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Fluid bearings have features of high speed and high rotation accuracy, and therefore, they are used in spindle motors of hard disk drives, cooling fans of central processing units, and other devices. Further, these bearings have microherringbone grooves on the shaft or sleeve inner surface that help generate dynamic pressure in the lubricant fluid around the shaft. Although the depth of the groove is constant, dynamic pressure can be increased by decreasing the depth from both ends to the central corner of each groove on a micron scale. This study aims to verify the effect of sloped herringbone grooves using computational fluid dynamics (CFD) analysis and to develop a new microfabrication method for manufacturing microsloped herringbone grooves on the shaft surface using abrasive jet machining. The generated dynamic pressure is analyzed using CFD; the results indicated that the sloped herringbone grooves result in an increase in the dynamic pressure at the groove tips and cause a decrease in the fluctuations in dynamic pressure in the circumferential direction.

The ionomers distributed on carbon particles in the catalyst layer of polymer electrolyte fuel cells (PEFCs) govern electrical power via proton transport and oxygen permeation to active platinum. Thus, ionomer distribution is a key to PEFC performance. This distribution is characterized by ionomer adsorption and deposition onto carbon during the catalyst-ink coating process; however, the adsorbed and deposited ionomers cannot easily be distinguished in the catalyst layer. Therefore, we identified these two types of ionomers based on the positional correlation between the ionomer and carbon particles. The cross-correlation function for the catalyst layer was obtained by small-angle neutron scattering measurements with varying contrast. From fitting with a model for a fractal aggregate of polydisperse core-shell spheres, we determined the adsorbed-ionomer thickness on the carbon particle to be 51 A and the deposited-ionomer amount for the total ionomer to be 50%. Our technique for ionomer differentiation can be used to optimally design PEFC catalyst layers.

Kazuhiro Shimizu,1 Mao Takahashi,1 Shuji Sato,1 Atsuhito Saiki,1 Daiji Nagayama,1 Masashi Harada,2 Chikao Miyazaki,2 Akira Takahara,3 Kohji Shirai1 1Department of Internal Medicine, Toho University Sakura Medical Center, Sakura, Chiba, Japan; 2Department of Neurosurgery, Toho University Omori Medical Center, Omori, Tokyo, Japan; 3Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, JapanCorrespondence: Kohji ShiraiDepartment of Internal Medicine, Toho University Sakura Medical Center, 561-4 Shimoshizu, Sakura City, Chiba, 285-8741, JapanTel +81-43-462-8811Fax +81-43-462-8820Email kshirai@kb3.so-net.ne.jpAbstract: Cardiovascular diseases have been recognized as the main cause of death all over the world. Recently, the established cardio-ankle vascular index (CAVI) has become known as an index of arterial stiffness of the arterial tree from the origin of the aorta to the ankle. CAVI reflects the progress of arteriosclerosis, and a rapid rise in CAVI indicates arterial smooth muscle cell contraction. Considering the vasculature of the atheroma where vasa vasorum penetrates the smooth muscle cell layer and supplies blood to the intimal atheromatous lesion, a rapid rise of CAVI means “choked” atheroma. Thus, we proposed a “smooth muscle cell contraction” hypothesis of plaque rupture.Keywords: arterial stiffness, atherosclerosis, smooth muscle cell contraction, CAVI

Comprehensive analyses were performed using neutron reflectivity and hard X-ray photoelectron spectroscopy to understand the structure and composition of the solid electrolyte interphase (SEI) layer during charge-discharge processes and because of the addition of lithium bis(oxalate)borate (LiBOB) to improve the battery performance. The chemical composition of the SEI was assessed using these methods, and the amount of Li

The Japanese archipelago is comprised of four main islands—Hokkaido, Honshu, Shikoku, and Kyushu—which contain high mountainous areas that likely allowed for lineage differentiation and population genetic structuring during the climatic changes of the late Pleistocene. Here, we assess the historical background of the evolutionary dynamics of herbivorous red-backed voles (Myodes) in Japan, examining the evolutionary trends of mitochondrial cytochrome b gene (Cytb) sequence variation. Four apparent signals from rapid expansion events were detected in three species, M. rufocanus and M. rutilus from Hokkaido and M. smithii from central Honshu. Taken together with results from previous studies on Japanese wood mice (Apodemus spp.), three of the expansion events were considered to be associated with predicted bottleneck events at the marine isotope stage (MIS) 4 period, in which glaciers are thought to have expanded extensively, especially at higher elevations. In the late Pleistocene, the possible candidates are transitions MIS 6/5, MIS 4/3, and MIS 2/1, which can be characterized by the cold periods of the penultimate glacial maximum, MIS 4, and the last glacial maximum, respectively. Our data further reveal the genetic footprints of repeated range expansion and contraction in the northern and southern lineages of the vole species currently found in central Honshu, namely M. andersoni and M. smithii, in response to climatic oscillation during the late Pleistocene. The time-dependent evolutionary rates of the mitochondrial Cytb presented here would provide a possible way for assessing population dynamics of cricetid rodents responding to the late Pleistocene environmental fluctuation.

