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1.
J Comp Pathol ; 168: 8-12, 2019 Apr.
Article in English | MEDLINE | ID: mdl-31103059

ABSTRACT

An 11-year-old female American shorthair cat was presented with a 3-month history of hindlimb ataxia and knuckling of the left forelimb. Clinical abnormalities included weight loss, hyperaesthesia of the neck and back, cardiac murmur and systemic muscle atrophy. The cat died 10 days after the initial presentation and a necropsy examination was performed. Grossly, extensive pale lesions were seen in the wall of the left ventricle and the septum of the heart. There were no detectable masses in the heart, skeletal muscles or peripheral nerves. Histopathological examination revealed diffuse, extensive infiltration of atypical lymphoid cells in the heart; the cardiac muscles were markedly degenerate and atrophic and were replaced by the neoplastic cells. Neoplastic cells with similar morphology were seen in all specimens of the skeletal muscles and peripheral nerves. Clonality analysis of the paraffin wax-embedded heart tissue revealed a monoclonal rearrangement of the gene encoding the T-cell receptor γ chain. Based on these findings, the case was diagnosed as T-cell lymphoma with tropism for striated muscle and peripheral nerve.


Subject(s)
Cat Diseases/pathology , Lymphoma, T-Cell/veterinary , Muscle, Striated/pathology , Peripheral Nerves/pathology , Animals , Cats , Female
3.
Epidemiol Psychiatr Sci ; 27(2): 199-208, 2018 04.
Article in English | MEDLINE | ID: mdl-27989255

ABSTRACT

AIMS: Public stigma alters attitudes towards people with mental illness, and is a particular concern for young people since most mental health problems occur in adolescence and young adulthood. However, little is known about the long-term effects of repeated filmed social contact (FSC) on reducing mental health-related stigma among young adults in the general population, compared with self-instructional Internet search (INS) and control interventions. METHODS: This study is a parallel-group randomised controlled trial over 12 months conducted in Tokyo, Japan. A total of 259 university students (male n = 150, mean age = 20.0 years, s.d. = 1.2) were recruited from 20 colleges and universities between November 2013 and July 2014, without being provided information about the mental health-related survey or trial. Participants were assigned to one of three groups before completion of the baseline survey (FSC/INS/control = 89/83/87). The FSC group received a computer-based 30-min social contact film with general mental health education and five follow-up web-based FSCs at 2-month intervals. The INS group undertook a 30-min search for mental health-related information with five follow-up web-based reminders for self-instructional searches at 2-month intervals. The control group played PC games and had no follow-up intervention. The main outcome measures were the future (intended behaviour) domain of the Reported and Intended Behaviour Scale at 12 months after the intervention. Analysis was conducted in September 2015. RESULTS: At the 12-month follow-up, 218 participants completed the survey (84.1%, 75:70:73). The FSC group showed the greatest change at the 12-month follow-up (FSC: mean change 2.11 [95% CI 1.49, 2.73], INS: 1.04 [0.29, 1.80], control: 0.71 [0.09, 1.33]; FSC v. INS p = 0.037, FSC v. controls p = 0.004). No adverse events were reported during the follow-up period. CONCLUSIONS: FSC was more successful in reducing stigma at 12 months after intervention than INS or control interventions. FSC could be used to reduce stigma in educational lectures and anti-stigma campaigns targeted at young people. STUDY REGISTRATION: This study is registered at UMIN-CTR (No. UMIN000012239).


Subject(s)
Health Education/methods , Health Knowledge, Attitudes, Practice , Mass Media , Mental Disorders/psychology , Social Discrimination , Social Stigma , Adolescent , Adult , Female , Humans , Japan , Outcome and Process Assessment, Health Care , Surveys and Questionnaires , Young Adult
4.
Phys Rev Lett ; 118(19): 195501, 2017 May 12.
Article in English | MEDLINE | ID: mdl-28548523

ABSTRACT

Computational modeling and experimental measurements on metal samples subject to a laser-driven, ablative Richtmyer-Meshkov instability showed differences between viscosity and strength effects. In particular, numerical and analytical solutions, coupled with measurements of fed-through perturbations, generated by perturbed shock fronts onto initially flat surfaces, show promise as a validation method for models of deviatoric response in the postshocked material. Analysis shows that measurements of shock perturbation amplitudes at low sample thickness-to-wavelength ratios are not enough to differentiate between strength and viscosity effects, but that surface displacement data of the fed-through perturbations appears to resolve the ambiguity. Additionally, analytical and numerical results show shock front perturbation evolution dependence on initial perturbation amplitude and wavelength is significantly different in viscous and materials with strength, suggesting simple experimental geometry changes should provide data supporting one model or the other.

