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As on land, oceans exhibit high temporal and spatial temperature variation. This "ocean weather" contributes to the physiological and ecological processes that ultimately determine the patterns of species distribution and abundance, yet is often unrecognized, especially in tropical oceans. Here, we tested the paradigm of temperature stability in shallow waters (<12.5 m) across different zones of latitude. We collated hundreds of in situ, high temporal-frequency ocean temperature time series globally to produce an intuitive measure of temperature variability, ranging in scale from quarter-diurnal to annual time spans. To estimate organismal sensitivity of ectotherms (i.e. microbes, algae, and animals whose body temperatures depend upon ocean temperature), we computed the corresponding range of biological rates (such as metabolic rate or photosynthesis) for each time span, assuming an exponential relationship. We found that subtropical regions had the broadest temperature ranges at time spans equal to or shorter than a month, while temperate and tropical systems both exhibited narrow (i.e. stable) short-term temperature range estimates. However, temperature-dependent biological rates in tropical regions displayed greater ranges than in temperate systems. Hence, our results suggest that tropical ectotherms may be relatively more sensitive to short-term thermal variability. We also highlight previously unexplained macroecological patterns that may be underpinned by short-term temperature variability.
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Background: The health benefits of physical activity are well recognised. This study assessed whether golfers were more physically active after lower limb arthroplasty when compared to those that did not play golf (primary outcome). In addition pre and postoperative changes in health-associated quality of life (HAQoL) and joint specific outcomes between golfers and none golfers were assessed (secondary outcomes). Methods: There were 304 patients [THA (n = 155) or TKA (n = 149)] prospectively registered during a 4-month period undergoing lower limb arthroplasty. The mean age was 70.0 (range 37-92, standard deviation 10.2) years and included 188 (61%) females and 120 (39%) males. They completed pre and postoperative questionnaires assessing recreational activity, physical activity, HAQoL (EuroQol [EQ]), joint specific health (Oxford scores), and satisfaction. Results: Golfers (n = 33, 10.9%) were more likely to achieve longer than 3 hours of moderate activity during a week (48.5% vs 38.0%, odds ratio (OR) 3.4, p = 0.045) and achieved their recommended activity level (96.8% vs 77.7%, OR 8.6, p = 0.015) compared to non-golfers following arthroplasty. Postoperative EQ5D (p = 0.034) and EQVAS (p = 0.019) were significantly greater in golfers. The joint specific Oxford hip score was greater in golfers compared to non-golfers (mean difference 5.6, p = 0.022), however no difference was observed in the Oxford knee score following TKA (p = 0.495). Conclusion: Golfers were more likely to achieve their weekly recommended level of physical activity and had a greater HAQoL relative to those that did not play golf following lower limb arthroplasty. More specifically after THA golfers also had a greater postoperative joint specific outcome, but no such advantage was observed in those following TKA. Evidence Level: Level II, diagnostic study.
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In an ocean that is rapidly warming and losing oxygen, accurate forecasting of species' responses must consider how this environmental change affects fundamental aspects of their physiology. Here, we develop an absolute metabolic index (ΦA) that quantifies how ocean temperature, dissolved oxygen and organismal mass interact to constrain the total oxygen budget an organism can use to fuel sustainable levels of aerobic metabolism. We calibrate species-specific parameters of ΦA with physiological measurements for red abalone (Haliotis rufescens) and purple urchin (Strongylocentrotus purpuratus). ΦA models highlight that the temperature where oxygen supply is greatest shifts cooler when water loses oxygen or organisms grow larger, providing a mechanistic explanation for observed thermal preference patterns. Viable habitat forecasts are disproportionally deleterious for red abalone, revealing how species-specific physiologies modulate the intensity of a common climate signal, captured in the newly developed ΦA framework.