Novel sophisticated derivatizing agents for the efficient enantioselective separation and mass spectrometric detection of d - and l -amino acids have been developed. Two new axially chiral reagents derived from 6,6′-dimethyl-2,2′-biphenyldiamine were synthesized. Their chiral separation and detection abilities were evaluated by derivatizing proteinogenic amino acid standards in reversed-phase liquid chromatography–tandem mass spectrometry (LC–MS/MS). The resulting diastereomers derived from the developed derivatizing agents and amino acids could be completely separated, because of the effective chiral environment constructed by the axially chiral biphenyl moiety. After optimizing the reactive group, (R)-4-nitrophenyl N-[2′-(diethylamino)-6,6′-dimethyl-[1,1′-biphenyl]-2-yl]carbamate hydrochloride ((R)-BiAC) was found to be the best reagent for highly sensitive simultaneous d , l -amino acid analysis. Using (R)-BiAC, the complete chiral separation of all derivatized proteinogenic amino acids was achieved within 11.5 min with Rs greater than 1.9, except for certain allo-isomers. An exceptional feature of this reagent was its control of elution order, i.e., it afforded elution of the diastereomers derived from d -amino acids before their l -amino acid counterparts for all 19 proteinogenic amino acids. Sensitive detection was also achieved by introducing a dialkyl amino group and selectively cleaving it at the binding site between the reagent and amino acid. Attomole (amol) detection limits (signal-to-noise ratio = 3) were obtained for the tested d , l -amino acids, in the range 7.0–127 amol. As an example of application, the method was applied to food sample analysis, and detected several d -amino acids. Consequently, the developed method seems likely to facilitate simultaneous determination of enantiomers, including the tiny amounts of d -amino acids found in nature.

Background The levels of plasma sLR11, released from intimal SMCs, are positively associated with intima-media thickness (IMT) in asymptomatic subjects. We have evaluated the yet unknown pathological significance of sLR11 for plaque conditions in patients with carotid artery stenosis. Methods The presence of LR11 in carotid plaques was investigated using autopsy specimens. A clinical ultrasonography study for elucidating relationships between sLR11 and plaque condition was performed in 46 patients. Results Immunohistochemistry showed high levels of LR11 in SMCs within thickened intima and at the media-intima border of atherosclerotic carotid plaques. The levels of sLR11 in patients were clearly elevated compared to healthy controls. Univariate analysis of sLR11 revealed significant positive correlation with plaque score and a tendency to correlate with the stenotic fraction. Univariate and multiple regression analyses of plaque scores showed that sLR11, maximum IMT, and HDL-cholesterol independently determined plaque score. Finally, univariate analysis of initial sLR11 levels for changes in imaging markers after one-year follow-up showed that initial sLR11 levels significantly correlated with stenotic fraction progression. Conclusions The levels of sLR11, abundantly expressed in carotid atherosclerotic plaques, are highly associated with increased plaque score. sLR11 levels may be predictive of plaque conditions in patients with advanced carotid atherosclerosis.

We discuss the formation of perpendicular cylinders from polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS), which were used to fabricate silica (SiO2) pillar arrays with an aspect ratio of 5. The solvent used in spin-coating solutions to form the initial films played an important role to lead the final morphology of the cylinders after solvent annealing. Tetrahydrofuran, a selective solvent for the major PS block, trapped PDMS spheres in isolation, opening a route to form highly aligned perpendicular cylinders after an induction period. Meanwhile, cyclohexane, a non-selective solvent, connected PDMS domains to some extent and provided a different route through which moderate regularity was achieved with gradual improvement. The transient morphological changes of the cylinders were precisely investigated using grazing-incidence small-angle X-ray scattering and scanning electron microscopy. The alignment of the final morphology of the cylinders was validated by reflectance and optical ellipsometry measurements. Oxygen plasma was used to completely remove organic substances and convert PDMS to SiO2, providing a platform suitable for various applications. As an example, a surface-enhanced Raman spectroscopy (SERS) platform was obtained by depositing gold on a perpendicular silica array. This platform exhibited substantial SERS enhancement using Rhodamine 6G as a probe molecule. Identical enhancements were observed throughout the platform, which was attributed to its uniform nanostructures.

