Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
1,174 result(s) for "H-R, Kim"
Sort by:
Light quantum control of persisting Higgs modes in iron-based superconductors
The Higgs mechanism, i.e., spontaneous symmetry breaking of the quantum vacuum, is a cross-disciplinary principle, universal for understanding dark energy, antimatter and quantum materials, from superconductivity to magnetism. Unlike one-band superconductors (SCs), a conceptually distinct Higgs amplitude mode can arise in multi-band, unconventional superconductors  via strong interband Coulomb interaction, but is yet to be accessed. Here we discover such hybrid Higgs mode and demonstrate its quantum control by light in iron-based high-temperature SCs. Using terahertz (THz) two-pulse coherent spectroscopy, we observe a tunable amplitude mode coherent oscillation of the complex order parameter from coupled lower and upper bands. The nonlinear dependence of the hybrid Higgs mode on the THz driving fields is distinct from any known SC results: we observe a large reversible modulation of resonance strength, yet with a persisting mode frequency. Together with quantum kinetic modeling of a hybrid Higgs mechanism, distinct from charge-density fluctuations and without invoking phonons or disorder, our result provides compelling evidence for a light-controlled coupling between the electron and hole amplitude modes assisted by strong interband quantum entanglement. Such light-control of Higgs hybridization can be extended to probe many-body entanglement and hidden symmetries in other complex systems. A collective excitation called Higgs mode may arise in multi-band superconductors via strong interband interaction, but it is yet to be accessed. Here, the authors observe a tunable coherent amplitude oscillation of the order parameter in Ba(Fe 1− x Co x ) 2 As 2 , suggesting appearance and control of the Higgs mode by light tuning interband interaction.
A modular factory testbed for the rapid reconfiguration of manufacturing systems
The recent manufacturing trend toward mass customization and further personalization of products requires factories to be smarter than ever before in order to: (1) quickly respond to customer requirements, (2) resiliently retool machinery and adjust operational parameters for unforeseen system failures and product quality problems, and (3) retrofit old systems with upcoming new technologies. Furthermore, product lifecycles are becoming shorter due to unbounded and unpredictable customer requirements, thereby requiring reconfigurable and versatile manufacturing systems that underpin the basic building blocks of smart factories. This study introduces a modular factory testbed, emphasizing transformability and modularity under a distributed shop-floor control architecture. The main technologies and methods, being developed and verified through the testbed, are presented from the four aspects of rapid factory transformation: self-layout recognition, rapid workstation and robot reprogramming, inter-layer information sharing, and configurable software for shop-floor monitoring.
Light-Driven Raman Coherence as a Nonthermal Route to Ultrafast Topology Switching in a Dirac Semimetal
A grand challenge underlies the entire field of topology-enabled quantum logic and information science: how to establish topological control principles driven by quantum coherence and understand the time dependence of such periodic driving. Here we demonstrate a few-cycle THz-pulse-induced phase transition in a Dirac semimetalZrTe5that is periodically driven by vibrational coherence due to excitation of the lowest Raman active mode. Above a critical THz-pump field threshold, there emerges a long-lived metastable phase, approximately 100 ps, with unique Raman phonon-assisted topological switching dynamics absent for optical pumping. The switching also manifests itself by distinct features: nonthermal spectral shape, relaxation slowing near the Lifshitz transition where the critical Dirac point occurs, and diminishing signals at the same temperature that the Berry-curvature-induced anomalous Hall effect magnetoresistance vanishes. These results, together with first-principles modeling, identify a mode-selective Raman coupling that drives the system from strong to weak topological insulators with a Dirac semimetal phase established at a critical atomic displacement controlled by the phonon coherent pumping. Harnessing of vibrational coherence can be extended to steer symmetry-breaking transitions, i.e., Dirac to Weyl ones, with implications for THz topological quantum gate and error correction applications.
STAT3 activation in endothelial cells is important for tumor metastasis via increased cell adhesion molecule expression
Metastasis is a life-threatening feature of cancer and is primarily responsible for cancer patient mortality. Cross talk between tumor cells and endothelium is important for tumor progression and metastasis. However, very little is known about the mechanisms by which endothelial cells (ECs) that are close to tumor cells, respond to the tumor cells during tumor progression and metastasis. In this study, we exploited the use of EC-specific signal transducer activator of transcription 3 (STAT3) knockout mice to investigate the role of STAT3 in ECs in tumor progression and metastasis. We found that the loss of STAT3 in ECs did not affect primary Lewis lung carcinoma (LLC) tumor growth, but it reduced in vivo LLC metastasis in experimental and spontaneous metastasis models. Mechanistically, STAT3 activation upregulated cell adhesion molecule expression, including E-selectin and P-selectin, in murine endothelial MS-1 cells treated with tumor cell-conditioned media in vitro and in pre-metastatic lungs of tumor-bearing mice in vivo . We also found that both E-selectin and P-selectin were, at least in part, responsible for STAT3-induced adhesion and invasion of LLC cells through an EC monolayer. However, tumor cell-conditioned media from B16F10 melanoma cells did not activate STAT3 in MS-1 cells. As a result, EC STAT3 knockout did not affect B16F10 melanoma cell metastasis. In addition, various human cancer cells activated STAT3 in human ECs (HUVECs), resulting in increased cell adhesion molecule expression. Collectively, our findings demonstrate that STAT3 activation in ECs promotes tumor metastasis through the induction of cell adhesion molecules, demonstrating a role for ECs in response to tumor cells during tumor metastasis.
