Heterogeneously integrated widely tunable laser using lattice filter and ring resonator on Si photonics platform.

We fabricated a tunable laser consisting of a Si lattice filter, a Si ring resonator, and a III-V gain region. The lattice filter, a cascade of interferometers with the same delay length, has periodic transmission peaks with a wide free spectral range (FSR). By connecting the lattice filter to a ring resonator with a narrow FSR, the lasing mode is selected from one of the resonance modes of the ring resonator. The lasing wavelength can be tuned by changing the transmission peak wavelength of the lattice filter, in which an integrated micro heater controls the refractive index of the longer or shorter arm. Since the length of the refractive index control region on both arms of the lattice filter can be extended while maintaining a wide FSR, a wide tuning range can be obtained. This laser facilitates the control of the lasing wavelength because of the simple configuration. The Si lattice filter and the Si ring resonator were fabricated on a Si photonics platform by a Si photonics foundry, and III-V gain region was heterogeneously integrated. The lasing wavelength is shifted to a longer (shorter) one by heating the longer (shorter) arm of the lattice filter, in which the tuning wavelength is 1529 to 1561 nm and side-mode suppression ratio is more than 40 dB. A Lorentzian linewidth for lasing wavelengths narrower than 40 kHz is also demonstrated.

Effects of an mHealth App (Kencom) With Integrated Functions for Healthy Lifestyles on Physical Activity Levels and Cardiovascular Risk Biomarkers: Observational Study of 12,602 Users.

BACKGROUND: Mobile health (mHealth) apps are considered to be potentially powerful tools for improving lifestyles and preventing cardiovascular disease (CVD), although only few have undergone large, well-designed epidemiological research. "kencom" is a novel mHealth app with integrated functions for healthy lifestyles such as monitoring daily health/step data, providing tailored health information, or facilitating physical activity through group-based game events. The app is linked to large-scale Japanese insurance claims databases and annual health check-up databases, thus comprising a large longitudinal cohort. OBJECTIVE: We aimed to assess the effects of kencom on physical activity levels and CVD risk factors such as obesity, hypertension, dyslipidemia, and diabetes mellitus in a large population in Japan. METHODS: Daily step count, annual health check-up data, and insurance claim data of the kencom users were integrated within the kencom system. Step analysis was conducted by comparing the 1-year average daily step count before and after kencom registration. In the CVD risk analysis, changes in CVD biomarkers following kencom registration were evaluated among the users grouped into the quintile according to their change in step count. RESULTS: A total of 12,602 kencom users were included for the step analysis and 5473 for the CVD risk analysis. The participants were generally healthy and their mean age was 44.1 (SD 10.2) years. The daily step count significantly increased following kencom registration by a mean of 510 steps/day (P<.001). In particular, participation in "Arukatsu" events held twice a year within the app was associated with a remarkable increase in step counts. In the CVD risk analysis, the users of the highest quintile in daily step change had, compared with those of the lowest quartile, a significant reduction in weight (-0.92 kg, P<.001), low-density lipoprotein cholesterol (-2.78 mg/dL, P=.004), hemoglobin A1c (HbA1c; -0.04%, P=.004), and increase in high-density lipoprotein cholesterol (+1.91 mg/dL, P<.001) after adjustment of confounders. CONCLUSIONS: The framework of kencom successfully integrated the Japanese health data from multiple data sources to generate a large, longitudinal data set. The use of the kencom app was significantly associated with enhanced physical activity, which might lead to weight loss and improvement in lipid profile.

Trajectories of kidney function and associated factors among community-dwelling older Japanese: a 16-year longitudinal study.

BACKGROUND: No study has reported trajectories of kidney function in later life. This long-term prospective study attempted to classify trajectories of estimated glomerular filtration rate (eGFR) and identify factors associated with these trajectories. METHODS: We collected data from annual geriatric health checkups conducted during 2002-2017 in Kusatsu Town, Gunma Prefecture, Japan. The participants were 1990 adults aged 65-90 years (mean [SD] age, 71.0 [5.7] years; 57.0% women), and the total number of observations was 9291. Data were analyzed with a group-based semiparametric mixture model and age-adjusted univariable cumulative logit models. RESULTS: Trajectory of kidney function, as determined by eGFR, was classified as low, middle, and high (4.8%, 38.9%, and 56.3% of men, respectively, and 5.2%, 31.5%, and 63.3% of women). Among men and women in the low trajectory group, chronic kidney disease (CKD) stage worsened from stage G3a (51.8 ml/min/1.73 m2 in men and 53.6 in women) at age 65 years to stage G4 (28.0 ml/min/1.73 m2 in men and 28.5 in women) by age 85 years. A history of hypertension (men and women) and heart disease (men) were more likely in the low trajectory group than in the middle and high trajectory groups. CONCLUSIONS: About 5% of community-dwelling older adults had an eGFR < 30 later in life. Our findings suggest that those with stage G3a CKD at age 65 years should be managed intensively, to control risk factors for CKD progression.