5.
Phys Chem Chem Phys ; 19(6): 4734-4740, 2017 Feb 08.
Article in English | MEDLINE | ID: mdl-28128823

ABSTRACT

Nano-layered hybrid compounds composed of a polyfluoroalkyl azobenzene surfactant (abbreviated as C3F-Azo-C6H) and layered inorganic nanosheets undergo three-dimensional morphological changes such as reversible shrinkage and expansion of interlayer spaces, and nanosheet sliding by photo-irradiation. Previously, we have investigated the photoreactivity of C3F-Azo-C6H/clay nano-layered hybrids in various microenvironments and found a remarkable enhancement in the photoreactivity for the cis-trans photo-isomerization reaction (Φcis-trans = 1.9). In this paper, nanosecond and microsecond dynamics of trans-C3F-Azo-C6H and its assembly in various microenvironments have been studied by laser flash photolysis to get deeper insight into the extraordinary reactivity of the molecular assembly in the nano-layered microenvironment. In solution, the molecular trans-C3F-Azo-C6H exhibited only a depletion of the trans-form of azobenzene upon the laser pulse excitation. On the other hand, in the case of the C3F-Azo-C6H/clay hybrid film, the depletion of the trans-form was drastically recovered in three steps on nano- and microsecond timescales. This indicates that the once reacted C3F-Azo-C6H molecule (cis-C3F-Azo-C6H) was reverted back to the trans-form after the laser pulse. It is considered that the excess energy provided by the photo-excitation, which is immediately dissipated to the surrounding media through the intermolecular vibrational modes in solution, is trapped in the nano-layered microenvironment to thermally revert the cis-form back to the trans-form. Conversely, in the case of cis-trans isomerization of the C3F-Azo-C6H/clay hybrid film upon photo-irradiation, the reactivity would be much enhanced by the additional contribution of the thermal excess energy efficiently trapped in the nano-layered microenvironment. As compared with the hydrocarbon analogue (C3H-Azo-C6H), the subsequent recovery was very much enhanced in the C3F-Azo-C6H/clay film. The polyfluoroalkyl part of the surfactant layer plays a key role in the retarded dissipation of the excess energy by photo-excitation, which might be coupled with the three-dimensional morphological motion with efficient isomerization reactions.

6.
Transl Psychiatry ; 7(1): e988, 2017 01 03.
Article in English | MEDLINE | ID: mdl-28045464

ABSTRACT

Schizophrenia is a common polygenetic disease affecting 0.5-1% of individuals across distinct ethnic populations. PGC-II, the largest genome-wide association study investigating genetic risk factors for schizophrenia, previously identified 128 independent schizophrenia-associated genetic variants (GVs). The current study examined the genetic variability of GVs across ethnic populations. To assess the genetic variability across populations, the 'variability indices' (VIs) of the 128 schizophrenia-associated GVs were calculated. We used 2504 genomes from the 1000 Genomes Project taken from 26 worldwide healthy samples comprising five major ethnicities: East Asian (EAS: n=504), European (EUR: n=503), African (AFR: n=661), American (AMR: n=347) and South Asian (SAS: n=489). The GV with the lowest variability was rs36068923 (VI=1.07). The minor allele frequencies (MAFs) were 0.189, 0.192, 0.256, 0.183 and 0.194 for EAS, EUR, AFR, AMR and SAS, respectively. The GV with the highest variability was rs7432375 (VI=9.46). The MAFs were 0.791, 0.435, 0.041, 0.594 and 0.508 for EAS, EUR, AFR, AMR and SAS, respectively. When we focused on the EAS and EUR population, the allele frequencies of 86 GVs significantly differed between the EAS and EUR (P<3.91 × 10-4). The GV with the highest variability was rs4330281 (P=1.55 × 10-138). The MAFs were 0.023 and 0.519 for the EAS and EUR, respectively. The GV with the lowest variability was rs2332700 (P=9.80 × 10-1). The MAFs were similar between these populations (that is, 0.246 and 0.247 for the EAS and EUR, respectively). Interestingly, the mean allele frequencies of the GVs did not significantly differ between these populations (P>0.05). Although genetic heterogeneities were observed in the schizophrenia-associated GVs across ethnic groups, the combination of these GVs might increase the risk of schizophrenia.


