Quantitative autistic traits ascertained in a national survey of 22 529 Japanese schoolchildren

OBJECTIVE

Recent epidemiologic studies worldwide have documented a rise in prevalence rates for autism spectrum disorders (ASD). Broadening of diagnostic criteria for ASD may be a major contributor to the rise in prevalence, particularly if superimposed on an underlying continuous distribution of autistic traits. This study sought to determine the nature of the population distribution of autistic traits using a quantitative trait measure in a large national population sample of children.

METHOD

The Japanese version of the Social Responsiveness Scale (SRS) was completed by parents on a nationally representative sample of 22 529 children, age 6-15.

RESULTS

Social Responsiveness Scale scores exhibited a skewed normal distribution in the Japanese population with a single-factor structure and no significant relation to IQ within the normal intellectual range. There was no evidence of a natural 'cutoff' that would differentiate populations of categorically affected children from unaffected children.

CONCLUSION

This study provides evidence of the continuous nature of autistic symptoms measured by the SRS, a validated quantitative trait measure. The findings reveal how paradigms for diagnosis that rest on arbitrarily imposed categorical cutoffs can result in substantial variation in prevalence estimation, especially when measurements used for case assignment are not standardized for a given population.

Electronic phase transition and an anomalous ordered phase in Ba2Ti13O22 with 3d1 ions on a triangle-based lattice

We found that Ba(2)Ti(13)O(22) with Ti(3+) (3d(1)) ions on a triangle-based lattice exhibits a phase transition at T(c)~200 K, below which the increase of electrical resistivity and decrease of magnetic susceptibility were observed. Transmission electron microscopy and optical reflectivity measurements indicate that the low-temperature phase of the present compound shares characteristics in common with a charge-density-wave state with remnant carriers, although a commensurate wave vector of the modulation and a linear temperature dependence of the magnetic susceptibility below T(c) suggest an exotic ordered state.

Effect of Processing Conditions on the Dispersion of Vapor Grown Carbon Fiber in a Polyamide 6 and the Crystalline Structure of their Composites by Melt Compounding

We present the preparation of polyamide 6 (PA6)/Vapor Grown Carbon Fiber (VGCF) composites by melt compounding. Two commercialized forms of PA6 with different melt flow rates (herein named PA6-low and PA6-high.) and two VGCF, VGCF-H (aspect ratio: 40) and VGCF-S (aspect ratio: 100) were used in this study. Young's modulus and the yield strength increased when small amount of VGCF (e.g. 1 wt.%) was added to PA6, and the properties of PA6-low/VGCF composites increased with a decrease in the aspect ratio of VGCF. According to scanning electron microscopy (SEM) observations, the dispersion state of VGCF in PA6-low/VGCF-S composites is superior to the PA6-low/VGCF-H composites. This may be due to the weakening of tensile properties caused by cracks between the adjoining crystals generated by the large amount of VGCF that act as nucleants. Hence, the aspect ratio of VGCF has an influence on the tensile properties of PA6/VGCF composites. The mechanical properties were shown to increase with VGCF-H length. Matrix viscosity and the screw rotation speed were also found to influence the mechanical properties of PA6/VGCF-H composites.

Current-induced magnetic domain wall motion below intrinsic threshold triggered by Walker breakdown

Controlling the position of a magnetic domain wall with electric current may allow for new types of non-volatile memory and logic devices. To be practical, however, the threshold current density necessary for domain wall motion must be reduced below present values. Intrinsic pinning due to magnetic anisotropy, as recently observed in perpendicularly magnetized Co/Ni nanowires, has been shown to give rise to an intrinsic current threshold J(th)(0). Here, we show that domain wall motion can be induced at current densities 40% below J(th)(0) when an external magnetic field of the order of the domain wall pinning field is applied. We observe that the velocity of the domain wall motion is the vector sum of current- and field-induced velocities, and that the domain wall can be driven against the direction of a magnetic field as large as 2,000 Oe, even at currents below J(th)(0). We show that this counterintuitive phenomenon is triggered by Walker breakdown, and that the additive velocities provide a unique way of simultaneously determining the spin polarization of current and the Gilbert damping constant.

