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The aim of this study was to examine whether the presence of risk alleles of the norepinephrine transporter gene (SLC6A2) polymorphisms is associated with differences in regional cerebral blood flow (rCBF) measured by 99mTc-HMPAO single photon emission computerized tomography in a Korean sample of ADHD.
The present study included 24 children with ADHD (9.5±2.4 years), consisting of 20 boys and 4 girls, aged 6-16 years. We investigated the G1287A and -3081(A/T) polymorphisms of the SLC6A2. The rCBF was compared between the ADHD subjects with and without risk alleles at the G1287A polymorphism and at the -3081(A/T) polymorphism. Image analyses were performed with voxelwise t-statistics using SPM2.
1) The ADHD subjects with the A allele (risk allele) at the G1287A polymorphism showed reduced perfusion in the left middle frontal gyrus, left inferior parietal lobule, precuneus, right superior frontal gyrus, and right superior parietal lobule as compared with ADHD subjects without the A allele (p< 0.001).
2) The ADHD subjects with the A allele at the G1287A polymorphism showed increased perfusion in the right middle frontal gyrus, right middle temporal gyrus, right superior temporal gyrus, right fusiform gyrus, right precentral gyrus, and right anterior lobe of cerebellum as compared with ADHD subjects without the A allele (p< 0.001).
3) No significant perfusion differences were found between ADHD subjects with and without the T allele (risk allele) at the -3081(A/T) polymorphism.
Our findings suggest that the SLC6A2 G1287A polymorphism might exert differential effects on rCBF in children with ADHD.
The objective of this family-based whole exome sequencing (WES) is to examine genetic variants of autism spectrum disorder (ASD) in Korean population.
The probands with ASD and their biological parents were recruited in this study. We ascertained diagnosis based on DSM-5™ criteria, using Autism Diagnostic Observation Schedule and Autism Diagnostic Interview–Revised. We selected probands with typical phenotypes of ASD both in social interaction/communication and repetitive behaviour/limited interest domains, with intellectual disability (IQ < 70), for attaining homogeneity of the phenotypes. First, we performed WES minimum 50× for 13 probands and high-coverage pooled sequencing for their parents. We performed additional WES for 38 trio families, at least 100× depth. De novo mutations were confirmed by Sanger sequencing. All the sequence reads were mapped onto the human reference genome (hg19 without Y chromosome). Bioinformatics analyses were performed by BWA-MEM, Picard, GATK, and snpEff for variant annotation. We selected de novo mutation candidates from probands, which are neither detected in two pooled samples nor both parents.
Fifty-one subjects with ASD (5 females, 40∼175 months, mean IQ 42) and their families were included in this study. We discovered 109 de novo variants from 46 families. Twenty-nine variants are expected to be amino acid changing, potentially causing deleterious effects. We assume CELSR3, MYH1, ATXN1, IDUA, NFKB1, and C4A/C4B may have adverse effect on central nerve system.
We observed novel de novo variants which are assumed to contribute to development of ASD with typical phenotypes and low intelligence in WES study.
Disclosure of interest
This work has been supported by Healthcare Technology R&D project (No: A120029) by Ministry of Health and Welfare, Republic of Korea.
The enhanced error monitoring in patients with obsessive–compulsive disorder (OCD), typically measured with the error-related negativity (ERN), has been found to be temporally stable and independent of symptom expression. Here, we examined whether the error monitoring in patients with OCD could be experimentally modulated by individually tailored symptom provocation.
Twenty patients with OCD and 20 healthy controls performed a flanker task in which OCD-relevant or neutral pictures were presented prior to a flanker stimulus. An individualized stimulus set consisting of the most provoking images in terms of OCD symptoms was selected for each patient with OCD. Response-locked event-related potentials were recorded and used to examine the error-related brain activity.
Patients with OCD showed larger ERN amplitudes than did control subjects in both the OCD-symptom provocation and neutral conditions. Additionally, while patients with OCD exhibited a significant increase in the ERN under the OCD-symptom provocation condition when compared with the neutral condition, control subjects showed no variation in the ERN between the conditions.
Our results strengthen earlier findings of hyperactive error monitoring in OCD, as indexed by higher ERN amplitudes in patients with OCD than in controls. Importantly, we showed that the patients’ overactive error-signals were experimentally enhanced by individually tailored OCD-symptom triggers, thus suggesting convincing evidence between OCD-symptoms and ERN. Such findings imply that therapeutic interventions should target affective regulation in order to alleviate the perceived threatening value of OCD triggers.
The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.
Glacier surface mass-balance measurements on Greenland started more than a century ago, but no compilation exists of the observations from the ablation area of the ice sheet and local glaciers. Such data could be used in the evaluation of modelled surface mass balance, or to document changes in glacier melt independently from model output. Here, we present a comprehensive database of Greenland glacier surface mass-balance observations from the ablation area of the ice sheet and local glaciers. The database spans the 123 a from 1892 to 2015, contains a total of ~3000 measurements from 46 sites, and is openly accessible through the PROMICE web portal (http://www.promice.dk). For each measurement we provide X, Y and Z coordinates, starting and ending dates as well as quality flags. We give sources for each entry and for all metadata. Two thirds of the data were collected from grey literature and unpublished archive documents. Roughly 60% of the measurements were performed by the Geological Survey of Denmark and Greenland (GEUS, previously GGU). The data cover all regions of Greenland except for the southernmost part of the east coast, but also emphasize the importance of long-term time series of which there are only two exceeding 20 a. We use the data to analyse uncertainties in point measurements of surface mass balance, as well as to estimate surface mass-balance profiles for most regions of Greenland.
