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This study investigates the fracture characteristics and damage mechanism of granite after treatment under different heating rates. The cracked straight-through Brazilian disc(CSTBD)specimen was used for high-temperature treatment with four heating rates under four sets of heating temperatures. The Brazilian splitting experiments were carried out using electro-hydraulic servo press after cooling down to room temperature, and the static fracture process was analyzed to investigate the effect of heating rate on the fracture mechanical properties of specimens. The results show that: (1) Granite treated at different high temperatures shifted from brittle to ductile damage. (2)The peak damage load of granite treated with different heating rates at the same temperature decreased with the increase of heating rate. At the same temperature, the increase of heating rate doesn't lead to obvious difference in the apparent color of granite, but with gradual increase of apparent cracks. (3)At different heating rates, the longitudinal wave velocity and elastic modulus at 200 ℃ and 400 ℃ show subtle changes, yet at 600 ℃ and above, the longitudinal wave velocity and elastic modulus decrease significantly with the increase of heating rate. (4) The fracture toughness of granite shows gradual decay with the increase of temperature. At the same temperature, type I fracture toughness of granite specimens decreases with the increase of heating rate. At 400 ℃, heating rate exerts maximum influence on the fracture toughness of granite.

Since its industrialization, China has been continuously promoting environmental governance, and it is worth studying whether this measure has been effective. In this paper, we use industrial pollution control to represent China's environmental governance. Further, we use growth drag caused by energy consumption to describe a win-win situation for energy conservation and economic development. This paper theoretically analyzes the impact of environmental governance on growth drag by incorporating the former into the growth drag model. Thereafter, using data from 283 cities for the period between 2003 and 2017, this paper applies the dynamic panel data model to investigate whether China's industrial pollution control can achieve a win-win situation and its transmission mechanism. The results show that industrial pollution control can alleviate growth drag, implying that China's environmental governance can achieve a win-win situation. However, the effect is more significant in Eastern China and areas with high industrial pollution control intensity. The transmission mechanism analysis shows that industrial pollution control achieves a win-win situation by improving technological innovation, promoting human capital accumulation, and optimizing manufacturing development, of which improving technological innovation is the most significant. [ABSTRACT FROM AUTHOR]

Analysis of the direct interaction between the NIT2 and NMR proteins, in the alpha-helices of the nitrogen regulatory circuit of the Neurospora crassa by using two different experimental approaches shows a specific interaction between the positive-acting NIT2 and the negative-acting NMR regulatory proteins, although the precise path of the interaction is not clear. Study suggests that the NMR carries out its negative regulatory role by directly binding to NIT2, where in the process blocks the NIT2 function by inhibiting its DNA-binding activity.

Abstract The entry of the SARS coronavirus (SCV) into cells is initiated by binding of its spike envelope glycoprotein (S) to a receptor, ACE2. We and others identified the receptor-binding domain (RBD) by using S fragments of various lengths but all including the amino acid residue 318 and two other potential glycosylation sites. To further characterize the role of glycosylation and identify residues important for its function as an interacting partner of ACE2, we have cloned, expressed and characterized various soluble fragments of S containing RBD, and mutated all potential glycosylation sites and 32 other residues. The shortest of these fragments still able to bind the receptor ACE2 did not include residue 318 (which is a potential glycosylation site), but started at residue 319, and has only two potential glycosylation sites (residues 330 and 357). Mutation of each of these sites to either alanine or glutamine, as well as mutation of residue 318 to alanine in longer fragments resulted in the same decrease of molecular weight (by approximately 3 kDa) suggesting that all glycosylation sites are functional. Simultaneous mutation of all glycosylation sites resulted in lack of expression suggesting that at least one glycosylation site (any of the three) is required for expression. Glycosylation did not affect binding to ACE2. Alanine scanning mutagenesis of the fragment S319–518 resulted in the identification of ten residues (K390, R426, D429, T431, I455, N473, F483, Q492, Y494, R495) that significantly reduced binding to ACE2, and one residue (D393) that appears to increase binding. Mutation of residue T431 reduced binding by about 2-fold, and mutation of the other eight residues – by more than 10-fold. Analysis of these data and the mapping of these mutations on the recently determined crystal structure of a fragment containing the RBD complexed to ACE2 (Li, F, Li, W, Farzan, M, and Harrison, S. C., submitted) suggested the existence of two hot spots on the S RBD surface, R426 and N473, which are likely to contribute significant portion of the binding energy. The finding that most of the mutations (23 out of 34 including glycosylation sites) do not affect the RBD binding function indicates possible mechanisms for evasion of immune responses.