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Gastrin-releasing peptide (GRP) has recently been identified as an itch-signaling molecule in the primary afferents and spinal cord of rodents. However, little information exists on the expression and localization of GRP in the trigeminal somatosensory system other than in rats. We examined the generality of the trigeminal GRP system in mammals using two distinct species, suncus as a model of specialized placental mammals known to have a well-developed trigeminal sensory system and mice as a representative small laboratory animal. We first analyzed the gross morphology of the trigeminal somatosensory system in suncus to provide a brainstem atlas on which to map GRP distribution. Immunohistochemical analyses showed that 8% of trigeminal ganglion neurons in suncus and 6% in mice expressed GRP. Expression was restricted to cells with smaller somata. The GRP-containing fibers were densely distributed in the superficial layers of the caudal part of the trigeminal spinal nucleus (Vc) but rare in the rostral parts, both in suncus and mice. Expression of GRP receptor mRNA and protein was also detected in the Vc of suncus. Taken together, these results suggest that the trigeminal GRP system mediating itch sensation is conserved in mammals.

Heavily tin (Sn)-doped Si crystals in a concentration up to 4×1019 cm−3 were grown by the Czochralski method. Variation of Sn concentration in the crystals was well expressed by the Pfann equation using a segregation coefficient of k=0.016. From the occurrence of growth interface instability and the appearance of Sn precipitates in the grown crystals, the solubility limit of Sn was considered to be around 5×1019 cm−3. Interstitially dissolved oxygen Oi was presented at a concentration of 8–9×1017 cm−3 in the grown Sn-doped crystals. The FT-IR absorption peak relating to a Si–Oi–Si quasi-molecule at 1106 cm−1 showed preferential occupation of Oi at the bond-centered position of Si–Si. The Oi peak shifted to the lower wave number side with increasing Sn concentration in Si, implying expansion of the Si–Si bond.

Heavily indium (In)-doped Si crystals were grown by the Czochralski method under a consideration of the effects of co-doping of electrically neutral group-IV elements (C, Ge or Sn). The In concentration in In-doped Si increased with the amount of In charged into the crucible and reached 3.5×1017 cm−3. The carrier concentration was at most 6×1016 cm−3, limited by the low ionization ratio of ~20% of In. Co-doping of C and Ge effectively enhanced the In concentration while Sn did not, which was examined in terms of the atomistic size, lattice parameter change, mutual bonding energy and solubility of group-IV elements in Si. However, no sufficient increase in carrier concentrations was detected in Si by the co-doping, and formation of some clusters or complexes was suggested.

Gastrin-releasing peptide (GRP) has recently been identified as an itch-specific neuropeptide in the spinal sensory system in mice, but there are no reports of the expression and distribution of GRP in the trigeminal sensory system in mammals. We characterized and compared GRP-immunoreactive (ir) neurons in the trigeminal ganglion (TG) with those in the rat spinal dorsal root ganglion (DRG). GRP immunoreactivity was expressed in 12% of TG and 6% of DRG neurons and was restricted to the small- and medium-sized type cells. In both the TG and DRG, many GRP-ir neurons also expressed substance P and calcitonin gene-related peptide, but not isolectin B4 . The different proportions of GRP and transient receptor potential vanilloid 1 double-positive neurons in the TG and DRG imply that itch sensations via the TG and DRG pathways are transmitted through distinct mechanisms. The distribution of the axon terminals of GRP-ir primary afferents and their synaptic connectivity with the rat trigeminal sensory nuclei and spinal dorsal horn were investigated by using light and electron microscopic histochemistry. Although GRP-ir fibers were rarely observed in the trigeminal sensory nucleus principalis, oralis, and interpolaris, they were predominant in the superficial layers of the trigeminal sensory nucleus caudalis (Vc), similar to the spinal dorsal horn. Ultrastructural analysis revealed that GRP-ir terminals contained clear microvesicles and large dense-cored vesicles, and formed asymmetric synaptic contacts with a few dendrites in the Vc and spinal dorsal horn. These results suggest that GRP-dependent orofacial and spinal pruriceptive inputs are processed mainly in the superficial laminae of the Vc and spinal dorsal horn.