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Gastrópodes , Oxigênio , Animais , Oxigênio/metabolismo , Água , Temperatura , Clima , Mudança Climática , Oceanos e Mares , Aquecimento GlobalRESUMO
Anthropogenic-induced climate change is having profound impacts on aquatic ecosystems, and the resilience of fish populations will be determined by their response to these impacts. The northern Namibian coast is an ocean warming hotspot, with temperatures rising faster than the global average. The rapid warming in Namibia has had considerable impacts on marine fauna, such as the southern extension of the distribution of Argyrosomus coronus from southern Angola into northern Namibian waters, where it now overlaps and hybridizes with the closely related Namibian species, A. inodorus. Understanding how these species (and their hybrids) perform at current and future temperatures is vital to optimize adaptive management for Argyrosomus species. Intermittent flow-through respirometry was used to quantify standard and maximum metabolic rates for Argyrosomus individuals across a range of temperatures. The modelled aerobic scope (AS) of A. inodorus was notably higher at cooler temperatures (12, 15, 18 and 21°C) compared with that of A. coronus, whereas the AS was similar at 24°C. Although only five hybrids were detected and three modelled, their AS was in the upper bounds of the models at 15, 18 and 24°C. These findings suggest that the warming conditions in northern Namibia may increasingly favour A. coronus and promote the poleward movement of the leading edge of their southern distribution. In contrast, the poor aerobic performance of both species at cold temperatures (12°C) suggests that the cold water associated with the permanent Lüderitz Upwelling Cell in the south may constrain both species to central Namibia. This is most concerning for A. inodorus because it may be subjected to a considerable coastal squeeze.
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Low back pain (LBP) is the most common injury in golfers of all abilities. The primary aim of this review was to improve understanding of human golf swing biomechanics associated with LBP. A systematic review using the PRISMA guidelines was performed. Nine studies satisfying inclusion criteria and dually reporting golf swing biomechanics and LBP were identified. Human golf swing biomechanics potentially associated with LBP include: reduced lumbar flexion velocity; reduced transition phase length; reduced lumbar torsional load; earlier onset of erector spinae contraction; increased lumbar lateral flexion velocity; reduced or greater erector spinae activity; and earlier onset of external oblique contraction. These potential associations were undermined by a very limited and conflicting quality of evidence, study designs which introduced a severe potential for bias and a lack of prospective study design. There is no conclusive evidence to support the commonly held belief that LBP is associated with "poor" golf swing technique. The potential associations identified should be further investigated by prospective studies of robust design, recruiting participants of both sexes and dexterities. Once firm associations have been identified, further research is required to establish how this knowledge can be best integrated into injury prevention and rehabilitation.
LBP has the highest incidence of any injury in elite, sub-elite and recreational golfers, causing a significant burden of injury worldwide.There is very limited and conflicting evidence that some human biomechanical factors in the golf swing may be associated with LBP.Prospective studies investigating the full movement pattern are required in order to improve understanding of the potential relationship between the biomechanics of the golf swing and LBP.
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Golfe , Dor Lombar , Golfe/fisiologia , Golfe/lesões , Humanos , Dor Lombar/fisiopatologia , Fenômenos Biomecânicos , Região Lombossacral/fisiologia , Região Lombossacral/fisiopatologia , Movimento/fisiologia , Músculos Paraespinais/fisiologia , Músculos Paraespinais/fisiopatologia , Contração Muscular/fisiologiaRESUMO
AbstractOxygen levels in the atmosphere and ocean have changed dramatically over Earth history, with major impacts on marine life. Because the early part of Earth's history lacked both atmospheric oxygen and animals, a persistent co-evolutionary narrative has developed linking oxygen change with changes in animal diversity. Although it was long believed that oxygen rose to essentially modern levels around the Cambrian period, a more muted increase is now believed likely. Thus, if oxygen increase facilitated the Cambrian explosion, it did so by crossing critical ecological thresholds at low O2. Atmospheric oxygen likely remained at low or moderate levels through the early Paleozoic era, and this likely contributed to high metazoan extinction rates until oxygen finally rose to modern levels in the later Paleozoic. After this point, ocean deoxygenation (and marine mass extinctions) is increasingly linked to large igneous province eruptions-massive volcanic carbon inputs to the Earth system that caused global warming, ocean acidification, and oxygen loss. Although the timescales of these ancient events limit their utility as exact analogs for modern anthropogenic global change, the clear message from the geologic record is that large and rapid CO2 injections into the Earth system consistently cause the same deadly trio of stressors that are observed today. The next frontier in understanding the impact of oxygen changes (or, more broadly, temperature-dependent hypoxia) in deep time requires approaches from ecophysiology that will help conservation biologists better calibrate the response of the biosphere at large taxonomic, spatial, and temporal scales.
