Highlights • Circadian system in mammals regulates metabolic functions. • Nutrient signals can organize and entrain peripheral circadian clocks. • Meal timing should be considered for maintaining our ...health and circadian clocks.
ABSTRACT
Planetesimal accretion is a key source for heavy-element enrichment in giant planets. It has been suggested that Jupiter’s enriched envelope is a result of planetesimal accretion during its ...growth, assuming it formed in a massive planetesimal disc. In this study, we simulate Jupiter’s formation in this scenario. We assume in situ formation and perform N-body simulations to infer the solid accretion rate. We find that tens-Earth masses of planetesimals can be captured by proto-Jupiter during the rapid gas accretion phase. However, if several embryos are formed near Jupiter’s core, which is an expected outcome in the case of a massive planetesimal disc, scattering from the embryos increases the eccentricity and inclination of planetesimals and therefore significantly reduces the accretion efficiency. We also compare our results with published semi-analytical models and show that these models cannot reproduce the N-body simulations especially when the planetesimal disc has a large eccentricity and inclination. We show that when the dynamical evolution of planetesimals is carefully modelled, the total mass of captured planetesimals Mcap,tot is 2M⊕ ≲ Mcap,tot ≲ 18M⊕. The metallicity of Jupiter’s envelope can be explained by the planetesimal accretion in our massive disc model despite the low accretion efficiency coming from the high eccentricity and inclination of planetesimals. Our study demonstrates the importance of detailed modelling of planetesimal accretion during the planetary growth and its implications to the heavy-element mass in gaseous planets.
The synchondrosis in the cranial base is an important growth center for the craniofacial region. Abnormalities in the synchondroses affect the development of adjacent regions, including the ...craniofacial skeleton. Here, we report that the transcription factor TBX1, the candidate gene for DiGeorge syndrome, is expressed in mesoderm-derived chondrocytes and plays an essential and specific role in spheno-occipital synchondrosis development by inhibiting the expression of genes involved in chondrocyte hypertrophy and osteogenesis. In Tbx1-deficient mice, the spheno-occipital synchondrosis was completely mineralized at birth. TBX1 interacts with RUNX2, a master molecule of osteoblastogenesis and a regulator of chondrocyte maturation, and suppresses its transcriptional activity. Indeed, deleting Tbx1 triggers accelerated mineralization due to accelerated chondrocyte differentiation, which is associated with ectopic expression of downstream targets of RUNX2 in the spheno-occipital synchondrosis. These findings reveal that TBX1 acts as a regulator of chondrocyte maturation and osteogenesis during the spheno-occipital synchondrosis development. Thus, the tight regulation of endochondral ossification by TBX1 is crucial for the normal progression of chondrocyte differentiation in the spheno-occipital synchondrosis.
Context. The composition of gas giant planets reflects their formation and evolution history. Revealing the origin of the high heavy-element masses in giant exoplanets is an objective of planet ...formation theories. Planetesimal accretion during the phase of planetary migration could lead to the delivery of heavy elements into gas giant planets. In our previous paper, we used dynamical simulations and showed that planetesimal accretion during planetary migration occurs in a rather narrow region of the protoplanetary disk, which we refer to as the “sweet spot” for accretion. Aims. Our understanding of the sweet spot, however, is still limited. The location of the sweet spot within the disk and how it changes as the disk evolves were not investigated in detail. The goal of this paper is to reveal the nature of the sweet spot using analytical calculations and to investigate the role of the sweet spot in determining the composition of gas giant planets. Methods. We analytically derived the required conditions for the sweet spot. Then, using the numerical integration of the orbits of planetesimals around a migrating planet, we compared the derived equations with the numerical results. Results. We find that the conditions required for the sweet spot can be expressed by the ratio of the aerodynamic gas damping timescale of the planetesimal orbits to the planetary migration timescale. If the planetary migration timescale depends on the surface density of disk gas inversely, the location of the sweet spot does not change with the disk evolution. We expect that the planets observed inner to the sweet spot include a much greater amount of heavy elements than the planets outer to the sweet spot. The mass of planetesimals accreted by the protoplanet in the sweet spot depends on the amount of planetesimals that are shepherded by mean motion resonances. Our analysis suggests that tens Earth-masses of planetesimals can be shepherded into the sweet spot without planetesimal collisions. However, as more planetesimals are trapped into mean motion resonances, collisional cascade can lead to fragmentation and the production of smaller planetesimals. This could affect the location of the sweet spot and the population of small objects in planetary systems. Conclusions. We conclude that the composition of gas giant planets depends on whether the planets crossed the sweet spot during their formation. Constraining the metallicity of cold giant planets, which are expected to be beyond the sweet spot, with future observations would reveal key information for understanding the origin of heavy elements in giant planets.
