Breath-holding as model for the evaluation of EEG signal during respiratory distress.

PURPOSE: Research describes the existence of a relationship between cortical activity and the regulation of bulbar respiratory centers through the evaluation of the electroencephalographic (EEG) signal during respiratory challenges. For example, we found evidences of a reduction in the frequency of the EEG (alpha band) in both divers and non-divers during apnea tests. For instance, this reduction was more prominent in divers due to the greater physiological disturbance resulting from longer apnea time. However, little is known about EEG adaptations during tests of maximal apnea, a test that voluntarily stops breathing and induces dyspnea. RESULTS: Through this mini-review, we verified that a protocol of successive apneas triggers a significant increase in the maximum apnea time and we hypothesized that successive maximal apnea test could be a powerful model for the study of cortical activity during respiratory distress. CONCLUSION: Dyspnea is a multifactorial symptom and we believe that performing a successive maximal apnea protocol is possible to understand some factors that determine the sensation of dyspnea through the EEG signal, especially in people not trained in apnea.

Behavioral Study of 3- and 5-Halocytisine Derivatives in Zebrafish Using the Novel Tank Diving Test (NTT).

Anxiety is a serious mental disorder, and recent statistics have determined that 35.12% of the global population had an anxiety disorder during the COVID-19 pandemic. A mechanism associated with anxiolytic effects is related to nicotinic acetylcholine receptor (nAChR) agonists, principally acting on the α4ß2 nAChR subtype. nAChRs are present in different animal models, including murine and teleosteos ones. Zebrafish has become an ideal animal model due to its high human genetic similarities (70%), giving it high versatility in different areas of study, among them in behavioral studies related to anxiety. The novel tank diving test (NTT) is one of the many paradigms used for studies on new drugs related to their anxiolytic effect. In this work, an adult zebrafish was used to determine the behavioral effects of 3- and 5-halocytisine derivatives, using the NTT at different doses. Our results show that substitution at position 3 by chlorine or bromine decreases the time spent by the fish at the bottom compared to the control. However, the 3-chloro derivative at higher doses increases the bottom dwelling time. In contrast, substitution at the 5 position increases bottom dwelling at all concentrations showing no anxiolytic effects in this model. Unexpected results were observed with the 5-chlorocytisine derivative, which at a concentration of 10 mg/L produced a significant decrease in bottom dwelling and showed high times of freezing. In conclusion, the 3-chloro and 3-bromo derivatives show an anxiolytic effect, the 3-chlorocytisine derivative being more potent than the 3-bromo derivative, with the lowest time at the bottom of the tank at 1mg/L. On the other hand, chlorine, and bromine at position 5 produce an opposite effect.

Dolphin leukocytes exhibit an attenuated cytokine response and increase heme oxygenase activity upon exposure to lipopolysaccharides.

Cetaceans exhibit physiological adaptations that allowed the transition to aquatic life, including a robust antioxidant defense system that prevents injury from repeated exposure to ischemia/reperfusion events associated with breath-hold diving. The signaling cascades that characterize ischemic inflammation in humans are well characterized. In contrast, cetaceans' molecular and biochemical mechanisms that confer tolerance to inflammatory events are poorly understood. Heme oxygenase (HO) is a cytoprotective protein with anti-inflammatory properties. HO catalyzes the first step in the oxidative degradation of heme. The inducible HO-1 isoform is regulated by various stimuli, including hypoxia, oxidant stress, and inflammatory cytokines. The objective of this study was to compare the response of HO-1 and cytokines to a proinflammatory challenge in leukocytes isolated from humans and bottlenose dolphins (Tursiops truncatus). We measured changes in HO activity, and abundance and expression of interleukin 1 beta (IL-1ß), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and heme oxygenase 1 (HMOX1) in leukocytes treated with lipopolysaccharide (LPS) for 24 and 48 h. HO activity increased (p < 0.05) in dolphin (48 h) but not human cells. TNF-α expression increased in human (24 h, 48 h), but not dolphin cells following LPS stimulation. LPS-induced cytokine expression was lower in dolphin than in human leukocytes, suggesting a blunted cytokine response in bottlenose dolphin leukocytes treated with LPS. Results suggest species-specific regulation of inflammatory cytokines in leukocytes treated with LPS, which may lead to differential responses to a pro-inflammatory challenge between marine and terrestrial mammals.

