14 research outputs found
Short Video Activism With and on Douyin: An Innovative Repertoire of Contention for Chinese Consumers
This article examines consumer video activism tactics in China and their impact on Chinese consumers and society. Drawing upon 56 semistructured interviews and a case study analysis of Chinese online consumer protest in 2018, we argue that short-video-activism tactics have become an innovative repertoire of contention for Chinese consumers and Douyin, the “sister app” of TikTok, has become a real-time updated database of this repertoire. Using Douyin as a case study, we argue that it plays three key roles in mediating Chinese consumer activism: a techno-cultural construct that affords highly heterogeneous users to present everyday experiences via short videos; a multisided market that profoundly affects the tactics consumers choose to amplify their voices; and a governing entity that both moderates content for its users and simultaneously is subject to government regulations
PET imaging of apoptosis in tumor-bearing mice and rabbits after paclitaxel treatment with (18)F(-)Labeled recombinant human His10-annexin V.
Monitoring response to chemo- or radiotherapy is of great importance in clinical practice. Apoptosis imaging serves as a very useful tool for the early evaluation of tumor response. The goal of this study was PET imaging of apoptosis with (18)F-labeled recombinant human annexin V linked with 10 histidine tag ((18)F-rh-His10-annexin V) in nude mice bearing an A549 tumor and rabbits bearing a VX2 lung cancer after paclitaxel therapy. (18)F-rh-His10-annexin V was prepared by conjugation of rh-His10-annexin V with N-succinimidyl 4-[(18)F]fluorobenzoate. Biodistribution was determined in mice by the dissection method and small-animal PET. Single-dose paclitaxel (175 mg/m(2)) was used to induce apoptosis in A549 and VX2 tumor models. (18)F-rh-His10-annexin V was injected into A549 mice and VX rabbits to acquire dynamic and static PET images 72 h after paclitaxel treatment. The uptake of (18)F-rh-His10-annexin V in apoptotic cells 4 h after induction was 6.45±0.52 fold higher than that in non-induced cells. High focal uptake of (18)F-rh-His10-annexin V was visualized in A549 (SUVmax: 0.35±0.13) and VX2 (0.41±0.23) tumor models after paclitaxel treatment, whereas lower uptake was found in the corresponding tumors before treatment (A549 SUVmax: 0.04±0.02; VX2: 0.009±0.002). The apoptotic index was 75.61±11.56% in the treated VX2 cancer, much higher than that in the untreated VX2 (8.03±2.81%). This study demonstrated the feasibility of (18)F-rh-His10-annexin V for the detection of apoptosis after chemotherapy in A549 and VX2 tumor models
Role of androgen receptor in progression of LNCaP prostate cancer cells from G1 to S phase.
BACKGROUND: The androgen receptor (AR) plays a critical role in the proliferation of prostate cancer cells. However, its mechanism of action in proliferation remains unknown. An understanding of the mechanism of AR action in proliferation may lead to the development of effective strategies for the treatment of prostate cancer. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report that pulse treatment of synchronized LNCaP cells with Casodex, an AR-antagonist, for 4 hours in mid-G(1) phase was sufficient to prevent cells from entering S phase. Since the assembly of pre-replication complex (pre-RC) in G(1) is required for the progression of cells from G(1) to S phase, the effect of Casodex during mid-G(1) suggested that the role of AR in proliferation might be to regulate the assembly of pre-RC. To test this possibility, we investigated the interaction between AR and Cdc6, an essential component of pre-RC in LNCaP cells. AR co-localized and co-immunoprecipitated with Cdc6, and Casodex treatment disrupted this interaction. AR-immunoprecipitate (AR-IP) also contained cyclin E and cyclin A, which play a critical role in pre-RC assembly and cell cycle entry into S phase, and DNA polymerase-α, PCNA, and ribonucleotide reductase, which are essential for the initiation of DNA synthesis. In addition, in cells in S phase, AR co-sedimented with components of the DNA replication machinery of cells that entered S phase. CONCLUSIONS/SIGNIFICANCE: Together, these observations suggest a novel role of AR as a component of the pre-RC to exert control over progression of LNCaP cells from G(1) to S phase through a mechanism that is independent of its role as a transcription factor
Catalyst-Free Thermoset Polyurethane with Permanent Shape Reconfigurability and Highly Tunable Triple-Shape Memory Performance
Thermoset shape memory
polymer (SMP) with dynamic covalent bonds
in the network is a new class of SMPs for which the permanent shape
can be reconfigured via topological rearrangement (plasticity). Catalyzed
transcarbamoylation has recently been established as an effective
exchange reaction for plasticity in cross-linked polyurethane networks.