Karyotypes of four Chinese species of field mice of the genus Apodemus were examined, including Apodemus chevrieri (diploid chromosome number, 2n=48, fundamental number of autosomal arms, FNa=56), A. draco (2n=48, FNa=48), A. ilex (2n=48, FNa=48), and A. latronum (2n=48, FNa=48). Karyotypes of A. chevrieri, A. draco, and A. ilex are reported here for the first time, providing useful information for their species taxonomy. Determining the karyotypes of all species of Apodemus in Asia, both in this and previous studies, provides a solid overview of the chromosome evolution and species differentiation of the genus in East Asia. In addition to allopatric speciation, chromosome rearrangements likely played an important role in the formation of the four Apodemus species groups as well as speciation within each group in East Asia. For example, increased centromeric heterochromatin in A. latronum may have contributed to the post-mating reproductive isolation from the A. draco-A. ilex-A. semotus clade.

Nocistatin (NST) is a neuropeptide produced from the same precursor protein of opioid peptide nociceptin/orphanin FQ, and it is involved in a broad range of central functions including pain transmission in the nervous system. However, the composition and structure of the receptor(s) for NST remain unclear. Here, we developed NST photoaffinity probe to identify NST receptor. The NST photoaffinity probe contains an azide moiety for the tagging of the binding protein as well as biotin for protein detection. Intrathecal administration of a NST photoaffinity probe, biotin-(AC5)2-[Y6,azF14]bNST, inhibited the nociceptin/orphanin FQ-evoked tactile pain allodynia in a manner similar to that of NST. The biotin-(AC5)2-[Y6,azF14]bNST-binding proteins were primarily localized in the gray matter of the spinal cord. After photo-crosslinking of the protein complex with biotin-(AC5)2-[Y6,azF14]bNST, two dominant binding protein bands were observed at 58 and 64 kDa. Thus, biotin-(AC5)2-[Y6,azF14]bNST has pharmacological activity and is useful for characterizing the NST receptor.

Angle-resolved photoelectron spectroscopy has been used to follow the valence band and near Fermi edge electronic band structure in the quasi-1D compound NaV 2 O 4 . In this current study we have acquired the very first high-quality, high-resolution ARPES data from this material. Our data clearly reveal two distinct dispersive bands that cross the Fermi level at different k F . This is a clear signature that the electronic properties of this material is affected by the presence of a mixed valence state on the different vanadium chains and possibly also the low-temperature magnetic spin order.

Organic-inorganic layered hybrids (OILHs) were synthesized by the copolymerization of organo alkoxysilane and metal salt. Nanoparticles were observed in the resulting OILHs using atomic force microscopy, while the inner structure was a speculative model based on X-ray diffraction and infrared absorption measurements. As the characterization using transmission electron microscopy did not result in clear images because of possible radiation damage, small-angle X-ray scattering and small-angle neutron scattering were measured for the dispersions of two types of OILHs containing Ti or Al. After the spectra were fitted using a flat cylinder model, it was determined that the OILHs have a core-shell structure of a clay sheet surrounded by organic layers. The difference in the dimensions of the core-shell structure for the Ti-containing OILH and the Al-containing OILH was quantitatively demonstrated.

Karyotypes of four Chinese species of field mice of the genus Apodemus were examined, including Apodemus chevrieri (diploid chromosome number, 2n=48, fundamental number of autosomal arms, FNa=56), A. draco (2n=48, FNa=48), A. ilex (2n=48, FNa=48), and A. latronum (2n=48, FNa=48). Karyotypes of A. chevrieri, A. draco, and A. ilex are reported here for the first time, providing useful information for their species taxonomy. Determining the karyotypes of all species of Apodemus in Asia, both in this and previous studies, provides a solid overview of the chromosome evolution and species differentiation of the genus in East Asia. In addition to allopatric speciation, chromosome rearrangements likely played an important role in the formation of the four Apodemus species groups as well as speciation within each group in East Asia. For example, increased centromeric heterochromatin in A. latronum may have contributed to the post-mating reproductive isolation from the A. draco-A. ilex-A. semotus clade.