Spine Trauma Secondary to Diving Accidents: A Seven-year Retrospective Study in Puerto Rico.

OBJECTIVE: Review the profile of patients with spinal trauma after diving accidents referred to the Puerto Rico Medical Center. This study intended to develop more awareness of the risks of spinal cord injury after diving. METHODS: The patient's records for diving accident cases referred to our center during January 2014 until December 2020 were assessed retrospectively. The cases were evaluated according to sex, age, vertebral level, and neurological deficit. The Puerto Rico Medical Center is the only level 1 trauma center in Puerto Rico; therefore, this study likely included all the cases of diving injury on the island. RESULTS: Sixty five patients with a median age of 29 years were identified consisting primarily of males (94%). The regions affected included the cervical (96%), thoracic (2%), and lumbar (2%) spine. Twenty-seven patients (42%) developed a spinal cord injury secondary to a diving accident. Involvement of the C4, C5, or C6 vertebral level, was significant for the development of a spinal cord injury. Diving accidents occurring at beaches were the most common cause. CONCLUSION: In Puerto Rico, there is a yearly incidence of 9.3 diving accidents causing spinal trauma; these accidents most frequently affect the C6 vertebra. These diving accidents mainly occur in young individuals, predominantly at beaches. Most of our patients were neurologically intact after their diving accident, although 42% sustained a spinal cord injury. This study provided a better understanding of this traumatic event and determined its most affected levels, accident sites, and population involved.

El buceo recreativo y la otorrinolaringología: ¿qué sabemos y deberíamos saber? / Recreational diving and otolaryngology: what do we know and should we know?

El buceo recreativo es una práctica cada vez más popular en la población mundial, sin embargo, no está exenta de riesgos. A medida que transcurre una inmersión, el buzo es susceptible a una serie de cambios de presión que afectan las distintas cavidades que contienen aire dentro del cuerpo humano, tales como el oído, cavidades paranasales y los pulmones. Existe un gran espectro de patologías asociadas al buceo, explicándose la mayoría de ellas por el barotrauma asociado, cuya gravedad depende de la magnitud del daño asociado, pudiendo presentar desde manifestaciones a nivel local, así como también a nivel sistémico. Las patologías otológicas suelen ser las más frecuentes y el principal motivo de consulta en este tipo de pacientes. Sin embargo, las afecciones otoneurológicas, rinosinusales, de vía aérea y sistémicas pueden ser comunes dependiendo de cada perfil de buceo. Actualmente no existen recomendaciones locales sobre esta práctica, por lo que el conocimiento de la fisiología, fisiopatología y el tratamiento de las patologías otorrinolaringológicas asociadas deben ser conocidas a medida que este deporte se vuelve cada vez más popular. Se realizó una revisión de la literatura sobre las distintas afecciones otorrinolaringológicas con el fin de sistematizarlas y elaborar recomendaciones para establecer una práctica segura.

Recreational diving is an increasingly popular practice in the world; however, it is not without risks. As a dive progresses, the diver is susceptible to a series of pressure changes that affect the air-containing cavities, such as the ear, paranasal cavities, and lungs. There is a large spectrum of pathologies associated with diving, most of them being explained by associated barotrauma, the severity of which depends on the magnitude of the associated damage, could present local manifestations, as well as at systemic level. Otological pathologies are usually the most frequent and the main reason for consultation in this type of patients, however, otoneurological, rhinosinusal, airway and systemic conditions can be common depending on each diving profile. Currently there are no local recommendations on this practice, therefore, knowledge of the physiology, pathophysiology and treatment of associated otorhinolaryngological pathologies should be known as this sport becomes increasingly popular. A review of the literature on the different ear, nose and throat conditions was carried out in order to systematize them and develop recommendations to establish a safe practice.

Ecomorphology of the tarsometatarsus of waterfowl (Anseriformes) based on geometric morphometrics and its application to fossils.

