Point Cloud-based Proactive Link Quality Prediction for Millimeter-wave Communications

This study demonstrates the feasibility of point cloud-based proactive link quality prediction for millimeter-wave (mmWave) communications. Previous studies have proposed machine learning-based methods to predict received signal strength for future time periods using time series of depth images to mitigate the line-of-sight (LOS) path blockage by pedestrians in mmWave communication. However, these image-based methods have limited applicability due to privacy concerns as camera images may contain sensitive information. This study proposes a point cloud-based method for mmWave link quality prediction and demonstrates its feasibility through experiments. Point clouds represent three-dimensional (3D) spaces as a set of points and are sparser and less likely to contain sensitive information than camera images. Additionally, point clouds provide 3D position and motion information, which is necessary for understanding the radio propagation environment involving pedestrians. This study designs the mmWave link quality prediction method and conducts realistic indoor experiments, where the link quality fluctuates significantly due to human blockage, using commercially available IEEE 802.11ad-based 60 GHz wireless LAN devices and Kinect v2 RGB-D camera and Velodyne VLP-16 light detection and ranging (LiDAR) for point cloud acquisition. The experimental results showed that our proposed method can predict future large attenuation of mmWave received signal strength and throughput induced by the LOS path blockage by pedestrians with comparable or superior accuracy to image-based prediction methods. Hence, our point cloud-based method can serve as a viable alternative to image-based methods.Comment: Submitted to IEEE Transactions on Machine Learning in Communications and Networkin

Establishment of Immunodeficient Retinal Degeneration Model Mice and Functional Maturation of Human ESC-Derived Retinal Sheets after Transplantation

Increasing demand for clinical retinal degeneration therapies featuring human ESC/iPSC-derived retinal tissue and cells warrants proof-of-concept studies. Here, we established two mouse models of end-stage retinal degeneration with immunodeficiency, NOG-rd1-2J and NOG-rd10, and characterized disease progress and immunodeficient status. We also transplanted human ESC-derived retinal sheets into NOG-rd1-2J and confirmed their long-term survival and maturation of the structured graft photoreceptor layer, without rejection or tumorigenesis. We recorded light responses from the host ganglion cells using a multi-electrode array system; this result was consistent with whole-mount immunostaining suggestive of host-graft synapse formation at the responding sites. This study demonstrates an application of our mouse models and provides a proof of concept for the clinical use of human ESC-derived retinal sheets

Strain preservation of experimental animals: Vitrification of two-cell stage embryos for multiple mouse strains

AbstractStrain preservation of experimental animals is crucial for experimental reproducibility. Maintaining complete animal strains, however, is costly and there is a risk for genetic mutations as well as complete loss due to disasters or illness. Therefore, the development of effective vitrification techniques for cryopreservation of multiple experimental animal strains is important. We examined whether a vitrification method using cryoprotectant solutions, P10 and PEPeS, is suitable for preservation of multiple inbred and outbred mouse strains. First, we investigated whether our vitrification method using cryoprotectant solutions was suitable for two-cell stage mouse embryos. In vitro development of embryos exposed to the cryoprotectant solutions was similar to that of fresh controls. Further, the survival rate of the vitrified embryos was extremely high (98.1%). Next, we collected and vitrified two-cell stage embryos of 14 mouse strains. The average number of embryos obtained from one female was 7.3–33.3. The survival rate of vitrified embryos ranged from 92.8% to 99.1%, with no significant differences among mouse strains. In vivo development did not differ significantly between fresh controls and vitrified embryos of each strain. For strain preservation using cryopreserved embryos, two offspring for inbred lines and one offspring for outbred lines must be produced from two-cell stage embryos collected from one female. The expected number of surviving fetuses obtained from embryos collected from one female of either the inbred or outbred strains ranged from 2.9 to 19.5. The findings of the present study indicated that this vitrification method is suitable for strain preservation of multiple mouse strains

Accuracy Assessment of Implant Placement in a Newly Developed Dynamic Navigation System: A Pilot Study

The aim of this pilot study was to evaluate the accuracy of a newly developed dynamic navigation system and to compare the accuracy between flapless and open-flap surgery, and between surgeons. The subjects were patients who were scheduled to receive implants of the same size using the newly developed dynamic navigation system. The study’s procedures included cone beam computed tomography (CBCT) filming with fiducials, virtual planning of implant placement and the use of motion tracking technology for calibration and practical implant placement. The accuracy was evaluated using preoperative (virtual implant) and postoperative (actual implant) CBCT images based on angular, apical, coronal and vertical deviations. The differences of deviations between flapless and open-flap surgery, and between two surgeons, were statistically compared. In total, 66 implants were placed in 39 patients. The median and interquartile range of angular, apical, coronal and vertical deviations were 3.07° (2.52–3.54°), 0.96 mm (0.75–1.42 mm), 0.76 mm (0.57–1.37 mm) and 0.71 mm (0.61–0.88 mm), respectively. These deviations were similar to those found in previous studies. Flapless surgery resulted in a more accurate placement with respect to apical and coronal deviations, and the differences between the two surgeons were limited. The newly developed dynamic navigation system is considered to be eligible for clinical use

