37 research outputs found
Modeling the Motivation of Usersâ Sharing Option: A Case Study Based on A Car-Sharing Digital Platform
Sharing economy is associated with a series of economic activities in terms of renting, lending, trading, bartering and swapping of goods, service, space or money, that take place in organized systems or digital platforms. In this research, we interviewed 50 drivers, a kind of users type who provides cars and service from a car-sharing digital platform. Based on the prior studies of motivation, we combined Social Exchange Theory (SET) and Technology Acceptance Model (TAM) to identify salient motivators in this context. Furthermore, building on Self-determination Theory (SDT), we propose a motivation model of usersâ sharing option in digital platform. The findings extend literatures of motivation researches in the context of sharing economy as well as help guide the development and operation of sharing economy digital platform
Text2Bundle: Towards Personalized Query-based Bundle Generation
Bundle generation aims to provide a bundle of items for the user, and has
been widely studied and applied on online service platforms. Existing bundle
generation methods mainly utilized user's preference from historical
interactions in common recommendation paradigm, and ignored the potential
textual query which is user's current explicit intention. There can be a
scenario in which a user proactively queries a bundle with some natural
language description, the system should be able to generate a bundle that
exactly matches the user's intention through the user's query and preferences.
In this work, we define this user-friendly scenario as Query-based Bundle
Generation task and propose a novel framework Text2Bundle that leverages both
the user's short-term interests from the query and the user's long-term
preferences from the historical interactions. Our framework consists of three
modules: (1) a query interest extractor that mines the user's fine-grained
interests from the query; (2) a unified state encoder that learns the current
bundle context state and the user's preferences based on historical interaction
and current query; and (3) a bundle generator that generates personalized and
complementary bundles using a reinforcement learning with specifically designed
rewards. We conduct extensive experiments on three real-world datasets and
demonstrate the effectiveness of our framework compared with several
state-of-the-art methods
Minimally Invasive Delivery of 3D Shape Recoverable Constructs with Ordered Structures for Tissue Repair
Minimally invasive procedures are becoming increasingly more common in surgery. However, the biomaterials capable of delivering biomimetic, three-dimensional (3D) functional tissues in a minimally invasive manner and exhibiting ordered structures after delivery are lacking. Herein, we reported the fabrication of gelatin methacryloyl (GelMA)-coated, 3D expanded nanofiber scaffolds and their potential applications in minimally invasive delivery of 3D functional tissue constructs with ordered structures and clinically appropriate sizes (4 cm Ă 2 cm Ă 1.5 mm). GelMA-coated, expanded 3D nanofiber scaffolds produced by combining electrospinning, gas-foaming expansion, hydrogel coating, and crosslinking are extremely shape recoverable after release of compressive strain, displaying a superelastic property. Such scaffolds can be seeded with various types of cells, including dermal fibroblasts, bone marrow-derived mesenchymal stem cells, and human neural stem/precursor cells to form 3D complex tissue constructs. Importantly, the developed 3D tissue constructs can be compressed and loaded into a 4-mm diameter glass tube for minimally invasive delivery without compromising the cell viability. Taken together, the method developed in this study could hold great promise for transplantation of biomimetic, 3D functional tissue constructs with well-organized structures for tissue repair and regeneration using minimally invasive procedures like laparoscopy and thoracoscopy
Evidence for Majorana bound state in an iron-based superconductor
The search for Majorana bound state (MBS) has recently emerged as one of the
most active research areas in condensed matter physics, fueled by the prospect
of using its non-Abelian statistics for robust quantum computation. A highly
sought-after platform for MBS is two-dimensional topological superconductors,
where MBS is predicted to exist as a zero-energy mode in the core of a vortex.
A clear observation of MBS, however, is often hindered by the presence of
additional low-lying bound states inside the vortex core. By using scanning
tunneling microscope on the newly discovered superconducting Dirac surface
state of iron-based superconductor FeTe1-xSex (x = 0.45, superconducting
transition temperature Tc = 14.5 K), we clearly observe a sharp and non-split
zero-bias peak inside a vortex core. Systematic studies of its evolution under
different magnetic fields, temperatures, and tunneling barriers strongly
suggest that this is the case of tunneling to a nearly pure MBS, separated from
non-topological bound states which is moved away from the zero energy due to
the high ratio between the superconducting gap and the Fermi energy in this
material. This observation offers a new, robust platform for realizing and
manipulating MBSs at a relatively high temperature.Comment: 27 pages, 11 figures, supplementary information include
Nearly quantized conductance plateau of vortex zero mode in an iron-based superconductor
Majorana zero-modes (MZMs) are spatially-localized zero-energy fractional
quasiparticles with non-Abelian braiding statistics that hold a great promise
for topological quantum computing. Due to its particle-antiparticle
equivalence, an MZM exhibits robust resonant Andreev reflection and 2e2/h
quantized conductance at low temperature. By utilizing variable-tunnel-coupled
scanning tunneling spectroscopy, we study tunneling conductance of vortex bound
states on FeTe0.55Se0.45 superconductors. We report observations of conductance
plateaus as a function of tunnel coupling for zero-energy vortex bound states
with values close to or even reaching the 2e2/h quantum conductance. In
contrast, no such plateau behaviors were observed on either finite energy
Caroli-de Genne-Matricon bound states or in the continuum of electronic states
outside the superconducting gap. This unique behavior of the zero-mode
conductance reaching a plateau strongly supports the existence of MZMs in this
iron-based superconductor, which serves as a promising single-material platform
for Majorana braiding at a relatively high temperature
Tunable vortex Majorana zero modes in LiFeAs superconductor
The recent realization of pristine Majorana zero modes (MZMs) in vortices of
iron-based superconductors (FeSCs) provides a promising platform for
long-sought-after fault-tolerant quantum computation. A large topological gap
between the MZMs and the lowest excitations enabled detailed characterization
of vortex MZMs in those materials. Despite those achievements, a practical
implementation of topological quantum computation based on MZM braiding remains
elusive in this new Majorana platform. Among the most pressing issues are the
lack of controllable tuning methods for vortex MZMs and inhomogeneity of the
FeSC Majorana compounds that destroys MZMs during the braiding process. Thus,
the realization of tunable vortex MZMs in a truly homogeneous compound of
stoichiometric composition and with a charge neutral cleavage surface is highly
desirable. Here we demonstrate experimentally that the stoichiometric
superconductor LiFeAs is a good candidate to overcome these two obstacles.
