121 research outputs found
Courtesans and soldier's wives: an analysis of three cases in the Qingming ji 清明集
No full textIn this article the author discusses three lawsuits in the Ming gong shu pan qingming ji 名公書判清明集 (“Collection of Enlightened Judgements”) which concern the punishment of women, either by registration as a government-courtesan or by being forced to become a soldier’s wife
Advances in Ultrafast Optics Advances in optical physics ;, v. 6./ Fei He and 5 others ; edited by Zhiyi, Wei.
No full textIn English.Includes bibliographical references and index.Wei, Zhiyi / Fang, Shaobo -- Zeng, Heping -- He, Fei / Liao, Yang / Lin, Jintian / Ni, Jielei / Zeng, Bin / Qiao, LingLing / Cheng, Ya -- Li, Derong / Lv, Xiaohua / Luo, Qingming / Zeng, Shaoqun -- Quan, Wei / Lai, Xuanyang / Liu, Xiaojun / Chen, Jing -- Wang, Shufeng / Meng, Kang / Gong, Qihuang -- Frontmatter -- Preface -- Contents -- 1. Ultrafast ultrahigh-intensity laser pulses / 2. Femtosecond optical frequency combs / 3. Three-dimensional integration of hybrid functionalities in transparent dielectrics by femtosecond laser direct writing / 4. Spatial and temporal broadening of a femtosecond laser pulse after angular dispersion / 5. Atomic physics in ultrafast intense laser fields / 6. Ultrafast spectroscopic techniques and ultrafast photophysics in polymers / Index.1 online resource (443 pages)
Recovery of gold from hydrometallurgical leaching solution of electronic waste via spontaneous reduction by polyaniline
No full textThe present study is primarily designed to develop an environmentally-benign approach for the recovery of precious metals, especially gold, from the ever increasingly-discarded electronic wastes (e-waste). By coupling the metal reduction process with an increase in the intrinsic oxidation state of the aniline polymers, and the subsequent re-protonation and reduction of the intrinsically oxidized polymer to the protonated emeraldine (EM) salt, polyaniline (PANi) films and polyaniline coated cotton fibers are able to recover metallic gold from acid/halide leaching solutions of electronic wastes spontaneously and sustainably. The current technique, which does not require the use of extensive extracting reagents or external energy input, can recover as much as 90% of gold from the leaching acidic solutions. The regeneration of polyaniline after gold recovery, as confirmed by the X-ray photoelectron spectroscopy measurements, promises the continuous operation using the current approach. The as-recovered elemental gold can be further concentrated and purified by incineration in air
The Versatile Attributes of MGMT: Its Repair Mechanism, Crosstalk with Other DNA Repair Pathways, and Its Role in Cancer
No full textO6-methylguanine-DNA methyltransferase (MGMT or AGT) is a DNA repair protein with the capability to remove alkyl groups from O6-AlkylG adducts. Moreover, MGMT plays a crucial role in repairing DNA damage induced by methylating agents like temozolomide and chloroethylating agents such as carmustine, and thereby contributes to chemotherapeutic resistance when these agents are used. This review delves into the structural roles and repair mechanisms of MGMT, with emphasis on the potential structural and functional roles of the N-terminal domain of MGMT. It also explores the development of cancer therapeutic strategies that target MGMT. Finally, it discusses the intriguing crosstalk between MGMT and other DNA repair pathways
Genetic Engineering a TGF-beta1 Tolerant Human Natural Killer Cell Line for Effective Anticancer Immunotherapy
No full text自然殺傷(NK)細胞在人類腫瘤固有免疫中扮演極為重要的角色。儘管如此，由於其所處腫瘤微環境中存在大量轉化生長因子b1 (TGF-b1)，而該因子已被廣泛證實能極大程度地抑制自然殺傷細胞的癌症殺傷效應。腫瘤細胞通過分泌大量轉化生長因子b1從而協助其逃避宿主免疫反應。我們前期試驗發現，TGF-b1/Smad3 信號是腫瘤進展過程中的關鍵性促進信號，荷瘤小鼠體內試驗證實抑制或敲除Smad3 能夠促進NK細胞發育及其抗腫瘤效應，並能有效阻止腫瘤的浸潤及轉移。儘管如此，通過全身注射Smad3抑制劑等方法來抑制Smad3 可能導致免疫系統的損傷。因此，此研究旨在通過特異性敲除NK細胞內的Smad3 來建立一種全新的抗腫瘤免疫療法。本研究將特異性靶向Smad3的短發卡狀RNA(shRNA)通過慢病毒載體成功導入NK-92 細胞，并建立Smad3穩定低水平表達的NK-92 細胞系（NK-92-S3KD），選擇NK-92作為本實驗的基因改造細胞主要因為其已進入二期臨床試驗，有利於將來新型改造細胞的臨床應用，具體過程列入本論文中第三章詳訴。我們體外檢測了NK-92-S3KD的細胞毒性及細胞因子的分泌水平，發現下調Smad3極大地提升了干擾素（IFN-ɣ）、颗粒酶B（Granzyme B）等细胞因子的水平。我們隨後在聯合免疫缺陷（NOD/SCID）小鼠上建立了侵襲性肝癌（HepG2）和黑色素瘤(A375)模型，并通過向荷瘤小鼠輸注NK-92-S3KD细胞以驗證該細胞的體內殺瘤效應，试验发现，NK-92-S3KD细胞与对照组相比能够极大的抑制肿瘤的生长。眾所周知，E4BP4在NK細胞發育過程中起著相當重要的作用。研究發現，TGF-b1可下調NK-92細胞E4BP4的表達。相反，下調Smad3可導致E4BP4表達上調。對NK-92-S3KD細胞進行E4BP4敲落的試驗結果表明，E4BP4的缺失可部份抵消由於Smad3敲落所致的IFN-ɣ提升的效應。進一步研究表明，Smad3通過直接作用於E4BP4的3’端非翻譯區（3’UTR） 對其轉錄水平進行調控。E4BP4繼而通過上調IFN-ɣ的啟動子活性促進IFN-ɣ的表達。因此，我們可以推斷，在腫瘤微環境中癌症細胞可能利用TGFβ1/Smad3/E4BP4這條信號傳遞軸來逃避NK細胞介導的免疫殺傷效應。