572 research outputs found
Biochemical Computation for Spine Structural Plasticity
The structural plasticity of dendritic spines is considered to be essential for various forms of synaptic plasticity, learning, and memory. The process is mediated by a complex signaling network consisting of numerous species of molecules. Furthermore, the spatiotemporal dynamics of the biochemical signaling are regulated in a complicated manner because of geometrical restrictions from the unique morphology of the dendritic branches and spines. Recent advances in optical techniques have enabled the exploration of the spatiotemporal aspects of the signal regulations in spines and dendrites and have provided many insights into the principle of the biochemical computation that underlies spine structural plasticity.Video Abstrac
Accurate measurements of the acoustical physical constants ofsynthetic α-quartz for SAW devices
科研費報告書収録論文(課題番号:13555085・基盤研究(B)(2) ・H13~H14/研究代表者:櫛引, 淳一/超高品質人工水晶の超音波マイクロスペクトロスコピー
Cytological alteration of cultured rat liver cells by 3'-methyl-4-dimethylaminoazobenzene with special reference to chromosome changes, changes of growth patterns at a colony level and alpha-fetoprotein production.
A near diploid clone derived from a rat liver cell line was continuously treated with various concentrations of 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) in culture. By treatment with 2.8 micrograms/ml, cells with 41 chromosomes formed a mode and which then shifted to 39. The chromosome numbers of cells treated with 5.4 micrograms/ml were widely distributed at early stages, but later the mode shifted to hypotetraploid region. Untreated control cells were confirmed as near diploid. Increased plating efficiency by 3'-Me-DAB as well as the appearance of large sized colonies was obtained. The production of alpha-fetoprotein (AFP) by the cells was slightly enhanced by treatment with 3'-Me-DAB. The cells treated with and without 3'-Me-DAB did not produce any tumor in rats 6 months after their intraperitoneal injection.</p
CAMRI Loss: Improving Recall of a Specific Class without Sacrificing Accuracy
In real-world applications of multi-class classification models,
misclassification in an important class (e.g., stop sign) can be significantly
more harmful than in other classes (e.g., speed limit). In this paper, we
propose a loss function that can improve the recall of an important class while
maintaining the same level of accuracy as the case using cross-entropy loss.
For our purpose, we need to make the separation of the important class better
than the other classes. However, existing methods that give a class-sensitive
penalty for cross-entropy loss do not improve the separation. On the other
hand, the method that gives a margin to the angle between the feature vectors
and the weight vectors of the last fully connected layer corresponding to each
feature can improve the separation. Therefore, we propose a loss function that
can improve the separation of the important class by setting the margin only
for the important class, called Class-sensitive Additive Angular Margin Loss
(CAMRI Loss). CAMRI loss is expected to reduce the variance of angles between
features and weights of the important class relative to other classes due to
the margin around the important class in the feature space by adding a penalty
to the angle. In addition, concentrating the penalty only on the important
classes hardly sacrifices the separation of the other classes. Experiments on
CIFAR-10, GTSRB, and AwA2 showed that the proposed method could improve up to
9% recall improvement on cross-entropy loss without sacrificing accuracy.Comment: 2022 International Joint Conference on Neural Networks (IJCNN 2022
Adsorption and removal of strontium in aqueous solution by synthetic hydroxyapatite
Hydroxyapatite (HAP) is a main mineral constituent of bone and tooth and has an outstanding biocompatibility. HAP is a possible sorbent for heavy metals in wastewater due to its high adsorption capacity and low water solubility. We developed a removal system of 90Sr from aqueous solution by HAP column procedure. More than 90 % of 90Sr was adsorbed and removed from the 90Sr containing solution. Divalent cations, Ca2+, had little effect on the removal of 90Sr up to a concentration of 1 mmol L−1. This clearly indicates that the HAP column technique is advantageous with respect to the capacity to adsorb 90Sr from water present in the environment
Drop on a Bent Fibre
Inspired by the huge droplets attached on cypress tree leaf tips after rain,
we find that a bent fibre can hold significantly more water in the corner than
a horizontally placed fibre (typically up to three times or more). The maximum
volume of the liquid that can be trapped is remarkably affected by the bending
angle of the fibre and surface tension of the liquid. We experimentally find
the optimal included angle () that holds the most water.
Analytical and semi-empirical models are developed to explain these
counter-intuitive experimental observations and predict the optimal angle. The
data and models could be useful for designing microfluidic and fog harvesting
devices
In Vivo Evaluation of α7 Nicotinic Acetylcholine Receptor Agonists [11C]A-582941 and [11C]A-844606 in Mice and Conscious Monkeys
BACKGROUND: The alpha7 nicotinic acetylcholine receptors (nAChRs) play an important role in the pathophysiology of neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. The goal of this study was to evaluate the two carbon-11-labeled alpha7 nAChR agonists [(11)C]A-582941 and [(11)C]A-844606 for their potential as novel positron emission tomography (PET) tracers. METHODOLOGY/PRINCIPAL FINDINGS: The two tracers were synthesized by methylation of the corresponding desmethyl precursors using [(11)C]methyl triflate. Effects of receptor blockade in mice were determined by coinjection of either tracer along with a carrier or an excess amount of a selective alpha7 nAChR agonist (SSR180711). Metabolic stability was investigated using radio-HPLC. Dynamic PET scans were performed in conscious monkeys with/without SSR180711-treatment. [(11)C]A-582941 and [(11)C]A-844606 showed high uptake in the mouse brain. Most radioactive compounds in the brain were detected as an unchanged form. However, regional selectivity and selective receptor blockade were not clearly observed for either compound in the mouse brain. On the other hand, the total distribution volume of [(11)C]A-582941 and [(11)C]A-844606 was high in the hippocampus and thalamus but low in the cerebellum in the conscious monkey brain, and reduced by pretreatment with SSR180711. CONCLUSIONS/SIGNIFICANCE: A nonhuman primate study suggests that [(11)C]A-582941 and [(11)C]A-844606 would be potential PET ligands for imaging alpha7 nAChRs in the human brain
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