Gastrin-releasing peptide (GRP) has recently been identified as an itch-signaling molecule in the primary afferents and spinal cord of rodents. However, little information exists on the expression and localization of GRP in the trigeminal somatosensory system other than in rats. We examined the generality of the trigeminal GRP system in mammals using two distinct species, suncus as a model of specialized placental mammals known to have a well-developed trigeminal sensory system and mice as a representative small laboratory animal. We first analyzed the gross morphology of the trigeminal somatosensory system in suncus to provide a brainstem atlas on which to map GRP distribution. Immunohistochemical analyses showed that 8% of trigeminal ganglion neurons in suncus and 6% in mice expressed GRP. Expression was restricted to cells with smaller somata. The GRP-containing fibers were densely distributed in the superficial layers of the caudal part of the trigeminal spinal nucleus (Vc) but rare in the rostral parts, both in suncus and mice. Expression of GRP receptor mRNA and protein was also detected in the Vc of suncus. Taken together, these results suggest that the trigeminal GRP system mediating itch sensation is conserved in mammals.

Czochralski Growth of Si Crystals Heavily Doped with in Impurity and Co-Doped with Electrically Neutral Impurity C or Ge Was Conducted in Order to Investigate the Solubility and Ionization Ratio of in in Si for Utilizing in Advanced ULSI and PV Devices. The Carrier Concentrations in the Grown in-Doped and (In+C) and (In+Ge) Co-Doped Crystals Were in a Range of 3.5~6.5 × 1016 Cm-3, much Lower than the Total Concentration of in Impurity due to the Low Ionization Ratio. Sufficient Increase of Carrier Concentrations by Co-Doping of C or Ge Impurity Was Not Detected for their Low Concentrations in the Grown Crystals Investigated.

