Nanosilica and copper ecotoxicity in Gambusia holbrooki fish.

When silica nanoparticles (SiNP) reach the water bodies interact with the already existing pollutants in the environments. This study aimed to evaluate the ecotoxicity of SiNP under the presence/absence of Cu in mosquitofish (Gambusia holbrooki). Fish were exposed to 0, 10 and 100 mg SiNP L-1, alone or mixed with Cu (0.25 mg L-1). After 96 h, the amount of colony forming units (CFU) of bacteria living on the skin mucus was analysed, and oxidative stress, tissue damage enzymes, and neurotoxicity were evaluated. We observed a reduction in CFU when Cu was present in the media. The liver was the target organ, evidencing a decrease in tissue damage enzymatic activities, activation of the antioxidant system in all treatments, and lipid oxidative damage when the SiNP and Cu were mixed. Overall, SiNP ecotoxicity was proved, which could also be enhanced by the presence of ubiquitous elements such as metals.

Biointerfacial behavior of stallion spermatozoa adhered to hydrogel surfaces: Impact of the hydrogel chemical composition and the culture medium.

Novel soft materials based on hydrogel are proposed to enhance the selection of high-quality stallion sperm based on their adhesion capacity. The hydrogel surfaces are derived from polyacrylamide (PAAm), which is copolymerized with neutral and ionic co-monomers to modify the interfacial properties. The hydrogels undergo characterization through FTIR spectroscopy, assessment of swelling capacity, and wettability under various experimental conditions. Sperm adhesion capacity on the hydrogels is examined through several parameters including the percentage of bound sperm (%Sp) to hydrogels, tail oscillation intensity and flagellar movement. The biointerfacial properties of sperm-hydrogel systems vary based on the chemical composition of hydrogel as well as the components present in the culture medium. High %Sp and excellent metabolic activity of the spermatozoa are observed on hydrogel surfaces that possess moderate hydrophilicity. Specifically, a cationic hydrogel in BGM3 culture medium and a neutral surface in BGM3 medium supplemented with BSA exhibit favorable outcomes. Scanning Electron Microscopy (SEM) reveals the normal morphology of the head and tail in spermatozoa adhered to the hydrogel. Therefore, these hydrogel surfaces are potential materials for selecting stallion sperm with high quality, and their application could be extended to the study of other mammalian reproductive cells.

Synthesis and Evaluation of a Chitosan-Silica-Based Bone Substitute for Tissue Engineering.

Bone defects have prompted the development of biomaterial-based bone substitutes for restoring the affected tissue completely. Although many biomaterials have been designed and evaluated, the combination of properties required in a biomaterial for bone tissue engineering still poses a challenge. In this study, a chitosan-silica-based biocomposite was synthetized, and its physicochemical characteristics and biocompatibility were characterized, with the aim of exploring the advantages and drawbacks of its use in bone tissue engineering. Dynamic light scattering measurements showed that the mean hydrodynamic size of solid silica particles (Sol-Si) was 482 ± 3 nm. Scanning electron microscopy of the biocomposite showed that Sol-Si were homogenously distributed within the chitosan (CS) matrix. The biocomposite swelled rapidly and was observed to have no cytotoxic effect on the [3T3] cell line within 24 h. Biocompatibility was also analyzed in vivo 14 days post-implant using a murine experimental model (Wistar rats). The biocomposite was implanted in the medullary compartment of both tibiae (n = 12). Histologically, no acute inflammatory infiltrate or multinucleated giant cells associated to the biocomposite were observed, indicating good biocompatibility. At the tissue-biocomposite interface, there was new formation of woven bone tissue in close contact with the biocomposite surface (osseointegration). The new bone formation may be attributed to the action of silica. Free silica particles originating from the biocomposite were observed at the tissue-biocomposite interface. According to our results, the biocomposite may act as a template for cellular interactions and extracellular matrix formation, providing a structural support for new bone tissue formation. The CS/Sol-Si biocomposite may act as a Si reservoir, promoting new bone formation. A scaffold with these properties is essential for cell differentiation and filling a bone defect.