A cross-sectional study of gender differences in quality of life domains in patients with neurofibromatosis type 1
Background There is limited data regarding gender differences in quality of life between women and men with Neurofibromatosis type 1. We aimed to study differences in quality of life domains between women and men with Neurofibromatosis type 1 living in Canada. Methods This is a cross sectional study of adults with Neurofibromatosis type 1 attending a tertiary NF centre at Toronto General Hospital between January 2016 to December 2017. Demographic and clinical data were collected. We compared scores of generic measures (SF-36, EQ-5D-5L, pain interference) and a disease-specific measure (PedsQL-NF1 module) between women and men. We also assessed the relationship between disease visibility scored by an examiner (Ablon’s visibility index) and self-reported perceived physical appearance, stratified by gender. Results One hundred and sixty-two participants were enrolled, 92 females and 70 males. Ablon’s index score 1 was in 43% and score 2 in 44%, while only 13% of patients had a score 3. Women had worse scores on the total PedsQL-NF1 scales, and also in the perceived physical appearance, anxiety and emotional health domains. In women, there was a low but significant correlation between Ablon’s index and perceived physical appearance (r = − 0.27, p = 0.01, ANOVA p < 0.001). In men, there was no difference in self-reported physical appearance by Ablon’s index. There were no differences between men and women in the SF-36 or EQ-5D-5L scores. Conclusion Women with NF1 reported worse NF1-related quality of life than men, with worse perceived physical appearance, anxiety, and mental health. Perceived physical appearance does not always correlate to disease visibility; therefore, healthcare providers should inquire about body image, physical appearance concerns, and mental health, especially among women with NF1.
Terahertz rectification in ring-shaped quantum barriers
Tunneling is the most fundamental quantum mechanical phenomenon with wide-ranging applications. Matter waves such as electrons in solids can tunnel through a one-dimensional potential barrier, e.g. an insulating layer sandwiched between conductors. A general approach to control tunneling currents is to apply voltage across the barrier. Here, we form closed loops of tunneling barriers exposed to external optical control to manipulate ultrafast tunneling electrons. Eddy currents induced by incoming electromagnetic pulses project upon the ring, spatiotemporally changing the local potential. The total tunneling current which is determined by the sum of contributions from all the parts along the perimeter is critically dependent upon the symmetry of the loop and the polarization of the incident fields, enabling full-wave rectification of terahertz pulses. By introducing global geometry and local operation to current-driven circuitry, our work provides a novel platform for ultrafast optoelectronics, macroscopic quantum phenomena, energy harvesting, and multi-functional quantum devices. Many experiments have been performed that study rectification by exciting electrons to tunnel across a single quantum barrier. Here, the authors take a 2-dimensional approach by combining 2D closed-loop tunneling barriers with broken symmetry to enable geometrically controllable rectification of THz fields.
BAX inhibitor-1 enhances cancer metastasis by altering glucose metabolism and activating the sodium-hydrogen exchanger: the alteration of mitochondrial function
The anti-apoptotic protein, BAX inhibitor-1 (BI-1), has a role in cancer/tumor progression. BI-1-overexpressing HT1080 and B16F10 cells produced higher lung weights and tumor volumes after injection into the tail veins of mice. Transfection of BI-1 siRNA into cells before injection blocked lung metastasis. in vitro , the overexpression of BI-1 increased cell mobility and invasiveness, with highly increased glucose consumption and cytosolic accumulation of lactate and pyruvate, but decreased mitochondrial O 2 consumption and ATP production. Glucose metabolism-associated extracellular pH also decreased as cells excreted more H + , and sodium hydrogen exchanger (NHE) activity increased, probably as a homeostatic mechanism for intracellular pH. These alterations activated MMP 2/9 and cell mobility and invasiveness, which were reversed by the NHE inhibitor, 5-( N -ethyl- N -isopropyl) amiloride (EIPA), suggesting a role for NHE in cancer metastasis. In both in vitro and in vivo experiments, C-terminal deleted (CΔBI-1) cells showed similar results to control cells, suggesting that the C-terminal motif is required for BI-1-associated alterations of glucose metabolism, NHE activation and cancer metastasis. These findings strongly suggest that BI-1 reduces extracellular pH and regulates metastasis by altering glucose metabolism and activating NHE, with the C-terminal tail having a pivotal role in these processes.