Subject(s)
Ethnicity/genetics , Schizophrenia/genetics , Asian People/genetics , Black People/genetics , Female , Gene Frequency , Genetic Variation , Genome-Wide Association Study , Hispanic or Latino/genetics , Humans , Male , Polymorphism, Single Nucleotide , White People/genetics
7.
Ann Surg Oncol ; 24(5): 1227-1233, 2017 May.
Article in English | MEDLINE | ID: mdl-27909824

ABSTRACT

BACKGROUND: Circulating tumor cells (CTCs) reportedly have been detected in the peripheral blood of more than 50% of breast carcinoma cases with distant metastases. Moreover, the survival period is shorter for patients who had more than five CTCs after a single chemotherapy treatment. However, a few data show the relationships between CTCs and expressions of disseminated tumor cells in the bone marrow (DTCs-BM), including treatment effects and prognoses in early breast carcinomas. METHODS: In this study, CTCs and DTC-BMs were measured by the CellSearch System for 20 patients with stages 1-3 carcinomas, who were followed for 8-11 years. RESULTS: CTCs in 2 (10%) of 20 breast carcinomas, more than 1 CTC was detected before adjuvant therapy, and both cases showed a decrease to 0 after chemotherapy. DTC-BMs in 19 (95%) of the 20 primary cases, more than 1 cell was found in the BM. After adjuvant therapy, 16 cases showed a decrease to 0-10 cells, 2 cases to 11-20 cells, and 2 cases to more than 21 cells. Six patients experienced recurrence. One of the two CTC-positive cases (>21 cells) had bone and liver metastasis within 11 months. Among the DTC-BM cases, only 1 (16.7%) of the 6 primary patients with 11-20 cells had recurrence, whereas 4 (80%) of the 5 patients with more than 21 cells had recurrence 3-6 years later. CONCLUSIONS: Detection of DTC-BMs is useful for observing adjuvant therapy effects and for predicting relatively late-phase metastasis. The cluster status of CTCs suggests early relapsing.


Subject(s)
Bone Marrow/pathology , Bone Neoplasms/secondary , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Carcinoma/drug therapy , Carcinoma/secondary , Liver Neoplasms/secondary , Neoplastic Cells, Circulating , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Aromatase Inhibitors/administration & dosage , Breast Neoplasms/surgery , Carcinoma/surgery , Cell Count , Chemotherapy, Adjuvant , Cyclophosphamide/administration & dosage , Epirubicin/administration & dosage , Female , Fluorouracil/administration & dosage , Follow-Up Studies , Gonadotropin-Releasing Hormone/agonists , Humans , Middle Aged , Neoplasm Staging , Neoplastic Cells, Circulating/drug effects , Prognosis , Tamoxifen/administration & dosage , Treatment Outcome
8.
J Periodontal Res ; 52(3): 471-478, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27561677

