Academia Sinica

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

The Prp19p-associated complex in spliceosome activation

Abstract: During spliceosome activation, a large structural rearrangement occurs that involves the release of two small nuclear RNAs, U1 and U4, and the addition of a protein complex associated with Prp19p. We show here that the Prp19p-associated complex is required for stable association of U5 and U6 with the spliceosome after U4 is dissociated. Ultraviolet crosslinking analysis revealed the existence of two modes of base pairing between U6 and the 5' splice site, as well as a switch of such base pairing from one to the other that required the Prp19p-associated complex during spliceosome activation. Moreover, a Prp19p-dependent structural change in U6 small nuclear ribonucleoprotein particles was detected that involves destabilization of Sm-like (Lsm) proteins to bring about interactions between the Lsm binding site of U6 and the intron sequence near the 5' splice site, indicating dynamic association of Lsm with U6 and a direct role of Lsm proteins in activation of the spliceosome.

A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China

Abstract: Dromaeosaurids, despite their notoriety, are poorly characterized meat-eating dinosaurs, and were previously known only from disarticulated or fragmentary specimens1. Many studies have denied their close relationship to birds2,3. Here we report the best represented and probably the earliest dromaeosaurid yet discovered, Sinornithosaurus millenii gen. et sp. nov., from Sihetun, the famous Mesozoic fish–dinosaur–bird locality in China4,5. Sinornithosaurus not only greatly increases our knowledge of Dromaeosauridae but also provides evidence for a filamentous integument in this group. It is remarkably similar to early birds postcranially. The shoulder girdle shows that terrestrial dromaeosaurids had attained the prerequisites for powered, flapping flight6, supporting the idea that bird flight originated from the ground up7,8. The discovery of Sinornithosaurus widens the distribution of integumentary filaments among non-avian theropods5,9,10. Phylogenetic analysis indicates that, among known theropods with integumentary filaments or feathers2,5, Dromaeosauridae is the most bird-like, and is more closely related to birds than is Troodontidae.

Antibodies to Envelope Glycoprotein of Dengue Virus during the Natural Course of Infection Are Predominantly Cross-Reactive and Recognize Epitopes Containing Highly Conserved Residues at the Fusion Loop of Domain II

Abstract: The antibody response to the envelope (E) glycoprotein of dengue virus (DENV) is known to play a critical role in both protection from and enhancement of disease, especially after primary infection. However, the relative amounts of homologous and heterologous anti-E antibodies and their epitopes remain unclear. In this study, we examined the antibody responses to E protein as well as to precursor membrane (PrM), capsid, and nonstructural protein 1 (NS1) of four serotypes of DENV by Western blot analysis of DENV serotype 2-infected patients with different disease severity and immune status during an outbreak in southern Taiwan in 2002. Based on the early-convalescent-phase sera tested, the rates of antibody responses to PrM and NS1 proteins were significantly higher in patients with secondary infection than in those with primary infection. A blocking experiment and neutralization assay showed that more than 90% of anti-E antibodies after primary infection were cross-reactive and nonneutralizing against heterologous serotypes and that only a minor proportion were type specific, which may account for the type-specific neutralization activity. Moreover, the E-binding activity in sera of 10 patients with primary infection was greatly reduced by amino acid replacements of three fusion loop residues, tryptophan at position 101, leucine at position 107, and phenylalanine at position 108, but not by replacements of those outside the fusion loop of domain II, suggesting that the predominantly cross-reactive anti-E antibodies recognized epitopes involving the highly conserved residues at the fusion loop of domain II. These findings have implications for our understanding of the pathogenesis of dengue and for the future design of subunit vaccine against DENV as well.

Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station.

Abstract: Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B=C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B=C spectral index is reported for the first time. The B=C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B=C ratio is well described by a single power law RΔ with index Δ ¼ −0.333 + 0.014ðfitÞ + 0.005ðsystÞ, in good agreement with the Kolmogorov theory of turbulence which predicts Δ ¼ −1=3 asymptotically.

Future Physics Programme of BESIII

Abstract: There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESIII and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESIII, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESIII during the remaining operation period of BEPCII. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCII to higher luminosity.