Social anxiety disorder in adolescents who stutter: A risk for school refusal.

BACKGROUND: Stuttering is a childhood-onset fluency disorder. Part of the counseling for middle and high school students with persistent stuttering is related to school refusal. Anxiety disorders are known to contribute to school refusal. However, it is not known whether social anxiety disorder (SAD) is a factor in school refusal among adolescents who stutter. METHODS: In our first study, we examined the relationship between school refusal and SAD in 84 middle and high school students who stutter; 26% of the 84 students were in the school refusal group and the remaining 74% were in the school attendance group. The second study examined whether SAD was associated with 10 factors related to speech and stuttering frequency using the Japanese version of the Liebowitz Social Anxiety Scale for Children and Adolescents to determine the presence of SAD. Of the 84 students in the first study, 40 participated in the second study. RESULTS: The school refusal group of adolescents who stutter had significantly higher rates of SAD than the school attendance group. Fifty percent of adolescents who stutter met the criteria for SAD. Moreover, adolescents who stutter with SAD had significantly higher scores on the items "When speaking in public, do you experience tremors in your limbs?" and "After you stutter, do you have negative thoughts about yourself?" than the adolescents who stutter without SAD. CONCLUSIONS: When examining adolescents who stutter, checking for comorbid SAD may lead to better support. Moreover, noticing their repetitive negative thinking, nervousness, and trembling during speech may help to resolve SAD.

Effect of linguistic factors on the occurrence of stuttering-like disfluency among Japanese-speaking preschool children who stutter.

This study aimed to investigate the linguistic factors involved in stuttering among Japanese-speaking preschool children. The participants included 10 Japanese children who stutter, with a mean age of 5 years and 9 months. Speech samples comprised spontaneous conversations of the participants with their parents for about 20 minutes. We compared the percentages of the occurrence of stuttering-like disfluencies (SLDs) at the word and sentence levels, using the Wilcoxon signed-rank test. The results showed no significant differences in SLDs based on syllable structure when comparing light and heavy syllables and comparing consonants and vowels in the initial position of each content word. SLDs occurred more frequently in the initial than non-initial position of words and in longer rather than shorter words. Additionally, SLDs occurred more frequently in sentences that contained more 'bunsetsu' (a kind of linguistic unit in Japanese). Our study is the first to show that both word and sentence-level factors could contribute to SLDs in preschool children who stutter in agglutinating languages, such as Japanese. This aspect is rarely reported in psycholinguistic studies based on stuttering occurrence in inflecting languages, such as English.

Observation of spin-current striction in a magnet.

The interplay among magnetization and deformation of solids has long been an important issue in magnetism, the elucidation of which has made great progress in material physics. Controlling volume and shapes of matter is now indispensable to realizing various actuators for precision machinery and nanotechnology. Here, we show that the volume of a solid can be manipulated by injecting a spin current: a spin current volume effect (SVE). By using a magnet Tb0.3Dy0.7Fe2 exhibiting strong spin-lattice coupling, we demonstrate that the sample volume changes in response to a spin current injected by spin Hall effects. Theoretical calculation reflecting spin-current induced modulation of magnetization fluctuation well reproduces the experimental results. The SVE expands the scope of spintronics into making mechanical drivers.

A Questionnaire Survey About Support Requests From School-Age Children and Adolescents Who Stutter.

Purpose Children who stutter (CWS) face communication difficulties in school activities and at home. Although the importance of receiving support from their surroundings has been documented, few studies have investigated potential requests of CWS from their surroundings. This study aimed to elucidate such requests. Method A total of 43 school-age children and 25 adolescents who stutter completed a free-description questionnaire, including questions such as "what you want your classmates/your classroom teacher/your family to do about your stuttering?" Their descriptions were summarized and categorized based on similarity. Results The results indicate that 90.6% of the participants had more than one request for their classmates, classroom teacher, or family. A total of 197 items were extracted and categorized into seven themes. In particular, the responses included "listen attentively," "treat us naturally," and "make arrangements." While participants tended to hope for classmates or family to "listen attentively" and "treat us naturally," the request to "make arrangements" was higher for their teacher. Their potential requests varied by age: While school-age CWS wanted people around them to "listen carefully," the hope of adolescents who stutter was "treat us naturally." Conclusions The various potential requests of CWS were categorized, and the responses shed light on the importance of increasing knowledge of stuttering. The difference between the requests could reflect psychosocial differences between school-age children and adolescents who stutter. In addition, social interaction among peers is more developed in adolescents, and they could harbor fear of being excluded within their community.

