Application of an open position splint integrated with a reference frame and registration markers for mandibular navigation surgery.

Navigation surgery plays an important role in modern craniomaxillofacial surgery, but it is difficult to apply navigation surgery to the mandible, due to its mobility. At present, headbands or headpins are widely used for fixation of the reference frame, and three strategies are generally used for the application of navigation surgery to the mandible. This article reports the application of a novel open position splint integrated with a reference frame and registration markers for mandibular navigation surgery as a fourth strategy. Using this custom-made integrated splint, a marker-based pair-point registration procedure was completed easily and non-invasively. Furthermore, the neurovascular canal tract could be easily identified, and the cyst, as well as the surrounding daughter cysts, could be removed with high accuracy. This strategy has potential for widespread clinical application in mandibular navigation surgery.

Gate-Tunable Spin-Charge Conversion and the Role of Spin-Orbit Interaction in Graphene.

The small spin-orbit interaction of carbon atoms in graphene promises a long spin diffusion length and the potential to create a spin field-effect transistor. However, for this reason, graphene was largely overlooked as a possible spin-charge conversion material. We report electric gate tuning of the spin-charge conversion voltage signal in single-layer graphene. Using spin pumping from an yttrium iron garnet ferrimagnetic insulator and ionic liquid top gate, we determined that the inverse spin Hall effect is the dominant spin-charge conversion mechanism in single-layer graphene. From the gate dependence of the electromotive force we showed the dominance of the intrinsic over Rashba spin-orbit interaction, a long-standing question in graphene research.

Electrically induced ambipolar spin vanishments in carbon nanotubes.

Carbon nanotubes (CNTs) exhibit various excellent properties, such as ballistic transport. However, their electrically induced charge carriers and the relation between their spin states and the ballistic transport have not yet been microscopically investigated because of experimental difficulties. Here we show an electron spin resonance (ESR) study of semiconducting single-walled CNT thin films to investigate their spin states and electrically induced charge carriers using transistor structures under device operation. The field-induced ESR technique is suitable for microscopic investigation because it can directly observe spins in the CNTs. We observed a clear correlation between the ESR decrease and the current increase under high charge density conditions, which directly demonstrated electrically induced ambipolar spin vanishments in the CNTs. The result provides a first clear evidence of antimagnetic interactions between spins of electrically induced charge carriers and vacancies in the CNTs. The ambipolar spin vanishments would contribute the improvement of transport properties of CNTs because of greatly reduced carrier scatterings.

Formation of a stable p-n junction in a liquid-gated MoS2 ambipolar transistor.

Molybdenum disulfide (MoS2) has gained attention because of its high mobility and circular dichroism. As a crucial step to merge these advantages into a single device, we present a method that electronically controls and locates p-n junctions in liquid-gated ambipolar MoS2 transistors. A bias-independent p-n junction was formed, and it displayed rectifying I-V characteristics. This p-n diode could perform a crucial role in the development of optoelectronic valleytronic devices.

In-crystal and surface charge transport of electric-field-induced carriers in organic single-crystal semiconductors.

Gate-voltage dependence of carrier mobility is measured in high-performance field-effect transistors of rubrene single crystals by simultaneous detection of the longitudinal conductivity sigma(square) and Hall coefficient R(H). The Hall mobility mu(H) (identical with sigma(square)R(H)) reaches nearly 10 cm(2)/V s when relatively low-density carriers (<10(11) cm(-2)) distribute into the crystal. mu(H) rapidly decreases with higher-density carriers as they are essentially confined to the surface and are subjected to randomness of the amorphous gate insulators. The mechanism to realize high carrier mobility in the organic transistor devices involves intrinsic-semiconductor character of the high-purity organic crystals and diffusive bandlike carrier transport in the bulk.

Overcorrection in vertical alveolar distraction osteogenesis for dental implants.

A decrease in bone height following alveolar distraction osteogenesis (DO) before implant placement is common, and can be severe when alveolar DO is performed soon after surgical intervention. The aim of this study was to investigate the decrease in bone height after vertical alveolar DO and determine the need for overcorrection with implant placement. Thirty-five patients (17 males and 18 females, mean age 43.9 years) underwent 38 procedures with successful placement of 141 dental implants. Alveolar ridge height was evaluated using digital orthopantomographic radiographs taken shortly after the end of distraction, at consolidation and before implant placement. The mean distraction was 9.7 mm. The total vertical alveolar bone decrease was 2.1mm (21%) during the consolidation period and 3.6mm (37%) at implant placement. Although the 20 sites with a healthy alveolus (surgery >6 months) had bone reductions of 1.5 and 2.5mm (15 and 25%) the 18 sites at which alveolar DO was performed within 6 months (mean 3.0) of surgical intervention had much greater bone loss of 2.7 and 4.8mm (28 and 50%), respectively ((**)P<0.01). These results indicate that any alveolar DO protocol should include a waiting period after the surgical intervention, as well as consider an overcorrection of more than 25% within the limits of the applied surgical protocol.

