en la flexibilidad en cadera, rodilla y tobillo en su mayoría, la extensión de rodilla se mantuvo igual, 84.61% derecha y 80.76% izquierda. La extensión de cadera izquierda permanece igual en un 50% y 53.84%, del lado derecho. La fuerza muscular incrementó en general en todos los grupos musculares de ambas extremidades inferiores. El trofismo de muslos aumentó en su diámetro, las pantorrillas en un 46% y más del 50% mantuvieron diámetros similares Algunos de los AM bajaron de peso, por lo tanto sus diámetros disminuyeron. Conclusiones Este programa mostró modificaciones significativas en la fuerza muscular y rangos de movimientos en los participantes del estudio, se pudo ver la asociación importante que existe entre el baile de Zumba Gold y Ejercicios de Resistencia con el incremento de la fuerza muscular, flexibilidad de las extremidades inferiores y el incremento en el nivel de la actividad en los adultos mayores. El ejercicio y la actividad física son importantes, por los efectos positivos que causan sobre la salud y la mejoría en el diámetro de los muslos y el aumento en la funcionalidad del adulto mayor.

Resumo Objetivo Para determinar o efeito de uma rotina de exercícios de resistência e dança nos membros inferiores de idosos não institucionalizados, cognitivamente íntegros e funcionais para atividades básicas da vida diária, sem risco de queda. Material e métodos Estudo quase experimental, determinou-se o efeito de uma intervenção sobre um único grupo, constituído por 26 pessoas AM de 60 anos considerando critérios de inclusão e não-inclusão. Utilizou-se o Short Portable Mental Status Questionnaire; a escala Katz e a escala de Tinetti. A informação obtida foi analisada em duas fases, descritiva e inferencial. Na primeira fase, foram obtidos tabelas de distribuição de frequência assim como medidas de tendência central e de dispersão para todas as variáveis, segundo se tratou de variáveis qualitativas ou quantitativas, respectivamente. Na segunda fase, avaliou-se o efeito da intervenção através da comparação da média de trofismo, força muscular e arcos de movimentos, individual, em grupo pré- e pós-intervenção. Resultados Houve uma tendência de melhora na flexibilidade do quadril, joelho e tornozelo principalmente, a extensão do joelho permaneceu a mesma, 84,61% direita e 80,76% para a esquerda. A extensão do quadril esquerdo permanece igual em um 50% e 53,84%, no lado direito. A força muscular aumentou geralmente em todos os grupos musculares de ambas as extremidades inferiores. O trofismo de coxas aumentou em diâmetro, pantorilha em um 46% e mais do 50% mantiveram diâmetros semelhantes. Alguns dos AM perderam peso, pelo que os seus diâmetros diminuíram. Conclusões Este programa mostrou mudanças significativas na força muscular e amplitude de movimento nas participantes do estudo, pôde-se ver a associação significativa que existe entre a dança Zumba Ouro e Exercícios de Resistência com o aumento da força muscular, flexibilidade das extremidades inferiores e o aumento no nível da atividade em adultos mais velhos. O exercício e a atividade física são importantes, pelos efeitos positivos que causam sobre a saúde e a melhoria do diâmetro das coxas e do aumento da funcionalidade do idoso.

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Synthesis of Au@Pt Core-Shell Nanoparticles as Efficient Electrocatalyst for Methanol Electro-Oxidation.

Bimetallic Au@Pt nanoparticles (NPs) with Pt monolayer shell are of much interest for applications in heterogeneous catalysts because of enhanced catalytic activity and very low Pt-utilization. However, precisely controlled synthesis with uniform Pt-monolayers and stability on the AuNPs seeds remain elusive. Herein, we report the controlled deposition of Pt-monolayer onto uniform AuNPs seeds to obtain Au@Pt core-shell NPs and their Pt-coverage dependent electrocatalytic activity for methanol electro-oxidation. The atomic ratio between Au/Pt was effectively tuned by varying the precursor solution ratio in the reaction solution. The morphology and atomic structure of the Au@Pt NPs were analyzed by high-resolution scanning transmission electron microcopy (HR-STEM) and X-ray diffraction (XRD) techniques. The results demonstrated that the Au@Pt core-shell NPs with Pt-shell thickness (atomic ratio 1:2) exhibit higher electrocatalytic activity for methanol electro-oxidation reaction, whereas higher and lower Pt ratios showed less overall catalytic performance. Such higher catalytic performance of Au@Pt NPs (1:2) can be attributed to the weakened CO binding on the Pt/monolayers surface. Our present synthesis strategy and optimization of the catalytic activity of Au@Pt core-shell NPs catalysts provide promising approach to rationally design highly active catalysts with less Pt-usage for high performance electrocatalysts for applications in fuel cells.

