81 research outputs found
Under Three Heavy Mountains—Identity Construction and Subjectivity Struggle of Chinese Women Workers
No full textThis paper examines contemporary Chinese women workers, whose experiences have gained increasing attention as rural labor forces migrate to urban areas and China’s status as the “factory of the world” evolves. It utilizes Pun Ngai’s ethnography “Made in China” as the primary text, alongside supporting texts such as “Rural Women in Urban China” (Jacka, 2006), “The change of factory regime in China and its impacts on workers” (Zhao, 2010). This paper provides a detailed analysis of the construction of these workers’ identities and their struggle for subjectivity. Confronted with triple oppression, female workers navigate and reshape their identities amidst the tensions between urban and rural settings
LFED: A Literary Fiction Evaluation Dataset for Large Language Models
No full textThe rapid evolution of large language models (LLMs) has ushered in the need
for comprehensive assessments of their performance across various dimensions.
In this paper, we propose LFED, a Literary Fiction Evaluation Dataset, which
aims to evaluate the capability of LLMs on the long fiction comprehension and
reasoning. We collect 95 literary fictions that are either originally written
in Chinese or translated into Chinese, covering a wide range of topics across
several centuries. We define a question taxonomy with 8 question categories to
guide the creation of 1,304 questions. Additionally, we conduct an in-depth
analysis to ascertain how specific attributes of literary fictions (e.g., novel
types, character numbers, the year of publication) impact LLM performance in
evaluations. Through a series of experiments with various state-of-the-art
LLMs, we demonstrate that these models face considerable challenges in
effectively addressing questions related to literary fictions, with ChatGPT
reaching only 57.08% under the zero-shot setting. The dataset will be publicly
available at https://github.com/tjunlp-lab/LFED.gi
An Effective Charging Torque Elimination Method for Dual-Channel Electric-Drive-Reconstructed Onboard Chargers
No full textThe idea of electric-drive-reconstructed onboard charger (EDROC) systems, along with the concept of dual-channel charging, offers a novel design, thought to enhance the integration and fault tolerance of the charging system of electric vehicles (EVs). This article investigates a dual-channel EDROC incorporating an asymmetrical six-phase permanent magnet synchronous machine (ASPMSM). A unique operation mode, called the unbalanced charging voltage operation mode, exists in this topology, in case the voltages of the two batteries are unequal. This unbalance results in different winding currents following through two channels, leading to an undesired charging torque in the machine. To ensure the safety of the system, an effective charging torque elimination method, based on dual-channel winding current balance, is proposed, which achieves a dot-shaped current path of torque generation-associated subspace (i.e., α–β subspace) by balancing the dual-channel charging power. Eventually, a controller is designed for the system and a prototype is created, to validate the effectiveness of the proposed method
CUHK electronic theses & dissertations collection