Common bile duct diameter by age groups in adult patients without bile duct pathology.

OBJECTIVE: To determine the average value of the diameter of the common bile duct by age group in adult patients without bile duct pathology. METHOD: A cross-sectional, observational, descriptive and prospective study in adults without bile duct pathology who underwent abdominal ultrasound. The internal diameter of the common bile duct was measured after questioning. In the descriptive analysis, absolute frequencies, percentages, mean and standard deviation were used in the inferential Student's t test and Pearson's correlation. RESULTS: 608 patients without bile duct pathology were included, the mean diameter of the common bile duct was 4.04 ± 1.11 mm; with a minimum of 1.9 mm and a maximum of 8.8 mm. The mean for the population under 30 years was 3.8 ± 0.87, for the 30-39 years group it was 4.27 ± 0.89, for the 40-49 years group it was 4.39 ± 0.83, for the 50-59 years 4.86 ± 1, for the 60-69 years group it was 5.4 ± 0.95, and for those over 70 years it was 6.9 ± 0.8. CONCLUSIONS: The diameter of the common bile duct in adult patients without biliary pathology is greater at older age.

OBJETIVO: Determinar el valor promedio del diámetro del conducto colédoco por grupos de edad en pacientes adultos sin patología de la vía biliar. MÉTODO: Estudio transversal, observacional, descriptivo y prospectivo en adultos sin patología de vía biliar que acudieron a la realización de ultrasonografía abdominal. Se realizó la medición del diámetro interno del colédoco después de un interrogatorio. En el análisis descriptivo se utilizaron frecuencias absolutas, porcentajes, media y desviación estándar; en el inferencial, prueba t de Student y correlación de Pearson. RESULTADOS: Se incluyeron 608 pacientes sin patología de vía biliar. La media del diámetro del colédoco fue de 4.04 ± 1.11 mm, con un mínimo de 1.9 mm y un máximo de 8.8 mm. La media para la población menor de 30 años fue de 3.84 ± 0.87, para el grupo de 30-39 años fue de 4.27 ± 0.89, para el de 40-49 años fue de 4.39 ± 0.83, para el de 50-59 años fue de 4.86 ± 1, para el de 60-69 años fue de 5.4 ± 0.95 y para el de mayores de 70 años fue de 6.9 ± 0.8. CONCLUSIONES: El diámetro del conducto colédoco en pacientes adultos sin patología biliar es mayor conforme avanza la edad.

Remarkably rapid, recent diversification of Cochemiea and Mammillaria in the Baja California, Mexico region.

PREMISE: The Cactaceae of northwestern Mexico and the southwestern United States constitute a major component of the angiosperm biodiversity of the region. The Mammilloid clade, (Cactaceae, tribe Cacteae), composed of the genera Cochemiea, Coryphantha, Cumarinia, Mammillaria, and Pelecyphora is especially species rich. We sought to understand the timing, geographical and climate influences correlated with expansion of the Mammilloid clade, through the Sonoran Desert into Baja California. METHODS: We reconstructed the historical biogeography of the Mammilloid clade, using Bayesian and maximum likelihood methods, based on a strongly supported molecular phylogeny. We also estimated divergence times, the timing of emergence of key characters, and diversification rates and rate shifts of the Mammilloid clade. RESULTS: We found that the most recent common ancestor of Cochemiea arrived in the Cape region of Baja California from the Sonoran Desert region approximately 5 million years ago, coinciding with the timing of peninsular rifting from the mainland, suggesting dispersal and vicariance as causes of species richness and endemism. The diversification rate for Cochemiea is estimated to be approximately 12 times that of the mean background diversification rate for angiosperms. Divergence time estimation shows that many of the extant taxa in Cochemiea and Baja California Mammillaria emerged from common ancestors 1 million to 200,000 years ago, having a mid-Pleistocene origin. CONCLUSIONS: Cochemiea and Mammillaria of the Baja California region are examples of recent, rapid diversification. Geological and climatic forces at multiple spatial and temporal scales are correlated with the western distributions of the Mammilloid clade.

