Reflectance spectra (0.3–4 μm) of powder samples of the third largest stone C0002 returned from the asteroid Ryugu by JAXA Hayabusa2 mission were measured and compared with proximity observation data ...taken by the Optical Navigation Camera - Telescopic (ONC-T) and the Near-Infrared Spectrometer (NIRS3) onboard the Hayabusa2 spacecraft. Although the characteristics of the 2.7 μm absorption band due to structural hydroxyl of the Ryugu powder samples are consistent with CI1 chondrite meteorites, NIRS3 spectra of the global surface of Ryugu exhibit a wavelength shift of +6 nm in the 2.7 μm absorption band center in comparison with those of both the powder samples and an artificial crater on the asteroid formed by the Small Carry-on Impactor (SCI). This is consistent with effects of solar wind-induced space weathering being present across the global surface of asteroid Ryugu. The darkness of the Ryugu surface in comparison with the returned samples and an upturn in reflectance observed in the average ONC-T spectrum at ultraviolet wavelengths may also be due to space weathering.
•Analysis of the 2.7 μm band of asteroid Ryugu samples confirms its composition as CI1 chondrite.•A shift in the 2.7 μm band position of Ryugu surface indicates space weathering by solar wind.•The rate of space weathering on Ryugu is faster than the lifetime of its optical surface material.
Asteroids (162173) Ryugu and (101955) Bennu observed by Hayabusa2 and Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) share many global ...properties, but high-spatial-resolution spectral observations by the telescopic Optical Navigation Camera (ONC-T) and MapCam detected subtle but significant differences (e.g., opposite space weathering trends), which may reflect differences in their origin and evolution. Comparing these differences on the same absolute scale is necessary for understanding their causes and obtaining implications for C-complex asteroids. However, ONC-T and MapCam have a large imager-to-imager systematic error of up to 15% caused by the difference in radiometric calibration targets. To resolve this problem, we cross calibrated albedo and color data between the two instruments using the Moon as the common calibration standard. The images of the Moon taken by ONC-T and MapCam were compared with those simulated using photometry models developed from lunar orbiter data. Our results show that the cross-calibrated reflectance of Ryugu and Bennu can be obtained by upscaling the pre-cross-calibrated reflectance of Bennu by 13.3 ± 1.6% at b band, 13.2 ± 1.5% at v band, 13.6 ± 1.7% at w band, and 14.8 ± 1.8% at x band, while those for Ryugu are kept the same. These factors compensate for the imager-to-imager bias caused by differences in targets used for radiometric calibration and solar irradiance models used for data reduction. Need for such large upscaling underscore the importance of using the cross-calibrated data for accurately comparing the Ryugu and Bennu data. The uncertainty in these factors show that the reflectance of Ryugu and Bennu can be compared with <2% accuracy after applying our results. By applying our cross calibration, the geometric albedo of Bennu became consistent with those observed by ground-based telescopes and the OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS). Our result can be simply applied by multiplying a constant to the publicly available data and enables accurate comparison of the optical spectra of Ryugu and Bennu in future studies.
•We cross calibrated the two imagers using the Moon as the common standard.•We reduced uncertainty in the v-band reflectance of Ryugu to Bennu from 15% to <2%.•Future studies can apply our results by multiplying a constant to the Bennu data.•The cross-calibrated geometric albedo is 4.1 ± 0.1% for Ryugu and 4.9 ± 0.1% for Bennu.•The results were validated against observations by the OSIRIS-REx visible and infrared spectrometer.
Structural characteristics of ovalbumin at acidic pH were investigated by a variety of analytical approaches. At pH 2.2, the protein appeared to assume a partially denatured, molten globule-like ...conformation as evaluated by the binding of a hydrophobic probe, anilino-1-naphthalene-8-sulfonate. The protein was, however, resistant to proteolysis with pepsin under conditions in which the urea-denatured form was extensively hydrolyzed. Furthermore, under more drastic proteolytic conditions, the acid ovalbumin was specifically proteolyzed at the N-terminal site of Ala351, which is located in close proximity to the canonical serpin cleavage site Ala352-Ser353 that is known to be the cleavage site at neutral pH with subtilisin and elastase in native ovalbumin. Among the four cysteine residues (Cys11, Cys30, Cys367, and Cys382), which are all known to be buried in the native ovalbumin molecule, only Cys367 was specifically modified with 2,2′-dithiodipyridine, generating a mixed-disulfide protein derivative. Upon incubation of the derivative with a high concentration of L-cysteine, the thiopyridine mixed disulfide did not undergo any bimolecular exchange reaction with the thiol in the absence of an added denaturant, indicating that the mixed disulfide group is inaccessible. The far-UV CD spectra indicated that the native secondary structure is retained in either the modified or non-modified protein; but as evaluated by the near-UV CD spectra, the asymmetric nature of aromatic side chains in the non-modified ovalbumin and of the mixed-disulfide group in the modified protein was almost lost at pH 2.2. These results are consistent with a highly ordered molten globule-like state for OVA at pH 2.2, in which side chains, but not the backbone chain, significantly fluctuate.