ABSTRACT

BACKGROUND AND OBJECTIVE: Hypophosphatasia is a rare inherited skeletal disorder characterized by defective bone mineralization and deficiency of tissue non-specific alkaline phosphatase (TNSALP) activity. The disease is caused by mutations in the liver/bone/kidney alkaline phosphatase gene (ALPL) encoding TNSALP. Early exfoliation of primary teeth owing to disturbed cementum formation, periodontal ligament weakness and alveolar bone resorption are major complications encountered in oral findings, and discovery of early loss of primary teeth in a dental examination often leads to early diagnosis of hypophosphatasia. Although there are no known fundamental treatments or effective dental approaches to prevent early exfoliation of primary teeth in affected patients, several possible treatments have recently been described, including gene therapy. Gene therapy has also been applied to TNSALP knockout mice (Alpl-/- ), which phenocopy the infantile form of hypophosphatasia, and improved their systemic condition. In the present study, we investigated whether gene therapy improved the dental condition of Alpl-/- mice. MATERIAL AND METHODS: Following sublethal irradiation (4 Gy) at the age of 2 d, Alpl-/- mice underwent gene therapy using bone marrow cells transduced with a lentiviral vector expressing a bone-targeted form of TNSALP injected into the jugular vein (n = 3). Wild-type (Alpl+/+ ), heterozygous mice (Alpl+/- ) and Alpl-/- mice were analyzed at 9 d of age (n = 3 of each), while Alpl+/+ mice and treated or untreated Alpl-/- mice were analyzed at 1 mo of age (n = 3 of each), and Alpl+/- mice and Alpl-/- mice with gene therapy were analyzed at 3 mo of age (n = 3 of each). A single mandibular hemi-section obtained at 1 mo of age was analyzed using a small animal computed tomography machine to assess alveolar bone formation. Other mandibular hemi-sections obtained at 9 d, 1 mo and 3 mo of age were subjected to hematoxylin and eosin staining and immunohistochemical analysis of osteopontin, a marker of cementum. RESULTS: Immunohistochemical analysis of osteopontin, a marker of acellular cementum, revealed that Alpl-/- mice displayed impaired formation of cementum and alveolar bone, similar to the human dental phenotype. Cementum formation was clearly present in Alpl-/- mice that underwent gene therapy, but did not recover to the same level as that in wild-type (Alpl+/+ ) mice. Micro-computed tomography examination showed that gene therapy improved alveolar bone mineral density in Alpl-/- mice to a similar level to that in Alpl+/+ mice. CONCLUSIONS: Our results suggest that gene therapy can improve the general condition of Alpl-/- mice, and induce significant alveolar bone formation and moderate improvement of cementum formation, which may contribute to inhibition of early spontaneous tooth exfoliation.


Subject(s)
Genetic Therapy/methods , Hypophosphatemia/therapy , Tooth Exfoliation/etiology , Alkaline Phosphatase/genetics , Alveolar Process/pathology , Animals , Bone Density , Dental Cementum/pathology , Disease Models, Animal , Hypophosphatemia/complications , Mice , Mice, Knockout , Tooth Exfoliation/therapy , Treatment Outcome
9.
Ann Oncol ; 27(8): 1601-6, 2016 08.
Article in English | MEDLINE | ID: mdl-27358385

ABSTRACT

BACKGROUND: There has been no phase III study of comparing the efficacy of first- and second-generation 5-HT3 receptor antagonists in the triplet regimen with dexamethasone and aprepitant for preventing chemotherapy-induced nausea and vomiting after highly emetogenic chemotherapy (HEC). PATIENTS AND METHODS: Patients with a malignant solid tumor who would receive HEC containing 50 mg/m(2) or more cisplatin were randomly assigned to either palonosetron (0.75 mg) arm (Arm P) or granisetron (1 mg) arm (Arm G), on day 1, both arms with dexamethasone (12 mg on day 1 and 8 mg on days 2-4) and aprepitant (125 mg on day 1 and 80 mg on days 2-3). The primary end point was complete response (CR; no vomiting/retching and no rescue medication) at the 0-120 h period and secondary end points included complete control (CC; no vomiting/retching, no rescue medication, and no more than mild nausea) and total control (TC; no vomiting/retching, no rescue medication, and no nausea). RESULTS: Between July 2011 and June 2012, 842 patients were enrolled. Of 827 evaluable, 272 of 414 patients (65.7%) in Arm P had a CR at the 0-120 h period when compared with 244 of 413 (59.1%) in Arm G (P = 0.0539). Both arms had the same CR rate of 91.8% at the acute (0-24 h) period, while at the delayed (24-120 h) period, Arm P had a significantly higher CR rate than Arm G (67.2% versus 59.1%; P = 0.0142). In secondary end points, Arm P had significantly higher rates than Arm G at the 0-120 h period (CC rate: 63.8% versus 55.9%, P = 0.0234; TC rate: 47.6% versus 40.7%, P = 0.0369) and delayed periods (CC rate: 65.2% versus 55.9%, P = 0.0053; TC rate: 48.6% versus 41.4%, P = 0.0369). CONCLUSION: The present study did not show the superiority of palonosetron when compared with granisetron in the triplet regimen regarding the primary end point. CLINICAL TRIAL REGISTRY IDENTIFIER: UMIN000004863.


