RESUMO
Of the ~25 directly imaged planets to date, all are younger than 500Myr and all but 6 are younger than 100Myr1. Eps Ind A (HD209100, HIP108870) is a K5V star of roughly solar age (recently derived as 3.7-5.7Gyr2 and 3.5 - 1.3 + 0.8 Gyr3). A long-term radial velocity trend 4,5 as well as an astrometric acceleration6,7 led to claims of a giant planet2,8,9 orbiting the nearby star (3.6384±0.0013pc10). Here we report JWST coronagraphic images that reveal a giant exoplanet which is consistent with these radial and astrometric measurements, but inconsistent with the previously claimed planet properties. The new planet has temperature ~275K, and is remarkably bright at 10.65µm and 15.50µm. Non-detections between 3.5-5µm indicate an unknown opacity source in the atmosphere, possibly suggesting a high metallicity, high carbon-to-oxygen ratio planet. The best-fit temperature of the planet is consistent with theoretical thermal evolution models, which are previously untested at this temperature range. The data indicates that this is likely the only giant planet in the system and we therefore refer to it as "b", despite it having significantly different orbital properties than the previously claimed planet "b".
RESUMO
Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species-in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec's PRISM mode9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10-12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.
RESUMO
Broad absorption signatures from alkali metals, such as the sodium (Na I) and potassium (K I) resonance doublets, have long been predicted in the optical atmospheric spectra of cloud-free irradiated gas giant exoplanets1-3. However, observations have revealed only the narrow cores of these features rather than the full pressure-broadened profiles4-6. Cloud and haze opacity at the day-night planetary terminator are considered to be responsible for obscuring the absorption-line wings, which hinders constraints on absolute atmospheric abundances7-9. Here we report an optical transmission spectrum for the 'hot Saturn' exoplanet WASP-96b obtained with the Very Large Telescope, which exhibits the complete pressure-broadened profile of the sodium absorption feature. The spectrum is in excellent agreement with cloud-free, solar-abundance models assuming chemical equilibrium. We are able to measure a precise, absolute sodium abundance of logεNa = [Formula: see text], and use it as a proxy for the planet's atmospheric metallicity relative to the solar value (Zp/ZÊ = [Formula: see text]). This result is consistent with the mass-metallicity trend observed for Solar System planets and exoplanets10-12.
RESUMO
The unprecedented advancement of global climate change is affecting thermal conditions across spatial and temporal scales. Reptiles with temperature-dependent sex determination (TSD) are uniquely vulnerable to even fine-scale variation in incubation conditions and are a model system for investigating the impacts of shifting temperatures on key physiological and life-history traits. The ways in which current and predicted future climatic conditions translate from macro- to ultra-fine scale temperature traces in subterranean nests is insufficiently understood. Reliably predicting the ways in which fine-scale, daily and seasonally fluctuating nest temperatures influence embryonic development and offspring phenotypes is a goal that remains constrained by many of the same logistical challenges that have persisted throughout more than four decades of research on TSD. However, recent advances in microclimate and developmental modeling should allow us to move farther away from relatively coarse metrics with limited predictive capacity and towards a fully mechanistic model of TSD that can predict incubation conditions and phenotypic outcomes for a variety of reptile species across space and time and for any climate scenario.
Assuntos
Mudança Climática , Processos de Determinação Sexual , Animais , Répteis , Razão de Masculinidade , TemperaturaRESUMO
This article reports on the near-surface atmospheric response at the High Arctic site of Svalbard, latitude 78° N, as a result of abrupt changes in solar insolation during the 20 March 2015 equinox total solar eclipse and notifies the atmospheric science community of the availability of a rare dataset. Svalbard was central in the path of totality, and had completely clear skies. Measurements of shaded air temperature and atmospheric pressure show only weak, if any, responses to the reduced insolation. A minimum in the air temperature at 1.5 m above the ground occurred starting 2 min following the end of totality, though this drop was only slightly beyond the observed variability for the midday period. Eclipse-produced variations in surface pressure, if present, were less than 0.3 hPa.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.
