14 research outputs found
Topologically-protected single-photon sources with topological slow light photonic crystal waveguides
Slow light waveguides are advantageous for implementing high-performance
single-photon sources required for scalable operation of integrated quantum
photonic circuits (IQPCs), though such waveguides are known to suffer from
propagation loss due to backscattering. A way to overcome the drawback is to
use topological photonics, in which robust waveguiding in
topologically-protected optical modes has recently been demonstrated. Here, we
report single-photon sources using single quantum dots (QDs) embedded in
topological slow light waveguides based on valley photonic crystals. We observe
Purcell-enhanced single-photon emission from a QD into a topological slow light
mode with a group index over 20 and its robust propagation even under the
presence of sharp bends. These results pave the way for the realization of
robust and high-performance single-photon sources indispensable for IQPCs
Contacts between the commissural axons and the floor plate cells are mediated by nectins
AbstractDuring development of the central nervous system (CNS), commissural axons grow toward the ventral midline. After crossing the floor plate, they abruptly change their trajectory from the circumferential to the longitudinal axis. The contacts between the commissural axons and the floor plate cells are involved in this axonal guidance, but their mechanisms or structures have not fully been understood. In this study, we found that nectin-1 and -3, immunoglobulin-like cell–cell adhesion molecules, asymmetrically localized at the contact sites between the commissural axons and the floor plate cells, respectively. In vitro perturbation of the endogenous trans-interaction between nectin-1 and -3 caused abnormal fasciculation of the commissural axons and impairment of the contacts, and resulted in failure in longitudinal turns of the commissural axons at the contralateral sites of the rat hindbrain. These results indicate that the contacts between the commissural axons and the floor plate cells are mediated by the hetero-trans-interaction between nectin-1 and -3 and involved in regulation of the trajectory of the commissural axons
Valley photonic crystal waveguides fabricated with CMOS-compatible process
Valley photonic crystal (VPhC) waveguides have attracted much attention
because of their ability to enable robust light propagation against sharp
bends. However, their demonstration using a complementary
metal-oxide-semiconductor (CMOS)-compatible process suitable for mass
production has not yet been reported at the telecom wavelengths. Here, by
tailoring the photomask to suppress the optical proximity effect, VPhC patterns
comprising equilateral triangular holes were successfully fabricated using
photolithography. We optically characterized the fabricated VPhC devices using
microscopic optics with near-infrared imaging. For comparison, we also
fabricated and characterized line-defect W1 PhC waveguides, in which the
transmission intensities decreased at some regions within the operating
bandwidth when sharp turns were introduced into the waveguide. In contrast, the
developed VPhC waveguides can robustly propagate light around the C-band
telecommunication wavelengths, even in the presence of sharp bends. Our results
highlight the potential of VPhC waveguides as an interconnection technology in
silicon topological photonic integrated circuits.Comment: 18 pages, 6 figure
Secondary CIC-rearranged sarcoma responsive to chemotherapy regimens for Ewing sarcoma: A case report
Capicua transcriptional repressor (CIC)-rearranged sarcoma is an Ewing-like sarcoma with an aggressive clinical course and poor prognosis. No standard treatment has been established. The present study describes a case of CIC-rearranged sarcoma with lung metastases developing in a 24-year-old woman as a therapy-associated malignancy following chemotherapy for anaplastic large cell lymphoma at nine years old. This was treated with palliative regimens used for Ewing sarcoma. The patient achieved disease control for one year. Of note, ifosfamide and etoposide (IE), which were used as a second line treatment lead to a partial response. The case described in the present study indicated that treatment with Ewing regimens is a reasonable option for patients with metastatic CIC-rearranged sarcoma, including those with a second malignant case
Characterization of brown adipose tissue thermogenesis in the naked mole-rat (Heterocephalus glaber), a heterothermic mammal
The naked mole-rat (NMR) is a heterothermic mammal that forms eusocial colonies consisting of one reproductive female (queen), several reproductive males, and subordinates. Despite their heterothermy, NMRs possess brown adipose tissue (BAT), which generally induces thermogenesis in cold and some non-cold environments. Previous studies suggest that NMR-BAT induces thermogenesis by cold exposure. However, detailed NMR-BAT characteristics and whether NMR-BAT thermogenesis occurs in non-cold environments are unknown. Here, we show beta-3 adrenergic receptor (ADRB3)-dependent thermogenic potential of NMR-BAT, which contributes to thermogenesis in the isolated queen in non-cold environments (30 degrees C). NMR-BAT expressed several brown adipocyte marker genes and showed noradrenaline-dependent thermogenic activity in vitro and in vivo. Although our ADRB3 inhibition experiments revealed that NMR-BAT thermogenesis slightly delays the decrease in body temperature in a cold environment (20 degrees C), it was insufficient to prevent the decrease in the body temperatures. Even at 30 degrees C, NMRs are known to prevent the decrease of and maintain their body temperature by heat-sharing behaviors within the colony. However, isolated NMRs maintained their body temperature at the same level as when they are in the colony. Interestingly, we found that queens, but not subordinates, induce BAT thermogenesis in this condition. Our research provides novel insights into NMR thermoregulation