Cardiac Resynchronization Therapy for Improving Non-Uniform Thickening of Left Ventricular Wall: Assessment by Quantitative Gated Myocardial Perfusion SPECT.

Cardiac resynchronization therapy (CRT) improves cardiac dyssynchrony in heart failure patients with a wide QRS electrocardiogram (ECG). Assessment of left ventricular (LV) dyssynchrony using echocardiography or other imaging modalities is important to predict CRT effectiveness. In this study, we retrospectively evaluated cardiac nuclear imaging of ECG-gated myocardial perfusion single-photon emission computed tomography (SPECT) with 99mTc-sestamibi for CRT candidate (n = 120) with severe heart failure and wide QRS (> 120 msec) in ECG. To analyze LV non-uniformity, we used the quantitative gated SPECT (QGS) software to calculate changes in regional LV wall thickness during a cardiac cycle (i.e., wall thickening scores). Cardiac events (heart failure, ventricular arrhythmias and cardiac death) after CRT during 38 ± 22 (SD) months were also evaluated. In 97 of 120 patients who underwent QGS before and 6 months after CRT, CRT homogenized non-uniform wall thickening between septal and lateral of the LV especially in CRT responders. This observation was indicated as increase in the lateral deflection (XWT) of wall thickening scores before CRT and its decrease after CRT. In 120 patients with QGS before CRT, the larger XWT before CRT (≥ 16.5) predicted better prognoses after CRT. This finding was similarly observed even in patients with narrower baseline QRS (≤ 140 msec; n = 41 of 120), who usually have less benefits from CRT. In conclusion, CRT improved non-uniformity of wall thickening between the LV septal and lateral regions evaluated using QGS, which is predictive of better prognosis in the chronic phase after CRT.

Membrane InGaAsP Mach-Zehnder modulator with SiN:D waveguides on Si platform.

A high-efficiency InGaAsP Mach-Zehnder modulator is integrated with hydrogen-free deuterated silicon nitride (SiN:D) waveguide circuits on a Si substrate. A thin InP-based layer provides a high optical confinement factor of around 50% and enables easy optical coupling to the SiN:D waveguides, which are fabricated by a low-temperature backend process. The fabricated Mach-Zehnder modulator with a 300-µm-long phase shifter shows a VπL of 0.4 Vcm, insertion loss of ~4.5 dB, and an error-free operation for 40-Gbit/s non-return-to-zero signal.

Phylogeography of freshwater planorbid snails reveals diversification patterns in Eurasian continental islands.

BACKGROUND: Islands have traditionally been the centre of evolutionary biological research, but the dynamics of immigration and differentiation at continental islands have not been well studied. Therefore, we focused on the Japanese archipelago, the continental islands located at the eastern end of the Eurasian continent. While the Japanese archipelago is characterised by high biodiversity and rich freshwater habitats, the origin and formation mechanisms of its freshwater organisms are not clear. In order to clarify the history of the planorbid gastropod fauna, we conducted phylogenetic analysis, divergence time estimation, ancestral state reconstruction, and lineage diversity estimations. RESULTS: Our analyses revealed the formation process of the planorbid fauna in the Japanese archipelago. Most lineages in the Japanese archipelago have closely related lineages on the continent, and the divergence within the Japanese lineages presumably occurred after the late Pliocene. In addition, each lineage is characterised by different phylogeographical patterns, suggesting that immigration routes from the continent to the Japanese archipelago differ among lineages. Furthermore, a regional lineage diversity plot showed that the present diversity in the Japanese archipelago potentially reflects the differentiation of lineages within the islands after the development of the Japanese archipelago. CONCLUSIONS: Although additional taxon sampling and genetic analysis focused on each lineage are needed, our results suggest that immigration from multiple routes just prior to the development of the Japanese archipelago and subsequent diversification within the islands are major causes of the present-day diversity of the Japanese planorbid fauna.