Using scanning tunneling microscopy, we discover that the MZMs, which are
absent on the natural surface, can appear in vortices influenced by native
impurities. Our detailed analysis and model calculations clarify the mechanism
of emergence of MZMs in this material, paving a way towards MZMs tunable by
controllable methods such as electrostatic gating. The tunability of MZMs in
this homogeneous material offers an unprecedented platform to manipulate and
braid MZMs, the essential ingredients for topological quantum computation.Comment: 21 pages, 10 figures. Suggestions and comments are welcom
Cytoplasmic p21 is a potential predictor for cisplatin sensitivity in ovarian cancer
<p>Abstract</p> <p>Background</p> <p>P21<sup>(WAF1/Cip1) </sup>binds to cyclin-dependent kinase complexes and inhibits their activities. It was originally described as an inhibitor of cancer cell proliferation. However, many recent studies have shown that p21 promotes tumor progression when accumulated in the cell cytoplasm. So far, little is known about the correlation between cytoplasmic p21 and drug resistance. This study was aimed to investigate the role of p21 in the cisplatin resistance of ovarian cancer.</p> <p>Methods</p> <p>RT-PCR, western blot and immunofluorescence were used to detect p21 expression and location in cisplatin-resistant ovarian cancer cell line C13* and its parental line OV2008. Regulation of cytoplasmic p21 was performed through transfection of p21 siRNA, Akt2 shRNA and Akt2 constitutively active vector in the two cell lines; their effects on cisplatin-induced apoptosis were evaluated by flow cytometry. Tumor tissue sections of clinical samples were analyzed by immunohistochemistry.</p> <p>Results</p> <p>p21 predominantly localizes to the cytoplasm in C13* compared to OV2008. Persistent exposure to low dose cisplatin in OV2008 leads to p21 translocation from nuclear to cytoplasm, while it had not impact on p21 localization in C13*. Knockdown of cytoplasmic p21 by p21 siRNA transfection in C13* notably increased cisplatin-induced apoptosis through activation of caspase 3. Inhibition of p21 translocation into the cytoplasm by transfection of Akt2 shRNA into C13* cells significantly increased cisplatin-induced apoptosis, while induction of p21 translocation into the cytoplasm by transfection of constitutively active Akt2 in OV2008 enhanced the resistance to cisplatin. Immunohistochemical analysis of clinical ovarian tumor tissues demonstrated that cytoplasmic p21 was negatively correlated with the response to cisplatin based treatment.</p> <p>Conclusions</p> <p>Cytoplasmic p21 is a novel biomarker of cisplatin resistance and it may represent a potential therapeutic target for ovarian tumors that are refractory to conventional treatment.</p
Lymphoma endothelium preferentially expresses Tim-3 and facilitates the progression of lymphoma by mediating immune evasion
Angiogenesis is increasingly recognized as an important prognosticator associated with the progression of lymphoma and as an attractive target for novel modalities. We report a previously unrecognized mechanism by which lymphoma endothelium facilitates the growth and dissemination of lymphoma by interacting with circulated T cells and suppresses the activation of CD4+ T cells. Global gene expression profiles of microdissected endothelium from lymphoma and reactive lymph nodes revealed that T cell immunoglobulin and mucin domainâcontaining molecule 3 (Tim-3) was preferentially expressed in lymphoma-derived endothelial cells (ECs). Clinically, the level of Tim-3 in B cell lymphoma endothelium was closely correlated to both dissemination and poor prognosis. In vitro, Tim-3+ ECs modulated T cell response to lymphoma surrogate antigens by suppressing activation of CD4+ T lymphocytes through the activation of the interleukin-6âSTAT3 pathway, inhibiting Th1 polarization, and providing protective immunity. In a lymphoma mouse model, Tim-3âexpressing ECs promoted the onset, growth, and dissemination of lymphoma by inhibiting activation of CD4+ T cells and Th1 polarization. Our findings strongly argue that the lymphoma endothelium is not only a vessel system but also a functional barrier facilitating the establishment of lymphoma immune tolerance. These findings highlight a novel molecular mechanism that is a potential target for enhancing the efficacy of tumor immunotherapy and controlling metastatic diseases