Anseriformes is a diverse group of birds that comprises screamers, the Magpie Goose, and swans ducks and geese, with a relatively rich fossil record. Waterfowl live in close relation to water bodies, but show a diversity of locomotory habits, being typically categorized as walkers, dabblers, and divers. Owing to its functional significance and high preservation potential, the tarsometatarsus has been considered to be a "key" element upon which to base ecomorphological inferences in fossil waterfowl. For instance, based on features of the tarsometatarsus the Miocene flightless duck Cayaoa bruneti and the Oligocene-Miocene large waterfowl Paranyroca have been inferred as divers. Herein, we use a geometric morphometric approach and comparative methods to assess the phylogenetic and ecomorphological signals in the shape and size of waterfowl tarsometatarsi in relation to their locomotory habits. We also apply phylogenetic flexible discriminant analysis (pFDA) to test the inferred diving habits in the extinct waterfowl Cayaoa and Paranyroca. Extant waterfowl species are largely distributed according to their locomotory habit along the main axis of variation in the shape space, a pattern mirrored by the phylogenetic generalized least squares model, which shows that a third of the shape variation is significantly explained by the habit. The pFDA reclassifies correctly almost all extant species and classified with high posterior probabilities the fossil Cayaoa and Paranyroca as a diver and as a dabbler, respectively. Our quantitative multivariate approach confirms the tarsometatarsus as a useful source of data upon which reliably assesses locomotory habits of fossil waterfowl.

Rocky reef biodiversity survey: Punta Pardelas, Argentina.

BACKGROUND: Temperate rocky reefs in the SW Atlantic are productive areas that support highly diverse communities of invertebrates, algae and fishes. Rocky outcrops form complex structures which offer a diversity of microhabitats that lead to a great variety of co-existing species. Subtidal biodiversity within the Natural Protected Area Península Valdés is largely unexplored and studies are mainly limited to fish. A total of 560 high definition photoquadrats from seven rocky reefs (1-25 m depth) at Punta Pardelas were obtained during March 2019. In total, 4491 occurrences were recorded and identified to phyla (n = 2), superclasses (n = 1), classes (n = 5), subclasses (n = 2), orders (n = 2), families (n = 1), subfamilies (n = 1), genera (n = 10) and species (n = 43) levels. This dataset was developed to provide a baseline inventory of Punta Pardelas inside the Natural Protected Area, that was only partially reported more than 50 years ago. Such data represent the first step towards monitoring these less-accessible ecosystems. NEW INFORMATION: Most of the available information about Atlantic Patagonian marine biodiversity is related to rocky intertidal communities or rocky reef fish communities. Despite having more than 4000 km of coastline, in the last 20 years only four studies have focused on subtidal benthic communities from shallow rocky reefs in Argentina (Genzano et al. 2011, Rechimont et al. 2013, Bravo et al. 2015, Bravo et al. 2020a). However, none of them described the epi-benthic community of different surface orientations on the rocky reefs. This dataset includes several surface orientations (i.e. horizontal, vertical, overhang and cave floor) and their microhabitats. We found almost double the number of taxa previously reported for the area. Through stratified sampling of different surface orientations, we recorded species that are often overlooked and thus registered as part of the existing biodiversity. For example, overhang surfaces in our study showed a unique assemblage and a great diversity of sponges. This work will be valuable as baseline information that is currently out of date in Nuevo Gulf rocky reefs.

Lung Function in Traditional Shellfish Divers in Southern Chile-A Cross-Sectional Study.

The long-term effects of diving on human lung function are controversially discussed. We investigated the lung function of traditional shellfish divers in southern Chile and identified risk factors for reduced lung volumes in divers. In a cross-sectional study, we assessed lung function in traditional shellfish divers and fishermen from two fishing communities. Male divers and fishermen aged 18-60 years were recruited. Participants' health and diving habits were assessed via standardized questionnaires. Descriptive statistics, chi-squared tests and multiple linear regression models were applied. Through door-to-door sampling, we recruited 112 divers and 63 fishermen (response 67%). Valid spirometries were obtained from 98 divers and 52 fishermen. Divers had higher values of forced vital capacity (FVC, Beta = 0.28, 95% confidence interval (CI): 0.09; 0.47) and forced expiratory volume in 1 s (FEV1, Beta = 0.23, 95%-CI: 0.07; 0.39) compared to fishermen. Among divers, lower values of FVC (Beta = -0.35, 95%-CI: -0.65; -0.05) were found in those with a high diving frequency, while diving depth was associated with higher values of FVC (Beta = 0.28, 95%-CI = 0.04; 0.52). Professional divers had better lung function compared to fishermen. However, among divers, lung function decreased with cumulative diving exposure, warranting approval in future studies to ensure the safety and health of divers.

