Measurable Levels of Short-Chain Chlorinated Paraffins in Western Hudson Bay Fishes but Limited Biomagnification from Fish to Ringed Seals.

We investigated short-chain (C10-13 ) chlorinated paraffins (SCCP) in an Arctic marine food web. In zooplankton, fishes, and ringed seals from western Hudson Bay, Canada, SCCP concentrations ranged from 38.3 to 687 ng g-1 lipid weight. Monte Carlo-simulated trophic-adjusted biomagnification factors of individual SCCP congeners ranged from 0.07 to 0.55 for small pelagic fishes to seals. Despite relatively high concentrations in fishes, biomagnification of SCCPs within this food web appears limited. Environ Toxicol Chem 2021;40:2990-2999. © 2021 SETAC.

Análise do perfil epidemiológico dos pacientes submetidos a transplante de córnea no Espírito Santo / Analysis of the epidemiological profile of patients submitted to corneal transplantation in the Espirito Santo

Resumo Objetivo: Descrever o perfil epidemiológico dos pacientes submetidos a transplante de córnea no estado do Espírito Santo. Métodos: Estudo transversal e descritivo realizado entre o período de janeiro de 2017 a janeiro de 2018, com o total de 1310 cadastrados na Central de Notificação, Captação e Distribuição de Órgãos do Espírito Santo (CNCDO/ES) por meio do Sistema Nacional de Transplantes (SNT) e que foram submetidos a transplante de córnea. Os dados foram apresentados em estatística descritiva como frequências e mediana e a análise dos dados foi realizada com o software SPSS versão 23. Resultados: em relação à frequência, obteve-se 54,3% do gênero feminino, 57,33% (751) provenientes da Região Metropolitana de Vitória. Os pacientes do Espírito Santo correspondem a 86% da frequência na fila, seguidos por Rio de Janeiro, Minas Gerais e Bahia, que juntos correspondem a 6,3%. O principal diagnóstico na indicação de transplante foi a Ceratopatia Bolhosa (25,9%), seguido por Ceratocone (16,5%) e Ceratite Intersticial (15,5%). A média de tempo de espera foi de 195 dias, sendo no máximo 1345 dias. Verificou-se que 1310 pacientes foram transplantados de córnea, a faixa etária dos transplantados é de 57 anos, sendo a maioria destes da Região Metropolitana de Vitória. Conclusão: Os diagnósticos mais prevalentes nos pacientes transplantados no Espírito Santo foram Ceratopatia Bolhosa e Ceratocone, em pacientes majoritariamente do sexo feminino, 57 anos em média, da região metropolitana da grande Vitória e provenientes do próprio estado. O estudo permite traçar estratégias de prevenção, cuidado e ações sociais de conscientização de doação de córnea.

Abstract Objective: To describe the epidemiological profile of patients submitted to corneal transplantation in state of Espirito Santo, Brazil. Methods: Transversal and descriptive study, with 1301 patients, in the period of January 2017 until to January 2018, the patients were registered in the Central Notification, Captation and Distribution of Organs of Espirito Santo (CNCDO/ES) through the National Transplant System (SNT) and submitted to corneal transplantation. The data were shown as descriptive statistics (frequencies and medians) and analysis of the data was performed using SPSS software, 23 version. Results: In relation to frequency, it was obtained 54.5% female, 57.33% from the metropolitan area of Vitória. Eighty-six percent were patients from Espirito Santo and the others 6.3% were from Rio de Janeiro, Minas Gerais and Bahia. The main indications for corneal transplantation were Bullous Keratopathy (25.9%), Keratoconus (16.5%) and interstitial keratitis (15.5%). The average of waiting time was 195 days and the longest was 1345 days. It was found that 1301 patients underwent corneal transplantation, they are in the 57-year age group, and the biggest part of them are from the metropolitan area of Vitória. Conclusion: The most prevalent diagnoses in patients submitted to corneal transplantation in state of Espirito Santo were Bullous Keratopathy and Keratoconus, in patients mostly female, 57 years old on average, from the metropolitan region of greater Vitória and from the state itself. The study allows to outline prevention strategies, care and social actions to raise awareness of corneal donation.

