45 research outputs found
Natural-artificial hybrid swarm: Cyborg-insect group navigation in unknown obstructed soft terrain
Navigating multi-robot systems in complex terrains has always been a
challenging task. This is due to the inherent limitations of traditional robots
in collision avoidance, adaptation to unknown environments, and sustained
energy efficiency. In order to overcome these limitations, this research
proposes a solution by integrating living insects with miniature electronic
controllers to enable robotic-like programmable control, and proposing a novel
control algorithm for swarming. Although these creatures, called cyborg
insects, have the ability to instinctively avoid collisions with neighbors and
obstacles while adapting to complex terrains, there is a lack of literature on
the control of multi-cyborg systems. This research gap is due to the difficulty
in coordinating the movements of a cyborg system under the presence of insects'
inherent individual variability in their reactions to control input. In
response to this issue, we propose a novel swarm navigation algorithm
addressing these challenges. The effectiveness of the algorithm is demonstrated
through an experimental validation in which a cyborg swarm was successfully
navigated through an unknown sandy field with obstacles and hills. This
research contributes to the domain of swarm robotics and showcases the
potential of integrating biological organisms with robotics and control theory
to create more intelligent autonomous systems with real-world applications
Preferential antitumor effect of the Src inhibitor dasatinib associated with a decreased proportion of aldehyde dehydrogenase 1-positive cells in breast cancer cells of the basal B subtype
<p>Abstract</p> <p>Background</p> <p>Recent studies have suggested that the Src inhibitor dasatinib preferentially inhibits the growth of breast cancer cells of the basal-like subtype. To clarify this finding and further investigate combined antitumor effects of dasatinib with cytotoxic agents, a panel of breast cancer cell lines of various subtypes was treated with dasatinib and/or chemotherapeutic agents.</p> <p>Methods</p> <p>Seven human breast cancer cell lines were treated with dasatinib and/or seven chemotherapeutic agents. Effects of the treatments on c-Src activation, cell growth, cell cycle, apoptosis and the proportion of aldehyde dehydrogenase (ALDH) 1-positive cells were examined.</p> <p>Results</p> <p>The 50%-growth inhibitory concentrations (IC<sub>50</sub>s) of dasatinib were much lower in two basal B cell lines than those in the other cell lines. The IC<sub>50</sub>s of chemotherapeutic agents were not substantially different among the cell lines. Dasatinib enhanced antitumor activity of etoposide in the basal B cell lines. Dasatinib induced a G1-S blockade with a slight apoptosis, and a combined treatment of dasatinib with etoposide also induced a G1-S blockade in the basal B cell lines. Dasatinib decreased the expression levels of phosphorylated Src in all cell lines. Interestingly, dasatinib significantly decreased the proportion of ALDH1-positive cells in the basal B cell lines but not in the other cell lines.</p> <p>Conclusions</p> <p>The present study indicates that dasatinib preferentially inhibits the growth of breast cancer cells of the basal B subtype associated with a significant loss of putative cancer stem cell population. A combined use of dasatinib with etoposide additively inhibits their growth. Further studies targeting breast cancers of the basal B subtype using dasatinib with cytotoxic agents are warranted.</p
Recent progress in the frequency selective metasurfaces in mid infrared wavelength
Here we summarized the recent progress of plasmonic meta surfaces in mid infrared wavelength region. The experimentally measured optical properties were com- pared with simulations by Finite difference time-domain calculations. Also, we demonstrate applications of these structures for the plasmonic IR-light sources and detec- tors.and another sensing devices
Detailed Experiment-Theory Comparison of Mid-Infrared Metasurface Perfect Absorbers
Realisation of a perfect absorber A = 1 with transmittance and reflectance T = R = 0 by a thin metasurface is one of the hot topics in recent nanophotonics prompted by energy harvesting and sensor applications ( A + R + T = 1 is the energy conservation). Here we tested the optical properties of over 400 structures of metal–insulator–metal (MIM) metasurfaces for a range of variation in thickness of insulator, diameter of a disc and intra-disc distance both experimentally and numerically. Conditions of a near perfect absorption A > 95 % with simultaneously occurring anti-reflection property ( R < 5 % ) was experimentally determined. Differences between the bulk vs. nano-thin film properties at mid-IR of the used materials can be of interest for plasmonic multi-metal alloys and high entropy metals
Absorption and scattering in perfect thermal radiation absorber-emitter metasurfaces
Detailed spectral analysis of radiation absorption and scattering behaviors of metasurfaces was carried out via finite-difference time-domain (FDTD) photonic simulations. It revealed that, for typical metal-insulator-metal (MIM) nanodisc metasurfaces, absorbance and scattering cross-sections exhibit a ratio of Sabs/Ssca = 1 at the absorption peak spectral position. This relationship was likewise found to limit the attainable photo-thermal conversion efficiency in experimental and application contexts. By increasing the absorption due to optical materials, such as Cr metal nano-films typically used as an adhesion layer, it is possible to control the total absorption efficiency h = Sabs/Ssca and to to make it the dominant extinction mechanism. This guided the design of MIM metasurfaces tailored for near-perfect-absorption and emission of thermal radiation. We present the fabrication as well as the numerical and experimental spectral characterization of such optical surfaces
Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals
Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterization of thin SiO2 and Si films sandwiched between two Au layers by way of experimental electromagnetic radiation absorption and thermal radiation emission measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data derived optical properties of multi-layer black metals provide guidelines for absorber/emitter structure design and potential applications. In addition, relatively simple lithography-free multi-layer structures are shown to exhibit absorber/emitter performance that is on par with what is reported in the literature for considerably more elaborate nano/micro-scale patterned metasurfaces
Bilateral ovarian endometriomas after laparoscopic hysterectomy following adjuvant tamoxifen therapy for breast cancer: A case report
Tamoxifen, a selective estrogen receptor modulator, is widely used as adjunctive therapy for women with breast cancer. However, tamoxifen has an agonistic effect on the endometrium and may be associated with endometrial proliferation, hyperplasia, polyp formation and carcinoma. The case report describes a 50-year-old woman who developed bilateral ovarian endometriomas while taking tamoxifen for breast cancer after total laparoscopic hysterectomy. She had undergone total laparoscopic hysterectomy for multiple uterine fibroids with no ovarian pathology at age 48Â years, had been diagnosed with breast cancer and had commenced tamoxifen as post-mastectomy adjuvant therapy. One year after starting tamoxifen, she developed bilateral ovarian swelling accompanied by acute abdominal pain. At laparoscopic bilateral salpingo-oophorectomy, endometriomas were visible on both ovaries. Pathological examination confirmed endometriotic cysts with no evidence of malignancy. Postoperatively, anastrozole (an aromatase inhibiter) was substituted for tamoxifen as adjuvant therapy for her breast cancer