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Oxigênio , Água do Mar , Animais , Concentração de Íons de Hidrogênio , Atmosfera , Temperatura , Oceanos e MaresRESUMO
AbstractOxygen bioavailability is declining in aquatic systems worldwide as a result of climate change and other anthropogenic stressors. For aquatic organisms, the consequences are poorly known but are likely to reflect both direct effects of declining oxygen bioavailability and interactions between oxygen and other stressors, including two-warming and acidification-that have received substantial attention in recent decades and that typically accompany oxygen changes. Drawing on the collected papers in this symposium volume ("An Oxygen Perspective on Climate Change"), we outline the causes and consequences of declining oxygen bioavailability. First, we discuss the scope of natural and predicted anthropogenic changes in aquatic oxygen levels. Although modern organisms are the result of long evolutionary histories during which they were exposed to natural oxygen regimes, anthropogenic change is now exposing them to more extreme conditions and novel combinations of low oxygen with other stressors. Second, we identify behavioral and physiological mechanisms that underlie the interactive effects of oxygen with other stressors, and we assess the range of potential organismal responses to oxygen limitation that occur across levels of biological organization and over multiple timescales. We argue that metabolism and energetics provide a powerful and unifying framework for understanding organism-oxygen interactions. Third, we conclude by outlining a set of approaches for maximizing the effectiveness of future work, including focusing on long-term experiments using biologically realistic variation in experimental factors and taking truly cross-disciplinary and integrative approaches to understanding and predicting future effects.
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Organismos Aquáticos , Mudança Climática , Animais , Evolução Biológica , Oxigênio , Estresse Fisiológico , EcossistemaRESUMO
The one-neutron knockout from ^{52}Ca in inverse kinematics onto a proton target was performed at â¼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states in ^{51}Ca and the momentum distributions corresponding to the removal of 1f_{7/2} and 2p_{3/2} neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f_{7/2} and 2p_{3/2} orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p_{3/2} orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
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Amongst cancer patients, bone pain due to skeletal metastases is a major cause of morbidity. A number of beta-emitting radiopharmaceuticals have been used to provide internal radiotherapy of bone metastases and provide palliative pain relief. In this article we describe the different physical characteristics of the various beta emitting radionuclides which have been used in this clinical setting and the potential impact of differences in dose-rate on radiobiological outcomes. A detailed review of the biodistribution of these treatments, based on both in-vivo clinical investigations and post mortem autoradiography assessments is provided. These treatments result in physiological delivery of radiation doses to the target disease as well as to critical healthy organs. Particular attention is paid to the radiation doses received by normal bone tissue, bone marrow as well as metastatic bone disease. The underlying models of radiation transport within bone and bone marrow are reviewed alongside the practical steps that must be taken to acquire and analyse the information require for clinical dosimetry assessments. The role of whole body measurements, blood and faecal assays as well as both planar and tomographic gamma camera imaging are considered. In addition we review the rationale for allocating measured bone uptake between trabecular and cortical bone tissue. The difference between bone volume and bone surface seeking radiopharmaceuticals are also discussed. This review also extends to the development of preclinical models of bone metastases which may inform future dosimetric calculations. Finally, we also present a comprehensive review of the dosimetry of the established treatments 89Strontium-chloride; 32Phosphorus; 188Rhenium-hydroxyethylidine disphosphonate; 186Rhenium-1,1-hydroxyethylidene disphosphonate (186Re-HEDP); 153Samarium-ethylenediaminetetramethylene phosphonate; as well as the emerging treatments 188Rhenium-zoledronic acid; 188Rhenium-ibedronat; 177Lutetium-zoledronic acid; and 177Lutetium ethylenediaminetetramethylene phosphonate. This review highlights not only the inter treatment differences in the radiation absorbed doses delivered to metastatic disease by different radiopharmaceuticals but also the intra treatment differences which result in a large range of observed doses between patients.