Identification and characterization of an adenine to guanine transition within intron 10 of the factor VIII gene as a causative mutation in a patient with mild haemophilia A

Haemophilia A is caused by various genetic mutations in the factor VIII gene (F8). However, after conventional analysis, no candidate mutation could be identified in the F8 of about 2% of haemophilia A patients. The F8 of a patient with mild congenital haemophilia A, in whom no candidate mutation was found in the exons or their flanking regions, was analysed in detail to identify the patient's aetiological genetic abnormality. We also characterized anti-FVIII antibody (inhibitor) development in this patient. Genomic DNA analysis revealed an adenine to guanine transition deep inside intron 10 (c.1478 + 325A>G) of F8 as a causative mutation. Analysis of the transcripts demonstrated that the majority of the patient's transcript was abnormal, with 226 bp of the intronic sequence inserted between exon 10 and 11. However, the analysis also indicated the existence of a small amount of normal transcript. Semi-quantification of ectopic F8 mRNA showed that about one-tenth of the normal mRNA level was present in the patient. After the use of a recombinant FVIII concentrate, the presence of an inhibitor was confirmed. The inhibitor was characterized as oligoclonal immunoglobulin IgG4 directed against both the A2 domain and light chain of the FVIII molecule with type I reaction kinetics of inhibition of FVIII activity. When no mutations are found by conventional analysis, deep intronic nucleotide substitutions may be responsible for mild haemophilia. The inhibitor development mechanism of the patient producing some normal FVIII was thought to be of interest.

Chiral magnetic soliton lattice on a chiral helimagnet

Using Lorenz microscopy and small-angle electron diffraction, we directly present that the chiral magnetic soliton lattice (CSL) continuously evolves from a chiral helimagnetic structure in small magnetic fields in Cr(1/3)NbS2. An incommensurate CSL undergoes a phase transition to a commensurate ferromagnetic state at the critical field strength. The period of a CSL, which exerts an effective potential for itinerant spins, is tuned by simply changing the field strength. Chiral magnetic orders observed do not exhibit any structural dislocation, indicating their high stability and robustness in Cr(1/3)NbS2.

Ferroelectric and Structural Antiphase Domains in Hexagonal RMnO3

We have investigated characteristic ferroelectric and structural antiphase domain structures in single crystals of hexagonal RMnO3 (R=Y, Ho, Lu, and Yb) by obtaining various electron diffraction patterns, dark-filed images and high-resolution lattice images. In the ferroelectric phase of RMnO3 characteristic domain structures consisting of six ferroelectric and structural antiphase domains, which can be identified as the “cloverleaf” pattern, is found in the (110) plane, in addition to the (001) plane, and are inherent to the ferroelectric phase of hexagonal RMnO3. In domain configuration with the cloverleaf pattern in the (110) plane, the structural antiphase boundaries are inclined to be parallel to the [001] direction.

Real space observation of current-induced magnetic domain wall displacement in Co/Ni nano-wire by photoemission electron microscopy

Current-induced magnetic domain wall (DW) displacement in a Co/Ni nano-wire with perpendicular magnetic anisotropy was investigated in real space by photoemission electron microscopy (PEEM) for the first time. DW velocity determined from the PEEM observation was 40 m s(-1) for the current density of 2.5 × 10(12) A m(-2), which was consistent with the result obtained by the electrical measurement used in our previous reports.

Paracrine control of mesenteric perivascular axo-axonal interaction

Immunohistochemical study of rat mesenteric arteries showed dense innervation of adrenergic nerves, calcitonin gene-related peptide (CGRP)-containing nerves (CGRPergic nerves), nitric oxide-containing nerves (nitrergic nerves). Double-immunostaining revealed that most CGRPergic or nitrergic nerves were in close contact with adrenergic nerves. CGRPergic and transient receptor potential vanilloid-1 (TRPV1)-immunopositive nerves appeared in the same neurone. In rat perfused mesenteric vascular beds without endothelium and with active tone, perfusion of nicotine, or bolus injection of capsaicin and acetylcholine and periarterial nerve stimulation (PNS) lowered pH levels of out flowed perfusate concomitant with vasodilation. Cold-storage denervation of preparations abolished pH lowering induced by nicotine and PNS. Guanethidine inhibited PNS- and nicotine-, but not acetylcholine- and capsaicin-, induced pH lowering. Pharmacological analysis showed that protons were released not only from adrenergic nerves but also from CGRPergic nerves. A study using a fluorescent pH indicator demonstrated that nicotine, acetylcholine and capsaicin applied outside small mesenteric artery lowered perivascular pH levels, which were not observed in Ca(2+) free medium. Exogenously injected hydrochloric acid in denuded preparations induced pH lowering and vasodilation, which was inhibited by denervation, TRPV1 antagonists and capsaicin without affecting pH lowering. These results suggest that excitement of adrenergic nerves releases protons to activate TRPV1 in CGRPergic nerves and thereby induce vasodilation. It is also suggested that CGRPergic nerves release protons with exocytosis to facilitate neurotransmission via a positive feedback mechanism.