Polarization reversal in multiferroic TbMnO3 with a rotating magnetic field direction.

For the memory application of magnetoelectric multiferroics, not only bistability (i.e., ferroelectricity) but also the switching of the polarization direction with some noneverlasting stimulus is necessary. Here, we report a novel method for the electric polarization reversal in TbMnO3 without the application of an electric field or heat. The direction of the magnetic-field-induced polarization along the a axis (Pa) is memorized even in the zero field where Pa is absent. The polarization direction can be reversed by rotating the magnetic-field direction in the ab plane.

Ferroelectric polarization flop in a frustrated magnet MnWO4 induced by a magnetic field.

The relationship between magnetic order and ferroelectric properties has been investigated for MnWO4 with a long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The magnetic-field dependence of electric polarization indicates that the noncollinear spin configuration plays a key role for the appearance of the ferroelectric phase. An electric polarization flop from the b direction to the a direction has been observed when a magnetic field above 10 T is applied along the b axis. This result demonstrates that an electric polarization flop can be induced by a magnetic field in a simple system without rare-earth 4f moments.

Large optical nonlinearity of semiconducting single-walled carbon nanotubes under resonant excitations.

We measured third-order nonlinear susceptibility (chi(3)) spectra in semiconducting single-walled carbon nanotubes (SWNTs) by the Z-scan method. |Imchi(3)| is remarkably enhanced under resonant excitation to the lowest interband transition, reaching 4.2 x 10(-6) esu and 1.5 x 10(-7) esu in SWNTs grown by the laser ablation and HiPco methods, respectively. A comparison of the transient absorption changes evaluated by degenerate and nondegenerate pump-probe measurements suggests that the resonant enhancement of |Imchi(3)| is dominated by a coherent process rather than by saturation of absorption.

Control of carrier density by self-assembled monolayers in organic field-effect transistors.

Organic thin-film transistors are attracting a great deal of attention due to the relatively high field-effect mobility in several organic materials. In these organic semiconductors, however, researchers have not established a reliable method of doping at a very low density level, although this has been crucial for the technological development of inorganic semiconductors. In the field-effect device structures, the conduction channel exists at the interface between organic thin films and SiO(2) gate insulators. Here, we discuss a new technique that enables us to control the charge density in the channel by using organosilane self-assembled monolayers (SAMs) on SiO(2) gate insulators. SAMs with fluorine and amino groups have been shown to accumulate holes and electrons, respectively, in the transistor channel: these properties are understood in terms of the effects of electric dipoles of the SAMs molecules, and weak charge transfer between organic films and SAMs.

Evidence for insulating behavior in the electric conduction of (NH(3))K(3)C(60) systems.

Microwave study using the cavity perturbation technique revealed that the conductivity of the antiferromagnet (NH(3))K(3-x)Rb(x)C(60) at 200 K is already 3-4 orders of magnitude smaller than those of superconductors, K(3)C(60) and (NH(3))(x)NaRb(2)C(60), and that the antiferromagnetic compounds are insulators below 250 K without metal-insulator transitions. The striking difference in the magnitude of the conductivity between these materials strongly suggests that the Mott-Hubbard transition in the ammoniated alkali fullerides is driven by a reduction of lattice symmetry from face-centered-cubic to face-centered-orthorhombic, rather than by the magnetic ordering.

Antiferromagnetism and phase diagram in ammoniated alkali fulleride salts

Intercalation of neutral ammonia molecules into trivalent face-centered-cubic (fcc) fulleride superconductors induces a dramatic change in electronic states. Monoammoniated alkali fulleride salts (NH3)K3-xRbxC60, forming an isostructural orthorhombic series, undergo an antiferromagnetic transition, which was found by the electron spin resonance experiment. The Neel temperature first increases with the interfullerene spacing and then decreases for (NH3)Rb3C60, forming a maximum at 76 K. This feature is explained by the generalized phase diagram of Mott-Hubbard transition with an antiferromagnetic ground state.

Modified sagittal split ramus osteotomy with a reciprocating saw and new retractors.

Modified sagittal split ramus osteotomy with new instruments and a reciprocating saw is reported. With this modification, the sagittal separation of the ramus is performed by the reciprocating saw with an original wide-blade buccal retractor and a new lingual retractor, instead of the traditional channeled retractor. The wide-blade retractor is inserted to the buccal aspect of the mandibular ramus, which ensures protection from instrumental injury to the adjacent soft tissues and vessels, and the new lingual retractor, instead of the channeled retractor, is inserted to the lingual aspect of the ramus. The osteotomy line follows that of Dal Pont's modification. Close attention must be paid to the direction of the saw blade. The separated bone plane should be located in the external cortical bone layer of the ramus, so as to avoid injury of the inferior alveolar neurovascular bundle. The osteotomy is completed with the smooth osteotomized interface, which facilitates positioning of the bone segments by the surgeon. The new instruments and the reciprocating saw may provide safe and rapid sagittal split ramus osteotomy.