[Visual processing of names in mental rotation tasks].

In this study, we examined the difference in the processing of one's own name and other people's names using a mental rotation task. In Experiment 1, the observer's own name and other common names were presented visually. In Experiment 2, the observer's name and the names of people who were familiar to the observer were presented. The observer saw the name and judged whether it was mirror-reversed or not. The results show that reaction times and error rates were shorter, when the observer processed his/her own name compared to when processing others names. These findings might be due to peculiarities and familiarity of one's own name.

Body mass index and waist circumference are independent risk factors for low vital capacity among Japanese participants of a health checkup: a single-institution cross-sectional study.

OBJECTIVE: This study aimed to examine the associations between obesity and percentage vital capacity (%VC), as well as lifestyle-related disorders, among Japanese participants of a voluntary health checkup. METHODS: Subjects were 7,892 individuals who participated in a medical health checkup from January to December 2007. Multivariate logistic regression analysis was performed to assess associations between low %VC (<80) and body mass index (BMI) and waist circumference (WC), as well as lifestyle-related disorders. RESULTS: Medical histories of hypertension and dyslipidemia were more frequent in the low %VC group than in the normal %VC group in both sexes. In men, BMI was significantly associated with low %VC (25.0 ≤ C2 < 27.5, odds ratio (OR) = 2.10; 27.5 ≤ C3 < 30.0, OR = 2.23; C4 ≥ 30.0, OR = 3.46) relative to the first category (C1 < 25.0). A significant association was also observed between WC and low %VC (85 ≤ C2 < 90, OR = 1.40; 90 ≤ C3 < 95, OR = 1.55; 95 ≤ C4, OR = 2.51; relative to C1 < 85.0 cm). In women, BMI was significantly associated with low %VC in C3 and C4 (C3, OR = 2.05; C4, OR = 2.84), and WC was significantly associated with low %VC in C4 (C4, OR = 2.32). CONCLUSION: Our results suggest that obesity may be associated with restrictive pulmonary function and underscore the importance of maintaining ideal body weight for the prevention of restrictive pulmonary dysfunction.

Compact and stable THz vector spectroscopy using silicon photonics technology.

We present a compact and stable terahertz (THz) vector spectroscopy system using silicon photonics technology. A silicon-based integrated phase control circuit greatly reduces the physical size of the continuous-wave THz spectroscopy system and enhances environmental phase stability. Differential lightwave phase control using two carrier-injection electro-optic modulators enables fast and linear phase sweeps of THz-waves. Using the silicon-photonic circuit, we demonstrate a THz vector spectrometer; the dynamic ranges are 65 and 35 dB at 300 GHz and 1 THz with 1-ms integration time and phase variation is less than ± 10° without thermal packaging.

Usefulness of stress myocardial perfusion imaging and baseline clinical factors for predicting cardiovascular events in patients with prior coronary artery disease.

BACKGROUND: Stress myocardial perfusion imaging (MPI) is a well-established diagnostic and prognostic tool for coronary artery disease (CAD). However, fixed and/or reversible stress MPI defects vary considerably among patients with CAD. The usefulness of stress MPI and baseline clinical factors as independent predictors of cardiovascular events in patients with prior CAD were assessed. METHODS AND RESULTS: Stress MPI was performed in 354 patients with prior CAD. Their mean age was 71 years; the mean duration from first revascularization and/or myocardial infarction (MI) onset until stress MPI was 7.1 years; and the mean follow-up period was 34 months. Cardiovascular events were observed in 100 patients (28%), and were categorized as cardiac-related death, non-fatal MI, unstable angina, heart failure and late (>2 months from stress MPI) coronary revascularization. Multivariate Cox regression analysis revealed that peripheral arterial disease (hazard ratio [HR]=2.95; P<0.001), current smoking (HR=2.36; P=0.006), chronic kidney disease (HR=2.15; P<0.001), left ventricular ejection fraction (HR=0.98; P=0.017), and grade of myocardial ischemia assessed by stress MPI (HR=1.14; P=0.007) were independent and significant predictors of cardiovascular events. CONCLUSIONS: In patients with prior CAD, baseline clinical factors and grade of myocardial ischemia assessed by stress MPI results are significant predictors of cardiovascular events.