No full textObstructive sleep apnea (OSA) is a common breathing and sleeping disorder, characterized by repeated episodes of airway obstruction during sleep resulting in intermittent hypoxia (IH). From clinical reports, patients with OSA are associated with behavioral and neuropsychological deficits, including impaired spatial learning memory and cognitive deficiencies. Previous studies proposed that reactive oxygen species (ROS) and apoptosis caused by intermittent hypoxia (IH) contributed to this cognitive deficits. However, the exact mechanism is still poorly understood and not settled.The endoplasmic reticulum (ER) is a cellular organelle in which all secretory and integral membrane proteins are folded and is also the site where proteins are post-translationally modified in ATP-dependent chaperone-mediated processes. In this study, we hypothesized that ER stress in the hippocampus is initiated in the OSA via elevated levels of ROS. Four groups of adult male mice were used, with two of them exposed to normoxia as control, and the other two exposed to IH treatment, each receiving either vehicle or tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor. Eight-armed radial maze was used to investigate the performance of reference memory during the whole IH/normoxia treatment. After behavior test, long-term potentiation (LTP) was measured to investigate synaptic plasticity in hippocampus. Furthermore, ER stress-associated pro-apoptotic effectors were detected by Western blotting, and ultra-structure of rough ER and the morphology of hippocampal dendritic spines and synapses in the hippocampal CA1 area were observed.LTP was impaired in the hippocampus after IH treatment, which was rescued by TUDCA. Furthermore, ER stress-associated pro-apoptotic effectors, CHOP and caspase-12, were up-regulated after chronic IH treatment and was abolished by co-infusion of TUDCA. Meanwhile, increased cleaved-caspase-3 after chronic IH treatment was reduced by TUDCA via increased expression of Bcl-2. On the other hand, ultrastructural analysis of rough ER in the hippocampal CA1 revealed IH-induced ER luminal swelling, and was attenuated by TUDCA. In addition, the length of synaptic active zone was significantly reduced after chronic IH treatment and was partially rescued by the application of TUDCA. Golgi staining also showed a decrease in mature dendritic spines in IH group, and reversed by TUDCA. In behavioral analysis, the number of reference memory errors significantly increased after IH treatment and rescued by TUDCA injection. Overall, the data suggest a critical role of ER stress underlying the impairment of long-term synaptic plasticity and neurocognitive deficits in chronic IH. Targeting ER stress could be a potential therapeutic strategy for neural dysfunction in OSA.On the other hand, neuronal firing, especially robust persistent activity of neuron in hippocampus, is critical role in memory formation. Increased ROS induced by IH has been implicated in long-term potentiation of neural activity. IH could be involved in a variety of K⁺ channels which eventually leads to excitotoxicity by increased Ca2⁺-dependent glutamate release. Although the results were just shown in acute IH treatment, the chronic effect of IH on the firing frequency of hippocampus is still unknown.Therefore, to investigate the effect of chronic IH treatment on firing activities and local field potentials of hippocampal neurons, implantation of multi-channel micro-wires electrode array into hippocampus of OSA model rat was performed to monitor spontaneous discharge. The results were shown the firing frequency of pyramidal neurons (PNs) was significantly elevated after 8 hours IH in second and third days, on the other hand, interneurons (INs) seem to be