除此之外，我們通過細胞因子抗体阵列發現Smad3 缺失上調了NK-92細胞中GM-CSF的表達水平。進一步研究發現，Smad3可能通過直接抑制基因啟動子活性下調GM-CSF表達。總之，TGF-b1/Smad3信號通過抑制NK細胞介導的抗腫瘤效應促進了癌症的進展。作為Smad3介導的NK細胞抑制效應的下游分子，E4BP4接受Smad3在基因轉錄水平的直接調控。更為重要的是，本研究通過基因改造技術成功建立了一Smad3穩定敲落的人源NK細胞株NK-92-S3KD。通過阻滯TGFβ1/Smad3/E4BP4 信號途徑，這種新型細胞株獲得了高效的抗腫瘤免疫效應。因此，NK-92-S3KD細胞免疫治療可望成為一可靠及安全的抗癌新方案。Natural killer (NK) cell is one of the major components of human innate immunity, but can be largely suppressed by the tumor microenvironment rich in cancer-derived transforming growth factor beta 1 (TGF-b1). Our previous work revealed that TGF-b1/Smad3 signaling is a curial promoter for cancer progression. Inhibition or deletion of Smad3 largely restored the TGF-b1 suppressed NK cell development and anti-cancer activities in tumor-bearing mice, thereby effectively preventing cancer invasion and metastasis. However, targeting Smad3 systemically may induce severer side effects by impairing the normal immune system. Thus, we aim to develop a NK cell specific Smad3-targeted anticancer immunotherapy by a genetic engineering approach in this project.As described in Chapter 3, a stable Smad3-knockdown human NK cell line (NK-92-S3KD) was established on a phase II clinical trial enrolled cell line NK-92 by transduction of lentivirus containing Smad3-shRNA sequence. Disruption of Smad3 alleviated the TGF-b1-suppressed cancer-killing activities of NK-92 cells against human invasive hepatoma HepG2 and melanoma A375 cells in vitro. Additionally, the TGF-b1-suppressed cytokine production (i.e. IFN-ɣ, granzyme B, perforin) was also restored by knockdown of Smad3. The therapeutic potential of NK-92-S3KD was further examined on two xenograft models by using HepG2 or A375 tumor bearing NK-deficient NOD/SCID mice. Tumor growth was largely inhibited by the adoptive transfer of NK-92-S3KD cells compared to the mice received empty vector control NK-92 (NK-92-EV) cells, enhanced production of NK cell derived cytokines were detected in the serum and tumor microenvironment.Mechanistic study revealed that deletion and inhibition of Smad3 significantly up-regulated the expression of an essential transcription factor for NK cell development, E4BP4, which was dramatically down-regulated in the NK-92-EV cells by TGF-b1. We found that TGF-b1 could reduce transcription of E4BP4 via triggering physical binding of Smad3 to the 3’ untranslated region (3’UTR) of E4BP4. Unexpectedly, IFN-ɣ production in NK-92 cells was largely enhanced by Smad3-knockdown but partially abrogated by the double knockdown of E4BP4 and Smad3, we eventually discovered that E4BP4 can directly bind to the promoter region and facilitate the transcription of IFN-ɣ in NK cells by performing luciferase reporter assay. Furthermore, using cytokine array we found that not only expression of IFN-ɣ but also GM-CSF, a cytokine important in restoration of immune function of leukocytes under inflammatory events, was also enhanced in the NK-92-S3KD cells, where Smad3 directly down-regulated GM-CSF transcription via suppressing the activity of promoter. Thus, cancer may utilize a TGFβ1/Smad3/E4BP4 axis to circumvent the NK cell-mediated immunity in the tumor microenvironment.In conclusion, TGF-b1/Smad3 signaling promotes cancer by suppressing the NK cell mediated anti-cancer immunity. E4BP4 is a direct Smad3 target gene and serves as the downstream effector for TGF-b1/Smad3-mediated inhibition of NK cell immunity against cancer. Most importantly, we have successfully developed a genetically engineered human NK cell line NK-92-S3KD to effectively promote the anti-cancer immunity of NK cells by blocking the TGFβ1/Smad3/E4BP4 axis in the tumor-friendly microenvironment. Thus, our novel TGF-b1 tolerant cell line NK-92-S3KD may represent a promising immunotherapy for cancer.Wang, Qingming.Thesis Ph.D. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …).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
Characterization of nanomechanical and piezoelectric properties of AlN thin film for thin film bulk acoustic wave resonators
No full textQuantifying the impact of human activities on geological hazards in mountainous areas: evidence from Shennongjia, China
No full textNumerical study of flow boiling in micro/mini channels