Computer-generated microsurgical anatomy of the paraclinoid area

To represent multiple microstructures, including perforators, dura, and cranial nerves, and to allow understanding of the three-dimensional relations of the paraclinoid area, we made a computer graphics model. The source of the input data is a variety of publications showing the detailed anatomy of the paraclinoid area. To produce the model, we traced such data, input selected points for each structure, smoothed the lines with a spline program, and added depth using wire-framing and color alterations. The computer graphic model of the paraclinoid area showing perforators, dural ring, optic nerve, and so forth, was made using a paint method for hidden line removal. It can be rotated and viewed from any direction and thus allows understanding of the relations of the area. Using our method, it may be possible to obtain a more detailed model of various anatomies including the skull base, and such data would be useful for preoperative simulation to understand relative regional relations for a specific case and as a new navigational system for open microneurosurgery. Concepts and technical details of the method are described.

Comparison of manual and automatic segmentation methods for brain structures in the presence of space-occupying lesions: a multi-expert study

The purpose of this work was to characterize expert variation in segmentation of intracranial structures pertinent to radiation therapy, and to assess a registration-driven atlas-based segmentation algorithm in that context. Eight experts were recruited to segment the brainstem, optic chiasm, optic nerves, and eyes, of 20 patients who underwent therapy for large space-occupying tumors. Performance variability was assessed through three geometric measures: volume, Dice similarity coefficient, and Euclidean distance. In addition, two simulated ground truth segmentations were calculated via the simultaneous truth and performance level estimation algorithm and a novel application of probability maps. The experts and automatic system were found to generate structures of similar volume, though the experts exhibited higher variation with respect to tubular structures. No difference was found between the mean Dice similarity coefficient (DSC) of the automatic and expert delineations as a group at a 5% significance level over all cases and organs. The larger structures of the brainstem and eyes exhibited mean DSC of approximately 0.8-0.9, whereas the tubular chiasm and nerves were lower, approximately 0.4-0.5. Similarly low DSCs have been reported previously without the context of several experts and patient volumes. This study, however, provides evidence that experts are similarly challenged. The average maximum distances (maximum inside, maximum outside) from a simulated ground truth ranged from (-4.3, +5.4) mm for the automatic system to (-3.9, +7.5) mm for the experts considered as a group. Over all the structures in a rank of true positive rates at a 2 mm threshold from the simulated ground truth, the automatic system ranked second of the nine raters. This work underscores the need for large scale studies utilizing statistically robust numbers of patients and experts in evaluating quality of automatic algorithms.

Arteriovenous fistula in a nerve root of the cauda equina fed by a proximal radiculo-medullary artery: a report of two cases

While there have been a few reports on cases of intradural spinal arteriovenous fistula located on the filum terminale, no cases of its location in a nerve root of the cauda equina have been reported to date.We describe two such cases and describe the intraoperative findings. A 40-year-old man presented weakness of his left leg. Another 62-year-old man presented paraparesis dominantly in his left leg with urinary hesitation. In both cases, spinal T2-weighted magnetic resonance images showed edema of the spinal cord, indicating a flow void around it. Digital subtraction angiography disclosed an anterior radicular artery branching from the anterior spinal artery on the surface of the conus medullaris and a turnaround vein running in the opposite direction within the cauda equina. In the first patient, while the feeding artery running along a nerve root was detected, the draining vein and the fistula were not identified at first sight. An incision into the respective nerve root exposed their location within it. In the second patient, unlike the first case, the feeding artery and the fistula were buried in a nerve root, while the draining vein was running along the nerve's surface. In both cases, permanent clips were applied to the draining vein closest to the fistula. The recognition of a hidden fistulous point in a nerve root of the cauda equina is essential for successful obliteration of the fistula.

Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire

The spin transfer torque is essential for electrical magnetization switching. When a magnetic domain wall is driven by an electric current through an adiabatic spin torque, the theory predicts a threshold current even for a perfect wire without any extrinsic pinning. The experimental confirmation of this 'intrinsic pinning', however, has long been missing. Here, we give evidence that this intrinsic pinning determines the threshold, and thus that the adiabatic spin torque dominates the domain wall motion in a perpendicularly magnetized Co/Ni nanowire. The intrinsic nature manifests itself both in the field-independent threshold current and in the presence of its minimum on tuning the wire width. The demonstrated domain wall motion purely due to the adiabatic spin torque will serve to achieve robust operation and low energy consumption in spintronic devices.