more sensitive to intermittent hypoxia since the higher firing frequency was sustained from third day to seventh day after 8 hours IH, however, at the end of 14 days IH treatment, the firing frequencies of PNs and INs are all both dramatically reduced. Meanwhile, the results in this part will enable us to understand the exact change of firing pattern and local field potential during intermittent hypoxia. The percentage of complex burst spikes was decreased after 14 days IH in PNs and the power of theta rhythms was also impaired. It suggests that the disorder of neuronal pattern and the change of local field potential are associated with cognitive impairment in OSA model. After 1 week recovery, the firing frequency of PNs was rescued again, but not for that of INs. We also found that the power of theta rhythms which had an important role in memory formation was weaker after 2 weeks IH treatment, however, the precise mechanism was still unknown. From the effect of intermittent hypoxia on spontaneous discharges and LFP of hippocampal neurons in free moving rat, it may reveal some roles of IH in cognitive impairment via disorder neuronal function in CA1 region.阻塞性睡眠呼吸暫停(OSA) 是一種常見的睡眠障礙疾病，這種疾病的主要特徵是在睡眠過程中反復發作的氣道阻塞，從而導致间歇性缺氧(IH)。從臨床報導中發現，OSA患者表現出行為和神經心理缺陷，包括空間學習記憶的受損和認知缺陷。通過之前的研究表明，活性氧(ROS)的增多和細胞凋亡是間歇性缺氧所引起認知功能障礙的主要機制之一，然而，其具體的機制仍不清楚。作為細胞重要的細胞器，內質網是分泌蛋白和膜蛋白折疊組裝的主要場所，同時，由ATP依賴的分子伴侶所介導的蛋白質翻譯後修飾這一過程也主要在內置網中完成。在本課題中，我們假設在OSA模型的海馬組織中，內質網應激的啟動是由於缺氧引起的與活性氧(ROS)的升高。在本課題中，我們使用了四組成年雄性小鼠，其中兩組作為正常對照組，分別接受生理鹽水和牛磺去氧膽酸（一種常用的內質網抑制劑）的腹腔注射，另外兩組接受缺氧處理，同時也分別接受照生理鹽水和牛磺去氧膽酸注射。八臂放射迷宮被用來研究參考記憶的表現。行為學結束之後，長時程增強(LTP)用來測定海馬的突觸可塑性。用免疫印跡的方法檢測內質網應激的相關凋亡蛋白的表達情況，並且觀察海馬CA1區域中，內質網超微結構和海馬樹突棘數目及突觸形態的變化。從實驗結果中，LTP在缺氧後減弱，而TUDCA能夠部分恢復由於缺氧所導致的LTP的降低。除此之外，內質網應激相關的促凋亡蛋白(CHOP和caspase-12)在缺氧組中表達升高，但是在TUDCA組中有所減低，同時，我們還發現，TUDCA也能夠減低缺氧組中cleaved-caspase-3的表達，而這一作用，可能與提高Bcl-2蛋白的表達（一個可標記的抗凋亡蛋白）有關。在間歇性缺氧組的海馬CA1區域中，粗面內質網出現管腔的腫脹，這一超微結構的變化表明在內質網出現官腔中有的許多未折疊蛋白聚集，並通過TUDCA的注射能夠降解未折疊蛋白來緩解這一現象的發生。同時，在IH處理後，突觸超微結構也發生了形態上的變化。突觸活性區的長度在IH處理組中顯著減少，但是在TUDCA組中有一定程度的恢復。高爾基染色顯示，成熟樹突棘（海馬突觸可塑性的結構基礎）的數目在間歇性缺氧組中有所下降，而在TUDCA治療後，成熟樹突棘的數目有所上升。我們發現參考記憶錯誤次數在缺氧後都有明顯的升高，而在注射TUDCA後，參考記憶錯誤次數都有所降低。總之，這些結果證明，內質網應激在間歇性缺氧的所引起的長時程突觸可塑性減弱和神經認知功能的損傷起到關鍵的作用，而抑制內質網應激對OSA中的出現神經功能紊亂起到一定的預防和治療效果。而另一方面，神經元的放電，特別是海馬中神經元穩定持久的放電形式，對記憶的形成起到關鍵的作用。間歇性缺氧所引起的ROS的升高對於長時程增強的神經活動存在一定的關係，因為，通過以往的研究發現，間歇性缺氧可以通過多種鉀離子通道的啟動，最終由於鈣離子依賴的谷氨酸釋放的增多从而導致興奮性毒性的神經遞質的釋放。而這些結果只在急性缺氧模型中發現，慢性的間歇性缺氧對海馬的放電頻率的影響仍是未知之數。因此，為了探討長時程的間歇性缺氧對海馬神經元的放電頻率和局部場電位的影響，多管道微絲電極陣列植入OSA大鼠的海馬中來監控自發放電的影響。結果表明，錐體細胞的放電頻率在第二天和第三天的8小時的間歇性低氧後明顯的升高了。另一方面，我們觀察到中間神經元似乎對間歇性缺氧更敏感，因為，從第三天到第七天缺氧8小時後，神經元的放電頻率都明顯的增高。但是在間歇性缺氧14天后，錐體細胞和中間神經元的放電頻率都所有顯著性的減少。同時，這一部分結果準確表明了海馬神經元的放電模式和局部場電位在間歇性缺氧的模型的是如何變化的。我們發現錐體細胞所具有的複合簇狀放電的比例減少，同時，theta波(與記憶的形成有關)的能量也有所減低。而這種神經元活動和局部的場電位的異常變化可能與OSA模型中出現的總認知功能障礙有關。在恢復一周後，錐體細胞的放電頻率有所增加，基本上可以恢復到缺氧前的狀態，但是中間神經元的頻率卻沒有多大的改變, 但是，其具體機制仍不清楚。從間歇性缺氧對大鼠海馬神經元自發放電和場電位影響的結果，它揭示了間歇性缺氧通過擾亂海馬CA1區域神經元的功能從而導致認知功能損傷。Xu, Linhao.Thesis (Ph.D.)--Chinese University of Hong Kong, 2014.Includes bibliographical references (leaves 167-199).Abstracts also in Chinese.Title from PDF title page (viewed on 03, October, 2016).Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only
Simultaneous variable selection and structural identification for time-varying coefficient models