RESUMO
The JAR human placental choriocarcinoma cells were found to transport carnitine into the intracellular space by a Na(+)-dependent process. The transport showed no requirement for anions. The Na+-dependent process was saturable and the apparent Michaelis-Menten constant for carnitine was 12.3 +/- 0.5 microM. Na+ activated the transport by increasing the affinity of the transport system for carnitine. The transport system specifically interacted with L-carnitine, D-carnitine, acetyl-DL-carnitine and betaine. 6-N-Trimethyllysine and choline had little or no effect on carnitine transport. Of the total transport measured, transport into the intracellular space represented 90%. Plasma membrane vesicles prepared from JAR cells were found to bind carnitine in a Na(+)-dependent manner. The binding was saturable with an apparent dissociation constant of 0.66 +/- 0.08 microM. The binding process was specific for L-carnitine, D-carnitine, acetyl-DL-carnitine, and betaine. 6-N-Trimethyllysine and choline showed little or no affinity. It is concluded that the JAR cells express a Na(+)-dependent high-affinity system for carnitine transport and that the Na(+)-dependent high-affinity carnitine binding detected in purified JAR cell plasma membrane vesicles is possibly related to the transmembrane transport process.
Assuntos
Carnitina/metabolismo , Coriocarcinoma/metabolismo , Placenta/metabolismo , Sódio/metabolismo , Neoplasias Uterinas/metabolismo , Sítios de Ligação , Transporte Biológico , Membrana Celular/metabolismo , Feminino , Humanos , Gravidez , Células Tumorais CultivadasRESUMO
The ornithine translocase of beef liver mitochondria was extracted with Lubrol WX and reconstituted in liposomes. The uptake of ornithine by the reconstituted vesicles followed Michaelis-Menten kinetics, and was dependent on the intraliposomal pH, the time of sonication of the reconstituted liposomes and the phospholipid to detergent ratio. It is concluded that the ornithine translocator can be reconstituted, which makes the purification of this translocator feasible.
Assuntos
Proteínas de Transporte/isolamento & purificação , Lipossomos/metabolismo , Proteínas de Membrana Transportadoras , Mitocôndrias Hepáticas/enzimologia , Ornitina/metabolismo , Polietilenoglicóis/farmacologia , Sistemas de Transporte de Aminoácidos Básicos , Amônia/sangue , Animais , Transporte Biológico Ativo , Bovinos , Citrulina/análogos & derivados , Citrulina/urina , Cinética , Ornitina/sangue , Solubilidade , SíndromeRESUMO
Lactate, pyruvate, and glucose were determined in groups of 10 patients, each receiving single drug therapy for their seizure disorder with either phenytoin, valproic acid, carbamazepine, or phenobarbital, and in patients not taking medication. All drug levels were in their therapeutic ranges. The characteristics of the groups were similar, except for the phenytoin group being significantly older. No significant differences were found in glucose or pyruvate concentrations. However, patients on valproic acid had reduced lactate (p less than 0.05) and L/P ratios (p less than 0.05). The reduction in lactate in patients on valproate therapy may mask inborn errors of metabolism that normally result in an increase in blood lactate levels.
Assuntos
Anticonvulsivantes/uso terapêutico , Glicemia/análise , Lactatos/sangue , Piruvatos/sangue , Convulsões/sangue , Humanos , Convulsões/tratamento farmacológicoRESUMO
A 25-year-old woman with Kearns-Sayre syndrome (KSS) had complete external ophthalmoplegia, short stature, ataxia, cardiac conduction defects, and pigmentary retinopathy. Muscle biopsy revealed ragged-red fibers. Electron microscopy showed increased numbers of mitochondria with disordered structure and paracrystalline inclusions. Enzymatic analysis revealed a deficiency of complex II of the mitochondrial respiratory chain, and, more specifically, a deficiency of succinic dehydrogenase, although both subunits of this enzyme proved to be present by immunologic analysis. Therapy with vitamin cofactors did not result in short-term improvement. This appears to be the first report of complex II deficiency in a patient with KSS.