Electrochemical Study of a Hybrid Polymethyl Methacrylate Coating using SiO2 Nanoparticles toward the Mitigation of the Corrosion in Marine Environments.

The demand for hydrophobic polymer-based protective coatings to impart high corrosion resistance has increased recently. The increase of the hydrophobicity in a hybrid coating is a new challenge, for that reason and in order to protect a metallic surface of oxidant agents, a poly (methyl methacrylate) (PMMA) coating with the addition of a different amount of silicon dioxide (SiO2) was developed. The hybrid coating was applied on a sample of stainless steel AISI 304 by the dip-coating method. The characterization of the coatings was determined by electrochemical impedance spectroscopy and with a scanning electrochemical microscopy. The best coatings were PMMA and PMMA + SiO2 0.01% that exhibits a real impedance in the Nyquist diagram of 760 and 427,800 MΩ⋅cm2, respectively, and the modulus of the real impedance in the Bode diagram present values of 2.2 × 108 and 3.3 × 108 Ω⋅cm2. Moreover, the phase angle presents constant values around 75° to 85° and 85° for the PMMA and PMMA + SiO2 0.01%, respectively. Moreover, the values of the real resistance for the PMMA + SiO2 0.01% coating present values in the order of Mega-ohms despite the coating exhibits an artificial defect in their surface. The contact angle test showed that the hydrophobicity of the hybrid PMMA + SiO2 0.01% coating is higher than that of the pure PMMA coatings. The hybrid PMMA + SiO2 coatings developed in this work are a very interesting and promising area of study in order to develop efficient products to protect metallic surfaces from corrosion phenomenon.

Rhenium (I) Complexes as Probes for Prokaryotic and Fungal Cells by Fluorescence Microscopy: Do Ligands Matter?

Re(I) complexes have exposed highly suitable properties for cellular imaging (especially for fluorescent microscopy) such as low cytotoxicity, good cellular uptake, and differential staining. These features can be modulated or tuned by modifying the ligands surrounding the metal core. However, most of Re(I)-based complexes have been tested for non-walled cells, such as epithelial cells. In this context, it has been proposed that Re(I) complexes are inefficient to stain walled cells (i.e., cells protected by a rigid cell wall, such as bacteria and fungi), presumably due to this physical barrier hampering cellular uptake. More recently, a series of studies have been published showing that a suitable combination of ligands is useful for obtaining Re(I)-based complexes able to stain walled cells. This review summarizes the main characteristics of different fluorophores used in bioimage, remarking the advantages of d6-based complexes, and focusing on Re(I) complexes. In addition, we explored different structural features of these complexes that allow for obtaining fluorophores especially designed for walled cells (bacteria and fungi), with especial emphasis on the ligand choice. Since many pathogens correspond to bacteria and fungi (yeasts and molds), and considering that these organisms have been increasingly used in several biotechnological applications, development of new tools for their study, such as the design of new fluorophores, is fundamental and attractive.

Potential to stabilize 16-vertex tetrahedral coinage-metal cluster architectures related to Au20.

DFT calculations were carried out on a series of tetrahedral 16-atom superatomic clusters having 20 or 18 jellium electrons (je) and structurally related to Au20, namely, [M16]4-/2- (M = Cu, Ag, and Au) and [M4'M12'']0/2+ (M' = Zn, Cd, Hg; M'' = Cu, Ag, Au). While the bare homonuclear 20-je species required further stabilization to be isolated, their 18-je counterparts exhibited better stability. Lowering the electron count led to structural modification from a compact structure (20-je) to a hollow sphere (18-je). Such a change could be potentially controlled by tuning redox properties. Among the 20-je heteronuclear [M4'M12''] neutral series, [Zn4Au12] appeared to meet the best stability criteria, but their 18-je relatives [M4'M12'']+, in particular [Zn4Cu12]2+ and [Cd4Au12]2+, offered better opportunities for obtaining stable species. Such species exhibit the smallest models for the M(111) surface of fcc metals, which expose designing rules towards novel high-dopant-ratio clusters as building blocks of nanostructured materials.

Classical and Quantum Mechanical Calculations of the Stacking Interaction of NdIII Complexes with Regular and Mismatched DNA Sequences.