Research on scientific sports training of students majoring in physical education / Pesquisa científica sobre o treinamento esportivo de alunos do curso de educação física / Investigación sobre la formación científico-deportiva de estudiantes de la carrera de educación física

ABSTRACT Introduction: The organization of high-level sports teams in colleges and universities is an important measure for my country's competitive sports to break the traditional monopoly and monopoly pattern and go to the market and society in an all-around way. It helps to improve the cultural quality of Chinese athletes and cultivate new sports talents for comprehensive development. It can make full use of universities' multidisciplinary and high-tech advantages, increase the technological content of competitive training, and accelerate the improvement of sports level. Objective: This article intends to take the diving team as an example to explain the role and significance of scientific training in developing competitive sports in my country's ordinary colleges and universities and put forward suggestions for the establishment, organization, and implementation of scientific training. Methods: The scientific research support system used in the thesis includes: physiological and biochemical monitoring, health and sports injury monitoring, nutrition and weight monitoring, psychological consultation and monitoring, technical training support system, training quality management system, physical training support system, and athlete training database. Results: The in-depth research on diving training focuses on: (1) the detection and evaluation of diving technique training; (2) the training of divers' specific strength qualities; (3) the monitoring of nutrition and weight of female athletes; (4) Pre-match psychological training for outstanding diving athletes. Conclusions: The diving team's training shows that scientific and systematic training is an important guarantee for high-level student-athletes training in ordinary universities in my country. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução: A organização de equipes esportivas de alto nível em faculdades e universidades é uma medida importante para que os esportes competitivos em meu país quebrem o padrão tradicional de monopólio e entrem no mercado e na sociedade de maneira abrangente. Ajuda a melhorar a qualidade cultural dos atletas chineses e a cultivar novos talentos esportivos para um desenvolvimento integral. Pode tirar o máximo proveito das vantagens multidisciplinares e de alta tecnologia das universidades, aumentar o conteúdo tecnológico do treinamento competitivo e acelerar a melhoria do nível esportivo. Objetivo: Este artigo visa tomar a equipe de mergulho como exemplo para explicar o papel e a importância da formação científica no desenvolvimento dos esportes competitivos em faculdades e universidades comuns do meu país e apresentar sugestões para o estabelecimento, organização e implementação da formação científica. Métodos: O sistema de apoio à investigação científica utilizado na tese inclui: monitorização fisiológica e bioquímica, monitorização de lesões na saúde e desportivas, monitorização da nutrição e peso, consulta e monitorização psicológica, sistema de apoio técnico à formação, sistema de gestão da qualidade da formação, apoio à formação física sistema e banco de dados de treinamento de atletas. Resultados: A pesquisa aprofundada sobre o treinamento em mergulho concentra-se em: (1) detecção e avaliação do treinamento em técnicas de mergulho; (2) treinar as qualidades específicas de força dos mergulhadores; (3) monitorar a nutrição e o peso dos atletas; (4) Treinamento psicológico pré-jogo para atletas de mergulho de destaque. Conclusões: O treinamento da equipe de mergulho mostra que o treinamento científico e sistemático é uma garantia importante para a formação de alunos-atletas de alto nível em universidades comuns de meu país. Nível de evidência II; Estudos terapêuticos: investigação dos resultados do tratamento.

RESUMEN Introducción: La organización de equipos deportivos de alto nivel en colegios y universidades es una medida importante para que el deporte competitivo de mi país rompa el patrón tradicional de monopolio e ingrese al mercado y a la sociedad de manera integral. Ayuda a mejorar la calidad cultural de los atletas chinos y a cultivar nuevos talentos deportivos para un desarrollo integral. Puede aprovechar al máximo las ventajas multidisciplinarias y de alta tecnología de las universidades, aumentar el contenido tecnológico de la formación competitiva y acelerar la mejora del nivel deportivo. Objetivo: Este artículo pretende tomar al equipo de buceo como ejemplo para explicar el papel y la importancia de la formación científica en el desarrollo de deportes competitivos en los colegios y universidades ordinarios de mi país y presentar sugerencias para el establecimiento, organización e implementación de la formación científica. Métodos: El sistema de apoyo a la investigación científica utilizado en la tesis incluye: seguimiento fisiológico y bioquímico, seguimiento de la salud y lesiones deportivas, seguimiento de la nutrición y el peso, consulta y seguimiento psicológico, sistema de apoyo al entrenamiento técnico, sistema de gestión de la calidad del entrenamiento, sistema de apoyo al entrenamiento físico, y base de datos de entrenamiento de atletas. Resultados: La investigación en profundidad sobre el entrenamiento de buceo se enfoca en: (1) la detección y evaluación del entrenamiento de técnicas de buceo; (2) el entrenamiento de las cualidades de fuerza específicas de los buzos; (3) el seguimiento de la nutrición y el peso de las atletas; (4) Entrenamiento psicológico previo al partido para atletas de buceo destacados. Conclusiones: La formación del equipo de buceo muestra que la formación científica y sistemática es una garantía importante para la formación de estudiantes-deportistas de alto nivel en las universidades ordinarias de mi país. Nivel de evidencia II; Estudios terapéuticos: investigación de los resultados del tratamiento.