No full textBoiling phenomena in micro scale has emerged as an interesting topic due to its complexity and increasing usage in micro electronic and mechanical systems (MEMS). Experimental visualization has discovered five main flow regimes: nucleate boiling, isolated bubbles, confine bubbly flow, elongated bubbly (or slug) flow, and annular flow. Two of these patterns (confine bubbles and slug flow) are rarely found in macro channels and are believed to have very different heat transfer mechanisms to that of nucleate boiling. The development of a phenomenological model demands a deep understanding of each flow regime as well as the transition process between them. While studies in every individual flow pattern are available in literature, the mechanisms of transition processes between them remain mysterious. More specifically, how the isolated bubbles evolve into a confined bubbly flow, and how this further evolves into elongated bubbles and finally an annular flow. The effects of boundary conditions such as wall heat flux, surface tension, and interfacial velocity are unclear, too. The aims of this thesis are to develop and validate a new numerical algorithm, perform a comprehensive numerical study on these transition processes, uncover the transition mechanisms and investigate effects of boundary and operating conditions. Firstly, a sophisticated and robust numerical model is developed by combining a coupled level set method (CLSVOF) and a non-equilibrium phase change model, which enables an accurate capture of the two-phase interface, as well as the interface temperature. Secondly, several flow regime transitions are studied in this thesis: nucleate bubbles to confined bubbly flow, multi confined bubbles moving consecutively in a micro channel, and slug to annular flow transition. Effects of surface tension, heat flux, mass flux, and fluid properties are examined. All these regimes are studied separately, which means an appropriate initial condition is needed for each regime. The author developed a simplified model based on energy balance to set the initial and boundary conditions.QC 20170403</p
Measuring Visual Saliency by Site Entropy Rate
No full textIn this paper, we propose a new computational model for visual saliency derived from the information maximization principle. The model is inspired by a few well acknowledged biological facts. To compute the saliency spots of an image, the model first extracts a number of sub-band feature maps using learned sparse codes. It adopts a fully-connected graph representation for each feature map, and runs random walks on the graphs to simulate the signal/information transmission among the interconnected neurons. We propose a new visual saliency measure called Site Entropy Rate (SER) to compute the average information transmitted from anode (neuron) to all the others during the random walk on the graphs/network. This saliency definition also explains the center-surround mechanism from computation aspect. We further extend our model to spatial-temporal domain so as to detect salient spots in videos. To evaluate the proposed model, we do extensive experiments on psychological stimuli, two well known image datasets, as well as a public video dataset. The experiments demonstrate encouraging results that the proposed model achieves the state-of-the-art performance of saliency detection in both still images and videos.Computer Science, Artificial IntelligenceComputer Science, Software EngineeringMathematics, AppliedImaging Science & Photographic TechnologyEICPCI-S(ISTP)4
On New Media Art, Its Development and Achievement in China
No full textThis essay is aimed to introduce the development status of the new media art in China; the author gave its definition based on his own understanding and observation, which included various forms. Moreover, the developing environment of the new media art in the world is presented systematically in the essay. The author combed the art history and technology history which are closely connected with the birth of the new media art. China has achieved many accomplishments in new media art forms, such as the successful hosting of 2008 World Olympic Games and 2010 World expo. In the opening ceremony of 2008 World Olympic Games, interactive art, installation art and virtual space are in perfect use. Especially, “scroll” has combined all the above technological methods into display, which brought about stunning sensory impact to the audiences. After two years, Shanghai was the focus of the world, 242 countries and international organizations that have attended 2010 Shanghai World expo. The new media art forms are bloomed and flourished, China pavilion’s Qingming Riverside was endowed with new vitality via these new art media forms
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