Spin transport in insulators without exchange stiffness.

The discovery of new materials that efficiently transmit spin currents has been important for spintronics and material science. The electric insulator Gd3Ga5O12 (GGG), a standard substrate for growing magnetic films, can be a spin current generator, but has never been considered as a superior conduit for spin currents. Here we report spin current propagation in paramagnetic GGG over several microns. Surprisingly, spin transport persists up to temperatures of 100 K [Formula: see text] Tg = 180 mK, the magnetic glass-like transition temperature of GGG. At 5 K and 3.5 T, we find a spin diffusion length λGGG = 1.8 ± 0.2 µm and a spin conductivity σGGG = (7.3 ± 0.3) × 104 Sm-1 that is larger than that of the record quality magnet Y3Fe5O12 (YIG). We conclude that exchange stiffness is not required for efficient spin transport, which challenges conventional models and provides new material-design strategies for spintronic devices.

The spin Nernst effect in tungsten.

The spin Hall effect allows the generation of spin current when charge current is passed along materials with large spin-orbit coupling. It has been recently predicted that heat current in a nonmagnetic metal can be converted into spin current via a process referred to as the spin Nernst effect. We report the observation of the spin Nernst effect in W. In W/CoFeB/MgO heterostructures, we find changes in the longitudinal and transverse voltages with magnetic field when temperature gradient is applied across the film. The field dependence of the voltage resembles that of the spin Hall magnetoresistance. A comparison of the temperature gradient-induced voltage and the spin Hall magnetoresistance allows direct estimation of the spin Nernst angle. We find the spin Nernst angle of W to be similar in magnitude but opposite in sign to its spin Hall angle. Under an open-circuit condition, this sign difference results in the spin current generation larger than otherwise. These results highlight the distinct characteristics of the spin Nernst and spin Hall effects, providing pathways to explore materials with unique band structures that may generate large spin current with high efficiency.

Generation of megahertz-band spin currents using nonlinear spin pumping.

Spin pumping enables the generation of d.c. and gigahertz-band (GHz-band) voltages from an applied microwave via magnetization dynamics when combined with inverse spin Hall effects. However, generating such voltages in the in-between frequency region, or the megahertz (MHz) band, has been difficult since ferromagnetic resonance usually occurs in the GHz band. Here we show that in spite of GHz-band microwaves applied, MHz-band voltages can be generated by spin pumping with use of nonlinear magnetization dynamics in Y3Fe5O12. The mechanism is ascribed to the MHz-band oscillation of the amplitude of the magnetization precession, which is projected onto a rectified voltage component via spin pumping. The present finding could be useful for frequency down-conversion thanks to the simple and durable structure, continuous-wave operation, and the tunability of an output frequency with low magnetic fields.

Optically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance.

Developing optically transparent magnets at room temperature is an important challenge. They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region. These films have a nanocomposite structure, in which nanometer-sized FeCo ferromagnetic granules are dispersed in an Al-fluoride crystallized matrix. The optical transmittance of these films is controlled by changing the magnetization. This is a new type of magneto-optical effect and is explained by spin-dependent charge oscillation between ferromagnetic granules due to quantum-mechanical tunneling.

Spin Hall Magnetoresistance in Metallic Bilayers.