Executive Function among Chilean Shellfish Divers: A Cross-Sectional Study Considering Working and Health Conditions in Artisanal Fishing.

Knowledge about professional diving-related risk factors for reduced executive function is limited. We therefore evaluated the association between decompression illness and executive functioning among artisanal divers in southern Chile. The cross-sectional study included 104 male divers and 58 male non-diving fishermen from two fishing communities. Divers self-reported frequency and severity of symptoms of decompression illness. Executive function was evaluated by perseverative responses and perseverative errors in the Wisconsin Card Sorting Test. Age, alcohol consumption, and symptoms of depression were a-priori defined as potential confounders and included in linear regression models. Comparing divers and non-divers, no differences in the executive function were found. Among divers, 75% reported a history of at least mild decompression sickness. Higher frequency and severity of symptoms of decompression illness were associated with reduced executive function. Therefore, intervention strategies for artisanal divers should focus on prevention of decompression illness.

Complete mitochondrial genome of a cave dwelling Desmopachria (Insecta: Coleoptera: Dytiscidae) from the Eastern Amazon.

Coleoptera presents most of the cave fauna biodiversity, with several troglobite species belonging to the aquatic family Dytiscidae. However, very little is known on both genetic and genomic diversity traits of Neotropical cave beetles. Thus, here we present the complete mitochondrial genome sequence of five specimens of Desmopachria collected in a ferruginous cave from Serra dos Carajás in Parauapebas (Pará, Brazil, Eastern Amazon). Besides the general characteristics of the mitogenome of the analyzed specimens, we present their phylogenetic position within the family, considering the available genome sequences of different subfamilies within Dytiscidae.

Um estado da arte sobre o mergulho autônomo recreativo no Brasil / A state of the art about recreational scuba diving in brazila state of the art about recreational scuba diving in Brazil

O mergulho autônomo recreativo é uma atividade de lazer realizada junto à natureza. Consiste em submergir, em água doce ou salgada, aberta ou confinada, usando o equipamento autônomo de respiração. A pesquisa analisou o que é discutido sobre o mergulho nas produções acadêmicas do País, por meio de um estado da arte nas principais plataformas de periódicos. Foram encontrados 12 textos. A aplicação manual do método de análise temática de conteúdo permitiu a compreensão de que o mergulho é uma atividade pouco estudada, sendo um fenômeno importante para ser compreendido pela perspectiva do lazer, uma vez que é bastante abordado pelas áreas do turismo e administração. É necessário maior aprofundamento na compreensão das relações que se estabelecem entre lazer, corpo e natureza na perspectiva do mergulho recreativo brasileiro.

Recreational scuba diving is a leisure activity carried out close to nature. It consists of submerging, in fresh or salt water, open or confined, using self-contained breathing apparatus. The research analyzed what has been discussed regarding diving in the academic productions of the country through a "state of the art" in the main journals platforms. 12 texts were identified. The manual application of the Thematic Content Analysis method allowed the understanding that diving is a poorly studied activity, being an important phenomenon to be understood from the perspective of leisure, since it is widely addressed by the areas of tourism and administration. It is necessary to deepen the understanding of the relationships established between leisure, body and nature in the perspective of Brazilian recreational diving.

Diel differences in blue whale (Balaenoptera musculus) dive behavior increase nighttime risk of ship strikes in northern Chilean Patagonia.

The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio-logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P < 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P < 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale.