The design of organometallic complexes used as selective intercalators to bind and react at DNA mismatch sites has concentrated efforts in the last few years. In this context, lanthanides have received attention to be employed as active optical centers due to their spectroscopic properties. Despite the fact that there are several experimental data about synthesis and DNA binding of these compounds, theoretical analyses describing their interaction with DNA are scarce. To understand the binding to regular and mismatched DNA sequences as well as to determine the effect of the intercalation on the spectroscopic properties of the complexes, a complete theoretical study going from classical to relativistic quantum mechanics calculations has been performed on some lanthanide complexes with phenanthroline derivatives synthesized and characterized herein, viz. [Nd(NO3)3(H2O)(dppz-R)] with R = H, NO2-, CN- and their [Nd(NO3)3(H2O)(dpq)] analogue, which was computationally modeled. The results were in correct agreement with the available experimental data showing that dppz complexes have higher binding affinities to DNA than dpq one and supporting the idea that these complexes are not selective to mismatch sites in the sampled time scale. Finally, the spectroscopic analysis evidence an intercalative binding mode and made possible the elucidation of the emission mechanism of these systems. This approach is proposed as a benchmark study to extend this methodology on similar systems and constitutes the first theoretical insight in the interaction between DNA and lanthanide complexes.

Abdominal Etching: Surgical Technique and Outcomes.

BACKGROUND: The ideal body is characterized by a muscular physique and defined anterior abdominal wall. Despite diet and exercise, many are unable to achieve this desired result. Liposuction with abdominal etching is used to achieve high-definition abdominal aesthetics. The etching technique is performed with liposuction in a superficial plane, to create indentures consistent with "six-pack abs," or definition of vertical abdominal lines. METHODS: The authors' abdominal etching preoperative markings, surgical technique, and postoperative care are discussed. The surgeons' experience with abdominal etching in 50 consecutive patients is reviewed, including rate of complications and patient satisfaction. RESULTS: The average patient age was 36.4 years. We had an almost equal number of men (n = 26) and women (n = 24), with an average body mass index of 26.7 kg/m. The average blood loss was 275 ml, the average tumescence was 6 liters, and the average lipoaspirate was 5 liters. There were no major complications such as fat embolus, deep venous thrombosis, or intraabdominal injury. The most common minor postoperative complications were contour irregularities (12 percent), seromas (10 percent), and hyperpigmentation (2 percent). The majority of patients were satisfied (98 percent). The average length of postoperative follow-up was 27 months. CONCLUSIONS: Abdominal etching is a safe and effective method of creating a defined anterior abdominal wall for patients who desire the muscular definition of vertical abdominal lines. Almost all of our patients reviewed were satisfied with this procedure, maintained long-term results, and had an acceptable rate of complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Molecular and Electronic Structure, and Hydrolytic Reactivity of a Samarium(II) Crown Ether Complex.

The reaction of SmI2 with dibenzo-30-crown-10 (DB30C10), followed by metathesis with [Bu4N][BPh4], allows for the isolation of [SmII(DB30C10)][BPh4]2 as bright-red crystals in good yield. Exposure of [Sm(DB30C10)]2+ to solvents containing trace water results in the conversion to the dinuclear SmIII complex, Sm2(DB30C10)(OH)2I4. Structural analysis of both complexes shows substantial rearrangement of the crown ether from a folded, Pac-Man form with SmII to a twisted conformation with SmIII. The optical properties of [SmII(DB30C10)][BPh4]2 exhibit a strong temperature dependence and change from broad-band absorption features indicative of domination by 5d states to fine features characteristic of 4f → 4f transitions at low temperatures. Examination of the electronic structure of these complexes via ab initio wave function calculations (SO-CASSCF) shows that the ground state of SmII in [SmII(DB30C10)]2+ is a 4f6 state with low-lying 4f55d1 states, where the latter states have been lowered in energy by ∼12 000 cm-1 with respect to the free ion. The decacoordination of the SmII cation by the crown ether is responsible for this alteration in the energies of the excited state and demonstrates the ability to tune the electronic structure of SmII.

Answer to Comment on article "Professionalism in physicians in a second-level hospital" / Respuesta a Comentario al artículo "Profesionalismo en médicos de un hospital de segundo nivel"

In relation to the letter to the editor on the article "Professionalism in physicians in a second-level hospital" this reply is issued.