However, ensuring the plasticity severely constrains the network design
which adversely affects the ability to tune other classical shape
memory properties for practical applications. Facing this new challenge,
we design an amorphous polyurethane system for which the cross-linking
density can be adjusted in a wide range. We discovered that the use
of an aromatic diisocyanate in the synthesis of the polyurethanes
facilitates achieving plasticity without requiring any catalyst. The
overall network design leads to tunable recovery stress and shape
memory transition temperatures without sacrificing the plasticity.
The versatility of our polyurethane SMP is further reflected in its
triple-shape memory performance. We anticipate that our tunable polyurethanes
will benefit a variety of potential SMP device applications
Casodex dose-response inhibition of LNCaP cell AR activity in FCS- vs. CSS- containing medium.
<p>Exponentially growing LNCaP cells were washed twice with serum- and hormone- free medium and transferred to RPMI medium containing 10% fetal calf serum (FCS) or 6% charcoal-stripped serum (CSS). After 24 hours, Casodex was added and cells were incubated for an additional 24 hours. RNA isolated from control and Casodex treated cells was subjected to RT-PCR and qRT-PCR analysis of PSA as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056692#s2" target="_blank">Materials and Methods</a>. (A) RT-PCR products of PSA and GAPDH separated on 1% agarose gel. The ratio of band density PSA/GAPDH (P/G ratio) of cells in FCS without Casodex was set at 1.0 and the P/G ratio of other treatment conditions is expressed relative to this control. (B) Relative PSA levels, as determined by qRT-PCR, are plotted as a function of Casodex concentration. And (C) Relative PSA levels in Fig. 1B are plotted as a percentage of control without Casodex calculated separately for FCS- and CSS- medium. Closed circle, FCS-medium; and open circles, CSS-medium. The data is representative of two independent experiments.</p
Model of AR interaction with pre-RC and replication machinery as cells progress from G<sub>1</sub> to S phase.
<p>Pre-RC assembly involves sequential recruitment of Cdc6, Cdt1, and mini-chromosome maintenance (Mcm) proteins to the origin recognition complex (ORC), which serves as a “launching pad” for the assembly of DNA replication complexes/machinery at the origin of DNA replication. Cyclin-dependent kinases, such as Dbf4-Cdc7 kinase (not shown), cyclin E-Cdk-2 and cyclin A-Cdk-2, play a role in the recruitment of Mcm proteins and enzymes of DNA synthesis to form DNA replication machinery as cells progress from G<sub>1</sub> to S phase. AR integrates into DNA replication machinery through its interaction with pre-RC components. Events occurring at one of the many origins of DNA replication that exist in a proliferating cell are depicted.</p
AR-IP contains cyclin A and cyclin E, but not cyclin B:
<p>AR-IP prepared from exponentially growing LNCaP cells was subjected to Western blot analysis.</p
Casodex inhibits the progression of synchronized LNCaP cells from G<sub>1</sub> to S phase:
<p>LNCaP cells were synchronized by isoleucine-deprivation and released into complete medium. A) Casodex was added at the indicated time after release from isoleucine-block and maintained in the medium until <sup>3</sup>H-TdR incorporation was determined at 20 hours after release from isoleucine-block. Results are expressed as percentage of <sup>3</sup>H-TdR incorporation in control cells that were released into complete medium in the absence of Casodex. A) Casodex was added for a 4-hour period as shown in the top panel, and <sup>3</sup>H-thymidine (<sup>3</sup>H-TdR) incorporation into DNA was determined every 4 hours after release from isoleucine-block and after removal of Casodex. Each data point is the average of triplicate samples with <10% variation; data shown are representative of two independent experiments.</p
Casodex inhibits AR-Cdc6 interaction in LNCaP cells:
<p>A) Exponentially growing LNCaP cells were treated with Casodex or vehicle (control) for 24 hours and AR-IP prepared from treated and control cells was subjected to Western blot analysis to detect AR and Cdc6. B) LNCaP cells grown on slides were synchronized by isoleucine-deprivation and released into complete medium in the presence of vehicle (control) or Casodex. At 24 hours after release from isoleucine-block (when control cells are expected to enter S phase), cells were fixed and processed for immunoflourescent staining using anti-AR (AR-441) mouse monoclonal and anti-Cdc6 (H-304) rabbit polyclonal antibodies.</p
AR in LNCaP cell extracts co-immunoprecipitates with Cdc6:
<p>A) Cdc6-IP was prepared from exponentially growing LNCaP cells and was subjected to Western blot analysis. B) AR-IPs were prepared from synchronized G<sub>1</sub> phase (1 hour after release from isoleucine-block) or S phase (20 hours after release from isoleucine-block) LNCaP cells, and subjected to Western blot analysis. IgG heavy chain in AR-IP and IgG-IP is indicated by arrow.</p