Uso de máscaras de buceo modificadas para aplicación segura de ventilación no invasiva. Estudio piloto / Modified snorkeling facemasks for safe application of non-invasive ventilation. A pilot study / Uso de máscaras de mergulho modificadas para aplicação segura de ventilação não invasiva. Estudo piloto

Resumen: Introducción: en el contexto de la pandemia de SARS-CoV-2, diferentes autores propusieron adaptaciones a máscaras de buceo comerciales (máscaras modificadas, MM) para proporcionar oxigenoterapia a pacientes con o sin presión positiva. Hasta la fecha, ninguno ha evaluado su desempeño como interfaz para la ventilación no invasiva (VNI) en el modo de soporte de presión inspiratoria (PSI). Objetivos: desarrollar una interfaz de VNI utilizando MM y evaluar su rendimiento en comparación con una máscara oronasal (MC) convencional. Métodos: las MM se adaptaron como interfaces VNI utilizando dos piezas creadas mediante impresión 3D. Se comparó su desempeño contra una MC en 10 voluntarios sanos en modo PSI (3 cmH2O) con dos niveles de presión positiva al final de la espiración (PEEP 4 y 8 cmH2O). Se compararon: fugas del sistema, frecuencia respiratoria, volumen corriente, oximetría de pulso, CO2 transcutáneo y comodidad. Resultados: con 4 cmH2O de PEEP no hubo diferencias significativas entre las máscaras en ninguna de las variables estudiadas. Con 8 cmH2O de PEEP, el uso de MM se asoció con un menor nivel de CO2tc (41,0±5,7 vs 43,5±8,1 mmHg; p=0,03) y un mayor confort (8,3±1,1 vs 6,5±1,4; p<0,01) que las MC. Conclusiones: el uso de MM para realizar VNI presenta, en voluntarios sanos, un rendimiento similar a las mascarillas oronasales estándar, con la ventaja de mayor comodidad y menor costo. Si bien restan estudios para avalar su utilización, en la emergencia sanitaria provocada por la pandemia SARS-CoV-2, la adaptación de máscaras de buceo podría representar una opción válida frente a la escasez de interfaces comerciales.

Abstract: Introduction: within the context of the SARS-CoV-2 pandemic, different authors proposed adaptations to snorkeling masks available in the market (modified masks: MM) to provide oxygen therapy with positive pressure ventilation or not. Until today, none of them has assessed its performance as an interface for non-invasive ventilation (NIV) in the inspiratory pressure support mode. Objective: to develop an interface of NIV using MM and assess its performance with a conventional full mask. Method: the MM were adapted as NIV interfaces using two pieces created by 3D printing. Their performance was compared to a that of a conventional mask in 10 healthy volunteers in inspiratory pressure support (3 cmH2O) mode with two levels of positive pressure towards the end of expiration (PEEP 4 and 8 cmH2O). The following were compared: system leaks, respiratory rate, normal volume, pulse oximetry, transcutaneous car bon dioxide and comfort. Results: with 4 cmH2O of PEEP, no significant differences were found between masks in none of the variables studied. With 8 cmH2O de PEEP, the use of MM were associated to a lower level of CO2tc (41.0±5.7 vs 43.5±8.1 mmHg; p=0.03) and greater comfort (8.3±1.1 vs 6.5±1.4; p<0.01) than conventional masks (CM). Conclusions: in healthy volunteers, MM for NIV evidence a similar performance than that of standard oronasal masks, and have a further advantage, as they are more comfortable and cheaper. Even if further studies are needed to support its use, modified snorkeling masks could represent a valid option during the health emergency caused by the SARS-CoV-2 pandemic in consideration of the scarce interfaces available in the market.

Resumo: Introdução: no contexto da pandemia de SARS-CoV2, diferentes autores propuseram adaptações às máscaras de mergulho comerciais (máscaras modificadas, MM) para fornecer oxigenoterapia a pacientes com ou sem pressão positiva. Até o momento, nenhum avaliou seu desempenho como interface para ventilação não invasiva (VNI) no modo de suporte de pressão inspiratória (PSI). Objetivos: desenvolver uma interface de VNI usando MM e avaliar seu desempenho em comparação com uma máscara oronasal convencional (MC). Métodos: as MMs foram adaptadas como interfaces VNI usando duas peças criadas por impressão 3D. Seu desempenho contra uma MC foi comparado em 10 voluntários saudáveis no modo PSI (3 cmH2O) com dois níveis de pressão positiva no final da expiração (PEEP 4 e 8 cmH2O). Vazamentos do sistema, frequência respiratória, volume corrente, oximetria de pulso, CO2 transcutâneo e conforto foram comparados. Resultados: com 4 cmH2O de PEEP, não se observaram diferenças significativas entre as máscaras em nenhuma das variáveis estudadas. Com PEEP de 8 cmH2O, o uso de MM foi associado a um menor nível de CO2tc (41,0 ± 5,7 vs 43,5 ± 8,1 mmHg; p = 0,03) e maior conforto (8,3 ± 1,1 vs 6,5 ± 1,4; p <0,01) do que a MC. Conclusões: o uso do MM para a realização da VNI apresenta, em voluntários saudáveis, desempenho semelhante às máscaras oronasais padrão, com a vantagem de maior conforto e menor custo. Embora ainda sejam necessários mais estudos que embasem seu uso, na emergência sanitária ocasionada pela pandemia do SARS-CoV-2, a adaptação de máscaras de mergulho pode representar uma opção válida diante da escassez de interfaces comerciais.