Assuntos
Síndrome de Kearns-Sayre/complicações , Complexos Multienzimáticos/deficiência , Oftalmoplegia/complicações , Oxirredutases/deficiência , Succinato Desidrogenase/deficiência , Adulto , Biópsia , Complexo II de Transporte de Elétrons , Feminino , Histocitoquímica , Humanos , Síndrome de Kearns-Sayre/patologia , Microscopia Eletrônica , Músculos/enzimologia , Músculos/patologia , Músculos/ultraestrutura , Succinato Desidrogenase/metabolismoRESUMO
Propionic acidemia usually presents in the newborn period with severe metabolic acidosis and lethargy. A 31-year-old man with adult onset chorea and dementia had propionic acidemia due to propionyl CoA carboxylase deficiency. Metabolic investigations may prove useful in patients with movement disorder of unknown etiology.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/complicações , Coreia/etiologia , Demência/etiologia , Propionatos/sangue , Adulto , Humanos , Masculino , Propionatos/metabolismoRESUMO
The kidney plays an important role in the homeostasis of carnitine by its ability to reabsorb carnitine almost completely from the glomerular filtrate. The transport process responsible for this reabsorption has been investigated thus far only in laboratory animals. Here we report on the characteristics of carnitine uptake in a proximal tubular epithelial cell line derived from human kidney. The uptake process was found to be obligatorily dependent on Na+ with no involvement of anions. The process was saturable, with a Michaelis-Menten constant of 14 +/- 1 microM. The Na+:carnitine stoichiometry was 1:1. The same process also was found to be responsible for the uptake of acetylcarnitine and propionylcarnitine, two acyl esters of carnitine with potential for therapeutic use in humans. The uptake process was specific for carnitine and its acyl esters. Betaine, a structural analog of carnitine, interacted with the uptake process to a significant extent. The present studies also showed that sulfonylureas, oral hypoglycemic agents currently used in the management of type 2 diabetes, inhibited the carnitine uptake system. Among the sulfonylureas tested, glibenclamide was the most potent inhibitor. The inhibition was competitive. Glibenclamide inhibited the uptake not only of carnitine but also of acetylcarnitine and propionylcarnitine. The inhibition most likely was the result of direct interaction of the compound with the carnitine transporter because the inhibition could be demonstrated in purified rat kidney brush border membrane vesicles.
Assuntos
Carnitina/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Compostos de Sulfonilureia/farmacologia , Administração Oral , Animais , Transporte Biológico/efeitos dos fármacos , Carnitina/análogos & derivados , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Hipoglicemiantes/farmacologia , Túbulos Renais Proximais/metabolismo , Microvilosidades/efeitos dos fármacos , Microvilosidades/metabolismo , RatosRESUMO
This study was initiated to determine whether factors are present in human sperm-free seminal plasma (HSP) that regulate the uptake and release of carnitine from sperm. Bovine caput epididymal sperm cells accumulated more carnitine than caudal sperm cells. A significant reduction in carnitine uptake by caput sperm was observed in the presence of HSP from normal subjects, but not from three subjects with reduced motility. A factor has been isolated from HSP that inhibits carnitine uptake by caput sperm and has the following properties: it is nondialyzable, stable to freeze-thawing, soluble in 60% ammonium sulfate, and has an approximate molecular weight of 158 kd. These data are consistent with the existence of a relatively high molecular weight protein in HSP responsible for the preservation of carnitine concentrations in sperm.
Assuntos
Carnitina/farmacocinética , Sêmen/análise , Espermatozoides/metabolismo , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Epididimo , Humanos , Masculino , Peso Molecular , Motilidade dos EspermatozoidesRESUMO
This review article presents the biosynthesis, metabolism, sources, levels, and general functions of carnitine. Emphasis is placed on the expression of carnitine deficiency and insufficiency as well as the causes of these conditions. The various functions of carnitine are discussed as they may relate to disease treatment.
Assuntos
Carnitina/biossíntese , Carnitina/metabolismo , Animais , Fenômenos Químicos , Química , HumanosRESUMO
This study was designed to 1) determine whether isokinetic dynamometry is appropriate and safe for ambulatory patients with multiple sclerosis and 2) describe the idiosyncrasies the patients with multiple sclerosis exhibited during testing. Ten patients with multiple sclerosis and 20 healthy subjects were matched for age, sex, and weight. The isokinetic peak torque and endurance measurements of knee extensor and knee flexor muscles were recorded at selected angular velocities ranging from 0 to 275 degrees/sec and extensor:flexor muscle strength ratios were calculated. Statistical analysis (t tests) revealed that both the extensor and flexor muscle peak torque values for patients with multiple sclerosis were significantly lower than those for healthy subjects at all angular velocities (p less than .005 to p less than .001), and yet were similar in shape and slope. Mean extensor:flexor ratios for healthy subjects and for patients with multiple sclerosis were not significantly different at 70, 190, and 230 degrees/sec. Individual chart recordings identified any contractile difficulties or increased contraction time. Isokinetic testing is judged to be a safe and reliable form of objective neuromuscular testing for ambulatory patients with multiple sclerosis.