Influence of the Near-Cortical Over-Drilling Technique on the Mechanical Behaviour of Locking Plate Constructs Applied in Maned Wolf's Femur.

OBJECTIVE: The aim of this study was to evaluate the influence of near-cortical over-drilling holes on the mechanical behaviour of locking plate constructs applied in maned wolf's femur by using mechanical testing and finite element method (FEM). STUDY DESIGN: Seven pairs of adult maned wolves (Chrysocyon brachyurus) femur bones were randomly distributed into four groups. In all groups, a 3.5 mm locking compression plate, designed with 12 combi-holes and one locked, was applied to the lateral surface of the femur. G1 (n = 4) received bicortical locking screws placed in holes 1, 3, 5, 8, 10 and 12. In G2 (n = 5), the plate was applied as used in G1, but the application of the locked screws involved the near-cortical over-drilling technique. In G3 (n = 4), the plate was applied as used in G2, but the size of the near-cortical over-drilling was larger. The combi-holes 6 and 7 were maintained over a 10 mm fracture gap without screws. All constructs were tested for failure in the axial load. The axial load was applied eccentrically to the femoral head. RESULTS: Statistical differences were observed in the maximum load with G3 > G1 and G3 > G2, and in the deflection with G2 > G1 and G2 > G3. The FEM showed the lowest total displacement of the bone-plate constructs as well as of the plate in G1 compared with G2 and G3. CONCLUSION: The near-cortical over-drilling technique used in unstable fractures induced in the maned wolf's femur showed by static axial compression test that maximum load and deflection are dependent on drill hole size induced in the near-cortex. Based on FEM, the lowest total displacement of the bone-plate constructs was observed in Group 1.

Characteristics of bacterial infections and prevalence of multidrug-resistant bacteria in hospitalized patients with liver cirrhosis in Germany.

INTRODUCTION AND OBJECTIVES: Bacterial infections are associated with a dismal prognosis in patients with liver cirrhosis. Data on their prevalence and the associated pathogen spectra in Germany are scarce. This study aimed to evaluate the impact of bacterial infections on mortality in hospitalized patients with liver cirrhosis and to analyze the prevalence of multidrug-resistant (MDR) bacteria in a German tertiary care center. PATIENTS AND METHODS: Consecutive, non-electively hospitalized patients with liver cirrhosis were enrolled in this study between 03/2019-06/2021. All patients underwent clinical, laboratory and microbiological testing to detect potential bacterial infections. Patients were followed for 30 days regarding the composite endpoint of death or liver transplantation (mortality). RESULTS: In total, 239 patients were recruited (median MELD 18). Bacterial infection was detected in 81 patients (33.9%) at study inclusion. A total of 70 patients (29.3%) developed a hospital-acquired infection. When comparing community-acquired and hospital-acquired infections, the pathogen pattern shifted from a gram-negative to a more gram-positive spectrum and showed an increase of Staphylococcus spp.. MDR bacteria were detected in seven infected patients (5.8%). 34 patients reached the composite endpoint during 30-days follow-up. In multivariable logistic regression analysis, the presence of infection during hospitalization remained independently associated with higher mortality (OR 2.522, 95% CI 1.044 - 6.091, p = 0.040). CONCLUSIONS: This study demonstrates that bacterial infections are common in hospitalized patients with liver cirrhosis in Germany and are a major determinant of short-term mortality. Our data highlight the importance of regional differences in MDR bacteria and may guide physicians' decision-making regarding calculated antibiotic treatment.

Immunotherapeutic nanoparticles: From autoimmune disease control to the development of vaccines.