Dysbaric osteonecrosis (DON) among the artisanal diving fishermen of Yucatán, Mexico.

INTRODUCTION: Artisanal diving fishermen in Yucatán, Mexico have high rates of decompression sickness as a result of frequently unsafe diving practices with surface supplied compressed air. In this study, we investigated the prevalence of dysbaric osteonecrosis (DON), a type of avascular necrosis, in the most susceptible joints in a cohort of these fishermen. METHODS: We performed radiographs of bilateral shoulders, hips, and knees of 39 fishermen in Mexico and surveyed them about their medical and diving histories. We performed pairwise correlations to examine if the fishermen's diving behaviours affected the numbers of joints with DON. RESULTS: The radiographs revealed Grade II or higher DON in 30/39 (76.9%) of the fishermen. Twenty-two of 39 fishermen (56.4%) had at least two affected joints. The number of joints with DON positively correlates with the lifetime maximum diving depth and average bottom time. CONCLUSIONS: These findings represent among the highest prevalence rates of DON in divers and reflect the wide-spread scale of decompression sickness among these fishermen. Through this work, we hope to further educate the fishermen on the sequelae of their diving with the aim of improving their diving safety.

Under pressure: the extraordinary survival of seal lice in the deep sea.

Lice from pinnipeds - sea lions, seals and walruses - are the only insects capable of surviving marine dives. Throughout their evolutionary history, they have adapted to tolerate hypoxia, high salinity, low temperature and, in particular, to tolerate conditions of high hydrostatic pressure. To understand the limits of the capacity of lice to survive during host deep dives, we conducted a series of controlled experiments in the laboratory. We collected lice from elephant seals and submitted the different life stages to high pressure conditions. Lice were first exposed to one of four hydrostatic pressures: 30, 80, 150 or 200 kg cm-2 They were then exposed a second time to higher or lower hydrostatic pressure conditions to test for the impact of the first experience, which could either be deleterious or trigger physiological adaption, allowing them a better tolerance to high pressure. We found that lice from elephant seals can tolerate hydrostatic pressures higher than 200 kg cm-2 (close to 200 atm), which is equivalent to 2000 m depth. Adults exhibited lower recovery times than nymphs after immersion at high hydrostatic pressure. Our findings show that lice have developed unique adaptations to endure extreme marine conditions. We discuss these extreme performances in relation to the morphological characteristics and physiological responses to diving in these insects.

Two new species of Agaporomorphus Guignot from Suriname (Coleoptera, Adephaga, Dytiscidae, Copelatinae).

Two new species are described in the Neotropical genus Agaporomorphus Guignot from Suriname: A. hamatocoles sp. nov. and A. tortus sp. nov. The species are included in a phylogenetic parsimony analysis of 13 morphological characters and all 12 known species. Two equally parsimonious arrangements are found with the only difference a rearrangement among the A. knischi clade. Agaporomorphus tortus belongs to the A. dolichodactylus group based on presence of an elongate, club-like lobe on the dorsal, basal surface of the male median lobe and long, subsinuate male mesotarsal claws and a small lobe at the apex of male mesotarsomere V. Agaporomorphus hamatocoles does not belong to a known species group and is phylogenetically isolated lacking synapomorphies characterizing the other groups, so the species is placed in its own species group. Male genitalia are illustrated for the new species and redrawn for all the species of the A. dolichodactylus group, and male mesotarsal claws are illustrated for A. tortus and redrawn for other members of the A. dolichodactylus group. New distribution records are reported for Suriname for the species A. colberti Miller and Wheeler and A. pereirai Guignot.