Limited effects of changing prey fish communities on food quality for aquatic predators in the eastern Canadian Arctic in terms of essential fatty acids, methylmercury and selenium.

We determined concentrations of eicosapentaenoic and docosahexaenoic acids (EPA + DHA), Σomega-3, polyunsaturated fatty acids (ΣPUFA), selenium, methylmercury, and selenium:methylmercury (Se:Hg) ratios in native and northward-redistributing sub-Arctic marine fish and invertebrates from low, mid-, and high Canadian Arctic latitudes. There was no clear latitudinal trend in nutrient or contaminant concentrations. Among species, EPA + DHA concentrations in native Arctic cod (Boreogadus saida) were similar to concentrations in sub-Arctic capelin (Mallotus villosus) and sand lance (Ammodytes spp.) (444-658 mg.100 g-1), and higher than in most other species. Concentrations of EPA + DHA were related to lipid content, but to a greater extent for higher trophic position species (R2 = 0.83) than for species at lower trophic positions (R2 = 0.61). Selenium concentrations were higher in sand lance (1.15 ±â€¯0.16 µg g-1) than in all other species (0.30-0.69 µg g-1), which was significantly, but weakly, explained by more pelagic feeding in sand lance. Methylmercury concentrations were similar (and Se:Hg ratios were higher) in capelin, sand lance, and Arctic cod (0.01-0.03 µg g-1 wet weight (ww)) and lower than in other prey (0.12-0.26 µg g-1 ww), which was significantly explained by the smaller size of these species and more pelagic feeding habits than other fish. These results suggested that a shift in prey fish composition from Arctic cod to capelin and/or sand lance is unlikely to reduce the food quality of the prey available to marine predators at least with respect to concentrations of essential fatty acids, selenium, and Se:Hg ratios.

Ecological Change Drives a Decline in Mercury Concentrations in Southern Beaufort Sea Polar Bears.

We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 µg g-1 dry weight (mean: 3.5 ± 0.2 µg g-1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.

Mercury and persistent organic pollutants in native and invading forage species of the Canadian Arctic: Consequences for food web dynamics.

Contaminant dynamics within Arctic marine food webs may be altered through the climate-driven northward invasions of temperate/boreal species. Here, we compare tissue concentrations of total mercury (THg) and legacy and emerging persistent organic pollutants (POPs) in native versus invading forage species sampled from 2012 to 2014 near Arviat, Clyde River, and Resolute Bay, NU, representing, low, mid- and high eastern Canadian Arctic regions, respectively. Concentrations of THg, legacy Σ-polychlorinated biphenyls (ΣPCB) and Σ-organochlorine (ΣOC) pesticides were detected in all forage species, whereas emerging halogenated flame retardants were detected in only a few individuals. Concentrations of major contaminant groups among regions did not vary for Arctic cod (Boreogadus saida), while for sculpin (Cottoidea) there was no clear latitudinal trend. Thus, considering interspecific variation, native sculpin and northern shrimp (Pandalus borealis) had the highest overall concentrations of THg (0.17 ± 0.02 and 0.21 ± 0.01 µg g-1 wet weight, respectively), ΣPCB (322 ± 35 and 245 ± 25 ng g-1 lipid weight (lw), respectively), and ΣOC (413 ± 38 and 734 ± 64 ng g-1 lw, respectively). Comparing the keystone native species, Arctic cod, to its 'replacement' species, capelin (Mallotus villosus) and sandlance (Ammodytes spp.), THg concentrations were higher in Arctic cod compared to capelin (p < 0.001), which was partly explained by differences in fish length. Conversely, capelin and sandlance had higher concentrations of most POPs than Arctic cod (p < 0.02). Neither feeding habitat (based on δ13C), trophic position (based on δ15N), nor fish length significantly explained these differences in POPs between Arctic cod, capelin and sandlance. Higher POPs concentrations, as well as variation in congener/compound patterns, in capelin and sandlance relative to Arctic cod seem, therefore, more likely related to a more "temperate"-type contaminant signature in the invaders. Nevertheless, the relatively small (up to two-fold) magnitude of these differences suggested limited effects of these ecological changes on contaminant uptake by Arctic piscivores.