Amino acids and their related metabolites play important roles in various physiological processes and have consequently become biomarkers for diseases. However, accurate quantification methods have only been established for major compounds, such as amino acids and a limited number of target metabolites. We previously reported a highly sensitive high-throughput method for the simultaneous quantification of amines using 3-aminopyridyl- N -succinimidyl carbamate as a derivatization reagent combined with liquid chromatography–tandem mass spectrometry (LC-MS/MS). Herein, we report the successful development of a practical and accurate LC-MS/MS method to analyze low concentrations of 40 physiological amines in 19 min. Thirty-five of these amines showed good linearity, limits of quantification, accuracy, precision, and recovery characteristics in plasma, with scheduled selected reaction monitoring acquisitions. Plasma samples from 10 healthy volunteers were evaluated using our newly developed method. The results revealed that 27 amines were detected in one of the samples, and that 24 of these compounds could be quantified. Notably, this new method successfully quantified metabolites with high accuracy across three orders of magnitude, with lowest and highest averaged concentrations of 31.7 nM (for spermine) and 18.3 μM (for α-aminobutyric acid), respectively.

Long-eared bats of the genus Plecotus are known to occur predominantly in the Palaearctic Region, and at the margins of the Afrotropical and Indomalayan regions. In 2014, four specimens of the genus Plecotus were collected in a high altitude montane temperate forest in the Hoang Lien National Park, northern Vietnam, representing the first record of Plecotus from the Indochinese subregion, and considerably extending the southern border of the genus' distribution range. Detailed morphological comparisons and phylogenetic reconstructions based on the mitochondrial control region suggest that these specimens can be assigned to P. homochrous, a mountain-dwelling bat from the Himalayas. Moreover, for the first time, we provide information on the species' echolocation call and karyological characteristics. Our results also indicate that the taxonomic status of some Plecotus species recognized by previous studies is doubtful and must be revised. Although rarely encountered, Plecotus is likely to be widely distributed at the higher elevations of the Himalayan chain in southern China and the adjoining northern areas of Vietnam, Laos, and Myanmar. Our findings strongly support the importance of the mountainous areas within the Indo-Burma biodiversity hotspot.

Fluid dynamic bearings, which have an advantage in high-accuracy revolutions, are employed for spindle motors of hard disk drive, cooling fans for central processing unit, spindles of machine tool, etc. Micro herring-bone grooves are manufactured on cylindrical surface of the shafts in the bearing units, and they generate dynamic pressure during spins. Although the depth of the herring-bone grooves is generally constant, the shafts of which groove depth decreases from the ends of the groove array to its center improve the performance of bearing. The micro grooves are mainly manufactured by chemical etching, electrochemical machining, cutting and form rolling. However, the chemical etching and the electrochemical machining are difficult to control 3D machining profiles with high accuracy. The cutting and the form rolling have problems in tool lives and manufacturing costs. On the other hand, blasting is expected as one of micro fabrication methods. Therefore, we focused on blasting, and have investigated its material removal capabilities by fundamental tests. The purpose of this study is to control machining profiles in cylindrical blasting. The machining profiles of cylindrical workpieces in blasting were simulated based on the material removal capabilities obtained by the fundamental blasting tests. Then, the simulated profiles agreed well with the experimental ones by blasting under the same experimental condition.

Human zoonotic onchocercosis is caused by Onchocerca dewittei japonica, parasitic in wild boars (Sus scrofa leucomystax) in Japan. Previously, microfilariae longer than those of Onchocerca dewittei japonica were observed in skin snips from wild boars during the study of O. dewittei japonica. Moreover, the third-stage larvae (L3) of these longer microfilariae were obtained from the blackfly Simulium bidentatum after experimental injections. Based on morphometric and molecular studies, similar L3 were found in blackflies during fieldwork in Oita, Japan. However, except for O. dewittei japonica, adult worms of Onchocerca have not been found in wild boars. In this study, we discovered adult females of a novel Onchocerca species in the skin of a wild boar in Oita, and named it Onchocerca takaokai n. sp. Females of this new species had longer microfilariae and differed from O. dewittei japonica in terms of their morphological characteristics and parasitic location. The molecular characteristics of the cytochrome c oxidase subunit 1 and 12S rRNA genes of the new species were identical to those of the longer microfilariae and L3 previously detected, but they differed from those of O. dewittei japonica at the species level. However, both species indicated a close affinity among their congeners and Onchocerca ramachandrini, parasitic in the warthog in Africa, was basal in the Suidae cluster of the 12S rRNA tree.