No full textPh.D.Time-varying coefficient models are important tools in time series analysis because of their flexibility. To improve the accuracy of these models, it is important to identify covariates with null, constant and time-varying effects and to estimate their corresponding coefficients. One common approach is to combine methods for function estimation and shrinkage. In this model setting, because the predictors and the error term can be nonstationary processes, some estimation methods may not be consistent. However, Zhou and Wu proved the consistency of the local linear estimation method under such situation. Therefore, this thesis studies a combination of the local linear smoothing method and the adaptive group LASSO penalty to achieve covariate identification and coefficient estimation. The penalty term consists of two parts. The first term penalises the norm of the coefficient function, which is used to select relevant variables. The second term penalises the norm of the derivative function, which is used to identify the constancy of the coefficient functions. The asymptotic properties of the proposed method are established. The performance is demonstrated using simulated data and an application to data on air quality and health in Hong Kong.時間變係數模型由於其靈活性成為了時間序列數據分析中的重要工具。為了能夠得到更加準確的模型，在時間變係數模型當中分辨出具有零效應，恆定效應和時變效應的協變量並估計他們的相應係數是非常有意義的。一種常見的方法是將函數估計與懲罰項相結合。由於在我們的模型假定下，預測變量和噪聲項是非平穩時間過程，只有局部線性估計方法被證明具有相合性。因此本論文通過結合同部線性估計方法和自適應的群LASSO來實現這一目標。懲罰項分為兩部分，第一部分用來懲罰係數函數的範數來進行變量的選擇，男一部分是對係數導數範數的懲罰來判斷係數凶數是否為常數。本論文證明了該方法的極限理論性質。最後我們通過統計模擬以及對香港空氣質量和健康的數據進行分析證明了該方法的表現。Gao, Linhao.Thesis Ph.D. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 60-69).Abstracts also in Chinese.Title from PDF title page (viewed on 17, December, 2020)
Hydroxyapatite Supported Manganese Oxide as a Heterogeneous Catalyst for the Synthesis of 2, 5-Diformylfuran
No full textFunding Information: The research was supported by the Natural Science Foundation of China (21808163 and 21690083). Publisher Copyright: © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.A series of hydroxyapatite (HAP) supports with different Ca/P ratios were synthesized to prepare the MnOx/HAP catalysts. A MnOx/HAP catalyst showed highly efficient conversion of 5-hydroxymethylfurfural (HMF) into 2, 5-diformylfuran (DFF) in toluene solvent under no-alkali condition. 86.4% conversion of HMF with 90.9% selectivity of DFF at 120 °C for 12 h under 1.0 MPa O2 over the MnOx/HAP-10.0-400 were obtained. The redox of Mn4+/Mn3+ improved the oxidation of 5-HMF to DFF by the lattice oxygen, and the lattice oxygen was replenished by adsorbing O2 molecules. The reusability tests were found the catalyst could be reused up to four cycles without notable loss of catalytic activity. The MnOx/HAP-10.0-400 was a stable and reusable material for further industrial exploration of DFF in an environmentally friendly way.Peer reviewe
Ancient Medicinal Insect Steleophaga Plancyi (Boleny)-Derived Extracellular Vesicle-Like Particles Enhances Autophagic Activity to Promote Osteogenic Differentiation via Melatonin in Osteoporosis
No full textJiaxu Lu,1,2,* Jiaxian Chen,2,* Youping Jiang,1,2 Yuanyuan Liu,1,2 Sheng Yu,2 Zhen Shi,2 Peicong Chen,2 Hao Lin,2 Peng Li1,2 1Stem Cell Research and Cellular Therapy Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, People’s Republic of China; 2Orthopedic Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hao Lin, Orthopedic Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, People’s Republic of China, Email [email protected] Peng Li, Stem Cell Research and Cellular Therapy Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, People’s Republic of China, Email [email protected]: Osteoporosis, a critical public health challenge, is marked by skeletal deformities and heightened fracture risk. Steleophaga plancyi (Boleny) (SP), a