The development of nanoparticles (NPs) with potential therapeutic uses represents an area of vast interest in the scientific community during the last years. Recently, the pandemic caused by COVID-19 motivated a race for vaccines creation to overcome the crisis generated. This is a good demonstration that nanotechnology will most likely be the basis of future immunotherapy. Moreover, the number of publications based on nanosystems has significantly increased in recent years and it is expected that most of these developments can go on to experimentation in clinical stages soon. The therapeutic use of NPs to combat different diseases such as cancer, allergies or autoimmune diseases will depend on their characteristics, their targets, and the transported molecules. This review presents an in-depth analysis of recent advances that have been developed in order to obtain novel nanoparticulate based tools for the treatment of allergies, autoimmune diseases and for their use in vaccines. Moreover, it is highlighted that by providing targeted delivery an increase in the potential of vaccines to induce an immune response is expected in the future. Definitively, the here gathered analysis is a good demonstration that nanotechnology will be the basis of future immunotherapy.

Influencia de un panel molecular de reacción de polimerasa en cadena múltiple en el diagnóstico o descarte de neumonía asociada a ventilación mecánica en una cohorte chilena de pacientes críticos con COVID-19 / Influence of a multiple polymerase chain reaction panel on the diagnosis or discard of ventilator-associated pneumonia in a Chilean COVID-19 critical patients cohort

INTRODUCCIÓN: La neumonía asociada a ventilación mecánica (NAVM) es frecuente en pacientes críticos con COVID-19. Su diagnóstico precoz es fundamental para su pronóstico. OBJETIVO: Demostrar la utilidad del panel FilmArray Pneumo (PFA-P) en la confirmación o descarte de NAVM en estos pacientes. MÉTODOS: Estudio retrospectivo de 71 pacientes críticos con COVID-19 con sospecha de NAVM en quienes se realizó cultivos y PFA-P para confirmación diagnóstica. Se describen las características clínicas, microbiología y mortalidad. Se define la validez y seguridad de PFA-P. RESULTADOS: El uso de FAP-P y cultivos descartó NAVM en 29 pacientes (40,8%). En 41 pacientes se confirmó NAVM y la mortalidad a 30 días fue 48,8%. Se estudiaron 48 muestras, los cultivos fueron positivos en 30 (62,5%) y se detectaron 33 bacterias, PFA-P detectó 32 de estas 33 bacterias; 37 bacterias fueron detectadas exclusivamente por PFA-P. Las bacterias prevalentes fueron Klebsiella pneumoniae (31,4%) Pseudomonas aeruginosa (21,4%) y Acinetobacter calcoaceticusbaumannii (14,2%). La sensibilidad, especificidad, valor predictor positivo y valor predictor negativo de PFA-P con respecto a cultivos fue 96,9%, 92,5%, 46,4% y 99,8, respectivamente. Un paciente tuvo NAVM por Burkholderia cepacia bacteria no detectada por FAP-P. CONCLUSIONES: La FAP-P es una técnica molecular eficaz para descartar y diagnosticar la NAVM permitiendo una suspensión rápida de los antimicrobianos o un tratamiento dirigido temprano.

BACKGROUND: Ventilator-associated pneumonia (VAP) is frequent in critical COVID-19 patients. Its early diagnosis is essential for its prognosis. AIM: To demonstrate the usefulness of the FilmArray Pneumo panel (FAP-P) in confirming or ruling out VAP in these patients. METHODS: Retrospective study of 71 critical COVID-19 patients with suspected VAP in whom cultures and FAP-P were performed for diagnostic confirmation. Clinical characteristics, microbiology and mortality are described. The validity and safety of FAP-P is defined. RESULTS: The use of FAP-P and cultures ruled out VAP in 29 patients (40.8%). In 41 patients, VAP was confirmed and the 30-day mortality was 48.8%. Forty-eight samples were studied, the cultures were positive in 30 (62.5%) and 33 bacteria were detected, FAP-P detected 32 of these 33 bacteria; 37 bacteria were exclusively detected by PFA-P. The most prevalent bacteria were Klebsiella pneumoniae (31.4%), Pseudomonas aeruginosa (21.4%) and Acinetobacter calcoaceticus-baumannii (14.2%). The sensitivity, specificity, positive predictive value and negative predictive value of FAP-P with respect to cultures were 96.9%, 92.5%, 46.4% and 99.8%, respectively. One patient had VAP due to Burkholderia cepacia bacteria not detected by FAP-P. CONCLUSIONS: FAP-P is an effective molecular technique to rule out and diagnose VAP, allowing rapid suspension of antibiotics or early targeted treatment.