ResumenSe describen dos nuevas especies en el género neotrópico Agaporomorphus Guignot de Surinam: A. hamatocoles sp. nov. y A. tortus sp. nov. Las especies se incluyen en un análisis de parsimonia filogenética de 13 carácteres morfológicos y las 12 especies conocidas. Se encuentran dos arreglos igualmente parsimoniosos, con la única diferencia de un reordenamiento entre el clado de A. knischi. Agaporomorphus tortus pertenece al grupo A. dolichodactylus basado en la presencia en el macho de un lóbulo alargado, que parece un palo en la superficie dorsal, al base del lóbulo mediano ; las largas garras mesotarsales subsinuosas; y un lóbulo pequeño en el ápice del mesotarsómero V. Agaporomorphus hamatocoles no pertenece a ningún grupo de especies conocidas, está aislada filogenéticamente y carece de sinapormorfias que caracterizan los otros grupos, así que la especie se coloca en su propio grupo . Los genitales de los machos se ilustran para las nuevas especies y también para todas las especies del grupo A. dolichodactylus. Las garras mesotarsales de los machosse ilustran para A. tortus y también para los otros miembros del grupo A. dolichodactylus. Se informan nuevos registros de distribución para Surinam para las especies A. colberti Miller y Wheeler y A. pereirai Guignot.

A study of decompression sickness using recorded depth-time profiles.

Introduction: 122,129 dives by 10,358 recreational divers were recorded by dive computers from 11 manufacturers in an exploratory study of how dive profile, breathing gas (air or nitrox [N2/O2] mixes), repetitive diving, gender, age, and dive site conditions influenced observed decompression sickness (DCSobs). Thirty-eight reports were judged as DCS. Overall DCSobs was 3.1 cases/104 dives. Methods: Three dive groups were studied: Basic (live-aboard and shore/dayboat), Cozumel Dive Guides, and Scapa Flow wreck divers. A probabilistic decompression model, BVM(3), controlled dive profile variability. Chi-squared test, t-test, logistic regression, and log-rank tests evaluated statistical associations. Results: (a) DCSobs was 0.7/104 (Basic), 7.6/104 (Guides), and 17.3/104 (Scapa) and differed after control for dive variability (p ≺ 0.001). (b) DCSobs was greater for 22%-29% nitrox (12.6/104) than for 30%-50% nitrox (2.04/104) (p ≤ 0.0064) which did not differ from air (2.97/10104). (c) For daily repetitive dives (≺12-hour surface intervals (SI)), DCS occurred only following one or two dives (4.3/10104 DCSobs; p ≺ 0.001) where SIs were shorter than after three or more dives. (d) For multiday repetitive dives (SIs ≺ 48 hours), DCS was associated with high multiday repetitive dive counts only for Guides (p = 0.0018). (e) DCSobs decreased with age at 3%/year (p ≤ 0.0144). (f) Males dived deeper (p ≺ 0.001) but for less time than females (p ≺ 0.001). Conclusion: Collecting dive profiles with dive computers and controlling for profile variability by probabilistic modeling was feasible, but analytical results require independent confirmation due to limited observed DCS. Future studies appear promising if more DCS cases are gathered, stakeholders cooperate, and identified data collection problems are corrected.

A review of Peruvian diving beetles of the genus Hydaticus Leach, 1817, with description of Hydaticus (Prodaticus) panguana sp. nov. and notes on other Neotropical species (Coleoptera: Dytiscidae).

We review the Peruvian Hydaticus Leach, 1817 (Coleoptera: Dytiscidae) and describe Hydaticus panguana sp. nov. from Huánuco Department. In the context of this work, we also provide new country records for several species: Hydaticus lateralis Laporte, 1835 (for Peru, Guyana, Venezuela, Suriname); H. xanthomelas (Brullé, 1837) (for Peru); H. subfasciatus Laporte, 1835 (for Colombia); H. fractivittis Guignot, 1951 (for Paraguay). Hydaticus riehli Wehncke, 1876 and H. verecundus Clark, 1864, described from "Cuba" and "South America", respectively, were probably mislabelled specimens, and do not belong to the Neotropical fauna. Diagnostic characters, including illustrations of male genitalia and habitus, are presented for seven of the 11 Neotropical species, and a modified key is provided. Altogether four species of Hydaticus are now known from Peru.