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Neoplasias Ósseas , Rênio , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/radioterapia , Osso e Ossos , Humanos , Lutécio , Dor/tratamento farmacológico , Dor/etiologia , Dor/radioterapia , Compostos Radiofarmacêuticos/uso terapêutico , Rênio/uso terapêutico , Distribuição Tecidual , Ácido ZoledrônicoRESUMO
PURPOSE: The Forgotten Joint Score (FJS-12) is a valid tool in the evaluation of patients undergoing hip arthroscopy, assessing the unique concept of joint awareness in the setting of a patient's hip pathology. The preoperative burden on patients' mental wellbeing of impaired joint function or symptoms is well established. The purpose of this study was to determine patients' awareness of their hip joint whilst awaiting hip arthroscopy for femoroacetabular impingement, to explore any association between joint awareness and mental health status, and to determine whether this relates to time spent waiting for arthroscopy preoperatively. METHODS: A prospective database of patients undergoing hip arthroscopy between January 2018 and November 2020 was analysed. All patients with a diagnosis of femoroacetabular impingement (FAI) undergoing arthroscopic treatment were included. Questionnaires included the FJS-12, twelve item international hip outcome tool (iHOT-12), EuroQol 5D-5L (EQ-5D-5L) and the Tegner activity score. Pearson's correlation coefficient was used to assess relationships between continuous variables. RESULTS: Preoperative functional outcomes were completed by 81 patients (97.5%) prior to undergoing hip arthroscopy. Median preoperative FJS-12 score was 16.67 (IQR 8.33 - 29.68). Forty-four patients reported any level of anxiety/depression preoperatively (54.3%). Preoperative FJS-12 showed a significant negative correlation with worsening mental health status (r = - 0.359, p < 0.001), and a significant positive correlation with EQ-5D-5L (r = 0.445, p < 0.001). The duration of symptoms or time on the waiting list did not correlate with increased joint awareness or worsened mental health. CONCLUSION: Joint awareness is high when awaiting hip arthroscopy for FAI. Increasing levels of joint awareness correlate with poorer mental health status and poorer quality of life measures, however these parameters do not seem to be associated with increased duration of symptoms prior to surgery or time on the waiting list for surgery.
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Direct proton-knockout reactions of ^{55}Sc at â¼220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of ^{54}Ca were investigated through γ-ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological internucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the ^{55}Sc ground state with states in ^{54}Ca. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of ^{55}Sc, valence proton removals populated predominantly the ground state of ^{54}Ca. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
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Anthropogenic induced climate change is predicted to increase the thermal variability in coastal waters, which can have strong physiological effects on individuals and populations of marine ectotherms. The magnitude and direction of these thermal effects varies depending on species, life stage, biogeography, habitat and season. This study aimed to compare the thermal tolerance of a range of juvenile fish and adult macro-invertebrates from intertidal and estuarine habitats in a warm-temperate, thermally variable region on the south-east coast of South Africa. Seasonal variability in thermal tolerance was compared between species, taxonomic groups, biogeographical distribution and habitat affinity and related to existing and projected water temperature data to gauge the local vulnerability of each species. Critical thermal maximum (CTmax), critical thermal minimum (CTmin), thermal breadths and scopes, and the thermal safety margins of each species were quantified. The greatest differences in thermal tolerance patterns were based on taxonomy, with macro-invertebrates having broader thermal tolerance compared to fish, with the exception of the Cape sea urchin, in both summer and winter. Relatively narrow lower breadths in tolerance and safety margin values for transient juvenile sub-tropical and temperate fish species from the intertidal rocky low-shore habitat were observed in both summer and winter. This indicates that these fish species and the Cape sea urchin may be more vulnerable to projected increases in cold temperature (upwelling in summer) than warm temperature variability in this warm-temperate region if they are unable to seek thermal habitat refuge.