Subject(s)
Cisplatin/administration & dosage , Granisetron/administration & dosage , Isoquinolines/administration & dosage , Neoplasms/drug therapy , Quinuclidines/administration & dosage , Adult , Aged , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Cisplatin/adverse effects , Double-Blind Method , Drug-Related Side Effects and Adverse Reactions/pathology , Female , Granisetron/adverse effects , Humans , Isoquinolines/adverse effects , Male , Middle Aged , Nausea/chemically induced , Nausea/pathology , Neoplasms/pathology , Palonosetron , Quinuclidines/adverse effects , Serotonin Antagonists/administration & dosage , Serotonin Antagonists/adverse effects , Vomiting/chemically induced , Vomiting/pathology
10.
Eur Psychiatry ; 35: 25-31, 2016 05.
Article in English | MEDLINE | ID: mdl-27061374

ABSTRACT

BACKGROUND: Reduced gray matter volumes in the superior temporal gyrus (STG) have been reported in patients with schizophrenia. Such volumetric abnormalities might denote alterations in cortical thickness, surface area, local gyrification or all of these factors. The STG can be anatomically divided into five subregions using automatic parcellation in FreeSurfer: lateral aspect of the STG, anterior transverse temporal gyrus of Heschl gyrus (HG), planum polare (PP) of the STG, planum temporale (PT) of the STG and transverse temporal sulcus. METHODS: We acquired magnetic resonance imaging (MRI) 3T scans from 40 age- and sex-matched patients with schizophrenia and 40 healthy subjects, and the scans were automatically processed using FreeSurfer. General linear models were used to assess group differences in regional volumes and detailed thickness, surface area and local gyrification. RESULTS: As expected, patients with schizophrenia had significantly smaller bilateral STG volumes than healthy subjects. Of the five subregions in the STG, patients with schizophrenia showed significantly and marginally reduced volumes in the lateral aspect of the STG and PT of the STG bilaterally compared with healthy subjects. The volumetric alteration in bilateral lateral STG was derived from both the cortical thickness and surface area but not local gyrification. There was no significant laterality of the alteration in the lateral STG between patients and controls and no correlation among the structures and clinical characteristics. CONCLUSIONS: These findings suggest that of five anatomical subregions in the STG, the lateral STG is one of the most meaningful regions for brain pathophysiology in schizophrenia.


Subject(s)
Schizophrenia/pathology , Temporal Lobe/pathology , Adult , Auditory Cortex/pathology , Case-Control Studies , Female , Functional Laterality , Gray Matter/pathology , Humans , Imaging, Three-Dimensional , Magnetic Resonance Imaging/methods , Male
11.
Epidemiol Infect ; 144(3): 602-6, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26169980

ABSTRACT

In 2013, an unusual increase of paratyphoid fever cases in travellers returning from Cambodia was reported in Japan. From December 2012 to September 2013, 18 cases of Salmonella Paratyphi A infection were identified. Microbiological analyses revealed that most isolates had the same clonal identity, although the epidemiological link between these cases remains unclear. It was inferred that the outbreak was caused by a common and persistent source in Cambodia that was likely to have continued during 2014. The information of surveillance and laboratory data from cases arising in travellers from countries with limited surveillance systems should be timely shared with the country of origin.