Pitfalls of voxel-based amyloid PET analyses for diagnosis of Alzheimer's disease: artifacts due to non-specific uptake in the white matter and the skull.

Two methods are commonly used in brain image voxel-based analyses widely used for dementia work-ups: 3-dimensional stereotactic surface projections (3D-SSP) and statistical parametric mapping (SPM). The methods calculate the Z-scores of the cortical voxels that represent the significance of differences compared to a database of brain images with normal findings, and visualize them as surface brain maps. The methods are considered useful in amyloid positron emission tomography (PET) analyses to detect small amounts of amyloid-ß deposits in early-stage Alzheimer's disease (AD), but are not fully validated. We analyzed the (11)C-labeled 2-(2-[2-dimethylaminothiazol-5-yl]ethenyl)-6-(2-[fluoro]ethoxy)benzoxazole (BF-227) amyloid PET imaging of 56 subjects (20 individuals with mild cognitive impairment [MCI], 19 AD patients, and 17 non-demented [ND] volunteers) with 3D-SSP and the easy Z-score imaging system (eZIS) that is an SPM-based method. To clarify these methods' limitations, we visually compared Z-score maps output from the two methods and investigated the causes of discrepancies between them. Discrepancies were found in 27 subjects (9 MCI, 13 AD, and 5 ND). Relatively high white matter uptake was considered to cause higher Z-scores on 3D-SSP in 4 subjects (1 MCI and 3 ND). Meanwhile, in 17 subjects (6 MCI, 9 AD, and 2 ND), Z-score overestimation on eZIS corresponded with high skull uptake and disappeared after removing the skull uptake ("scalping"). Our results suggest that non-specific uptakes in the white matter and skull account for errors in voxel-based amyloid PET analyses. Thus, diagnoses based on 3D-SSP data require checking white matter uptake, and "scalping" is recommended before eZIS analysis.

cis-Cinnamic acid selective suppressors distinct from auxin inhibitors.

The activity of cis-cinnamic acid (cis-CA), one of the allelochemicals, in plants is very similar to that of indole-3-acetic acid (IAA), a natural auxin, and thus cis-CA has long been believed to be an analog of auxin. We have reported some structure-activity relationships studies by synthesizing over 250 cis-CA derivatives and estimating their inhibitory activities on root growth inhibition in lettuce. In this study, the compounds that showed low- or no-activity on root growth inhibition were recruited as candidates suppressors against cis-CA and/or auxin and tested for their activity. In the presence of cis-CA, lettuce root growth was inhibited; however, the addition of some cis-CA derivatives restored control-level root growth. Four compounds, (Z)-3-(4-isopropylphenyl)acrylic acid, (Z)-3-(3-butoxyphenyl)acrylic acid, (Z)-3-[3-(pentyloxy)phenyl]acrylic acid, and (Z)-3-(naphthalen-1-yl)acrylic acid were selected as candidates for a cis-CA selective suppressor they allowed the recovery of root growth from inhibition by cis-CA treatment without any effects on the IAA-induced effect or elongating activity by themselves. Three candidates significantly ameliorated the root shortening by the potent inhibitor derived from cis-CA. In brief, we have found some cis-CA selective suppressors which have never been reported from inactive cis-CA derivatives for root growth inhibition. cis-CA selective suppressors will play an important role in elucidating the mechanism of plant growth regulation.

High-performance silicon photonics technology for telecommunications applications.

By way of a brief review of Si photonics technology, we show that significant improvements in device performance are necessary for practical telecommunications applications. In order to improve device performance in Si photonics, we have developed a Si-Ge-silica monolithic integration platform, on which compact Si-Ge-based modulators/detectors and silica-based high-performance wavelength filters are monolithically integrated. The platform features low-temperature silica film deposition, which cannot damage Si-Ge-based active devices. Using this platform, we have developed various integrated photonic devices for broadband telecommunications applications.

Evaluating the impact of a darts game intervention on cognitive function in older adults with and without mild cognitive impairment: a pilot study.

