分类： 生物学 >> 生物工程 提交时间： 2024-03-05
Zhang, Ming
Tang, Chao
Wang, Zichun
Chen, Shanchuan
Xu, Mengying
Li, Kaiju
Sun, Ke
Zhao, Changjian
Wang, Yu
Dai, Lunzhi
Lu, Guangwen
Shi, Hubing
Chen, Lu
Geng, Jia
摘要： Single-molecule discrimination among amino acids is crucial to the realization of next-generation protein sequencing. Owing to the heterogeneous charge and subtle volume difference of underivatized amino acids, it remains a challenge for single-molecule techniques to recognize each of them. Here, we report the direct detection of twenty proteinogenic amino acids using a copper(II)-functionalized MspA nanopore. The binding sites for copper(II) ion are constructed by introducing histidine mutation (N91H) to M2MspA protein. With copper ion binding to histidine residues, amino acids can reversibly coordinate the copper-histidine complex, generating well-defined current signals. Using this strategy, all twenty amino acids can be detected. Assisted by a machine learning algorithm, we can identify 100% of signals with 70.2% accuracy or 60% of signals with 93.4% accuracy in the validation set. In successively addition experiment, each amino acid in a mixture of 10 amino acids can be identified precisely. Furthermore, we use carboxypeptidase A1 to partly release the C-terminal amino acids of peptides with different lengths (9, 10 and 22 residues). The hydrolysates of peptides can be identified and distinguished. These results demonstrate the feasibility of this system for amino acids detection and peptide identification, shedding new lights on the development of single-molecule protein sequencing.
分类： 物理学 >> 核物理学 提交时间： 2023-09-07
摘要： The thermodynamic properties of charged particles, such as the energy density, pressure, entropy density, particle density, and squared speed of sound at the kinetic freeze-out in the $ mathrm{Au+Au}$ collisions from the relativistic heavy ion collider (RHIC) beam energy scan program ($ sqrt{s_ text{NN}}$=7.7--200 GeV) and in the $ mathrm{Cu+Cu}$ collisions at $ sqrt{s_ text{NN}}$=62.4, 200 GeV are studied using the thermodynamically consistent Tsallis distribution. The energy density, pressure, and particle density decrease monotonically with the collision energy for the same collision centrality; These properties also decrease monotonically from the central to peripheral collisions at the same collision energy. While the scaled energy density $ varepsilon/T^4$ and scaled entropy density $s/T^3$ demonstrate the opposite trend with the collision energy for the same collision centrality. There is a correlation between $ varepsilon/T^4$ and $s/T^3$ at the same centrality. In addition, the squared speed of sound was calculated to determine that all the collision energies share nearly the same value at different collision centralities.
分类： 心理学 >> 社会心理学 提交时间： 2021-01-28
摘要： Previous studies have demonstrated the possibility that when people are in standing than sitting postures, they have a stronger cognitive control propensity, making them inclined to agree more to sacrificing one innocent and saving more people. Furthermore, this postural effect can be moderated by dual processes. In three studies, participants read dilemma scenarios followed by a proposed behavior to sacrifice one innocent and save five or more people. The participants in sitting or standing postures were asked whether the described action was morally acceptable (moral judgment) and whether they would perform the described action (moral action). The results demonstrated that participants were more approving of the behavioral proposal in the moral action perspective than in the moral judgment perspective across the three studies. The hypothesized postural effect was found in a field study (Study 1) and replicated in a pre-registered replication study (Study 2) and further supported in an experimental study (Study 3). Compared with those in sitting postures, participants in standing postures expressed higher approval of the behavioral proposal compared to their sitting counterparts. Furthermore, the postural effect was dismissed when participants made moral decisions with a dual task to increase cognitive load, and it was reversed when they made moral decisions after deliberate consideration of the behavioral proposal (Study 3). The present research supports and extends the dual-process morality theory by demonstrating that body posture can affect moral decision-making; it also offers novel evidence revealing the moderating role of dual process on embodiment effects. It enriches our knowledge that morality is evolutionarily embodied in postures and that the dual process can moderate embodiment effects.
分类： 心理学 >> 社会心理学 分类： 心理学 >> 医学心理学 提交时间： 2021-01-14
摘要： Previous research found that people with higher level of psychopathy trait would endorse more to the harmful but beneficial action in traditional moral dilemmas. Three possibilities for this effect were confounded: People with higher psychopathy trait, 1) care more about the beneficial consequences; 2) care less about the “no harm” norms; 3) just prefer action irrespective of consequences and norms. A multinomial processing tree model named “CNI” was developed and claimed to dissociated these three possibilities. Four studies have applied CNI model to study the psychopathy-moral decision relationship. However, the CNI model presupposes the agent sequentially processes consequences-norms-generalized inaction/action preferences, which makes the estimated parameters biased and untenable. More recently, an alternative algorithm named “CAN” was developed based on the same data structure to overcome the limitations of CNI model. We applied CAN algorithm and reanalyzed the raw data of the four studies on psychopathy-moral decision relationship. The results demonstrated that people with higher psychopathy trait have weaker consequences and norms sensitivities, stronger overall action preferences, stronger inaction/action preferences irrespective of norms and consequences, and weaker moral principles obedience. Furthermore, the mediation and moderation reanalysis explorations demonstrated that instrumental harm and moral identity partly mediate the psychopathy-moral decision relationship and that perceived societal standards rather than personal standards when making moral decisions can alleviate the positive effects of psychopathy on overall action preference and action preference irrespective of norms and consequences. Present reanalysis exploration study clarified and deepened our insights on the relationship between psychopathy and moral decisions. Theoretical and methodological implications were also discussed.
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