The strong magnetic anomalies observed over Mars originate from remanence of deep crust, which should be preserved during 4 billion years. We estimate the relaxation time of remanence carried by ...various types of magnetite, considering temperature and pressure dependences of magnetic parameters. The estimation shows that acicular‐shaped single‐domain magnetite is needed to retain the thick magnetized layer during 4 billion years in a low‐Urey ratio scenario, whereas acicular‐shaped single‐domain, equidimensional single‐domain, and pseudo‐single‐domain magnetites can be the source of anomalies in a high‐Urey ratio scenario. In each case, fine‐grained (<10 μm) and preferably high‐aspect‐ratio magnetite in deep crust is needed to explain the observed anomalies.
Key Points
Relaxation time of acicular‐shaped SD, equidimensional SD, PSD, and MD magnetites in the Martian crustal condition are investigated
Temperature and pressure effects on magnetic parameters and thermal evolution of crust are properly included in relaxation time calculation
Fine‐grained magnetite in the deep crust is needed to retain the source of the Martian magnetic anomalies during 4 Gyr
Shp2 is a positive regulator for Erk activation downstream of receptor tyrosine kinases for growth factors. It has been controversial how Shp2 induces Erk activation. We here demonstrate that EphA2 ...is responsible for Shp2-mediated Erk activation by phosphorylating Tyr542 and Tyr580 of Shp2 in the cells stimulated with growth factors. In NMuMG mammary epithelial cells stimulated with hepatocyte growth factor (HGF), HGF-dependent Erk phosphorylation was prolonged only in the presence of EphA2. This Erk activation paralleled the phosphorylation of Tyr542/580 of Shp2 and the association of Grb2 with Shp2, suggesting the positive signal involving Grb2 signal to activate Ras-Erk pathway. Immunohistochemical studies of mammary cancer specimens revealed that the cancer progression was associated with both Tyr580 phosphorylation of Shp2 and increased expression of EphA2, which were also correlated with increased Erk phosphorylation. Overexpression of either Shp2Thr468Met (a phosphatase-defective mutant found in Lentigines, Electrocardiographic abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormal genitalia, Retardation of growth and sensorineural Deafness (LEOPARD) syndrome) or Shp2Asn308Asp (a phosphatase-active mutant found in Noonan syndrome) with EphA2 exhibited comparable activation of Erk and stronger activation than wild-type Shp2, suggesting the phosphatase-independent Erk activation. Expression of Shp2Thr468Met with Tyr542/580Phe mutations resulted in the suppression of Erk activation. Phosphatase-active and -inactive, and wild-type Shp2s bound equally to Grb2, suggesting that phosphorylation of Tyr542/580 of Shp2 was essential but not sufficient for Shp2-mediated Erk activation. We found that Gab1 (Grb2-associated binder 1) was involved in the mutant Shp2-mediated Erk activation. Zebrafish injected with Shp2Thr468Met mRNA showed cardiac edema, whereas those depleted of EphA2b showed less phenotype, suggesting that EphA2 might partly account for the phenotype of LEOPARD syndrome. Collectively, tyrosine phosphorylation of Shp2 by EphA2 contributes to the phosphatase-independent Shp2-mediated activation of Erk and might be involved in Shp2-associated diseases.
We performed astrometric observations with the Very Long Baseline Army of WB89-437, an H2O maser source in the Outer spiral arm of the Galaxy. We measure an annual parallax of 0.167 ± 0.006 mas, ...corresponding to a heliocentric distance of 6.0 ± 0.2 kpc or a Galactocentric distance of 13.4 ± 0.2 kpc. This value for the heliocentric distance is considerably smaller than the kinematic distance of 8.6 kpc. This confirms the presence of a faint Outer arm toward l = 135°. We also measured the full space motion of the object and find a large peculiar motion of ~20 km s-1 toward the Galactic center. This peculiar motion explains the large error in the kinematic distance estimate. We also find that WB89-437 has the same rotation speed as the LSR, providing more evidence for a flat rotation curve and thus the presence of dark matter in the outer Galaxy.
The electron density distribution in the vicinity of the lunar surface was explored with the radio occultation technique using a subsatellite on the SELENE mission. Although the measurements suffer ...from contamination by the terrestrial ionosphere and interplanetary plasma, an analysis of more than 300 measurements provides adequate statistics and reveals a general trend. The result suggests that a dense ionosphere covering the whole sunlit side, as suggested by the radio occultation measurements on the Soviet Luna 19 and 22 missions, does not exist. However, weak signatures of electron density enhancement with densities on the order of 100 cm−3 are observed below 30 km altitude at solar zenith angles less than 60°. The statistically averaged density reaches a peak at around 15 km altitude and decreases gradually at higher altitudes and toward the surface. Although the suggested electron layer is thinner and less extended horizontally than that reported by Luna 19 and 22, the existence of such an ionized layer is still difficult to explain by conventional ionosphere generation mechanisms. An alternative source of electrons may be required.
Key Points
Electron density near the lunar surface was measured by radio occultation
Repeated observations revealed the dependence on the solar zenith angle
Weak signature of density enhancement was observed near sub‐solar region
The role of dynamin 3 in the testis Vaid, K.S.; Guttman, J.A.; Babyak, N. ...
Journal of cellular physiology,
March 2007, Letnik:
210, Številka:
3
Journal Article
Cerebrovascular disease is the third most common cause of death in developed countries, but our understanding of the cells that compose the cerebral vasculature is limited. Here, using vascular ...single-cell transcriptomics, we provide molecular definitions for the principal types of blood vascular and vessel-associated cells in the adult mouse brain. We uncover the transcriptional basis of the gradual phenotypic change (zonation) along the arteriovenous axis and reveal unexpected cell type differences: a seamless continuum for endothelial cells versus a punctuated continuum for mural cells. We also provide insight into pericyte organotypicity and define a population of perivascular fibroblast-like cells that are present on all vessel types except capillaries. Our work illustrates the power of single-cell transcriptomics to decode the higher organizational principles of a tissue and may provide the initial chapter in a molecular encyclopaedia of the mammalian vasculature.
Sore throat and hoarseness are common complications, but these have not been studied after total i.v. anaesthesia.
We prospectively studied 418 surgical patients, aged 15–92 yr, after total i.v. ...anaesthesia with propofol, fentanyl and ketamine to assess possible factors associated with sore throat and hoarseness.
We found sore throat in 50% and hoarseness in 55% of patients immediately after surgery. This decreased to 25% for sore throat and 24% for hoarseness on the day after surgery. Both sore throat and hoarseness were more common in females and when lidocaine spray had been used. Cricoid pressure during laryngoscopy was inversely associated with the risk of sore throat.
Knowledge of these factors may reduce postoperative throat complications, and improve patient satisfaction.
The aim of this study was to develop a comprehensive analytical method for the characterisation of stevia sweeteners in soft drinks. By using LC and time-of-flight MS, we detected 30 steviol ...glycosides from nine stevia sweeteners. The mass spectral data of these compounds were applied to the analysis to determine steviol glycosides in nine soft drinks. On the basis of chromatographic data and principal-component analysis, these soft drinks were classified into three groups, and the soft drinks of each group, respectively, contained high-rebaudioside A extract, normal stevia extract or alfa-glucosyltransferase–treated stevia extract.
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