Assuntos
Movimento , Esclerose Múltipla/fisiopatologia , Contração Muscular , Adulto , Feminino , Humanos , Joelho , Masculino , Métodos , Pessoa de Meia-Idade , Esclerose Múltipla/reabilitação , Resistência Física , RiscoRESUMO
Hope is commonly regarded as the feeling that what is desired is also possible. Today, the concensus is that this feeling can increase one's overall ability to cope with stress by reducing fears and anxieties. It is our assumption, therefore, that much of the illness of mankind can be eliminated by enhancing the hope of human individuals.To be able to enhance hope, one must first know what hope actually is and from where it comes by identifying its true determinants. We have, therefore, chosen the task of defining hope and attempting to dissect it into its relevant components so that this important health related property of the human individual may no longer remain in abstraction. This paper reports our approach to this task, the methods used, results obtained, and conclusions drawn.
Assuntos
Atitude Frente a Saúde , Atitude Frente a Morte , Saúde Holística , Humanos , Neoplasias/psicologiaRESUMO
Although many clinical observations suggest that Hope influences the onset, duration, prognosis, and recovery from mental and physical illnesses, a lack of direct scientific proof persists because no method exists for the objective assessment of hope. We have now constructed the Hope Index Scale, a testing instrument for the measurement of this rather elusive human attribute. Upon testing control and experimental subjects, it was found that score distribution on the Hope Index Scale correlates negatively with Beck's Hopelessness Scale (Pearson r = -.88, P <.001) and is independent of age, race, or sex. It is concluded that this tool can help identify individuals with varying degrees of psychosocial problems and that scores of 150 or below are indicative of pathologic hope deficit often associated with suicide.
Assuntos
Transtornos Mentais/psicologia , Testes Psicológicos , Tentativa de Suicídio/psicologia , Adulto , Ego , Emoções , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
A surprisingly large number of fish and amphibian species reproduce terrestrially despite the absence of the key evolutionary innovation of the amniotic egg. In contrast with shelled eggs of reptiles and birds, eggs of teleost fish and amphibians are typically much smaller and enclosed in relatively simple chorionic membranes. Incubation times may be brief or prolonged, and resultant hatchlings typically require the return to an aquatic habitat. Advantages of terrestrial incubation include the increased availability of warmer temperatures and avoidance of aquatic hypoxia, whereas disadvantages include desiccation, exposure to novel predators, and the risk of hatching into a hostile habitat. Hatching may be environmentally cued. Use of energy in the yolk may require trade-offs between growth of the embryo and extended incubation, as exemplified by a case study of the California Grunion. The physical challenges of terrestrial incubation, constraints for hatching, effects of egg size, and parental care are explored. Eight different types of early life history among anamniotic embryos incubating in a terrestrial environment are identified, with examples of these alternate routes to the invasion of land by vertebrates.
Assuntos
Anfíbios/embriologia , Evolução Biológica , Embrião não Mamífero/fisiologia , Desenvolvimento Embrionário/fisiologia , Peixes/embriologia , Óvulo/fisiologia , Animais , Ecossistema , Casca de Ovo , Meio AmbienteRESUMO
OBJECTIVE: Wingless-type mouse mammary tumor virus integration site family, member 5A (WNT5A), is expressed in mouse decidua and is thought to play an important role in decidualization. We examined expression of the receptor for WNT5A, receptor tyrosine kinase-like orphan receptor 2 (ROR2), in the uteri of cycling and pregnant mice. STUDY DESIGN: Reverse transcription (RT)-PCR and immunohistochemistry were performed. RESULTS: RT-PCR revealed that transcripts for Ror2, Wnt3a, Wnt5a and inhibitor of WNT signaling, Dickkopf homolog 1 (Dkk1), were present in the pregnant uterus. Immunohistochemistry revealed that in the virgin uterus, ROR2 is expressed in stromal cells and on the basal side of uterine gland and endometrial epithelial cells. During pregnancy, both the luminal and basal side of uterine gland epithelial cells expressed ROR2, stromal cell expression of ROR2 became more frequent and ROR2 expressing uterine Natural Killer (NK) cells and cells lining the maternal vascular space emerged. Immunofluorescence imaging and flow cytometry revealed that although uterine NK cells expressed ROR2, NK cells of the spleen were ROR2 negative. CONCLUSION: The expression of ROR2 by endometrial epithelial cells may suggest WNT signaling has roles in uterine epithelial cell polarity or implantation. Expression of ROR2 by uterine NK cells may suggest WNT signaling regulates uterine NK cell functions such angiogenesis and regulation of trophoblast migration. In summary, our results show that ROR2 expression by maternal uterine cells is influenced by pregnancy.