Subject(s)
Bacteriophage Typing , Disease Outbreaks , Paratyphoid Fever/epidemiology , Salmonella paratyphi A/classification , Travel , Adult , Aged , Anti-Bacterial Agents/pharmacology , Cambodia , Drug Resistance, Bacterial , Female , Humans , Japan/epidemiology , Male , Middle Aged , Paratyphoid Fever/microbiology , Salmonella paratyphi A/drug effects , Young Adult
12.
Heredity (Edinb) ; 116(1): 52-9, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26219230

ABSTRACT

Many lepidopteran insects exhibit body colour variations, where the high phenotypic diversity observed in the wings and bodies of adults provides opportunities for studying adaptive morphological evolution. In the silkworm Bombyx mori, two genes responsible for moth colour mutation, Bm and Ws, have been mapped to 0.0 and 14.7 cM of the B. mori genetic linkage group 17; however, these genes have not been identified at the molecular level. We performed positional cloning of both genes to elucidate the molecular mechanisms that underlie the moth wing- and body-colour patterns in B. mori. We successfully narrowed down Bm and Ws to ~2-Mb-long and 100-kb-long regions on the same scaffold Bm_scaf33. Gene prediction analysis of this region identified 77 candidate genes in the Bm region, whereas there were no candidate genes in the Ws region. Fluorescence in-situ hybridisation analysis in Bm mutant detected chromosome inversion, which explains why there are no recombination in the corresponding region. The comparative genomic analysis demonstrated that the candidate regions of both genes shared synteny with a region associated with wing- and body-colour variations in other lepidopteran species including Biston betularia and Heliconius butterflies. These results suggest that the genes responsible for wing and body colour in B. mori may be associated with similar genes in other Lepidoptera.


Subject(s)
Bombyx/genetics , Chromosome Mapping , Genetic Linkage , Pigmentation/genetics , Wings, Animal , Animals , Genes, Insect , In Situ Hybridization, Fluorescence , Mutation , Phenotype , Recombination, Genetic , Synteny
13.
Insect Mol Biol ; 24(5): 561-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26154510

ABSTRACT

We recently showed that the Masculinizer gene (Masc) plays a primary role in sex determination in the lepidopteran model insect Bombyx mori. However, it remains unknown whether this Masc protein-dependent sex determination system is conserved amongst lepidopteran insects or within the family Bombycidae. Here we cloned and characterized a Masc homologue (TvMasc) in Trilocha varians (Lepidoptera: Bombycidae), a species closely related to B. mori. To elucidate the role of TvMasc in the sex determination cascade of T. varians, TvMasc expression was knocked down in early embryos by the injection of small interfering RNAs (siRNAs) that targeted TvMasc mRNAs. Both female- and male-type splice variants of Tvdsx, a doublesex (dsx) homologue in T. varians were observed in control siRNA-injected embryos. By contrast, only female-type splice variants were observed in TvMasc siRNA-injected embryos. These results indicate that the TvMasc protein directly or indirectly regulates the splicing patterns of Tvdsx. Furthermore, we found that male-type splice variants of B. mori dsx (Bmdsx) were produced in TvMasc-overexpressing BmN4 cells. The mRNA level of B. mori Imp, a gene whose product induces male-specific Bmdsx splicing also increased. These results suggest that Masc genes play similar roles in the sex-determination cascade in Bombycidae.


Subject(s)
Insect Proteins/metabolism , Moths/genetics , Animals , Female , Gene Knockdown Techniques , Insect Proteins/genetics , Male , Moths/embryology , RNA Splicing , RNA, Messenger/genetics , RNA, Small Interfering/genetics , Sex Determination Processes
15.
Nat Commun ; 6: 6335, 2015 Feb 27.
Article in English | MEDLINE | ID: mdl-25721203

ABSTRACT

In single-walled carbon nanotubes, electron-hole pairs form tightly bound excitons because of limited screening. These excitons display a variety of interactions and processes that could be exploited for applications in nanoscale photonics and optoelectronics. Here we report on optical pulse-train generation from individual air-suspended carbon nanotubes under an application of square-wave gate voltages. Electrostatically induced carrier accumulation quenches photoluminescence, while a voltage sign reversal purges those carriers, resetting the nanotubes to become luminescent temporarily. Frequency-domain measurements reveal photoluminescence recovery with characteristic frequencies that increase with excitation laser power, showing that photoexcited carriers provide a self-limiting mechanism for pulsed emission. Time-resolved measurements directly confirm the presence of an optical pulse train synchronized to the gate voltage signal, and flexible control over pulse timing and duration is also demonstrated. These results identify an unconventional route for optical pulse generation and electrical-to-optical signal conversion, opening up new prospects for controlling light at the nanoscale.