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Mudança Climática , Ecossistema , Animais , África do Sul , Temperatura , ÁguaRESUMO
Purpose: To investigate the safety and efficacy of the IOPTx™ system - a novel wearable, electroceutical treatment to lower intraocular pressure. Methods: Patients wear the customized contact lens and spectacles of the IOPTx™ system and undergo three 15-minute randomized stimulation trials at different stimulus amplitudes with 15 minutes of rest in between. The parameters for the stimulation trials include a frequency of 50 Hz, a pulse width of 100 µs, and current amplitudes between 90-150 µA. The optometrist measures the intraocular pressure (IOP) before, immediately after, and 15 minutes after the trial, and performs topography, a slit eye examination, and specular microscopy before and after the entire study to check the health of the eye and confirm the safety of the system. Results: The IOPTx™ system successfully modulates a patient's IOP. By testing various currents, we create individual tuning curves examining the effect of the stimulation amplitude on the change in IOP. Each patient may have an optimal dose-response curve and by normalizing to this value, the IOPTx™ system decreased IOP by an average of 17.7% with fifteen minutes of therapy. No Adverse Events or Adverse Device Effects occurred.Conclusions: The results of this clinical case series provide preliminary evidence of efficacy and safety of the IOPTx™ system and its potential usefulness to lower IOP in glaucoma and ocular hypertension.
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Lentes de Contato , Terapia por Estimulação Elétrica/instrumentação , Glaucoma de Ângulo Aberto/terapia , Pressão Intraocular/fisiologia , Dispositivos Eletrônicos Vestíveis , Idoso , Idoso de 80 Anos ou mais , Feminino , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Masculino , Hipertensão Ocular/fisiopatologia , Hipertensão Ocular/terapia , Projetos PilotoRESUMO
Treatments of bone metastases using radionuclides are now well established in oncology. It is also a field that continues to develop. This article reviews the evidence base that led to the approval of strontium-89 and samarium-153 ethylenediaminetetramethylene phophanate (EDTMP) for the palliation of pain from bone metastases, as well as the evidence for the use of radium-223 in metastatic castrate-resistant prostate cancer. Efforts to optimise treatments and improve response rates, either by safely increasing the radiation dose to bone metastases or by combining treatment with non-radiation-based therapies, are discussed. In addition, the development of both alpha- and beta-particle-emitting radiopharmaceuticals designed to target prostate-specific membrane antigen are reviewed.
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Neoplasias Ósseas , Neoplasias da Próstata , Neoplasias Ósseas/radioterapia , Neoplasias Ósseas/secundário , Humanos , Masculino , Cuidados Paliativos , Radioisótopos , Compostos RadiofarmacêuticosRESUMO
PURPOSE: The forgotten joint score-12 (FJS-12) is an outcome questionnaire designed to evaluate joint awareness. The responsiveness and validity of the English language version of the FJS-12 in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) is not known. METHODS: Consecutive patients undergoing hip arthroscopy for a diagnosis of FAI were prospectively followed up over a 1 year period. Patients completed preoperative and postoperative FJS-12, EuroQol 5 Dimension (EQ-5D-5L), and the 12-item international hip outcome tool (iHOT-12). We evaluated construct validity with Spearman correlation coefficients for the FJS-12, and responsiveness by way of effect size and ceiling effects. RESULTS: Forty-six patients underwent hip arthroscopy, of which 42 (91%) completed post-operative PROMs at 1 year follow-up. Construct validity was strong with the iHOT-12 (r = 0.87) and also the EQ-5D-5L (r = 0.83). The median postoperative FJS score was 50.2 (IQR 64). The mean change in score for the FJS-12 was 31 points (SD 31) (p < 0.001), with an effect size (Cohen's d) of 1.16. Preoperatively, three patients scored the lowest possible value resulting in a floor effect of 7.1%. Similarly, only three patients (7.1%) scored the best possible score post-operatively. CONCLUSION: This is the first evaluation of the joint awareness concept in the English language version of the FJS-12 following hip arthroscopy for FAI. The FJS-12 is a valid and responsive tool for the assessment of this cohort of patients. LEVEL OF EVIDENCE: II.