Comportamiento del consumo de oxígeno durante una sesión de rehabilitación cardíaca / Behavior of Oxygen Consumption During a Cardiac Rehabilitation Session

RESUMEN Objetivo: estudiar el comportamiento del consumo de oxígeno en pacientes con miocardiopatía dilatada durante una sesión de rehabilitación cardíaca. Material y métodos: diseño observacional, transversal, analítico relacional. Muestra: 10 pacientes masculinos con miocardiopatía dilatada, con deterioro de moderado a grave de la función ventricular. Se evaluó a los pacientes en laboratorio y en una sesión de rehabilitación mediante un analizador de gases portátil Medgraphics® VO 2000. La sesión de rehabilitación consistió en ejercicios en bicicleta fija de 10 minutos, step, escalera coordinativa, fuerza con mancuerna para bíceps y hombros, cuádriceps en camilla y dorsales en máquina. Resultados: Edad (años) 57,4 ± 14,6. Peso (kg) 91,4 ± 22,2. Talla (cm) 168,1 ± 6,2. Laboratorio: VO2max relativo (ml/kg/min) 21,8 ± 7,3. Tasa de intercambio respiratorio, RER (VCO2/VO2)1,05 ± 0,09. Volumen ventilado (L/min) 65,7 ± 18,5. Frecuencia cardíaca (lat./min) en VO2max 127,8 ± 23,8. Sesión: Duración (min) 37,5 ± 10. VO2pico (ml/kg/min) 14,6 ± 3 (69,9 ± 16,7% del VO2max). Coeficiente de correlación entre VO2max y tiempo con VO2 < 50% del VO2max (min) 0,662 (p = 0,037) y entre VO2pico en rehabilitación y tiempo en RER entre 0,85-1(min) 0,787 (p = 0,007). Los pacientes con mejor aptitud ejercitaron en zona de baja intensidad. Al aumentar el esfuerzo, aumentaron los minutos en intensidad moderada. Conclusión: Se constató en este estudio que los pacientes alcanzaron un VO2pico en las sesiones inferiores a sus máximos obtenidos en laboratorio. Si bien cualquier dosis de entrenamiento en estos pacientes es más beneficiosa que la inactividad física, el diseño y la planificación de las sesiones de RHC, valorando las intensidades de trabajo intrasesión, podrían generar mayor impacto en la mortalidad, las reinternaciones y en la calidad de vida.

ABSTRACT Objective: The aim of this study was to analyze the response of oxygen consumption in patients with dilated cardiomyopathy during a cardiac rehabilitation session. Methods: This was an observational, cross-sectional, relational analytical study. Ten male patients with dilated cardiomyopathy and moderate to severe ventricular dysfunction were included in the study. Patients were evaluated in the laboratory and during a rehabilitation session using a Medgraphics VO 2000 portable gas analyzer. The rehabilitation session consisted in 10 minutes of stationary bike exercises, step, coordinaton stairs, and muscle strength using dumbbells for biceps and shoulder, a quadriceps stretcher and a dorsal muscle machine. Results: Mean age was 57.4 ± 14.6 years, weight 91.4 ± 22.2 kg and height 168.1 ± 6.2 cm. In the laboratory, VO2max was 21.8 ± 7.3 ml/kg/min, respiratory exchange rate (RER) (VCO2/VO2) 1.05 ± 0.09, ventilated volume 65.7 ± 18.5 L/min and heart rate in VO2max 127.8 ± 23.8 beats/min. Rehabilitation session duration was 37.5 ± 10 min with peakVO2 14.6 ± 3 ml kg/min (69.9 ± 16.7 % VO2max). The correlation coefficient between VO2max and time with VO2 <50% VO2max(min) was 0.662 (p = 0.037) and between peakVO2 in rehabilitation and time in RER between 0.85-1 (min) was 0.787 (p = 0.007). Patients with better fitness exercised in the low-intensity zone. As exercise increased, the minutes in moderate intensity also increased. Conclusion: The study showed that patients reached peakVO2 in sessions below the maximum values obtained in the laboratory. Even though any dose of training in these patients was more beneficial than physical inactivity, cardiac rehabilitation session design and planning, taking into account intrasession exercise intensities, could generate greater impact on mortality, rehospitalizations and quality of life.