Introduction: The current study investigated the relationship between the characteristics of a darts game, including the throwing motion toward a target, and mild cognitive impairment (MCI). To this end, we examined the associations between cognitive function and mental health, and the shift in center of gravity while throwing darts. In a preliminary investigation, a 1-month dart game intervention was conducted among older individuals living in the community. The participants were divided into the non-MCI and MCI groups, and the relationship between center of gravity movement during throwing and the presence of dementia was examined. Methods: The intervention lasted for 1 month and was tested on healthy older individuals (aged ≥ 65 years) recruited from the community. The Japanese version of the Montreal Cognitive Assessment and the Trail Making Test was used to assess cognitive function. Mental health was evaluated using the Kessler Psychological Distress Scale and the Subjective Well-being Inventory. The center of pressure was analyzed to determine the center of gravity shift during dart throwing. Results: The analysis of factors influencing the determination of the MCI score during the intervention revealed a tendency for the center of gravity shift to be associated as a protective factor in the non-MCI group, although this association did not reach statistical significance (odds ratio = 0.942, p = 0.084). In the MCI group, a significant effect of age was observed in the MCI score (odds ratio = 1.539, p = 0.007). Conclusion: The current findings suggest that conducting center of gravity shift testing could potentially provide a helpful tool for predicting early decline in cognitive function.

Leptomeningeal carcinomatosis from breast cancer initially mimicking cerebral infarction on MRI.

A female patient in her early 50s with breast cancer underwent breast-conserving surgery, followed by radiation therapy. She developed multiple lung and bone metastases and was started on chemotherapy with bevacizumab and paclitaxel 3 years later. After 6 months of chemotherapy, she developed a decline in conversation and memory. Magnetic resonance imaging (MRI) was conducted and showed multiple cortical and subcortical lesions and nodules with restricted diffusion but with no contrast enhancement on gadolinium (Gd) enhanced T1-weighted image, raising a suspicion of Trousseau's syndrome. A follow-up MRI revealed unchanged signal intensity of the lesions but with minimal enlargement. The cerebrospinal fluid cytology was negative for malignancy. Consequently, an open biopsy of the cortical lesion was conducted. Histopathology showed that the tumor cells were morphologically similar to the primary breast cancer extending from the brain surface along the Virchow-Robin spaces, which yielded a diagnosis of leptomeningeal carcinomatosis from breast cancer. Contrast enhancement on Gd-MRI may be impaired in case of tumor spread along the perivascular space or in patients treated with bevacizumab.

SARS-CoV-2 seroprevalence among healthcare workers in a highly vaccinated Japanese medical center from 2020-2023.

Infection-induced SARS-CoV-2 seroprevalence has been studied worldwide. At Juntendo University Hospital (JUH) in Tokyo, Japan, we have consistently conducted serological studies using the blood residue of healthcare workers (HCWs) at annual health examinations since 2020. In this 2023 study (n = 3,594), N-specific seroprevalence (infection-induced) was examined while univariate and multivariate logistic regression analyses were performed to compute ORs of seroprevalence with respect to basic characteristics of participants. We found that the N-specific seroprevalence in 2023 was 54.1%-a jump from 17.7% in 2022, and 1.6% in 2021-with 37.9% as non-PCR-confirmed asymptomatic infection cases. Those younger than 50 (adjusted OR = 1.62; p < .001) and recipients with 4 doses or less of vaccine had a higher risk to be N-positive, ranging from 1.45 times higher for the participants with 4 doses (p < .001) to 4.31 times higher for the participants with 1 dose (p < .001), compared to those with 5 or more doses. Our findings indicate that robust vaccination programs may have helped alleviate symptoms but consequently caused asymptomatic spread in this hospital, especially among younger HCWs. Although having four doses or less was found to be associated with higher risk of infection, the optimal constitution and intervals for effective booster vaccines warrant further investigations.

A longitudinal study of the relationship between personality traits and the annual rate of volume changes in regional gray matter in healthy adults.

To investigate whether personality traits affect the rate of decline of gray matter volume, we analyzed the relationships between personality traits and the annual rate of changes of gray matter volume in 274 healthy community dwelling subjects with a large age range by applying a longitudinal design over 6 years, using brain magnetic resonance images (MRI) and the Revised NEO Personality Inventory (NEO-PI-R) at baseline. Brain MRI data were processed using voxel-based morphometry with a custom template by applying the DARTEL diffeomorphic registration tool. For each subject, we used NEO-PI-R to evaluate the five major personality traits, including neuroticism, extraversion, openness, agreeableness, and conscientiousness. The results show that the annual rate of change in regional gray matter volume in the right inferior parietal lobule was correlated significantly and negatively with a personality of openness, which is known to be related to intellect, intellectual curiosity, and creativity adjusting for age, gender, and intracranial volume. This result indicates that subjects with a personality trait of less openness have an accelerated loss of gray matter volume in the right inferior parietal lobule, compared with subjects with a personality trait of more openness. Because the right inferior parietal lobule is involved in higher cognitive function such as working memory and creativity, a personality trait of openness is thought to be important for preserving gray matter volume and cognitive function of the right inferior parietal lobule in healthy adults.