Polycrystalline materials with grain boundaries (GBs), involving excess free energy because of their structural imperfection, can reduce their energy by the nanoscopic structural changes of the GBs via impurity segregation. Those local changes at GBs can stabilize non-equilibrium nanostructures, resulting in the drastic change in the macroscopic properties of those materials. The mechanism of GB segregation is, however, far from being understood due to difficulties in characterizing both crystallographic and chemical properties of the same GB at atomistic levels. We have therefore developed an analytical method to determine the impurity segregation ability on the same GB at the same nanoscopic location by a joint use of scanning transmission electron microscopy (STEM) and atom probe tomography (APT) combined with ab-initio calculations, and discussed the segregation mechanism in terms of bond distortions at the GB. In the present work, we examined the GBs in Si ingots used for solar cells. They have serious impacts on the solar cell efficiency via the segregation of detrimental impurity atoms, such as oxygen and transition metals introduced inevitably during crystal growth and cell processing, depending on their structural condition at those GBs. Accordingly, precise understanding of the segregation mechanism of impurity atoms is one important issue to produce cost-effective solar cells by engineering the structural condition of impurity atoms segregating at GBs. Three-dimensional distribution of impurity atoms was systematically determined at the typical large-angle GBs (i.e., Σ3{111}, Σ5{013}, Σ9{221}, Σ9{114}, Σ9{111}/{115}, and Σ27{552}) [1-3] and small-angle GBs [3-5] by APT with a low impurity detection limit (0.01 at.% on a GB plane) simultaneously with a high spatial resolution (about 0.4 nm), and it was correlated with the atomic stresses around the GBs estimated by ab-initio calculations based on atomic-resolution scanning TEM data (for large-angle GBs [2]) and by calculations with the elastic theory based on dark-field TEM data (for small-angle GBs [4]). It was hypothesized that oxygen atoms segregate at the bond-centered positions under tensile stresses above about 2 GPa so as to attain more stable bonding network by reducing the local stresses [6]. The number of segregating atoms per unit GB area (N GB ) is in proportion to both the number of the stressed positions per unit GB area (n bc) and the average concentration of oxygen atoms around the GB ([Oi]) with N GB ~ 50n bc[Oi]. This indicates that the probability of oxygen atoms at the segregation positions would be, on average, fifty times larger than in bond-centered positions in defect-free regions. This nanoscopic finding may provide a general guidance to control compositions and band structures at GBs via oxygen segregation. References: [1] Y. Ohno, et al., Appl. Phys. Lett. 103 (2013) 102102; [2] Y. Ohno, et al., Appl. Phys. Lett. 110 (2017) 062105; [3] Y. Ohno, et al., Appl. Phys. Lett. 109 (2016) 142105; [4] Y. Ohno, et al., Appl. Phys. Lett. 106 (2015) 251603; [5] Y. Ohno, et al., Phys. Rev. B 91 (2015) 235315; [6] Y. Ohno, et al., J. Microsc. 268 (2017) 230. Acknowledgments: This work was supported by “Multicrystalline informatics toward establishment of general grain boundary physics & realization of high-quality silicon ingot with ideal microstructures” in “Revolutional material development by fusion of strong experiments with theory/data science” project in JST/CREST, Grant No. JPMJCR17J1 (2017-2023). STEM and APT were, respectively, performed at ISIR under the Cooperative Research Program of "Network Joint Research Center for Materials and Devices: Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials" and at The Oarai Center under under the Inter-University Cooperative Research Program in IMR. Figure caption: Analyses of oxygen segregation at large-angle GBs in Si [2]. (a, c) Bonding network and (b, d) distribution of atomic stress P atomic at (a, b) Σ9{221} and (c, d) Σ9{114} GBs. (e, f) Number of bond-centered positions under a tensile stress P bc above 1.5 GPa and (g, h) oxygen density across the GB plane for (e, g) Σ9{221} and (f, h) Σ9{114} GBs. Figure 1

Local vibrations of oxygen in Ge crystals grown by the Czochralski method adopting liquid-B2O3 encapsulation and GeO2 powder doping were investigated by Fourier-transform infrared spectroscopy. Strong absorption peaks at 855 cm−1, originating in local vibration of interstitially dissolved oxygen Oi as Ge–Oi–Ge quasi-molecules, developed depending on the doped amount of GeO2. Similarly, an absorption peak related to the combined vibration of Ge–Oi–Ge was found at 1264 cm−1 and the conversion factor from the peak intensity to the oxygen concentration was evaluated to be 1.15×1019 cm−2. By prolonged annealing at 350 °C an absorption peak developed at 780 cm−1, indicating formation of oxygen-related thermal donors. From the variations of carrier density and oxygen concentration, one donor was found to possess about 15 Oi atoms.

Using the atom probe tomography, transmission electron microscopy, and ab initio calculations, we investigate the three-dimensional distributions of oxygen atoms segregating at the typical large-angle grain boundaries (GBs) ( Σ 3 { 111 } , Σ 9 { 221 } , Σ 9 { 114 } , Σ 9 { 111 } / { 115 }, and Σ 27 { 552 }) in Czochralski-grown silicon ingots. Oxygen atoms with a covalent radius that is larger than half of the silicon's radius would segregate at bond-centered positions under tensile stresses above about 2 GPa, so as to attain a more stable bonding network by reducing the local stresses. The number of oxygen atoms segregating in a unit GB area N GB (in atoms/nm2) is hypothesized to be proportional to both the number of the tensilely-stressed positions in a unit boundary area n bc and the average concentration of oxygen atoms around the boundary [ O i] (in at. %) with N GB ∼ 50 n bc [ O i ]. This indicates that the probability of oxygen atoms at the segregation positions would be, on average, fifty ti...