En relación a la carta al editor sobre el artículo "Profesionalismo en médicos de segundo nivel" se emite esta réplica.

In-Situ Preparation of CdTe Quantum Dots Capped with a ß-Cyclodextrin-Epichlorohydrin Polymer: Polymer Influence on the Nanocrystal's Optical Properties.

ß-Cyclodextrin (ßCD), the less water soluble of the cyclodextrins, has been used as a capping agent in the preparation of semiconductor nanocrystals or quantum dots (QDs). Nevertheless, no reports have been found in the use of the highly water-soluble polymer of this, prepared by the crosslinking of the ßCD units with epichlorohydrin in basic medium (ßCDP). This polymer, besides to overcome the low solubility of the ßCD, increases the inclusion constant of the guest; two parameters that deserve its use as capping agent, instead of the native cyclodextrin. In the present manuscript, we afforded the in-situ aqueous preparation of cadmium telluride (CdTe) QDs capped with ßCDP. The polymer influence on the photoluminescent properties of the nanocrystals was analyzed. The ßCDP controls the nanocrystals growth during the Oswald ripening stage. Consequently, the CdTe capped ßCDP QDs showed lower Stokes-shift values, higher photoluminescent efficiency, and narrower size distribution than for nanocrystals obtained in the absence of polymer. Transmission electron microscopy (TEM) micrographs and energy dispersive X-ray spectroscopy (EDS) analysis revealed the composition and crystallinity of the CdTe QDs. This ßCDP capped CdTe QDs is a potential scaffold for the supramolecular modification of QDs surface.

New Properties of a Bioinspired Pyridine Benzimidazole Compound as a Novel Differential Staining Agent for Endoplasmic Reticulum and Golgi Apparatus in Fluorescence Live Cell Imaging.

In this study, we explored new properties of the bioinspired pyridine benzimidazole compound B2 (2,4-di-tert-butyl-6-(3H-imidazo[4,5-c]pyridine-2-yl)phenol) regarding its potential use as a differential biomarker. For that, we performed 1D 1HNMR (TOCSY), UV-Vis absorption spectra in different organic solvents, voltammetry profile (including a scan-rate study), and TD-DFT calculations that including NBO analyses, to provide valuable information about B2 structure and luminescence. In our study, we found that the B2 structure is highly stable, where the presence of an intramolecular hydrogen bond (IHB) seems to have a crucial role in the stability of luminescence, and its emission can be assigned as fluorescence. In fact, we found that the relatively large Stokes Shift observed for B2 (around 175 nm) may be attributed to the stability of the B2 geometry and the strength of its IHB. On the other hand, we determined that B2 is biocompatible by cytotoxicity experiments in HeLa cells, an epithelial cell line. Furthermore, in cellular assays we found that B2 could be internalized by passive diffusion in absence of artificial permeabilization at short incubation times (15 min to 30 min). Fluorescence microscopy studies confirmed that B2 accumulates in the endoplasmic reticulum (ER) and Golgi apparatus, two organelles involved in the secretory pathway. Finally, we determined that B2 exhibited no noticeable blinking or bleaching after 1 h of continuous exposure. Thus, B2 provides a biocompatible, rapid, simple, and efficient way to fluorescently label particular organelles, producing similar results to that obtained with other well-established but more complex methods.

Rare-Earth Metal(II) Aryloxides: Structure, Synthesis, and EPR Spectroscopy of [K(2.2.2-cryptand)][Sc(OC6 H2 tBu2 -2,6-Me-4)3 ].

The suitability of aryloxide ligands for stabilizing +2 oxidation states of Sc and Y has been examined and EPR evidence indicating the first O-donor complexes of ScII and YII has been obtained, as well as an X-ray crystal structure of a ScII aryloxide complex. The trivalent rare-earth metal aryloxide precursors, Ln(OAr')3 , 1-Ln (Ln=Sc, Y, Gd, Dy, Ho, Er; OAr'=OC6 H2 tBu2 -2,6-Me-4), were synthesized from the corresponding rare-earth metal trichlorides and LiOAr'⋅OEt2 . Reduction of THF solutions of 1-Ln with potassium graphite in the presence of 2.2.2-cryptand (crypt) yielded dark-colored solutions, 2-Ln, whose EPR spectra at 77 K are characteristic of the LnII ions: a two-line spectrum (g∥ =1.99, g□ =1.97, Aave =154 G) for 2-Y and an eight-line spectrum (gave =2.01 and Aave =291 G) for 2-Sc. Solutions of 2-Y decompose within one minute at room temperature, wheras 2-Sc persists up to 40 min at room temperature. 2-Sc was identified by X-ray crystallography as [K(crypt)][Sc(OAr')3 ], which has a trigonal-planar arrangement of oxygen-donor atoms around ScII . Analogous reductions of 1-Ln for Ln=Gd, Dy, Ho, and Er also gave dark solutions of limited stability. Theoretical analysis using time-dependent density functional theory (TD-DFT) along with complete active space self-consistent field (CASSCF) methods, and structural analysis with the Guzei ligand solid angle G-parameter method are presented.

