The Variation Characteristics of the Thymus Cell Cycle Regulatory Proteins during Long-term Incremental Exercise

The Variation Characteristics of the Thymus Cell Cycle Regulatory Proteins during Long-term Incremental Exercise XINLEI ZHANG, FEI QIN, YANG RUAN and YANYAN SUN. School of PE and Sport Science; South China Normal University; Guangzhou, China. ABSTRACT Objective: High-intensity exercise may lead to imbalance and retardation of T cell development. While orderly operation is the guarantee for the normal development of cell cycle. This study aimed to observe the changes of rat thymus cell cycle regulatory proteins related to G1/S phase and G2/M phase during long-term incremental exercise, explore the relationship among the proteins, to discuss how the exercise influence cellular immune. Methods:80 male SD rats, aged 6 weeks, were divided into sedentary group(S) and exercise group(E) randomly. E group is going to had an incremental treadmill exercise for six weeks. Rat thymus samples were taken at first day (WK0) and the end of WK2, WK4 and WK6. The positive expression of CyclinE, p21 and CyclinB1 were measured by immunohistochemistry. Results: 1) CyclinE increased slightly in WK2 compared with WK0. While it reduced deeply and changed significantly(P\u3c0.01) in WK4 compared with WK2. And then it increased statistically(P\u3c0.05) in WK6 compared with WK4, but it still lower than WK0 and WK2. 2) Making p21 expression in WK0 as a reference, it increased extremely in WK2 (P\u3c0.01) . WK4 reduced drastically(P\u3c0.01) compared with WK2. The expression slightly increased in WK6. The cortex and medulla of thymus lobule become fused in WK6. 3) CyclinB1 in WK2 was higher than WK0. Then it reduced in WK4, while increased slightly in WK6. And the thymic medulla was smaller than previous weeks. The expression of CyclinB1 changed smoothly among every week(P\u3e0.05). Conclusions: 1) The cell cycle may be blocked in G1/S phase in WK2. The destruction of the cell cycle was relieved in WK4 to maintain the body balance. In WK6, the thymus cell cycle operation improved, but the atrophy of the thymus may also cause the decline of immune function. 2) The expression of CyclinB1 increase firstly and then decrease. The reason for this variation is the adaptable regulation of the body faced to exercise. 3) The block of thymus cell cycle due to high-intensity exercise mainly because the G1/S block

Gradient Metaphoricity of the Preposition in: A Corpus-based Approach to Chinese Academic Writing in English

In Cognitive Linguistics, a conceptual metaphor is a systematic set of correspondences between two domains of experience (Kövecses 2020: 2). In order to have an extensive understanding of metaphors, metaphoricity (Müller and Tag 2010; Dunn 2011; Jensen and Cuffari 2014; Nacey and Jensen 2017) has been emphasized to address one of the properties of metaphors in language usage: gradience (Hanks 2006; Dunn 2011, 2014), which indicates that metaphorical expressions can be measured. Despite many noteworthy contributions, studies of metaphoricity are often accused of subjectivity (Müller 2008; Jensen and Cuffari 2014; Jensen 2017), this is why this study uses a big corpus as a database. Therefore, the main aim of this dissertation is to measure the gradient senses of the preposition in in an objective way, thus mapping the highly systematic semantic extension. Based on these gradient senses, the semantic and syntactic features of the preposition in produced by advanced Chinese English-major learners are investigated, combining quantitative and qualitative research methods. A quantitative analysis of the literal and other ten metaphorical senses of the preposition in is made at first. In accounting for the five factors influencing image schemata of each sense: “scale of Landmark”, “visibility”, “path”, “inclusion” and “boundary”, the formula of measuring the gradability of metaphorical degree is deduced: Metaphoricity=[[#Visibility] +[#Path] +[#Inclusion] +[#Boundary]]*[#Scale of Landmark]. The result is that the primary sense has the highest value:12, and all other extended senses have values down to zero. The more shared features with proto-scene, the higher the value of the metaphorical sense, and the less metaphorical the sense. EVENT and PERSON are the “least metaphoric” (value = 9-11); SITUATION, NUMBER, CONTENT and FIELD are “weak metaphoric” (value = 6-8); Also included are SEGMENTATION, TIME and MANNER (value = 3-5), and they are “strong metaphoric”; PURPOSE shares the least feature with proto-scene, and it has the lowest value, so it is “most metaphoric” (value = 0-2). Then, a corpus-based approach is employed, which offers a model for employing a corpus-based approach in Cognitive Linguistics. It compares two compiled sub-corpora: Chinese Master Academic Writing Corpus and Chinese Doctorate Academic Writing Corpus. The findings show that, on the semantic level, Chinese English-major students overuse in with a low level of metaphoricity, even advanced learners use the most metaphorical in rarely. In terms of syntactic behaviours, the most frequent nouns in [in+noun] construction are weakly metaphoric, whilst the nouns in the construction [in the noun of] are EVENT sense, which is least metaphorical. Moreover, action verbs tend to be used in the construction [verb+in] and [in doing sth.] in both master and doctorate groups. In the qualitative study, the divergent usages of the preposition in are explored. The preposition in is often substituted with other prepositions, such as on and at. The fundamental reason for the Chinese learners’ weakness is the negative transfer from their mother tongue (Wang 2001; Gong 2007; Zhang 2010). Although in and its Chinese equivalence zai...li (在...里) share the same proto-scene, there are discrepancies: the metaphorical senses of the preposition in are TIME, PURPOSE, NUMBER, CONTENT, FIELD, EVENT, SITUATION, SEGMENTATION, MANNER, PERSON, while those of zai...li (在...里) are only five: TIME, CONTENT, EVENT, SITUATION and PERSON. Thus the image schemata of each sense cannot be correspondingly mapped onto each other in different languages. This study also provides evidence for the universality and variation of spatial metaphors on the ground of cultural models. Philosophically, it supports the standpoint of Embodiment philosophy that abstract concepts are constructed on the basis of spatial metaphors that are grounded in the physical and cultural experience

