Two Models for RHEED Specular Spot Intensity Recovery in Laser-triggered Chemical Beam Epitaxy GaP Growth

RHEED specular spot intensity (RSSI) has been observed while growing GaP by laser-triggered chemical beam epitaxy. The intensity decreases after each laser pulse, and then it recovers the original value. We present two models in order to explain the RSSI changes. The first model takes the chemisorption velocity of metalorganics as a limiting factor in RSSI recovery speed. On the other hand, the second model considers the reaction time of gallium with phosphorus as a limiting factor. The second model properly fits the experimental data and it allows a deeper understanding of chemical reactions on GaP surface during chemical beam epitaxial growth

Dynamic stability during level walking and obstacle crossing in children aged 2–5 years estimated by marker-less motion capture

In the present study, dynamic stability during level walking and obstacle crossing in typically developing children aged 2–5 years (n = 13) and healthy young adults (n = 19) was investigated. The participants were asked to walk along unobstructed and obstructed walkways. The height of the obstacle was set at 10% of the leg length. Gait motion was captured by three RGB cameras. 2D body landmarks were estimated using OpenPose, a marker-less motion capture algorithm, and converted to 3D using direct linear transformation (DLT). Dynamic stability was evaluated using the margin of stability (MoS) in the forward and lateral directions. All the participants successfully crossed the obstacles. Younger children crossed the obstacle more carefully to avoid falls, as evidenced by obviously decreased gait speed just before the obstacle in 2-year-olds and the increased in maximum toe height with younger age. There was no significant difference in the MoS at the instant of heel contact between children and adults during level walking and obstacle crossing in the forward direction, although children increased the step length of the lead leg to a greater extent than the adults to ensure base of support (BoS)-center of mass (CoM) distance. In the lateral direction, children exhibited a greater MoS than adults during level walking [children: 9.5%, adults: 6.5%, median, W = 39.000, p < .001, rank-biserial correlation = −0.684]; however, some children exhibited a smaller MoS during obstacle crossing [lead leg: −5.9% to 3.6% (min–max) for 4 children, 4.7%–6.4% [95% confidence interval (CI)] for adults, p < 0.05; trail leg: 0.1%–4.4% (min–max) for 4 children, 4.7%–6.4% (95% CI) for adults, p < 0.05]]. These results indicate that in early childhood, locomotor adjustment needed to avoid contact with obstacles can be observed, whereas lateral dynamic stability is frangible

Transcriptionally linked simultaneous overexpression of P450 genes for broad-spectrum herbicide resistance

雑草が獲得した最強の除草剤抵抗性メカニズムの解明 --解毒酵素の一斉活性化--. 京都大学プレスリリース. 2023-06-14.Broad-spectrum herbicide resistance (BSHR), often linked to weeds with metabolism-based herbicide resistance, poses a threat to food production. Past studies have revealed that overexpression of catalytically promiscuous enzymes explains BSHR in some weeds; however, the mechanism of BSHR expression remains poorly understood. Here, we investigated the molecular basis of high-level resistance to diclofop-methyl in BSHR late watergrass (Echinochloa phyllopogon) found in the United States, which cannot be solely explained by the overexpression of promiscuous cytochrome P450 monooxygenases CYP81A12/21. The BSHR late watergrass line rapidly produced 2 distinct hydroxylated diclofop acids, only 1 of which was the major metabolite produced by CYP81A12/21. RNA-seq and subsequent reverse transcription quantitative PCR (RT-qPCR)-based segregation screening identified the transcriptionally linked overexpression of a gene, CYP709C69, with CYP81A12/21 in the BSHR line. The gene conferred diclofop-methyl resistance in plants and produced another hydroxylated diclofop acid in yeast (Saccharomyces cerevisiae). Unlike CYP81A12/21, CYP709C69 showed no other herbicide-metabolizing function except for a presumed clomazone-activating function. The overexpression of the 3 herbicide-metabolizing genes was also identified in another BSHR late watergrass in Japan, suggesting a convergence of BSHR evolution at the molecular level. Synteny analysis of the P450 genes implied that they are located at mutually independent loci, which supports the idea that a single trans-element regulates the 3 genes. We propose that transcriptionally linked simultaneous overexpression of herbicide-metabolizing genes enhances and broadens the metabolic resistance in weeds. The convergence of the complex mechanism in BSHR late watergrass from 2 countries suggests that BSHR evolved through co-opting a conserved gene regulatory system in late watergrass

Primary Care Education at Kawasaki Medical School

Department of Primary Care Medicine was established in 1981 at Kawasaki Medical School as a first place to educate students about primary care in Japan. Since the history of Department of Primary Care Medicine is so short, many problems which should be resolved were left over. Brief history of primary care activities in Japan was reviewed and strategies for primary care education were discussed