Spin Hall magnetoresistance (SMR) is studied in metallic bilayers that consist of a heavy metal (HM) layer and a ferromagnetic metal (FM) layer. We find a nearly tenfold increase of SMR in W/CoFeB compared to previously studied HM/ferromagnetic insulator systems. The SMR increases with decreasing temperature despite the negligible change in the W layer resistivity. A model is developed to account for the absorption of the longitudinal spin current to the FM layer, one of the key characteristics of a metallic ferromagnet. We find that the model not only quantitatively describes the HM layer thickness dependence of SMR, allowing accurate estimation of the spin Hall angle and the spin diffusion length of the HM layer, but also can account for the temperature dependence of SMR by assuming a temperature dependent spin polarization of the FM layer. These results illustrate the unique role a metallic ferromagnetic layer plays in defining spin transmission across the HM/FM interface.

Theory of spin Hall magnetoresistance (SMR) and related phenomena.

We review the so-called spin Hall magnetoresistance (SMR) in bilayers of a magnetic insulator and a metal, in which spin currents are generated in the normal metal by the spin Hall effect. The associated angular momentum transfer to the ferromagnetic layer and thereby the electrical resistance is modulated by the angle between the applied current and the magnetization direction. The SMR provides a convenient tool to non-invasively measure the magnetization direction and spin-transfer torque to an insulator. We introduce the minimal theoretical instruments to calculate the SMR, i.e. spin diffusion theory and quantum mechanical boundary conditions. This leads to a small set of parameters that can be fitted to experiments. We discuss the limitations of the theory as well as alternative mechanisms such as the ferromagnetic proximity effect and Rashba spin-orbit torques, and point out new developments.

Giant dielectric and magnetoelectric responses in insulating nanogranular films at room temperature.

The electric and magnetic properties of matter are of great interest for materials science and their use in electronic applications. Large dielectric and magnetoelectric responses of materials at room temperature are a great advantage for electromagnetic device applications. Here we present a study of FeCo-MgF nanogranular films exhibiting giant dielectric and magnetoelectric responses at room temperature; with dielectric constant ε'=490 and magnetoelectric response Δε'/ε'0=3%. In these films, Fe-Co alloy-based nanometer-sized magnetic granules are dispersed in a Mg-fluoride-based insulator matrix. Insulating nanogranular films are a new class of multifunctional materials. The giant responses are caused by spin-dependent charge oscillation between magnetic granules via quantum-mechanical tunnelling. A possible application of such insulating nanogranular materials with giant response is in the construction of a tunable device, in which impedance components such as capacitance and inductance are tunable at room temperature.

Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves.

The non-local spin injection in lateral spin valves is strongly expected to be an effective method to generate a pure spin current for potential spintronic application. However, the spin-valve voltage, which determines the magnitude of the spin current flowing into an additional ferromagnetic wire, is typically of the order of 1 µV. Here we show that lateral spin valves with low-resistivity NiFe/MgO/Ag junctions enable efficient spin injection with high applied current density, which leads to the spin-valve voltage increasing 100-fold. Hanle effect measurements demonstrate a long-distance collective 2π spin precession along a 6-µm-long Ag wire. These results suggest a route to faster and manipulable spin transport for the development of pure spin-current-based memory, logic and sensing devices.

Extremely long quasiparticle spin lifetimes in superconducting aluminium using MgO tunnel spin injectors.

There has been an intense search in recent years for long-lived spin-polarized carriers for spintronic and quantum-computing devices. Here we report that spin-polarized quasiparticles in superconducting aluminium layers have surprisingly long spin lifetimes, nearly a million times longer than in their normal state. The lifetime is determined from the suppression of the aluminium's superconductivity resulting from the accumulation of spin-polarized carriers in the aluminium layer using tunnel spin injectors. A Hanle effect, observed in the presence of small in-plane orthogonal fields, is shown to be quantitatively consistent with the presence of long-lived spin-polarized quasiparticles. Our experiments show that the superconducting state can be significantly modified by small electric currents, much smaller than the critical current, which is potentially useful for devices involving superconducting qubits.

Giant spin Hall effect in perpendicularly spin-polarized FePt/Au devices.