16.
Sci Rep ; 5: 8160, 2015 Feb 02.
Article in English | MEDLINE | ID: mdl-25640966

ABSTRACT

Recent studies suggest that an exemplary Kondo insulator SmB6 belongs to a new class of topological insulators (TIs), in which non-trivial spin-polarized metallic states emerge on surface upon the formation of Kondo hybridization gap in the bulk. Remarkably, the bulk resistivity reaches more than 20 Ω cm at 4 K, making SmB6 a candidate for a so-called bulk-insulating TI. We here investigate optical-pulse responses of SmB6 by pump-and-probe photoemission spectroscopy. Surface photovoltage effect is observed below ~90 K. This indicates that an optically-active band bending region develops beneath the novel metallic surface upon the bulk-gap evolution. The photovoltaic effect persists for >200 µs, which is long enough to be detected by electronics devices, and could be utilized for optical gating of the novel metallic surface.

17.
Insect Mol Biol ; 24(2): 213-21, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25469867

ABSTRACT

The giant egg (Ge) locus is a Z-linked mutation that leads to the production of large eggs. Cytological observations suggest that an unusual translocation of a large fragment of the W chromosome bearing a putative egg size-determining gene, Esd, gave rise to giant egg mutants. However, there is currently no molecular evidence confirming either a W-Z translocation or the presence of Esd on the W chromosome. To elucidate the origin of giant egg mutants, we performed positional cloning. We observed that the Bombyx mori. orthologue of the human Phytanoyl-CoA dioxygenase domain containing 1 gene (PHYHD1) is disrupted in giant egg mutants. PHYHD1 is highly conserved in eukaryotes and is predicted to be a Fe(II) and 2-oxoglutarate-dependent oxygenase. Exon skipping in one of the two available Ge mutants is probably caused by the insertion of a non-long terminal repeat transposon into intron 4 in the vicinity of the 5' splice site. Segmental duplication in Ge(2) , an independent allele, was caused by unequal recombination between short interspersed elements inserted into introns 3 and 5. Our results indicate that (1) Bombyx PHYHD1 is responsible for the Ge mutants and that (2) the Ge locus is unrelated to the W-linked putative Esd. To our knowledge, this is the first report describing the phenotypic defects caused by mutations in PHYHD1 orthologues.


Subject(s)
Bombyx/genetics , Genetic Loci , Sex Chromosomes/genetics , Animals , Base Sequence , Chromosome Mapping , Cloning, Molecular , Female , Genetic Techniques , Molecular Sequence Data , Mutation , Oogenesis/genetics , Ovum/cytology
18.
Nat Commun ; 5: 5580, 2014 Nov 25.
Article in English | MEDLINE | ID: mdl-25420679

ABSTRACT

The unique emission properties of single-walled carbon nanotubes are attractive for achieving increased functionality in integrated photonics. In addition to being room-temperature telecom-band emitters that can be directly grown on silicon, they are ideal for coupling to nanoscale photonic structures. Here we report on high-efficiency coupling of individual air-suspended carbon nanotubes to silicon photonic crystal nanobeam cavities. Photoluminescence images of dielectric- and air-mode cavities reflect their distinctly different mode profiles and show that fields in the air are important for coupling. We find that the air-mode cavities couple more efficiently, and estimated spontaneous emission coupling factors reach a value as high as 0.85. Our results demonstrate advantages of ultralow mode-volumes in air-mode cavities for coupling to low-dimensional nanoscale emitters.

19.
Phys Rev Lett ; 112(11): 117401, 2014 Mar 21.
Article in English | MEDLINE | ID: mdl-24702413

ABSTRACT

Simultaneous photoluminescence and photocurrent measurements on individual single-walled carbon nanotubes reveal spontaneous dissociation of excitons into free electron-hole pairs. The correlation of luminescence intensity and photocurrent shows that a significant fraction of excitons are dissociating before recombination. Furthermore, the combination of optical and electrical signals also allows for extraction of the absorption cross section and the oscillator strength. Our observations explain the reasons why photoconductivity measurements in single-walled carbon nanotubes are straightforward despite the large exciton binding energies.

20.
Rev Sci Instrum ; 85(2): 02C309, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24593646

ABSTRACT

Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration.

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