Blubber-depth distribution and bioaccumulation of PCBs and organochlorine pesticides in Arctic-invading killer whales.

Sightings of killer whales (Orcinus orca) in Greenland have increased in recent years, coincident with sea ice loss. These killer whales are likely from fish-feeding North Atlantic populations, but may have access to marine mammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (PCB) and organochlorine (OC) contaminants in killer whales have used biopsies which may not be representative of contaminant concentrations through the entire blubber depth. Here, we measured PCB and OC concentrations in 10 equal-length blubber sections of 18 killer whales harvested in southeast Greenland (2012-2014), and 3 stranded in the Faroe Islands (2008) and Denmark (2005). Overall, very high concentrations of ΣPCB, Σchlordanes (ΣCHL), and Σdichlorodiphenyltrichloroethane (ΣDDT) were found in the southeast Greenland and Denmark individuals (means of ~40 to 70mgkg-1 lipid weight). These concentrations were higher than in the Faroe Island individuals (means of ~2 to 5mgkg-1 lipid weight) and above those previously reported for other fish-feeding killer whales in the North Atlantic, likely in part due to additional feeding on marine mammals. On a wet weight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15-0.65cm) compared to all other layers (p<0.01), except for Σhexachlorocyclohexanes. However, after lipid correction, no variation was found for ΣCHL and Σchlorobenzene concentrations, while the outermost layer(s) still showed significantly lower ΣPCB, ΣDDT, Σmirex, Σendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differences was low (up to 2-fold) suggesting that a typical biopsy may be a reasonable representation of the PCB and OC concentrations reported in killer whales, at least on a lipid weight basis.

Ultrasensitive multiplex optical quantification of bacteria in large samples of biofluids.

Efficient treatments in bacterial infections require the fast and accurate recognition of pathogens, with concentrations as low as one per milliliter in the case of septicemia. Detecting and quantifying bacteria in such low concentrations is challenging and typically demands cultures of large samples of blood (~1 milliliter) extending over 24-72 hours. This delay seriously compromises the health of patients. Here we demonstrate a fast microorganism optical detection system for the exhaustive identification and quantification of pathogens in volumes of biofluids with clinical relevance (~1 milliliter) in minutes. We drive each type of bacteria to accumulate antibody functionalized SERS-labelled silver nanoparticles. Particle aggregation on the bacteria membranes renders dense arrays of inter-particle gaps in which the Raman signal is exponentially amplified by several orders of magnitude relative to the dispersed particles. This enables a multiplex identification of the microorganisms through the molecule-specific spectral fingerprints.

Ultrasensitive Direct Quantification of Nucleobase Modifications in DNA by Surface-Enhanced Raman Scattering: The Case of Cytosine.

Recognition of chemical modifications in canonical nucleobases of nucleic acids is of key importance since such modified variants act as different genetic encoders, introducing variability in the biological information contained in DNA. Herein, we demonstrate the feasibility of direct SERS in combination with chemometrics and microfluidics for the identification and relative quantification of 4 different cytosine modifications in both single- and double-stranded DNA. The minute amount of DNA required per measurement, in the sub-nanogram regime, removes the necessity of pre-amplification or enrichment steps (which are also potential sources of artificial DNA damages). These findings show great potentials for the development of fast, low-cost and high-throughput screening analytical devices capable of detecting known and unknown modifications in nucleic acids (DNA and RNA) opening new windows of activity in several fields such as biology, medicine and forensic sciences.

Feathers as a Tool to Assess Mercury Contamination in Gentoo Penguins: Variations at the Individual Level.