In order to elucidate the dependence of the magnetic ground state on the Ca content (x) in Sr1-xCaxCo2P2 (0 ≤x ≤1, ThCr2Si2-type structure), we have performed muon spin rotation− and relaxation (μ+SR) experiments on Sr1-xCax Co2P2 powder samples mainly in a zero applied field. The end member compound, SrCo2P2, is found to be paramagnetic down to 19 mK. As x increases, such a paramagnetic ground state is observed down to 1.8K until x = 0.45. Then, as x increases further, a short-range antiferromagnetic (AF) ordered phase appears at low temperatures for 0.48 ≤ x ≤ 0.75, and finally, a long-range AF ordered phase is stabilized for x > 0.75. The internal magnetic field of the other end member compound, CaCo2P2, is well consistent with that of the A-type AF order state, which was proposed from neutron scattering experiments. The phase diagram determined with μ+SR is different from that proposed by macroscopic measurements. For an isostructural compound, LaCo2P2, static magnetic order is found to be formed below

The magnetic nature of a novel one-dimensional compound NaCr 2 O 4 with zigzag CrO 2 chains has been studied by muon spin rotation and relaxation ( μ +SR) and neutron diffraction (ND). It is found that NaCr 2 O 4 undergoes an antiferromagnetic transition at T N = 125 K, below which the Cr moments in each zigzag chain align ferromagnetically along the c -axis but antiferromagnetically along the a -axis between adjacent zigzag chains. For the solid solution system Ca 1-x Na x Cr 2 O 4 , μ + SR measurements reveal the evolution of a complex magnetic order with increasing Ca content (1- x ), which finally enters into an incommensurate AF ordered state below T N = 21 for CaCr 2 O 4 .

Magnetization reversal process in Nd-Fe-B nanocrystalline magnets was investigated by small-angle neutron scattering (SANS) using a non-polarized neutron beam. The magnetic-field dependence of the SANS intensities was obtained for as-deformed and Pr-Cu infiltrated Nd-Fe-B magnets. The SANS intensity variation with the magnetic field is suppressed in Pr-Cu infiltrated sample as compared with that in as-deformed sample. The isolation of Nd2Fe14B grains along the [001]-axis direction was found to be caused by the infiltration of the Pr-Cu eutectic alloy, resulting in coercive force enhancement. The results suggest that magnetic isolation of the grains is the key to developing magnets with high coercive force.

A diffusive behavior of Li+ ion in a garnet-type oxide, Li5 + xLa3ZrxNb2 − x012 with x = 0–2, has been investigated by both a positive muon-spin relaxation (μ+SR) and quasi-elastic neutron scattering (QENS) technique using powder samples. The μ+SR results revealed that Li+ ions start to diffuse above ~ 150 K for the whole samples measured. The activation energy of Li diffusion (Ea) estimated from the μ+SR data was in good agreement with Ea obtained by the QENS measurements. However, both Eas were about a half of Ea of ionic conductivity of Li+ (σLi), which was evaluated by AC-impedance measurements on sintered pellets. This indicated the serious effect of grain boundary and/or surface on Ea. Furthermore, since the diffusion coefficient of Li+ estimated by μ+SR is roughly independent of x, the number of mobile Li+ in the garnet lattice was found to be the predominant parameter to determine σLi.

We report here efficient catalytic imine-imine cross-coupling reactions based on an umpolung strategy; an imine bearing a 9-fluorenyl moiety on its nitrogen atom, which acted as a nucleophile, reacted with another imine to afford an imine-imine cross-coupling adduct in high yield. Furthermore, a chiral guanidine acted as a chiral catalyst for these coupling reactions, and optically active 1,2-diamines were obtained in high yields with high enantioselectivities.

β-Detected nuclear spin relaxation of (8)Li(+) has been used to study the microscopic diffusion of lithium ions in thin films of poly(ethylene oxide) (PEO), where the implanted lithium ions are present in extremely low concentration, and PEO with 30 wt % LiCF3SO3 over a wide range of temperatures both above and below the glass transition temperature. Recent measurements by Do et al. [Phys. Rev. Lett. 2013, 111, 018301] found that the temperature dependence of the Li(+) conductivity was identical to that of the dielectric α relaxation and was well described by the Vogel-Fulcher-Tammann relation, implying the α relaxation dominates the Li(+) transport process. In contrast, we find the hopping of Li(+) in both samples in the high temperature viscoelastic phase follows an Arrhenius law and depends significantly on the salt content. We propose that the hopping of Li(+) between cages involves motion of the polymer but that it is only for long-range diffusion where the α relaxation plays an important role.