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Artroscopia/métodos , Impacto Femoroacetabular/cirurgia , Articulação do Quadril/cirurgia , Medidas de Resultados Relatados pelo Paciente , Adolescente , Adulto , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Psicometria , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Inquéritos e Questionários , Resultado do Tratamento , Adulto JovemRESUMO
PURPOSE: The purpose of this study was to perform a systematic review of the reparticipation in sport at mid-term follow up in athletes who underwent biologic treatment of chondral defects in the knee and compare the rates amongst different biologic procedures. METHODS: A search of PubMed/Medline and Embase was performed in May 2020 in keeping with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The criteria for inclusion were observational, published research articles studying the outcomes and rates of participation in sport following biologic treatments of the knee with a minimum mean/median follow up of 5 years. Interventions included microfracture, osteochondral autograft transfer (OAT), autologous chondrocyte implantation (ACI), matrix-induced autologous chondrocyte implantation (MACI), osteochondral allograft, or platelet rich plasma (PRP) and peripheral blood stem cells (PBSC). A random effects model of head-to-head evidence was used to determine rates of sporting participation following each intervention. RESULTS: There were twenty-nine studies which met the inclusion criteria with a total of 1276 patients (67% male, 33% female). The mean age was 32.8 years (13-69, SD 5.7) and the mean follow up was 89 months (SD 42.4). The number of studies reporting OAT was 8 (27.6%), ACI was 6 (20.7%), MACI was 7 (24.1%), microfracture was 5 (17.2%), osteochondral allograft was 4 (13.8%), and one study (3.4%) reported on PRP and PBSC. The overall return to any level of sport was 80%, with 58.6% returning to preinjury levels. PRP and PBSC (100%) and OAT (84.4%) had the highest rates of sporting participation, followed by allograft (83.9%) and ACI (80.7%). The lowest rates of participation were seen following MACI (74%) and microfracture (64.2%). CONCLUSIONS: High rates of re-participation in sport are sustained for at least 5 years following biologic intervention for chondral injuries in the knee. Where possible, OAT should be considered as the treatment of choice when prolonged participation in sport is a priority for patients. However, MACI may achieve the highest probability of returning to the same pre-injury sporting level. LEVEL OF EVIDENCE: IV.
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We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.
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As marine environments are influenced by global warming there is a need to thoroughly understand the relationship between physiological limits and temperature in fish. One quick screening method of a physiological thermal tipping point is the temperature at which maximum heart rate (ƒHmax) can no longer scale predictably with warming and is referred to as the Arrhenius break temperature (TAB). The use of this method has been successful for freshwater fish by using external electrodes to detect an electrocardiogram (ECG), however, the properties of this equipment pose challenges in salt water when evaluating marine fish. To overcome these challenges, this study aimed to explore the potential use of implantable heart rate loggers to quantify the TAB of Chrysoblephus laticeps, a marine Sparid, following the ECG method protocols where ƒHmax is monitored over an acute warming event and the TAB is subsequently identified using a piece-wise linear regression model. Of the nine experimental fish, only five (56%) returned accurate ƒHmax data. The TAB of successful trials was identified each time and ranged from 18.09 to 20.10⯰C. This study therefore provides evidence that implantable heart rate loggers can estimate TAB of fish which can be applied to many marine species.
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Determinação da Frequência Cardíaca/métodos , Frequência Cardíaca , Perciformes/fisiologia , Termotolerância , Animais , Eletrodos Implantados , Determinação da Frequência Cardíaca/instrumentaçãoRESUMO
Quantifying how the heart rate of ectothermic organisms responds to environmental conditions (e.g. water temperature) is important information to quantify their sensitivity to environmental change. Heart rate studies have typically been conducted in lab environments where fish are confined. However, commercially available implantable heart rate biologgers provide the opportunity to study free-swimming fish. Our study aimed to determine the applicability of an implantable device, typically used on fusiform-shaped fish (e.g. salmonids), for a perciform fish where morphology and anatomy prevent ventral incisions normally used on fusiform-shaped fish. We found that ventrolateral incisions allowed placement near the heart, but efficacy of the loggers was sensitive to their orientation and the positioning of the electrodes. Electrocardiogram detection, signal strength and subsequent heart rate readings were strongly influenced by logger orientation with a significant effect on the quality and quantity of heart rate recordings. We provide details on the surgical procedures and orientation to guide future heart rate biologger studies on perciform-shaped fish.