Conversion of charge current into pure spin current and vice versa in non-magnetic semiconductors or metals, which are called the direct and inverse spin Hall effects (SHEs), provide a new functionality of materials for future spin-electronic architectures. Thus, the realization of a large SHE in a device with a simple and practical geometry is a crucial issue for its applications. Here, we present a multi-terminal device with a Au Hall cross and an FePt perpendicular spin injector to detect giant direct and inverse SHEs at room temperature. Perpendicularly magnetized FePt injects or detects perpendicularly polarized spin current without magnetic field, enabling the unambiguous identification of SHEs. The unprecedentedly large spin Hall resistance of up to 2.9 mOmega is attributed to the large spin Hall angle in Au through the skew scattering mechanism and the highly efficient spin injection due to the well-matched spin resistances of the chosen materials.

Spin current, spin accumulation and spin Hall effect.

Nonlocal spin transport in nanostructured devices with ferromagnetic injector (F1) and detector (F2) electrodes connected to a normal conductor (N) is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin-orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin-orbit coupling in nonmagnetic metals is proposed.

Possible link between childhood separation anxiety and adulthood personality disorder in patients with anxiety disorders in Japan.

OBJECTIVE: The aim of this study was to examine whether childhood separation anxiety symptoms associate with adulthood anxiety disorders or personality disorders. METHOD: Separation Anxiety Symptom Inventory (SASI), Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II), and Global Assessment of Functioning (GAF) were administered to 134 outpatients with anxiety disorders and SASI was administered to 176 healthy volunteers (controls) recruited in Japan from April 1999 through November 2003. RESULTS: SASI scores were not correlated with age or sex in controls. In contrast, SASI scores were higher in patients with anxiety disorders than in controls, especially in women. SASI showed good test-retest reliability (Pearson correlation coefficient = 0.8). One hundred thirteen patients (84.3%) had no comorbid anxiety disorder while 21 (15.7%) had any, and those with comorbid anxiety disorder tended to show higher SASI scores (p = .053). In total, 60 (44.8%) of 134 patients had at least 1 personality disorder, and the most frequent disorders were from cluster C (36.6%). The subgroup with comorbid personality disorders showed earlier onset (p < .01), higher SASI scores (p < .01), and poorer recovery of global functioning (p < .05) than the noncomorbid subgroup. Stepwise multiple regression analysis revealed that SASI scores were higher in female (p < .05) and younger (p < .01) patients and most strongly correlated with number of comorbid personality disorders in adulthood (p < .01). CONCLUSION: These results suggest that there is a continuum of anxiety disorders from childhood to adulthood, the severity of separation anxiety appears to increase the risk of severe anxious-fearful personality disorders in adulthood, and those with severe separation anxiety, particularly females, may progress to suffer from comorbid adult anxiety disorders.

Putative temperament of patients with generalized anxiety disorder: two-years' interval test-retest reliability of a Japanese version of the Generalized Anxious Temperament.

This study examined long-interval test-retest reliability of the Generalized Anxious Temperament (GAT) Japanese version, which is a self-rated questionnaire to measure the temperament of patients with generalized anxiety disorder (GAD). First, we investigated the prevalence of GAT in 214 healthy Japanese subjects (107 females and 107 males). Second, we administered GAT to the 117 (77 females and 40 males) patients with GAD, together with GAF (Global Assessment of Functioning) and HAM-A (Hamilton Anxiety Scale), and readministered after 2 years to examine its reliability. GAT showed good test-retest reliability (Pearson's correlation coefficient = 0.8). Cronbach's alpha of the 26 GAT items was 0.93 that indicated a high level of internal consistency. GAT scores were not influenced by psychological, social or occupational functioning, nor by anxiety symptoms and remained stable over 2 years. GAT scores did not correlate with the age or sex of the control subjects. GAT scores were higher in patients with GAD than they were in control subjects, particularly in females. Twenty-three of 26 GAT items were significantly higher in patients with GAD than in healthy subjects. Stepwise multiple regression analysis revealed that GAT scores in patients with GAD were higher in females than in males (P < 0.01) and in those with early onset of the disorder (P < 0.05). These results suggest that the anxious temperament appears to increase the risk of early onset of GAD, particularly in females. This long interval and large sample research of test-retest reliability on GAT indicated its usefulness for understanding the core features of GAD.