Spin-polarized small-angle neutron scattering (Pol-SANS) measurements for nano-crystalline Nd-Fe-B magnet have been performed in order to clarify the magnetic reversal behavior. Due to high transparency of neutron beam, magnetic and nuclear microstructures in the `bulk' can be observed by SANS. Obtained SANS patterns arising from magnetic domain changes were analyzed by Teubner-Stray model, phenomenological correlation length model, to quantify the periodicity, density and morphology of magnetic domains. The results indicate that magnetic reversal evolves with magnetic domains which have the similar size of the grains. However, even in nano-crystalline system, single domain grain reversal is not realized.

In order to elucidate the details of successive magnetic transitions in the rare earth cobalt arsenic oxides ( RE CoAsO), we have measured muon-spin rotation and relaxation( μ + SR) spectra of powder samples with RE = La, Ce, Pr, Nd, Sm, and Gd. Together with the result of magnetization measurements, it was found that all the compounds enter into abulk static ferromagnetic ordered phase below around 70 K(= T C ). Furthermore, additional transitions into a static antiferromagnetic ordered phase were found for the RE = Nd, Sm, and Gd compounds; namely T N1 = 15 K and T N2 = 7 K for Nd, T N1 = 41.5 K and T N2 = 17.5 K for Sm, and T N = 3K for Gd.

Diffusion of Li+ ionsin solidsisa basic principle behindthe operationof Li-ion batteries. Suchdiffusive behavior is represented by the diffusion equation (Fick's law), J = − D × δ ϕ/ δ x , where J is the diffusion flux, D is the self diffusion coeffcient, ϕ is the concentration, and x is the position. Although D of Li + ions( D Li)in solids is usually evaluatedby 7 Li-NMR, diffculties arise for materials that contain magnetic ions. This is because the magnetic ions contribute additional spin-lattice relaxation processes thatis considerably larger than the1/ T 1 expected from only Li diffusion [1] , [2] , [3] . This implies that 7Li-NMRprovidesa rough estimateof D Li for the positive electrode materials of Li-ion batteries, which include transition metal ions in order to compensate charge neutrality during a Li + intercala-tion/deintercalation reaction. This is an unsatisfactory situation since D Li is one of the primary parameters that govern the charge/discharge rate of a Li-ion battery. We have, therefore, attempted to measure D Li for lithium-transition-metal-oxides with muon-spin relaxation (μ + SR) since 2005 [4] , [5] , [6] . Muons do not feel fluctuating magnetic moments at high T, but instead sense the change in nuclear dipole field due to Li diffusion. Even if magnetic moments still affect the muon-spin depolarization rate, such aneffectis, in principle, distinguishablefromthatof nucleardipole fields.In particular,aweak longitudinal field can be applied that decouples the magnetic and nuclear dipole interactions [7] , [8] . Here, we wish to summarize our μ + SR study on the lithium-transition-metal-oxides, LixCoO2, LiNiO2, and LiCrO2.

Adventitious shoots can be regenerated from the cut surface of the primary shoot and lateral branches in decapitated plants in vivo. This inherent regenerative ability of plants is useful for mass propagation. In the present study, we conducted histological observations of shoot regeneration and applied auxin and cytokinin to decapitated seedlings in four tomato cultivars. The cultivars produced different numbers of adventitious shoots after decapitation; ‘Petit’ produced the largest number of adventitious shoots (78.5 ± 10.2) and ‘Momotaro’ produced the fewest (12.1 ± 3.3). Histological observation of ‘Petit’ revealed that adventitious shoots regenerated from calli formed at the cut surface of stems. Adventitious shoot formation was inhibited by the presence of lateral branches. Shoot regeneration was prevented by application of 1-naphthaleneacetic acid to ‘Petit’. Application of 6-benzyladenine promoted shoot regeneration in ‘Momotaro’. These results suggest auxin synthesized de novo from the lateral branches inhibited shoot regeneration after decapitation and endogenous cytokinin might stimulate shoot regeneration. Chemical names: 1-naphthaleneacetic acid (NAA); 6-benzyladenine (BA)