Formation of thermal double donors (TDDs) by aggregation of interstitially dissolved oxygen (Oi) was investigated for an oxygen-enriched Ge in an annealing at 300-500°C by infrared absorption spectroscopy. The formation of TDDs was supposed to be two reactions: In the primary stage of annealing, the merge reaction of two Ois is dominant to form an oxygen-dimer as a TDD nucleus. In the secondary stage, TDDs grow larger by absorbing an Oi is dominant. At higher temperatures dissociation of TDDs should be included. In the thermal equilibrium state at 325-400°C TDD involves 16-19 Oi in average.

With a scanning tunneling microscope we have measured the apparent barrier height (ABH) on large terraces of the clean Cu(111) surface and large Au(111) terraces of the Au/Cu(111) surface, and the results are in good agreement with the correspondent surface work function. From the ABH images of these surfaces low-value valleys along steps are clearly visible, as expected from ``Smoluchowki smoothing.'' A simple simulation of the valley makes us to be able to determine that the smoothing-induced dipole moment for Au and Cu steps is $0.16\ifmmode\pm\else\textpm\fi{}0.05$ and $0.5\ifmmode\pm\else\textpm\fi{}0.15\mathrm{D}/\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{p}\mathrm{ }\mathrm{atom},$ respectively.

Gastrin-releasing peptide (GRP) has recently been identified as an itch-specific neuropeptide in the spinal sensory system in mice, but there are no reports of the expression and distribution of GRP in the trigeminal sensory system in mammals. We characterized and compared GRP-immunoreactive (ir) neurons in the trigeminal ganglion (TG) with those in the rat spinal dorsal root ganglion (DRG). GRP immunoreactivity was expressed in 12% of TG and 6% of DRG neurons and was restricted to the small- and medium-sized type cells. In both the TG and DRG, many GRP-ir neurons also expressed substance P and calcitonin gene-related peptide, but not isolectin B4 . The different proportions of GRP and transient receptor potential vanilloid 1 double-positive neurons in the TG and DRG imply that itch sensations via the TG and DRG pathways are transmitted through distinct mechanisms. The distribution of the axon terminals of GRP-ir primary afferents and their synaptic connectivity with the rat trigeminal sensory nuclei and spinal dorsal horn were investigated by using light and electron microscopic histochemistry. Although GRP-ir fibers were rarely observed in the trigeminal sensory nucleus principalis, oralis, and interpolaris, they were predominant in the superficial layers of the trigeminal sensory nucleus caudalis (Vc), similar to the spinal dorsal horn. Ultrastructural analysis revealed that GRP-ir terminals contained clear microvesicles and large dense-cored vesicles, and formed asymmetric synaptic contacts with a few dendrites in the Vc and spinal dorsal horn. These results suggest that GRP-dependent orofacial and spinal pruriceptive inputs are processed mainly in the superficial laminae of the Vc and spinal dorsal horn.

Three-dimensional distribution of oxygen atoms at small-angle tilt boundaries (SATBs) in Czochralski-grown p-type silicon ingots was investigated by atom probe tomography combined with transmission electron microscopy. Oxygen gettering along edge dislocations composing SATBs, post crystal growth, was observed. The gettering ability of SATBs would depend both on the dislocation strain and on the dislocation density. Oxygen atoms would agglomerate in the atomic sites under the tensile hydrostatic stress larger than about 2.0 GPa induced by the dislocations. It was suggested that the density of the atomic sites, depending on the tilt angle of SATBs, determined the gettering ability of SATBs.

Three-dimensional distribution of impurities (boron, phosphorus, oxygen, and copper) at Σ3{111} grain boundaries was determined in a Czochralski-grown silicon single crystal by laser-assisted atom probe tomography (APT) combined with transmission electron microscopy, with a detection limit as low as the order of 0.001 at. %. The location of a boundary was determined by APT even when the boundary was not contaminated. Unlike the boundaries in multicrystalline silicon grown by the casting method, the impurities did not segregate at the boundaries even when the impurity concentrations were high. The gettering ability of the boundaries was discussed.