We study fundamental properties of transonic galactic outflows in the gravitational potential of a cold dark matter halo (DMH) with a central super-massive black hole (SMBH) assuming a polytropic, steady and spherically symmetric state. We have classified the transonic solutions with respect to their topology in the phase space. As a result, we have found two types of transonic solutions characterized by a magnitude relationship between the gravity of DMH and that of SMBH. These two types of solutions have different loci of the transonic points; one transonic point is formed at a central region (< 0.01kpc) and another is at a distant region (> 100kpc). Also, mass fluxes and outflow velocities are different between the two solutions. These two transonic solutions may play different roles on the star formation history of galaxies and the metal contamination of intergalactic space. Furthermore, we have applied our model to the Sombrero galaxy. In this galaxy, the wide-spread hot gas is detected as an apparent trace of galactic outflows while the star-formation rate is disproportionately low, and the observed gas density distribution is quite similar to the hydrostatic state (Li et al. 2011). To solve this discrepancy, we propose a slowly accelerating outflow in which the transonic point forms in a distant region (~ 120 kpc) and the subsonic region spreads across the stellar distribution. In the subsonic region, the gas density distribution is similar to that of the hydrostatic state. Our model predicts the possibility of the slowly accelerating outflow in the Sombrero galaxy. Igarashi et al. 2014 used the isothermal model and well reproduced the observed gas density distribution, but the estimated mass flux (1.8M⊙/yr) is lager than the mass of the gas supplied by stars (0.3-0.4M⊙/yr). Then, we expect that the polytropic model may reproduce the observational mass of the supplied gas (Igarashi et al. 2015). Such slowly accelerating outflows should be distinguished from the conventional supersonic outflows frequently argued in star-forming galaxies.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
Additional high-quality evidence for predictors of peritonsillar abscess recurrence could lead to better-informed treatment decisions regarding tonsillectomy.
In this study, 172 patients, who had been diagnosed and treated for peritonsillar abscess, were evaluated at follow up. A retrospective review of medical records and a telephone survey were performed. The clinical characteristics analysed included underlying disease, laboratory findings and computed tomography findings. Cox proportional hazard models were used to identify risk factors for peritonsillar abscess recurrence.
The recurrence rate of peritonsillar abscess was 13.9 per cent. Univariate analysis indicated that extraperitonsillar spread of the abscess (beyond the peritonsillar area) on computed tomography and a history of recurrent tonsillitis were associated with recurrence. Multivariate analysis also indicated that extraperitonsillar spread (p = 0.007; hazard ratio = 3.399) and recurrent tonsillitis history (p < 0.001; hazard ratio = 11.953) were significant risk factors for recurrence.
Our results suggest that tonsillectomy may be indicated as a treatment for peritonsillar abscess in patients with a history of recurrent tonsillitis or extraperitonsillar spread on computed tomography.
Previous studies have implicated the relationship between environmental phthalate exposure and attention deficit hyperactivity disorder (ADHD) symptoms of childhood, but no studies have been conducted in children who have a confirmed diagnosis of ADHD obtained through meticulous diagnostic testing. We aimed to determine whether phthalate metabolites in urine would be higher in children with ADHD than in those without ADHD and would correlate with symptom severity and cortical thickness in ADHD children.
A cross-sectional examination of urine phthalate metabolite concentrations was performed; scores for ADHD symptoms, externalizing problems, and continuous performance tests were obtained from 180 children with ADHD, and brain-imaging data were obtained from 115 participants. For the control group, children without ADHD (N = 438) were recruited. Correlations between phthalate metabolite concentrations and clinical measures and brain cortical thickness were investigated.
Concentrations of phthalate metabolites, particularly the di(2-ethylhexyl) phthalate (DEHP) metabolite, were significantly higher in boys with ADHD than in boys without ADHD. Concentrations of the di-n-butyl phthalate (DBP) metabolite were significantly higher in the combined or hyperactive-impulsive subtypes compared to the inattentive subtype, and the metabolite was positively correlated with the severity of externalizing symptoms. Concentrations of the DEHP metabolite were negatively correlated with cortical thickness in the right middle and superior temporal gyri.
The results of this study suggest an association between phthalate concentrations and both the diagnosis and symptom severity of ADHD. Imaging findings suggest a negative impact of phthalates on regional cortical maturation in children with ADHD.
We examined the cross-sectional relationship between environmental tobacco smoke exposure, continuous performance test (CPT) measures, and attention deficit hyperactivity disorder (ADHD) or learning disability symptoms in school-aged children.