component of traditional Chinese medicine, is known to enhance bone health, but the molecular mechanisms behind its osteoprotective effects are not well understood.Methods: We isolated extracellular vesicle (EV)-like particles from SP (SP-EVLP) using differential velocity centrifugation and investigated their effects on human bone marrow stromal cells (hBMSCs) in vitro. We utilized CCK-8, Alkaline phosphatase (ALP) and alizarin red staining (ARS), RNA-seq, bioinformatics, immunofluorescence, and Western blot to elucidate the osteoprotective role and mechanisms of SP-EVLP. The therapeutic potential of SP-EVLP was evaluated in an ovariectomized (OVX) rat model, a standard model for osteoporosis, by encapsulating them in enteric-coated capsules.Results: SP-EVLP were successfully isolated and characterized, and they were shown to be effectively internalized by hBMSCs, enhancing osteogenic differentiation. In the OVX rat model, SP-EVLP encapsulated in enteric-coated capsules significantly increased bone mass, indicating a robust osteoprotective effect. Further mechanistic studies revealed that SP-EVLP promotes osteoblast proliferation by activating melatonin-induced autophagy, a pathway that may improve osteoporotic conditions.Conclusion: Our results establish SP-EVLP as a promising therapeutic candidate for osteoporosis. The activation of melatonin-induced autophagy by SP-EVLP suggests a molecular mechanism for its osteoprotective effects, opening new possibilities for osteoporosis treatment development.Keywords: Osteoporosis, Steleophaga plancyi (Boleny), extracellular vesicles (EV)-like particles, autophagy, melatoni
Study on Serviceability of Transition Section Between Road and Tunnel
No full textThe determination of allowable differential settlement in bridge transition is a key problem to prevent vehicle jump at bridge head, but there are few theoretical research achievements in this aspect atroduction home and abroad. In this paper, four different structures of the road surface of The Sanyangchuan tunnel and the lead project are studied. The allowable differential settlement of asphalt pavement is calculated by asphalt pavement-layer system, and the allowable differential settlement is calculated by Ladan Lasse transform
iSky:Efficient and Progressive Skyline Computing in a Structured P2P Network
No full textAn interesting problem in peer-based data management is efficient support for skyline queries within a multiattribute space. A skyline query retrieves from a set of multidimensional data points a subset of interesting points, compared to which no other points are better. Skyline queries play an important role in multi-criteria decision making and user preference applications. In this paper, we address the skyline computing problem in a structured P2P network. We exploit the iMinMax(θ) transformation to map high-dimensional data points to 1-dimensional values. All transformed data points are then distributed on a structured P2P network called BATON, where all peers are virtually organized as a balanced binary search tree. Subsequently, a progressive algorithm is proposed to compute skyline in the distributed P2P network. Further, we propose an adaptive skyline filtering technique to reduce both processing cost and communication cost during distributed skyline computing. Our performance study, with both synthetic and real datasets, shows that the proposed approach can dramatically reduce transferred data volume and gain quick response time
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