Stealing Links from Graph Neural Networks

Graph data, such as chemical networks and social networks, may be deemed confidential/private because the data owner often spends lots of resources collecting the data or the data contains sensitive information, e.g., social relationships. Recently, neural networks were extended to graph data, which are known as graph neural networks (GNNs). Due to their superior performance, GNNs have many applications, such as healthcare analytics, recommender systems, and fraud detection. In this work, we propose the first attacks to steal a graph from the outputs of a GNN model that is trained on the graph. Specifically, given a black-box access to a GNN model, our attacks can infer whether there exists a link between any pair of nodes in the graph used to train the model. We call our attacks link stealing attacks. We propose a threat model to systematically characterize an adversary's background knowledge along three dimensions which in total leads to a comprehensive taxonomy of 8 different link stealing attacks. We propose multiple novel methods to realize these 8 attacks. Extensive experiments on 8 real-world datasets show that our attacks are effective at stealing links, e.g., AUC (area under the ROC curve) is above 0.95 in multiple cases. Our results indicate that the outputs of a GNN model reveal rich information about the structure of the graph used to train the model.Comment: To appear in the 30th Usenix Security Symposium, August 2021, Vancouver, B.C., Canad

Interfacial design strategies for selective electrocatalytic CO2 reduction through control of proton coupled electron transfer

The aim of this project was to construct and study a novel copper-based electrocatalyst embedded in a microenvironment with well-defined hydrophobicity to control proton activity and improve CO2 mass transport to modify the selectivity of the CO2 reduction reaction (CO2RR). Specifically, anodized aluminium oxide (AAO) membranes were used to grow and confine Cu nanowires (CuNWs) and the hydrophobicity of the CuNW-AAO composite electrode was increased by reaction with various silane molecules. Uniformly distributed CuNWs were successfully prepared in a commercial AAO porous membrane by square-wave pulsed electrodeposition. The length and width of CuNWs can be controlled by adjusting deposition time and applied current density. Analysis of the electrochemical behaviour of the composite CuNW-AAO electrode using capacitance measurements and a methylviologen redox probe, shows that the electrochemical surface area (ECSA) and roughness factor are reflective of electrolyte penetration throughout the CuNW-AAO electrode, supporting electrocatalysis along the length of the CuNW’s surrounded by AAO. Next, the hydrophobicity of the CuNW-AAO electrode was increased by reaction with various silane molecules. Contact angle measurements were used to quantify hydrophobicity as a function of silane and study the stability of the silane coating to electrolyte and under electrochemical conditions. Analysis showed that silane modified CuNW-AAO electrodes maintain large ECSA and roughness factor, and that addition of the silane coating etches the CuNWs surface, presumably via generation of HCl, increasing the electrode surface roughness. Control experiments using Cu foil electrodes exposed to silane, show that Cu can also be directly modified with silane. CO2RR reactions of silane modified Cu foil electrodes, show promotion of CO2 to C2+ product. Contact angle measurements after reaction showed a reduction in hydrophobicity due to partial loss of the silane coating. CO2RR using silane modified and unmodified CuNW-AAO electrodes resulted in mechanical instability due to hydrogen bubble formation behind the AAO membrane

Test-Time Poisoning Attacks Against Test-Time Adaptation Models

Deploying machine learning (ML) models in the wild is challenging as it suffers from distribution shifts, where the model trained on an original domain cannot generalize well to unforeseen diverse transfer domains. To address this challenge, several test-time adaptation (TTA) methods have been proposed to improve the generalization ability of the target pre-trained models under test data to cope with the shifted distribution. The success of TTA can be credited to the continuous fine-tuning of the target model according to the distributional hint from the test samples during test time. Despite being powerful, it also opens a new attack surface, i.e., test-time poisoning attacks, which are substantially different from previous poisoning attacks that occur during the training time of ML models (i.e., adversaries cannot intervene in the training process). In this paper, we perform the first test-time poisoning attack against four mainstream TTA methods, including TTT, DUA, TENT, and RPL. Concretely, we generate poisoned samples based on the surrogate models and feed them to the target TTA models. Experimental results show that the TTA methods are generally vulnerable to test-time poisoning attacks. For instance, the adversary can feed as few as 10 poisoned samples to degrade the performance of the target model from 76.20% to 41.83%. Our results demonstrate that TTA algorithms lacking a rigorous security assessment are unsuitable for deployment in real-life scenarios. As such, we advocate for the integration of defenses against test-time poisoning attacks into the design of TTA methods.Comment: To Appear in the 45th IEEE Symposium on Security and Privacy, May 20-23, 202