Identification and functional analysis of a Masculinizer orthologue in Trilocha varians (Lepidoptera: Bombycidae)

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.

Acute transverse myelitis arising after combined general and thoracic epidural anesthesia

Acute transverse myelitis after surgery is a rare condition, but this complication is devastating. The relationship between anesthetic procedures and acute transverse myelitis is controversial. A 46-year-old woman was scheduled a colostomy closure, and general anesthesia with thoracic epidural anesthesia was performed. Epidural catheter was inserted at the T10–11 interspace, and insertion was smooth, and no blood or cerebrospinal fluid leakage was seen. However, 28 h after the surgery, the patient complained motor, sensory, and autonomic dysfunction. Two days after onset, a magnetic resonance imaging study demonstrated intramedullary hyperintensity, particularly in the gray matter, extending from T5–T9 and then diagnosed with acute transverse myelitis followed by the several examinations. High-dose IV methylprednisolone treatment was initiated and neurologic function restored 2 months after onset. Transverse myelitis may unpredictably occur following surgery. We are not able to determine the pathogenic relationship between anesthesia and myelitis with certainty, but proper diagnostic approach to myelitis may improve the prognosis.

Dense Deposition of Gold Nanoclusters Utilizing a Porphyrin/Inorganic Layered Material Complex as the Template

We examined the deposition of gold clusters through the reduction of a gold precursor sensitized by nonaggregated, assembled porphyrin molecules on an inorganic layered material surface in order to develop a novel strategy for constructing assemblies of gold clusters. Visible light irradiation on nonaggregated, assembled porphyrin on the inorganic surface in the presence of the gold precursor and an electron donor induced the deposition of gold NPs on the surface of the inorganic layered material. Uniform gold clusters, with an average diameter of 1.5 nm, were deposited on the surface without aggregation. The average interparticle distance between adjacent gold clusters (center to center) was 2.3 nm, which agrees well with the average intermolecular distance of the nonaggregated, assembled porphyrin molecules on the inorganic surface. Thus, the generated gold clusters appear to reflect the nonaggregated, assembled structure of the porphyrin molecules on the inorganic surface. This method, termed the photosensitized template reduction (PTR) method, is a useful and novel technique for the deposition of metal nanoparticles on the surfaces of supporting materials.

Positional cloning of the sex-linked giant egg (Ge) locus in the silkworm, Bombyx mori

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.

Gate-controlled generation of optical pulse trains using individual carbon nanotubes

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.

The photocurrent and luminescence of carbon nanotubes is governed by excitonic processes with diverse uses in nano-photonics. Here, Jiang et al. generate optical pulses from individual air-suspended carbon nanotubes under an application of square-wave gate voltages with control over pulse timing and duration.

Structure resembling effect of clay surface on photochemical properties of meso-phenyl or pyridyl-substituted monocationic antimony(v) porphyrin derivatives

The more hydrophobic antimony(v) porphyrin showed greater absorption transition probability increase and fluorescence quantum yield enhancement on the clay surface. These unique effects were discussed using the potential energy curves of porphyrin.

Ultralow mode-volume photonic crystal nanobeam cavities for high-efficiency coupling to individual carbon nanotube emitters

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.

Direct detection of key reaction intermediates in photochemical CO2 reduction sensitized by a rhenium bipyridine complex

Photochemical CO2 reduction sensitized by rhenium-bipyridyl complexes has been studied through multiple approaches during the past several decades. However, a key reaction intermediate, the CO2-coordinated Re-bipyridyl complex, which should govern the activity of CO2 reduction in the photocatalytic cycle, has never been detected in a direct way. In this study on photoreduction of CO2 catalyzed by the 4,4'-dimethyl-2,2'-bipyridine (dmbpy) complex, [Re(dmbpy)(CO)3Cl] (1), we successfully detect the solvent-coordinated Re complex [Re(dmbpy)(CO)3DMF] (2) as the light-absorbing species to drive photoreduction of CO2. The key intermediate, the CO2-coordinated Re-bipyridyl complex, [Re(dmbpy)(CO)3(COOH)], is also successfully detected for the first time by means of cold-spray ionization spectrometry (CSI-MS). Mass spectra for a reaction mixture with isotopically labeled (13)CO2 provide clear evidence for the incorporation of CO2 into the Re-bipyridyl complex. It is revealed that the starting chloride complex 1 was rapidly transformed into the DMF-coordinated Re complex 2 through the initial cycle of photoreduction of CO2. The observed induction period in the time profile of the CSI-MS signals can well explain the subsequent formation of the CO2-coordinated intermediate from the solvent-coordinated Re-bipyridyl complex. An FTIR study of the reaction mixture in dimethyl sulfoxide clearly shows the appearance of a signal at 1682 cm(-1), which shifts to 1647 cm(-1) for the (13)CO2-labeled counterpart; this is assigned as the CO2-coordinated intermediate, Re(II)-COOH. Thus, a detailed understanding has now been obtained for the mechanism of the archetypical photochemical CO2 reduction sensitized by a Re-bipyridyl complex.