Regulation of the hTERT promoter activity by MSH2, the hnRNPs K and D, and GRHL2 in human oral squamous cell carcinoma cells
Higher expression of human telomerase reverse transcriptase (hTERT) and subsequent activation of telomerase occur during cellular immortalization and are maintained in cancer cells. To understand the mode of hTERT expression in cancer cells, we identified cancer-specific trans -regulatory proteins that interact with the hTERT promoter, using the promoter magnetic precipitation assay coupled with mass spectrometry. The identified proteins include MutS homolog 2 (MSH2), heterogeneous nuclear ribonucleoprotein (hnRNP) D, hnRNP K and grainyhead-like 2 (GRHL2). We noticed a higher expression of these proteins in human oral squamous cell carcinoma (OSCC) cells than in normal cells, which do not exhibit telomerase activity. Knockdown of MSH2, hnRNP D and GRHL2 resulted in a notable reduction of the hTERT promoter activity in tested cancer cells. Silencing of the above genes resulted in a significant reduction of the telomerase activity in OSCC cells. Interestingly, among the four identified genes, silencing of GRHL2 was essential in reducing telomerase activity and viability of tested cancer cells. These results suggest a possible role of GRHL2 in telomerase activation during cellular immortalization.
Dose-related effect of urinary cotinine levels on bone mineral density among Korean females
Summary To evaluate the dose-dependent relationship between smoking and bone mineral density (BMD), the present study used the BMD dataset of the Korean National Health and Nutrition Examination Survey IV (KNHANES IV). The linearity of BMD for urinary cotinine levels was demonstrated with statistical significance in postmenopausal females. Introduction It is well established that smoking is an important lifestyle risk factor for bone health (bone loss, osteoporosis, and fracture). However, several studies demonstrated conflicting evidence for a dose-dependent relationship between smoking and bone health. To evaluate the dose-dependent relationship between smoking and BMD, the present study estimated dose-related effects of smoking (urinary cotinine level) on BMD at various sites (femur neck, total femur, and lumbar spine) in females with controlling menopausal status. Methods The present study used the BMD dataset of the KNHANES IV, which was performed in 2008 and 2009. A total of 4,260 pre- and postmenopausal females were included in the present study. Dose–response relationships between BMD and urinary cotinine levels were estimated using analysis of covariance in pre-menopausal females and postmenopausal females, respectively. Results In postmenopausal females, the regression coefficients for BMD with urinary cotinine levels were −0.006, −0.006, and −0.008 (g/cm 2 per ng/ml) at femur neck, total femur, and lumbar spine, respectively ( p value < 0.05). Thus, the linearity of BMD for urinary cotinine levels was demonstrated with statistical significance in postmenopausal females. Conclusion Our findings suggested a significant dose-related effect of urinary cotinine level with BMD at femur neck, total femur, and lumbar spine among postmenopausal females.
Insulin-sparing and fungible effects of E4orf1 combined with an adipocyte-targeting sequence in mouse models of type 1 and type 2 diabetes
Obesity impairs glycemic control and causes insulin resistance and type 2 diabetes. Adenovirus 36 (Ad36) infection can increase the uptake of excess glucose from blood into adipocytes by increasing GLUT4 translocation through the Ras–Akt signaling pathway, which bypasses PI3K–Akt-mediated insulin receptor signaling. E4orf1 , a viral gene expressed early during Ad36 infection, is responsible for this insulin-sparing effect and may be an alternative target for improving insulin resistance. To deliver the gene to adipocytes only, we connected the adipocyte-targeting sequence ( ATS ) to the 5′ end of E4orf1 ( ATS–E4orf1 ). In vitro transfection of ATS–E4orf1 into preadipocytes activated factors for GLUT4 translocation and adipogenesis to the same extent as did Hemagglutinin ( HA)-E4orf1 transfection as positive reference. Moreover, the Transwell migration assay also showed that ATS–E4orf1 secreted by liver cells activated Akt in preadipocytes. We used a hydrodynamic gene delivery technique to deliver ATS–E4orf1 into high-fat diet-fed and streptozotocin-injected mice (disease models of type 2 and type 1 diabetes, respectively). ATS–E4orf1 improved the ability to eliminate excess glucose from the blood and ameliorated liver function in both disease models. These findings suggest that ATS–E4orf1 has insulin-sparing and fungible effects in type 2 and 1 diabetes independent of the presence of insulin.