Academia Sinica

About: Academia Sinica is a facility organization based out in Taipei, Taiwan. It is known for research contribution in the topics: Population & Gene. The organization has 52086 authors who have published 65998 publications receiving 1728114 citations. The organization is also known as: Central Research Academy.

An AMR Study of the Common-envelope Phase of Binary Evolution

Abstract: The hydrodynamic evolution of the common-envelope (CE) phase of a low-mass binary composed of a 1.05 M ☉ red giant and a 0.6 M ☉ companion has been followed for five orbits of the system using a high-resolution method in three spatial dimensions. During the rapid inspiral phase, the interaction of the companion with the red giant's extended atmosphere causes about 25% of the CE to be ejected from the system, with mass continuing to be lost at the end of the simulation at a rate ~2 M ☉ yr–1. In the process the resulting loss of angular momentum and energy reduces the orbital separation by a factor of seven. After this inspiral phase the eccentricity of the orbit rapidly decreases with time. The gravitational drag dominates hydrodynamic drag at all times in the evolution, and the commonly used Bondi-Hoyle-Lyttleton prescription for estimating the accretion rate onto the companion significantly overestimates the true rate. On scales comparable to the orbital separation, the gas flow in the orbital plane in the vicinity of the two cores is subsonic with the gas nearly corotating with the red giant core and circulating about the red giant companion. On larger scales, 90% of the outflow is contained within 30° of the orbital plane, and the spiral shocks in this material leave an imprint on the density and velocity structure. Of the energy released by the inspiral of the cores, only about 25% goes toward ejection of the envelope.

Opposite Effects of M1 and M2 Macrophage Subtypes on Lung Cancer Progression

Abstract: Macrophages in a tumor microenvironment have been characterized as M1- and M2-polarized subtypes. Here, we discovered the different macrophages' impacts on lung cancer cell A549. The M2a/M2c subtypes promoted A549 invasion and xenograft tumor growth. The M1 subtype suppressed angiogenesis. M1 enhanced the sensitivity of A549 to cisplatin and decreased the tube formation activity and cell viability of A549 cells by inducing apoptosis and senescence. Different macrophage subtypes regulated genes involved in the immune response, cytoskeletal remodeling, coagulation, cell adhesion, and apoptosis pathways in A549 cells, which was a pattern that correlated with the altered behaviors of the A549 cells. Furthermore, we found that the identified M1/M2 gene signatures were significantly correlated with the extended overall survival of lung cancer patients. These results suggest that M1/M2 gene expression signature may be used as a prognostic indicator for lung cancer patients, and M1/M2 polarization may be a target of investigation of immune-modulating therapies for lung cancer in the future.

Torque method for the theoretical determination of magnetocrystalline anisotropy

Abstract: We propose a torque method for the theoretical determination of the magnetocrystalline anisotropy (MCA) energy for systems with uniaxial symmetry. While the dependence of the total energy on the angle between the magnetization and the normal axis (\ensuremath{\theta}) can be expressed as E(\ensuremath{\theta})=${\mathit{E}}_{0}$+${\mathit{K}}_{2}$${\mathrm{sin}}^{2}$(\ensuremath{\theta})+${\mathit{K}}_{4}$${\mathrm{sin}}^{4}$(\ensuremath{\theta}), we show that the MCA energy [defined as ${\mathit{E}}_{\mathrm{MCA}}$=E(\ensuremath{\theta}=90\ifmmode^\circ\else\textdegree\fi{})-E(\ensuremath{\theta}=0\ifmmode^\circ\else\textdegree\fi{})=${\mathit{K}}_{2}$+${\mathit{K}}_{4}$] can be easily evaluated through the expectation value of the angular derivative of the spin-orbit coupling Hamiltonian (torque) at an angle of \ensuremath{\theta}=${45}^{\mathit{o}}$. Unlike other procedures, the proposed method is independent of the validity of the MCA force theorem, or of the absolute accuracy of two total energy calculations. Calculated MCA energies for the free Fe monolayer with different lattice constants are analyzed and compared with results of other ab initio calculations, especially those obtained with our previously reported state tracking method. \textcopyright{} 1996 The American Physical Society.

Direct Comparison of Liposomal Doxorubicin with or without Polyethylene Glycol Coating in C-26 Tumor-bearing Mice Is Surface Coating with Polyethylene Glycol Beneficial?

Abstract: Sterically stabilized liposome is characterized by a surface coating of polyethylene glycol (PEG) or other polymers that can reduce opsonization of the liposome by plasma proteins. It has a higher plasma area under the concentration-time curve (AUC), which is believed to correlate with better therapeutic efficacy. However, the presence of large molecules on the liposomal surface may reduce the interactions of liposomes with cells and hinder entry of liposomes into the tumor tissue. Using a stable liposomal system composed of distearoyl phosphatidylcholine/cholesterol, we examined the effect of PEG (Mr 2000) on the pharmacokinetics and on the efficacy of liposomal doxorubicin with C-26 syngeneic tumor model in BALB/c mice. The plasma AUC of liposomal doxorubicin with 6 mol-% PEG-modified distearoyl phosphatidylethanolamine (PEG-DSPE) was approximately twice that of liposomal doxorubicin without PEG at various dosages, regardless of whether the mice were tumor-bearing. Paradoxically, the group of mice treated with liposomal doxorubicin without PEG had higher tumor doxorubicin concentrations. The 72-h tumor AUC was 1.44 times that of liposomal doxorubicin with 6% PEG-DSPE. The tumor-accumulation efficiency (AUC(Tumor)/AUC(Plasma)) of liposomal doxorubicin without PEG was 0.87, and this was more than twice that of the liposomal doxorubicin with 6% PEG-DSPE (0.31). At a dose of 10 mg/kg, although both liposomal groups were better than the free drug group in terms of clinically relevant parameters, including toxicity, tumor shrinkage, and survival, there was no difference between the two liposomal drug groups. In this stable liposome system, surface coating with PEG offered no benefit for liposomal doxorubicin in the C-26 tumor model. To enhance the therapeutic index of liposomal doxorubicin, simply increasing plasma AUC by surface coating with PEG may not be satisfactory.

Global Climate Variations Connected with Sea Surface Temperature Anomalies in the Eastern Equatorial Pacific Ocean for the 1958–73 Period

Abstract: The sea surface temperature anomalies in the eastern equatorial Pacific Ocean are shown to demarcate a “key region” new 130°W for observed variations in the global general circulation. Various techniques are used to describe global conditions during warm and cold sea surface conditions in the key region based on a global 15-year set of surface and upper air analyses. Earlier work is confirmed that during warm episodes 1) the westerly jets in both hemispheres are strengthened, and 2) some of the semi-permanent circulation features, such as the intertropical convergence zone, the subtropical high over the western and central Pacific, and the Aleutian low, increase in strength, and vice versa for cold episodes. The time series of monthly-mean atmospheric temperature averaged over the entire man of the Northern Hemisphere is found to be highly correlated with the sea surface temperature anomalies in the key region. The highest correlation of r = 0.65 is found when the atmosphere lags the ocean by 6 m...