Spontaneous exciton dissociation in carbon nanotubes

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.

Inhibition of S100A6 induces GVL effects in MLL/AF4-positive ALL in human PBMC-SCID mice

Mixed-lineage leukemia (MLL)/AF4-positive ALL is associated with a poor prognosis even after allogeneic hematopoietic SCT (allo-HSCT). We reported previously that MLL/AF4-positive ALL shows resistance to TNF-α, which is the main factor in the GVL effect, by upregulation of S100A6 expression followed by interference with the p53-caspase 8-caspase 3 pathway in vitro. We examined whether inhibition of S100A6 can induce an effective GVL effect on MLL/AF4-positive ALL in a mouse model. MLL/AF4-positive ALL cell lines (SEM) transduced with lentiviral vectors expressing both S100A6 siRNA and luciferase (SEM-Luc-S100A6 siRNA) were produced. SEM-Luc-S100A6 siRNA cells and SEM-Luc-control siRNA cells were injected into groups of five SCID mice (1 × 10(7)/body). After confirmation of engraftment of SEM cells by in vivo imaging, the mice in each group were injected with 4.8 × 10(7) human PBMCs. SEM-Luc-S100A6 siRNA-injected mice showed significantly longer survival periods than SEM-Luc-control siRNA-injected mice (P=0.002). SEM-Luc-S100A6 siRNA-injected mice showed significantly slower tumor growth than those injected with SEM-Luc-control siRNA (P<0.0001). These results suggested that inhibition of S100A6 may be a promising therapeutic target for MLL/AF4-positive ALL in combination with allo-HSCT.

Long-term correction of biochemical and neurological abnormalities in MLD mice model by neonatal systemic injection of an AAV serotype 9 vector

As both the immune system and the blood-brain barrier (BBB) are likely to be developmentally immature in the perinatal period, neonatal gene transfer may be useful for the treatment of lysosomal storage disease (LSD) with neurological involvements such as metachromatic leukodystrophy (MLD). In this experiment, we examined the feasibility of single-strand adeno-associated viral serotype-9 (ssAAV9)-mediated systemic neonatal gene therapy of MLD mice. ssAAV9 vector expressing human arylsulfatase A (ASA) and green fluorescent protein (GFP) (ssAAV9/ASA) was injected into the jugular vein of newborn MLD mice. High levels of ASA expression were observed in the muscle and heart for at least 15 months. ASA was continuously secreted into plasma without development of antibodies against ASA. Global gene transfer into the brain and spinal cord (SC), across the BBB, and long-term ASA expression in the central nervous system were detected in treated mice. Significant inhibition of the accumulation of sulfatide (Sulf) in the brain and cervical SC was confirmed by Alcian blue staining and biochemical analysis of the Sulf content. In a behavior test, treated mice showed a greater ability to traverse narrow balance beams than untreated mice. These data clearly demonstrate that MLD mice model can be effectively treated through neonatal systemic injection of ssAAV9/ASA.

Quasi-steady carbon plasma source for neutral beam injector

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.

Pinning effect for photoisomerization of a dicationic azobenzene derivative by anionic sites of the clay surface

The photoisomerization behaviour of a dicationic azobenzene derivative on the inorganic surface was examined. The isomerization reaction was controlled by the charged array of the inorganic surface due to the "pinning effect" because of the electrostatic interaction between anionic charged sites on the inorganic surface and cationic charged sites in dye molecules.

Remarkable enhancement of the photoreactivity of a polyfluoroalkyl azobenzene derivative in an organic–inorganic nano-layered microenvironment

The quantum yield of photo-isomerization exceeds unity (Φ = 1.9) in an organic–inorganic nano-layered microenvironment.

Fe whisker growth revisited: effect of Au catalysis for [021̄] oriented nanowires with 100 nm diameter

The growth mechanism of Fe nanowires and the role of Au nanoparticle catalysis were revealed using transmission electron microscopy and electron diffraction analysis. Fe nanowire has a high aspect ratio and unique [021̄] orientation.