A longitudinal study of age- and gender-related annual rate of volume changes in regional gray matter in healthy adults.

The aim of this study was to analyze correlations among the annual rate of gray matter volume change, age, gender, and cerebrovascular risk factors in 381 healthy community-dwelling subjects with a large age range by applying a longitudinal design over 6 years using brain magnetic resonance images (MRIs). Brain MRI data were processed with voxel-based morphometry using a custom template by applying diffeomorphic anatomical registration using the exponentiated lie algebra procedure. The annual rate of regional gray matter volume change showed significant positive correlations with age in several regions, including the bilateral temporal pole, caudate nucleus, ventral and dorsolateral prefrontal cortices, insula, hippocampus, and temporoparietal cortex, whereas significant negative correlations with age were observed in several regions including the bilateral cingulate gyri and anterior lobe of the cerebellum. Additionally, a significant age-by-gender interaction was found for the annual rate of regional gray matter volume change in the bilateral hippocampus. No significant correlations were observed between the annual rate of regional gray matter volume change and body mass index or systolic blood pressure. A significant positive correlation between the annual rate of gray matter volume change and age indicates that the region shows not linear but accelerated gray matter loss with age. Therefore, evaluating the annual rate of the gray matter volume change with age in healthy subjects is important in understanding how gray matter volume changes with aging in each brain region and in anticipating what cognitive functions are likely to show accelerated decline with aging.

Linear and curvilinear correlations of brain gray matter volume and density with age using voxel-based morphometry with the Akaike information criterion in 291 healthy children.

We examined linear and curvilinear correlations of gray matter volume and density in cortical and subcortical gray matter with age using magnetic resonance images (MRI) in a large number of healthy children. We applied voxel-based morphometry (VBM) and region-of-interest (ROI) analyses with the Akaike information criterion (AIC), which was used to determine the best-fit model by selecting which predictor terms should be included. We collected data on brain structural MRI in 291 healthy children aged 5-18 years. Structural MRI data were segmented and normalized using a custom template by applying the diffeomorphic anatomical registration using exponentiated lie algebra (DARTEL) procedure. Next, we analyzed the correlations of gray matter volume and density with age in VBM with AIC by estimating linear, quadratic, and cubic polynomial functions. Several regions such as the prefrontal cortex, the precentral gyrus, and cerebellum showed significant linear or curvilinear correlations between gray matter volume and age on an increasing trajectory, and between gray matter density and age on a decreasing trajectory in VBM and ROI analyses with AIC. Because the trajectory of gray matter volume and density with age suggests the progress of brain maturation, our results may contribute to clarifying brain maturation in healthy children from the viewpoint of brain structure.

Linear and curvilinear correlations of brain white matter volume, fractional anisotropy, and mean diffusivity with age using voxel-based and region-of-interest analyses in 246 healthy children.

In this study, we examined linear and curvilinear correlations of fractional anisotropy (FA), mean diffusivity (MD), and white matter volume with age by using brain structural and diffusion-tensor magnetic resonance imaging (MRI) in a large number of healthy children and voxel-based morphometry (VBM) and region-of-interest (ROI) analyses. We collected data by brain structural MRI in 246 healthy children, aged 5-18 years. FA and MD images were normalized using the normalization parameter of the corresponding structural MRI. Next, we analyzed the correlations between FA and age and between MD and age by estimating linear and logarithmic functions. We also analyzed the correlation between white matter volume and age by linear, quadratic, and cubic functions. Correlations between FA and age and between MD and age showed exponential trajectories in most ROIs in boys and girls, except for several fibers, such as the corpus callosum connecting the bilateral rectal gyri in boys. The correlation between white matter volume and age showed significant positive linear trajectories in most ROIs in boys and girls, except for a few fibers, such as the bilateral uncinate fasciculus. Additionally, maturational rates differed among major fibers, and in girls, the left superior longitudinal fasciculus, which connects the frontal and temporal lobes, showed a slower rate of maturation than other fibers. Our results may help to clarify the mechanisms of normal brain maturation from the viewpoint of brain white matter.