Feathers have been widely used to assess mercury contamination in birds as they reflect metal concentrations accumulated between successive moult periods: they are also easy to sample and have minimum impact on the study birds. Moult is considered the major pathway for mercury excretion in seabirds. Penguins are widely believed to undergo a complete, annual moult during which they do not feed. As penguins lose all their feathers, they are expected to have a low individual-variability in feather mercury concentration as all feathers are formed simultaneously from the same somatic reserves. This assumption is central to penguin studies that use feathers to examine the annual or among-individual variation in mercury concentrations in penguins. To test this assumption, we measured the mercury concentrations in 3-5 body feathers of 52 gentoo penguins (Pygoscelis papua) breeding at Bird Island, South Georgia (54°S 38°W). Twenty-five percent of the penguins studied showed substantial within-individual variation in the amount of mercury in their feathers (Coefficient of Variation: 34.7-96.7%). This variation may be caused by differences in moult patterns among individuals within the population leading to different interpretations in the overall population. Further investigation is now needed to fully understand individual variation in penguins' moult.

Versatile lock and key assembly for optical measurements with microfluidic platforms and cartridges.

A novel and versatile optical reader for microfluidic platforms is presented. The reader includes a modular insertion port based on the lock and key concept for reproducible alignment with a miniaturized optical detection system comprising an interchangeable light emitting diode (LED) and a photodiode. The modular nature of the insertion port allows the use of microfluidic platforms in variable shapes and fluidic configurations. Three different analytical methodologies based on absorbance or fluorescence measurements were used to demonstrate the flexibility and reproducibility of the proposed experimental setup.

Microreactor with integrated temperature control for the synthesis of CdSe nanocrystals.

The recent needs in the nanosciences field have promoted the interest towards the development of miniaturized and highly integrated devices able to improve and automate the current processes associated with efficient nanomaterials production. Herein, a green tape based microfluidic system to perform high temperature controlled synthetic reactions of nanocrystals is presented. The device, which integrates both the microfluidics and a thermally controlled platform, was applied to the automated and continuous synthesis of CdSe quantum dots. Since temperature can be accurately regulated as required, size-controlled and reproducible quantum dots could be obtained by regulating this parameter and the molar ratio of precursors. The obtained nanocrystals were characterized by UV-vis and fluorescence spectrophotometry. The band width of the emission peaks obtained indicates a narrow size distribution of the nanocrystals, which confirms the uniform temperature profile applied for each synthetic process, being the optimum temperature at 270 °C (full width at half maximum = 40 nm). This approach allows a temperature controlled, easy, low cost and automated method to produce quantum dots in organic media, enhancing its application from laboratory-scale to pilot-line scale processes.

A ceramic microreactor for the synthesis of water soluble CdS and CdS/ZnS nanocrystals with on-line optical characterization.

In this paper, a computer controlled microreactor to synthesize water soluble CdS and CdS/ZnS nanocrystals with in situ monitoring of the reaction progress is developed. It is based on ceramic tapes and the Low-Temperature Co-fired Ceramics technology (LTCC). As well the microsystem set-up, the microreactor fluidic design has also been thoroughly optimized. The final device is based on a hydrodynamic focusing of the reagents followed by a three-dimensional micromixer. This generates monodispersed and stable CdS and core-shell CdS/ZnS nanocrystals of 4.5 and 4.2 nm, respectively, with reproducible optical properties in terms of fluorescence emission wavelengths, bandwidth, and quantum yields, which is a key requirement for their future analytical applications. The synthetic process is also controlled in real time with the integration of an optical detection system for absorbance and fluorescence measurements based on commercial miniaturized optical components. This makes possible the efficient managing of the hydrodynamic variables to obtain the desired colloidal suspension. As a result, a simple, economic, robust and portable microsystem for the well controlled synthesis of CdS and CdS/ZnS nanocrystals is presented. Moreover, the reaction takes place in aqueous medium, thus allowing the direct modular integration of this microreactor in specific analytical microsystems, which require the use of such quantum dots as labels.