Nanosilver and Silver Nitrate Toxicity in Ex Vivo-Exposed Gills of Fish and Mitigation by Humic Acids.

Silver nanoparticles (AgNP) are unique because of their biocide properties. Once released to environment, AgNP interact with the natural organic matter which impact on their fate, dispersion, and ultimate toxicity. We carried out an ex vivo exposure of gill of Corydoras paleatus fish to 100 µg L-1 of AgNP or AgNO3, alone and in combination with 10 mg L-1 of humic acids (HA), with the aim to evaluate the potential mitigation of HA on AgNP toxic effects. We analyzed Ag accumulation and oxidative stress biomarkers. The results showed high bioaccumulation after the AgNO3+HA exposure. An inhibition of glutathione-S-transferase enzymatic activity and depletion of reduced glutathione levels were registered after the AgNO3 exposure, and increased lipid peroxidation levels in the case of AgNP one. Oxidative responses were mitigated when the HA were present in the media. Overall, the knowledge about the fate of this emergent pollutant was deepened through this study.

Surface chemistry modification of silica nanoparticles alters the activation of monocytes.

Aim: Nanoparticles (NPs) interaction with immune system is a growing topic of study. Materials & methods: Bare and amine grafted silica NPs effects on monocytes/macrophages cells were analyzed by flow cytometry, MTT test and LIVE/DEAD® viability/cytotoxicity assay. Results: Bare silica NPs inhibited proliferation and induced monocyte/macrophages activation (increasing CD40/CD80 expression besides pro-inflammatory cytokines and nitrite secretion). Furthermore, silica NPs increased cell membrane damage and reduced the number of living cells. In contrast, amine grafted silica NPs did not alter these parameters. Conclusion: Cell activation properties of bare silica NPs could be hindered after grafting with amine moieties. This strategy is useful to tune the immune system stimulation by NPs or to design NPs suitable to transport therapeutic molecules.

N-acetylcysteine delivery with silica nanoparticles into 3T3-L1 adipocytes.

Background: The addition of 5 mM N-acetylcysteine (NAC) to 3T3-L1 adipocytes culture inhibits the accumulation of triglycerides (Tg) by 50%, but after 48 h uptake was only 16% of total NAC available. Based on these results, the aim of this study is to increase the NAC cellular uptake by encapsulating it in silica nanoparticles (NPs). Materials & methods: Silica NPs, 20 ± 4.5 nm in size, were developed, with an inner cavity loaded with 5 mM NAC. At 48 h after treatment, there was a dose-dependent cytotoxic effect. We attempted to reduce the cytotoxicity of silica NPs by coating them with bovine serum albumin. Results: While we obtained nontoxic bovine serum albumin coated NPs, their effect on Tg cellular accumulation was also reduced.

Determination of Antibacterial Activity of Film Coatings Against Four Clinically Relevant Bacterial Strains.

Antibacterial coatings have currently gained great importance in biomedical technology investigations. Because of the spatial arrangement of the film coatings, evaluation of antibacterial activity presents a new challenge regarding traditional bacterial counting methods. In this protocol, four clinically relevant pathogens, Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were incubated on titania mesostructured thin film coatings for 24 h. Then, cell viability was studied considering three methods: counting of the number of colony forming units (CFU), live/dead staining, and quantification of extracellular DNA in suspension. Firstly, bacterial count was determined by the standard plate-count technique. Secondly, bacteria membrane integrity was evaluated by utilization of two fluorescent dyes, which allow distinction between live (membrane intact) and dead (membrane disrupted) bacteria. Lastly, extracellular DNA was quantified by spectrophotometry. In this manner, the three aforementioned techniques enabled the study of bacterial viability by qualitative and quantitative analyses.