Abstract
Population studies of exoplanets are key to unlocking their statistical properties. So far, the inferred properties have been mostly limited to planetary, orbital, and stellar parameters ...extracted from, e.g., Kepler, radial velocity, and Gaia data. More recently an increasing number of exoplanet atmospheres have been observed in detail from space and the ground. Generally, however, these atmospheric studies have focused on individual planets, with the exception of a couple of works that have detected the presence of water vapor and clouds in populations of gaseous planets via transmission spectroscopy. Here, using a suite of retrieval tools, we analyze spectroscopic and photometric data of 25 hot Jupiters, obtained with the Hubble and Spitzer Space Telescopes via the eclipse technique. By applying the tools uniformly across the entire set of 25 planets, we extract robust trends in the thermal structure and chemical properties of hot Jupiters not obtained in past studies. With the recent launch of the James Webb Space Telescope and the upcoming missions Twinkle and Ariel, population-based studies of exoplanet atmospheres, such as the one presented here, will be a key approach to understanding planet characteristics, formation, and evolution in our galaxy.
Symptoms and laboratory parameters of allergic diseases exhibit prominent ~24‐h variations. For instance, in most allergic rhinitis patients, symptoms worsen overnight or early in the morning. ...Accordingly, there are benefits to nighttime dosing of anti‐allergy medications in such patients. Although the circadian pathophysiology of allergic diseases is well documented, the biological basis of this phenomenon remains poorly understood. Recent studies have begun to reveal that the internal timekeeping system termed the circadian clock plays a key role in temporal regulation of allergic reaction, and may therefore underlie the circadian pathophysiology of allergic diseases. Here, we review new knowledge that highlights the emerging role of the circadian clock as a potent regulator of allergic reactions. Given the strong influence of circadian rhythms on allergic diseases, we believe that research on how the time of day impacts allergic reaction which we may call ‘chronoallergology’ will provide new insight into previously unknown aspects of the biology of allergies. Such knowledge should facilitate novel strategies for prevention and treatment of these diseases.
Lapatinib (GW572016) is a dual tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2/ErbB2), which are reported as overexpressed in ...15%–45% of gastric cancers, making them potential targets.
The primary objective of this study was to assess response rate. Secondary objectives included overall survival (OS), toxicity, and the relationship of EGFR, ErbB2, and markers of angiogenesis with clinical outcome. Lapatinib was administered to chemonaive metastatic gastric cancer patients at a dose of 1500 mg orally daily for 28 days.
The study enrolled 47 patients from February 2005 until May 2006. Four patients (9%) had a confirmed partial response (PR), 1 (2%) had an unconfirmed PR, and 10 (23%) had stable disease. Median (95% confidence interval) time to treatment failure was 1.9 (1.6–3.1) months and OS was 4.8 (3.2–7.4) months. Significant adverse events: one grade 4 cardiac ischemia/infarction, one grade 4 fatigue, and one grade 4 emesis. One treatment-related death was due to central nervous system ischemia. An exploratory analysis of markers revealed gene expression of HER2, interleukin (IL)-8 and genomic polymorphisms IL-8, and vascular endothelial growth factor correlated with OS.
Lapatinib is well tolerated, with modest single-agent activity in advanced/metastatic gastric cancer patients. Potential molecular correlatives were identified which warrant further validation.
ABSTRACT Previous works have suggested a correlation between the X-ray luminosity and the rotational luminosity of radio pulsars. However, none of the obtained regression lines is statistically ...acceptable due to large scatter. We construct a statistical model that has an intrinsic - relation and reproduces the observed distribution about it by using a Monte Carlo simulator, which takes into account the effects obscuring the intrinsic relation, i.e., the anisotropy of radiation, additional heating, uncertainty in distance, and the detection limit of the instruments. From the ATNF pulsar catalog we collect 57 "ordinary radio pulsars" with significant detection and 42 with upper limits. The sample does not include high-magnetic-field pulsars (>1013 G), which are analyzed separately. We obtain a statistically acceptable relation with c1 = 1.03 0.27 and L0 = 1035.38. The distribution about the obtained - relation is reproduced well by the simulator. Pulsars with abnormally high fall into two types: one is the soft gamma-ray pulsars, and the other is pulsars that are thermally bright in comparison with the standard cooling curve. On the other hand, pulsars showing low are found to have dim pulsar wind nebulae (PWNs). We argue that there is an unknown mechanism that governs both the magnetospheric emission and the PWNs, and it might involve the production rate of electron-positron pairs. High-field pulsars form a population that is distinct from ordinary pulsars due to their excess luminosities.
Biodegradable composites reinforced with bagasse fibre before and after alkali treatments were prepared, and mechanical properties were investigated. Mechanical properties of the composites made from ...alkali treated fibres were superior to the untreated fibres. Composites of 1% NaOH solution treated fibres showed maximum improvement. Approximately 13% improvement in tensile strength, 14% in flexural strength and 30% in impact strength had been found, respectively. After alkali treatment, increase in strength and aspect ratio of the fibre contributed to the enhancement in the mechanical properties of the composites. SEM observations on the fracture surface of composites showed that the surface modification of the fibre occurred and improved fibre–matrix adhesion.
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