Computer-aided diagnosis of lung nodule using gradient tree boosting and Bayesian optimization

We aimed to evaluate computer-aided diagnosis (CADx) system for lung nodule classification focusing on (i) usefulness of gradient tree boosting (XGBoost) and (ii) effectiveness of parameter optimization using Bayesian optimization (Tree Parzen Estimator, TPE) and random search. 99 lung nodules (62 lung cancers and 37 benign lung nodules) were included from public databases of CT images. A variant of local binary pattern was used for calculating feature vectors. Support vector machine (SVM) or XGBoost was trained using the feature vectors and their labels. TPE or random search was used for parameter optimization of SVM and XGBoost. Leave-one-out cross-validation was used for optimizing and evaluating the performance of our CADx system. Performance was evaluated using area under the curve (AUC) of receiver operating characteristic analysis. AUC was calculated 10 times, and its average was obtained. The best averaged AUC of SVM and XGBoost were 0.850 and 0.896, respectively; both were obtained using TPE. XGBoost was generally superior to SVM. Optimal parameters for achieving high AUC were obtained with fewer numbers of trials when using TPE, compared with random search. In conclusion, XGBoost was better than SVM for classifying lung nodules. TPE was more efficient than random search for parameter optimization.Comment: 29 pages, 4 figure

Far-infrared phonon-polariton dispersion probed by terahertz time-domain spectroscopy

We report observations of the intensity and phase transmission spectra related to phonon-polariton propagation using coherent far-infrared radiation for a high-quality ferroelectric bismuth titanate crystal plate. In order to determine the polariton-dispersion relation, the phase delay was determined minutely as a function of the THz radiation frequency in the region between 3 and 100 cm-1. The anisotropy of polariton dispersion relation was also successfully determined on the c plate simply by switching the polarization direction of an incident beam from E∥a to E∥b. The observed polariton dispersion relations are consistently reproduced by the calculation using Kurosawa’s formula

SORL1 Is Genetically Associated with Late-Onset Alzheimer’s Disease in Japanese, Koreans and Caucasians

To discover susceptibility genes of late-onset Alzheimer’s disease (LOAD), we conducted a 3-stage genome-wide association study (GWAS) using three populations: Japanese from the Japanese Genetic Consortium for Alzheimer Disease (JGSCAD), Koreans, and Caucasians from the Alzheimer Disease Genetic Consortium (ADGC). In Stage 1, we evaluated data for 5,877,918 genotyped and imputed SNPs in Japanese cases (n = 1,008) and controls (n = 1,016). Genome-wide significance was observed with 12 SNPs in the APOE region. Seven SNPs from other distinct regions with p-values ,261025 were genotyped in a second Japanese sample (885 cases, 985 controls), and evidence of association was confirmed for one SORL1 SNP (rs3781834, P=7.3361027 in the combined sample). Subsequent analysis combining results for several SORL1 SNPs in the Japanese, Korean (339 cases, 1,129 controls) and Caucasians (11,840 AD cases, 10,931 controls) revealed genome wide significance with rs11218343 (P=1.7761029) and rs3781834 (P=1.0461028). SNPs in previously established AD loci in Caucasians showed strong evidence of association in Japanese including rs3851179 near PICALM (P=1.7161025) and rs744373 near BIN1 (P = 1.3961024). The associated allele for each of these SNPs was the same as in Caucasians. These data demonstrate for the first time genome-wide significance of LOAD with SORL1 and confirm the role of other known loci for LOAD in Japanese. Our study highlights the importance of examining associations in multiple ethnic populations

Phosphine–Ligand Decoration toward Active and Robust Iron Catalysts in LRP

Phosphine ligands were designed to enhance the catalytic activity of iron­(II) complexes [FeBr₂(PR₃)₂] for metal-catalyzed living radical polymerization (LRP), and special efforts were directed to the improvement in catalytic activity and robustness against functional monomers. Introduction of an electron donating group {methoxy [P­(MeOPh)₃] or <i><i>N,N</i></i>′-dimethylamino [Ph₂P­(Me₂NPh)]} onto the <i>para</i> position of triphenyl phosphine (PPh₃) allowed active and robust Fe­(II) complexes that catalyzed LRP of poly­(ethylene glycol) methacrylate (PEGMA) smoothly proceeding to high conversion (∼90%), to form polymers of controlled molecular weights and its distributions (<i>M</i>_w/<i>M</i>_n < 1.2). In contrast, such an enhancement was absent with the parent ligand PPh₃ and those with electron-withdrawing substituents. Furthermore, the replacement of the three methoxy groups in P­(MeOPh)₃ with PEG chains led to a more robust catalyst, especially tolerant of the hydroxyl group in 2-hydroxyethyl methacrylate (HEMA). Accordingly, this catalyst enabled a four-component random living copolymerization of HEMA, PEGMA, and two alkyl methacrylates, where all the monomers randomly copolymerized into statistical copolymers of controlled molecular weights

Shuttling Catalyst for Living Radical Miniemulsion Polymerization: Thermoresponsive Ligand for Efficient Catalysis and Removal

In this report, we demonstrate the use of a thermoresponsive ligand for the ruthenium-catalyzed living radical polymerization of butyl methacrylate (BMA) in miniemulsion. A phosphine-ligand-functionalized polyethylene glycol chain (PPEG) in conjunction with a Cp*-based ruthenium complex (Cp*: pentamethylcyclopentadienyl) provided thermoresponsive character as well as catalysis for living polymerization: the complex migrated from the water phase to the oil phase for polymerization upon heating and then migrated from the oil to water phase when the temperature was decreased to quench polymerization. Consequently, simple treatment (i.e., water washing or methanol reprecipitation) yielded metal-free polymeric particles containing less than 10 μg/g (by ICP-AES) of ruthenium residue

Neuromelanin magnetic resonance imaging reveals increased dopaminergic neuron activity in the substantia nigra of patients with schizophrenia.

PURPOSE: The dopamine hypothesis suggests that excessive dopamine release results in the symptoms of schizophrenia. The purpose of this study was to elucidate the dopaminergic and noradrenergic neurons using 3-T neuromelanin magnetic resonance imaging (MRI) in patients with schizophrenia and healthy control subjects. METHODS: We prospectively examined 52 patients with schizophrenia (M: F = 27∶25, mean age, 35 years) and age- and sex-matched healthy controls. Using a 3T MRI unit, we obtained oblique T1-weighted axial images perpendicular to the brainstem. We measured the signal intensity and area for the substantia nigra (SNc), midbrain tegmentum, locus ceruleus (LC), and pons. We then calculated the contrast ratios (CR) for the SNc (CRSN) and LC (CRLC), which were compared between patients and healthy controls using unpaired t-tests. RESULTS: The SNc and LC were readily identified in both patients and healthy controls as areas with high signal intensities in the posterior part of the cerebral peduncle and in the upper pontine tegmentum. The CRSN values in patients were significantly higher than those in healthy controls (10.89±2.37 vs. 9.6±2.36, p<0.01). We observed no difference in the CRLC values between the patients and healthy controls (14.21±3.5 vs. 13.44±3.37, p = 0.25). Furthermore, there was no difference in area of the SNc and LC between schizophrenia patients and controls. CONCLUSIONS: Neuromelanin MRI might reveal increased signal intensity in the SNc of patients with schizophrenia. Our results indicate the presence of excessive dopamine products in the SNc of these patients