Mitigation of silver nanoparticle toxicity by humic acids in gills of Piaractus mesopotamicus fish.

Silver nanoparticles (AgNPs) are one of the most produced nanoproducts due to their unique biocide properties. The natural organic matter has an important impact on nanoparticle's dispersion as it may alter their fate and transport, as well as their bioavailability and toxicity. Therefore, this study aimed to evaluate the mitigatory effect of humic acids (HAs) on AgNP toxicity. For this purpose, we carried out an ex vivo exposure of gill of Piaractus mesopotamicus fish to 100 µg L-1 of AgNPs or AgNO3, alone and in combination with 10 mg L-1 of HAs. In parallel, a complete AgNP characterization in the media, including the presence of HAs, was provided, and the Ag+ release was measured. We analyzed Ag bioaccumulation, antioxidant enzymes activities, lipid peroxidation, antioxidant capacity against peroxyl radicals, and reduced glutathione levels in fish tissue. Our results indicated the Ag+ release from AgNPs decreased 28% when the HAs were present in the media. The Ag accumulation in gill tissue exposed to AgNPs alone was higher than the AgNO3 exposure, and sixfold higher than the treatment with the HA addition. Moreover, after both Ag forms, the catalase enzyme augmented its activity. However, those responses were mitigated when the HAs were present in the media. Then, our results suggested the mitigation by HAs under the exposure to both Ag forms, providing valuable information about the fate and behavior of this emergent pollutant.

Trace elements in muscle tissue of three commercial shark species: Prionace glauca, Carcharhinus falciformis, and Alopias pelagicus off the Manzanillo, Colima coast, Mexico.

Given their predatory characteristics, long life, and high trophic levels, sharks can have a remarkable ability to bioaccumulate and/or biomagnify trace elements (TE). In the present study, 13 TE (Hg, Pb, Cd, Cu, As, Se, Zn, Cr, V, Fe, Ni, Co, and Mn) were analyzed in the muscle tissue of three shark species (Prionace glauca, Carcharhinus falciformis, and Alopias pelagicus) using high-resolution mass spectrometry inductively coupled to a plasma generator (HR-ICP-MS); 30 shark specimens of each specie were obtained during commercial fish landings in the port of Manzanillo, Mexico. The morphometric characteristics and sex of the sharks were recorded. Shark A. pelagicus accumulated higher concentrations of TE, especially for Hg and Cd, than the other species. Significant differences in the TE levels were detected between sexes in P. glauca and A. pelagicus; in all cases, the highest concentrations were found in female muscle tissue. The ability of sharks to bioaccumulate ETs depends of the metals (essentials higher than non-essential) but is explained mainly by feeding habits associated to sexes (population segregation) and size (ontogeny). The association between TE in shark specimens was related to the essentiality, their antagonistic action, and origin. The Se/Hg ratio was significantly higher than 1, evidence of the protective role of dietary Se against Hg uptake and toxicity in all specimens of the three shark species. Also, the elevate inverse correlation of As and Cd versus Se could indicate a protective action of Se against these toxic metals, but the mechanism must be investigated.

A Survey on Analytical Methods for the Characterization of Green Synthesized Nanomaterials.

Nowadays, nanotechnologies are well established and the uses of a great variety of nanomaterials show exponential growth. The development of green synthesis procedures experienced a great development thanks to the contribution of researchers of diverse origins. The versatility of green chemistry allows producing a wide range of organic and inorganic nanomaterials with numerous promising applications. In all cases, it is of paramount importance to carefully characterize the resulting nanomaterials because their properties will determine their correct performance to accomplish the function to which they were synthesized or even their detrimental effects like nanotoxicological behavior. This review provides an overview of frequently employed characterization methods and their applications for green synthesized nanomaterials. However, while several different nanoscale materials and their associated green construction methodology are being developed, other important techniques would be extensively incorporated into this field soon. The aim is to encourage researchers in the field to employ a variety of these techniques for achieving an exhaustive characterization of new nanomaterials and for contributing to the development of validated green synthesis procedures.