Two New Fluorinated Phenol Derivatives Pyridine Schiff Bases: Synthesis, Spectral, Theoretical Characterization, Inclusion in Epichlorohydrin-ß-Cyclodextrin Polymer, and Antifungal Effect.

It has been reported that the structure of the Schiff bases is fundamental for their function in biomedical applications. Pyridine Schiff bases are characterized by the presence of a pyridine and a phenolic ring, connected by an azomethine group. In this case, the nitrogen present in the pyridine is responsible for antifungal effects, where the phenolic ring may be also participating in this bioactivity. In this study, we synthesized two new pyridine Schiff Bases: (E)-2-[(3-Amino-pyridin-4-ylimino)-methyl]-4,6-difluoro-phenol (F1) and (E)- 2-[(3-Amino-pyridin-4-ylimino)-methyl]-6-fluoro-phenol (F2), which only differ in the fluorine substitutions in the phenolic ring. We fully characterized both F1 and F2 by FTIR, UV-vis, 1H; 13C; 19F-NMR, DEPT, HHCOSY, TOCSY, and cyclic voltammetry, as well as by computational studies (DFT), and NBO analysis. In addition, we assessed the antifungal activity of both F1 (two fluorine substitution at positions 4 and 6 in the phenolic ring) and F2 (one fluorine substitution at position 6 in the phenolic ring) against yeasts. We found that only F1 exerted a clear antifungal activity, showing that, for these kind of Schiff bases, the phenolic ring substitutions can modulate biological properties. In addition, we included F1 and F2 into in epichlorohydrin-ß-cyclodextrin polymer (ßCD), where the Schiff bases remained inside the ßCD as determined by the ki , TGA, DSC, and SBET. We found that the inclusion in ßCD improved the solubility in aqueous media and the antifungal activity of both F1 and F2, revealing antimicrobial effects normally hidden by the presence of common solvents (e.g., DMSO) with some cellular inhibitory activity. The study of structural prerequisites for antimicrobial activity, and the inclusion in polymers to improve solubility, is important for the design of new drugs.

Theoretical Determination of Energy Transfer Processes and Influence of Symmetry in Lanthanide(III) Complexes: Methodological Considerations.

This work presents a theoretical protocol to analyze the symmetry effect on the allowed character of the transitions and to estimate the probability of energy transfer in lanthanide(III) complexes. For this purpose, a complete study was performed based on the multireference CASSCF/PT2 technique along with TDDFT, to build the energy level diagrams and determine the spectral overlap integrals, respectively. This approach was applied on a series of LnIII complexes, viz. [LnCl3(DMF)2(Dpq)]/[Ln(NO3)3(DMF)2(Dpq)], where Ln = SmIII, TbIII, ErIII/EuIII, NdIII and dpq = dipyridoquinoxaline, synthesized and characterized by Patra et al. ( Dalton Trans. 2015 , 44 ( 46 ), 19844 - 19855 ; CrystEngComm 2016 , 18 ( 23 ), 4313 - 4322 ; Inorg. Chim. Acta 2016 , 451 , 73 - 81 ). A fragmentation scheme was applied where both the ligand and the lanthanide fragments were treated separately but at the same level of theory. The symmetry analysis only partially reproduced the expected results, and a more detailed analysis of the crystal field became necessary. On the other hand, the most probable energy transfer pathways that take place in the complexes were elucidated from the energy gaps between the ligand-localized triplet state and the emitting levels of the lanthanide fragments. These gaps, which are related to the energy transfer rate, properly reproduced the trend reported experimentally for the best and worst yields. Finally, the spectral overlap integral was calculated from the emission spectra of the dpq ligand and the absorption spectra of the lanthanide fragment. The obtained values are in good agreement with the quantum yields calculated for the systems. The most remarkable aspect of this protocol was its ability to explain the emission and nonemission of the studied compounds.