The effects of photoperiod and temperature on the dormancy of two aphid parasitoids in Japan, Aphelinus asychis and A. albipodus, were studied in the laboratory. Adult (reproductive) dormancy was ...induced in A. asychis under 10L : 14D at moderate temperatures and under 15L : 9D at low temperatures. Dormant adults started oviposition 6–17 d after emergence under 10L : 14D at 15 and 18°C. Transferring newly emerged adults from 10L : 14D at 15 and 18°C to 15L : 9D at 20°C caused an apparent reversal of dormancy induction within 1–2 d. It was believed that adult dormancy in A. asychis conforms to “oligopause” rather than “diapause” sensu Mansingh (1971). Adults of A. asychis showed an apparent variation in abdominal coloration from yellowish brown to black. The proportion of females with dark abdominal coloration was higher under 10L : 14D than under 15L : 9D and high at lower temperatures. We regarded this polyphenism as a part of the “diapause syndrome” because oligopause and abdominal coloration were controlled by the same environmental factors. Aphelinus albipodus entered diapause as last instar larvae. The critical photoperiod for diapause induction was 11–12 h at 18°C, and diapause was terminated within six weeks by cold treatment (10L : 14D, 5°C).
A new method to adhere biological tissue to another or to metal such as stainless steel using integrated low-level energy sources, heat, pressure, and vibration is proposed. Heat, pressure, and ...vibration are simultaneously delivered by pressing the porcine aorta tissues on the vibration plate with the heated tip. Tensile tests on adhered specimens were performed to determine adhesion characteristics to adhesion temperature, time, pressure, and vibration. The effect of metal surface coating, fluorine-doped DLC coating, on the adhesion strength was examined. In one application, the inlet port of a ventricular assist device adhered to a porcine ventricle muscle by applying the novel method with a temperature of 80 degrees Centigrade for 120 seconds. Sufficient adhesion was observed without additional vibration. In a second application, the vessel adhesion apparatus was developed to connect a bypass graft to a coronary artery. The device has both a heating and pressurizing part on the tip, which was used to attach the bypass graft to the coronary artery by applying heat with a temperature of 120 degrees Centigrade for 120 seconds. The maximal shear tensile strength using the proposed novel adhesion method was 200 kPa, which is half the strength of the porcine aorta. Adhesion strength increased in proportion to temperature, time, and pressure. The adhesion strength can be controlled by surface treatment of metals. In the first application, the inlet port adhered to the ventricle muscle with a shear tensile strength of 91 kPa, which is enough to keep the pump attached to the ventricle. In the second application, the bypass graft adhered to the coronary artery with a shear tensile strength of 50 kPa, which is sufficient to maintain attachment when exposed to normal blood pressure. The proposed adhesion method indicates satisfactory performance.
We focused on the interventricular dyssynchrony caused by the shortened systole of left ventricle (LV) compared to right ventricle (RV) during left ventricular assist device (LVAD) support. The ...purpose of this study was to assess and quantify the mechanical interventricular dyssynchorny according to the support condition using conductance catheter. We studied five goats with normal heart condition. A centrifugal LVAD was implanted under general anesthesia. We inserted the conductance catheter into the LV and RV and obtained the pressure-volume relationship. We defined the dyssynchronous status by the sign (plus or minus) of the LV volume (LVV) change is opposite to that of RV volume (RVV). (i.e., (dLVV/dt)*(dRVV/dt)<0). Interventicular dyssynchrony (DYS) was quantified by calculating the percentage of time within the cardiac cycle. Bypass rate was set dividing the LVAD pump flow by the main pulmonary artery flow. We calculated the DYS under LVAD support with various bypass rate. The mean DYS of normal heart, LVAD clamp, LVAD support with bypass rate of 50%, 75 % and 100% were 6.0±1.3, 8.6±2.6, 9.6±1.8, 15.5±5.6, and 24.6±8.6, respectively. Also, there was a higher linear negative correlation between LV stroke volume and DYS. Interventricular dyssynchrony during LVAD support was assessed and quantified using conductance catheters. Dyssynchrony became significant when the LV was unloaded with high rotational speed under LVAD support. Assessment of influences for the right ventricular function and heart failure models will be studied in the further study.
MLF1 is a novel protein identified as the NPM-MLF1 chimeric protein produced by a t(3;5)(q25.1;q34) chromosomal translocation, which is associated with myelodysplastic syndrome (MDS), often prior to ...acute myeloid leukemia (AML), except for M3. The clinical features of t(3;5)-positive myeloid disorders suggest that this chimeric protein is involved in dysregulation of progenitor cells with the capability to differentiate into multiple lineages. So far, involvement of wild-type MLF1 in hematopoiesis or in leukemogenesis has not been fully investigated. In the present study, 65 patients with AML and 44 patients with MDS were tested for the expression of MLF1 using the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. A significantly higher level of MLF1 expression (ratio of MLF1/beta-actin mRNA >0.4) was readily detected in seven of 65 patients with de novo AML, three of 12 with post-MDS AML and seven of 44 with MDS, but not in any patients with ALL (n = 18). According to the FAB classification, high levels of MLF1 were found in patients with relatively immature subtypes of AML (M1, M2, M6 and M7) and high risk MDS (RAEB and RAEB-T). These findings indicate that the pattern of MLF1 expression is identical to the clinical morphology appearing in the t(3;5)-positive myeloid disorders and is correlated to the MDS-associated AML and transformation phase of MDS in t(3;5)-negative myeloid disorders. A CD34+ population of normal bone marrow cells preferentially expressed MLF1 with obviously decreasing levels of expression during maturation. Therefore, MLF1 normally functions in multi-potent progenitor cells and its dysregulation may take part in leukemogenesis from MDS.
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