In total, 989 children (526 boys, mean age 9.1 ± 0.7 years), recruited from five South Korean cities participated in this study. We used urine cotinine as a biomarker for environmental tobacco smoke exposure, and obtained the children's scores on a CPT. Parents completed the Korean versions of the ADHD Rating Scale – IV (ADHD-RS) and Learning Disability Evaluation Scale (LDES). Using generalized linear mixed model (GLMM), we assessed the associations between urine cotinine concentrations, neuropsychological variables, and symptoms of ADHD and learning disabilities. Additionally, we conducted structural equation models to explore the effects' pathways.
After adjusting for a range of relevant covariates, GLMM showed urinary cotinine levels were significantly and positively associated with CPT scores on omission errors, commission errors, response time, and response time variability, and with parent- and teacher-rated ADHD-RS scores. In addition, urine cotinine levels were negatively associated with LDES scores on spelling and mathematical calculations. The structural equation model revealed that CPT variables mediated the association between urine cotinine levels and parental reports of symptoms of ADHD and learning disabilities.
Our data indicate that environmental exposure to tobacco smoke is associated with ADHD and learning disabilities in children, and that impairments in attention and inhibitory control probably mediate the effect.
The incidence and severity of Clostridium difficile infections (CDI) have increased in Western countries. However, there are limited data regarding the epidemiology of CDI in Eastern countries. This nationwide study was conducted in 17 hospitals to determine temporal trends in CDI incidence (from 2004 to 2008) in South Korea. The total incidence of CDI in Korea was 1·7 cases/1000 adult admissions in 2004, and 2·7/1000 cases in 2008 (P = 0·028). When analysing the clinical features of 1367 CDI patients diagnosed in 2008, oral metronidazole was effective as a first-line treatment for CDI (61·9%). Relapse rate was 8·9% and complicated CDI was only observed in 3·6%. The incidence of CDI increased significantly in Korea from 2004 to 2008. Although the clinical features were milder than in Western countries, the increasing burden of CDI needs ongoing surveillance systems.
SiGe nanowires of different Ge atomic fractions up to 15% were grown and ex-situ n-type doped by diffusion from a solid source in contact with the sample. The phenomenon of dielectrophoresis was used to locate single nanowires between pairs of electrodes in order to carry out electrical measurements. The measured resistance of the as-grown nanowires is very high, but it decreases more than three orders of magnitude upon doping, indicating that the doping procedure used has been effective.
The oscillating piezoelectric field of a surface acoustic wave (SAW) is employed to transport photoexcited electrons and holes in GaAs nanowires (NWs) transferred to a SAW beam line on a LiNbO3 crystal. We show that carriers generated in the NW by a focused light spot can be acoustically transported to a second location, where they recombine emitting short light pulses. The results presented here demonstrate the high-frequency manipulation of carriers in NWs without the use of electrical contacts, which opens new perspectives for applications in opto-electronic devices operating at GHz frequencies.
The use of Ga-Au alloys as metal catalysts for the growth of SiGe nanowires has been investigated. The grown nanowires are cylindrical and straight, with a defect-free crystalline structure, sharp nanowire-droplet interfaces and an almost constant Ge atomic fraction throughout all their length. These features represent significant improvements over the results obtained using pure Au.
A multi-cross-correlation method (MCCM) was developed in a particle image velocimetry (PIV) auto-processing system to reduce spurious vectors and improve accuracy of measurements. This technique is an improvement based on conventional cross-correlation method (CCM). Four typical neighboring interrogation windows were specified to be overlapped and calculated by MCCM. A high cross-correlation value is obtained in which many particle images match up with their corresponding spatially shifted partners, and small cross-correlation peaks due to interference of noises during experiments are reduced. Several parameters such as out-of-plane motions, particle size, and seeding density are considered for checking both MCCM and conventional PIV algorithms. The examination gives authenticity to the merits of MCCM for avoiding particles loss or mistaken velocity vectors.
We present atomic force microscopy (AFM), Hall-effect measurement, and Raman spectroscopy results from graphene films on 6H-SiC (0001) and (000-1) faces (Si-face and C-face, respectively) produced by radiative heating in a high vacuum furnace chamber through thermal decomposition. We observe that the formation of graphene on the two faces of SiC is different in terms of the surface morphology, graphene thickness, Hall mobility, and Raman spectra. In general, graphene films on the SiC C-face are thicker with higher mobilities than those grown on the Si-face.
We examined the spatiotemporal distribution of laboratory-confirmed multidrug-resistant tuberculosis (MDR TB) cases and that of other TB cases in Lima, Peru with the aim of identifying mechanisms responsible for the rise of MDR TB in an urban setting. All incident cases of TB in two districts of Lima, Peru during 2005–2007 were included. The spatiotemporal distributions of MDR cases and other TB cases were compared with Ripley's K statistic. Of 11 711 notified cases, 1187 received drug susceptibility testing and 376 were found to be MDR. Spatial aggregation of patients with confirmed MDR disease appeared similar to that of other patients in 2005 and 2006; however, in 2007, cases with confirmed MDR disease were found to be more tightly grouped. Subgroup analysis suggests the appearance of resistance may be driven by increased transmission. Interventions should aim to reduce the infectious duration for those with drug-resistant disease and improve infection control.