Quantification of cyclic electron flow in spinach leaf discs

We quantified the photosynthetic cyclic electron flux (CEF) around Photosystem I as the difference between the total electron flux through PS I (ETR1) and the linear electron flux through both photosystems. Both measurements were made in the whole tissue of spinach leaf discs illuminated in the same geometry and in CO2-enriched air to suppress photorespiration. (1) CEF was negligibly small below 300 μmol photons m-2 s-1. Above this irradiance, CEF increased approximately linearly up to the highest irradiance used (1900 μmol photons m-2 s-1). (2) CEF at a fixed irradiance of 980 μmol m-2 s-1 increased by a factor of almost 3 as the temperature was increased from 5°C to 40°C. It did not decline, even when the linear electron flux decreased at high temperatures. (3) Antimycin A, at a high concentration, decreased CEF to about 10% of the control value without affecting the linear electron flux. This method appears to be reliable for quantifyin! g CEF non-intrusively. By contrast, estimation of the linear electron flux from chlorophyll fluorescence over-estimated CEF in the above treatments.A China Scholarship Council fellowship to (JK) and grants from the Australian Research Council to WSC (DP1093827)and MRB (Centre of Excellence in Plant Energy Biology)supported this work

Estimation of the Cyclic Electron Flux around Photosystem I in Leaf Discs

Quantification of the cyclic electron flux (CEF) around photosystem I (PSI) in leaves has been hampered by the absence of net product formation or net substrate consumption. We estimate CEF as the difference between the total electron flux through PSI and the linear electron flux through both photosystems, both fluxes measured in the same leaf tissue in identical conditions. This method can be applied to leaves of plants such as spinach grown in high light and in which the Mehler reaction and charge recombination are minimal. However, leaves of plants such as Arabidopsis grown in low light but tested in high light may have a large electron flux component that cycles within the PSI reaction centre by charge separation followed by charge recombination. In such leaves, CEF can be estimated as the antimycin A-sensitive component of the total electron flux through PSI. However, if CEF is significantly mediated by the nicotinamide adenine dinucleotide dehydrogenase-like complex (NDH), inhibition with a combination of antimycin A and an inhibitor of NDH would be necessary. The method has the potential to be fine-tuned to give a closer estimation of the actual CEF

Estimation of the steady-state cyclic electron flux around PSI in spinach leaf discs in white light,CO2-enriched air and other varied conditions

Cyclic electron flux (CEF) around PSI is essential for efficient photosynthesis and aids photoprotection, especially in stressful conditions, but the difficulty in quantifying CEF is non-trivial. The total electron flux through PSI (ETR1) and the linear electron flux (LEFO2) through both photosystems in spinach leaf discs were estimated from the photochemical yield of PSI and the gross oxygen evolution rate, respectively, in CO2-enriched air. ΔFlux = ETR1 – LEFO2 is an upper estimate of CEF. Infiltration of leaf discs with 150 μM antimycin A did not affect LEFO2, but decreased ΔFlux 10-fold. ΔFlux was practically negligible below 350 μmol photons m-2 s-1, but increased linearly above it. The following results were obtained at 980 μmol photons m-2 s-1. ΔFlux increased 3-fold as the temperature increased from 5°C to 40°C. It did not decline at high temperature, even when LEFO2 decreased. ΔFlux increased by 80% as the relative water content of leaf discs decreased from 100 to 40%, when LEFO2 decreased 2-fold. The method of using ΔFlux as a non-intrusive upper estimate of steady-state CEF in leaf tissue appears reasonable when photorespiration is suppressed.Grants from the Australian Research Council to WSC (DP1093827)

Estimation of the steady-state cyclic electron flux around PSI in spinach leaf discs in white light, CO2-enriched air and other varied conditions

Cyclic electron flux (CEF) around PSI is essential for efficient photosynthesis and aids photoprotection, especially in stressful conditions, but the difficulty in quantifying CEF is non-trivial. The total electron flux through PSI (ETR1) and the linear electron flux (LEFO2) through both photosystems in spinach leaf discs were estimated from the photochemical yield of PSI and the gross oxygen evolution rate, respectively, in CO2-enriched air. Delta Flux = ETR1 - LEFO2 is an upper estimate of CEF. Infiltration of leaf discs with 150 mu M antimycin A did not affect LEFO2, but decreased DFlux 10-fold. Delta Flux was practically negligible below 350 mu mol photons m(-2) s(-1), but increased linearly above it. The following results were obtained at 980 mmol photons m(-2) s(-1). Delta Flux increased 3-fold as the temperature increased from 5 degrees C to 40 degrees C. It did not decline at high temperature, even when LEFO2 decreased. Delta Flux increased by 80% as the relative water content of leaf discs decreased from 100 to 40%, when LEFO2 decreased 2-fold. The method of using Delta Flux as a non-intrusive upper estimate of steady-state CEF in leaf tissue appears reasonable when photorespiration is suppressed