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Asparaptine, a conjugate of arginine and asparagusic acid, was found in asparagus (Asparagus officinalis) as a naturally occurring inhibitor of angiotensin-converting enzyme (ACE) in vitro. The biosynthetic pathway to asparaptine is largely unknown; however, it is suggested that asparagusic acid may be biosynthesized from valine. To determine which metabolites are involved in the asparaptine biosynthetic pathway, we performed tandem mass spectrometry similarity-based metabolome network analysis using 13C labeled and non-labeled valine-fed asparagus calluses. We determined that valine is used as a starting material, S(2-carboxy-n-propyl)-cysteine as an intermediate, and two new metabolites as asparaptine analogs, lysine- and histidine-type conjugates, are involved in the pathway. Asparaptine was therefore renamed asparaptine A (arginine type), and the two analogs were named asparaptines B (lysine type) and C (histidine type). Oral feeding of asparaptine A to a hypertensive mouse species showed that this metabolite lowers both blood pressure and heart rate within two hours and both of which were back to normal two days later. These results suggest that asparaptine A may not only have effects as an ACE inhibitor, but also has β-antagonistic effects, which are well-known to be preventive for cardiovascular diseases.

Resin-ceramic hybrid materials for computer-aided design/computer-aided manufacturing (CAD/CAM resins) have been developed. In this study, the effects of the amount of light energy transmitted through the four types of 1.5-mm-thick CAD/CAM resin blocks on the bond performance of corresponding resin cement adhesive systems consisting of an adhesive and a dual-curable resin cement were examined. The bond strengths of the four types of resin cement adhesive systems decreased with decreasing the amount of light energy transmitted through CAD/CAM resin block, due to a decrease in the light-curable ability of dual-curable resin cements. However, the degradation behavior of the bond strengths was strongly affected by the types of adhesives and initiator systems utilized. The adhesive consisting of a dimethacrylate monomer and redox-initiators enhanced the bonding performance of the dual-curable resin cement more effectively than the adhesive, which consists of a dimethacrylate monomer and photo-initiators or a γ-me thacryloxypropyltrimethoxysilane and a 10-methacryloyloxydecyl dihydrogen phosphate.

Shimalactones A and B are neuritogenic polyketides possessing characteristic oxabicyclo[2.2.1]heptane and bicyclo[4.2.0]octadiene ring systems that are produced by the marine fungus Emericella variecolor GF10. We identified a candidate biosynthetic gene cluster and conducted heterologous expression analysis. Expression of ShmA polyketide synthase in Aspergillus oryzae resulted in the production of preshimalactone. Aspergillus oryzae and Saccharomyces cerevisiae transformants expressing ShmA and ShmB produced shimalactones A and B, thus suggesting that the double bicyclo-ring formation reactions proceed non-enzymatically from preshimalactone epoxide. DFT calculations strongly support the idea that oxabicyclo-ring formation and 8π-6π electrocyclization proceed spontaneously after opening of the preshimalactone epoxide ring through protonation. We confirmed the formation of preshimalactone epoxide in vitro, followed by its non-enzymatic conversion to shimalactones in the dark.

Nanocavity devices based on silicon that can operate in the 1.2-µm band would be beneficial for several applications. We fabricate fifteen cavities with resonance wavelengths between 1.20 and 1.23 µm. Experimental quality (Q) factors larger than one million are obtained and the average Q values are lower for shorter wavelengths. Furthermore, we observe continuous-wave operation of a Raman silicon laser with an excitation wavelength of 1.20 µm and a Raman laser wavelength of 1.28 µm. The Q values of the nanocavity modes used to confine the excitation light and the Raman scattered light are about half of those for our Raman silicon laser operating in the 1.55-µm band. Nevertheless, this device exhibits an input–output characteristic with a clear laser threshold. Finally, we consider the effect of the higher scattering probability at shorter wavelengths on the Raman laser performance in the 1.2-µm band.

The ingredients of an antipyretic (acetaminophen, AAP) and their metabolites excreted into fingerprint were detected by surface-assisted laser desorption ionization (SALDI) mass spectrometry using zeolite. In the fingerprint taken 4 h after AAP ingestion, not only AAP but also the glucuronic acid conjugate of AAP (GAAP), caffeine (Caf), ethenzamide (Eth), salicylamide (Sala, a metabolite of Eth), and urea were detected. Fingerprints were collected over time to determine how the amounts of AAP and its metabolite changed with time, and the time dependence of the peak intensities of protonated AAP and GAAP was measured. It was found that the increase of [GAAP+H]+ peak started later than that of [AAP+H]+ peak, reflecting the metabolism of AAP. Both AAP and GAAP reached maximum concentrations approximately 3 h after ingestion, and were excreted from the body with a half-life of approximately 3.3 h. In addition, fingerprint preservation was confirmed by optical microscopy, and fingerprint shape was retained even after laser irradiation of the fingerprint. Our method may be used in fingerprint analysis.

Raman silicon lasers based on photonic crystal nanocavities with a threshold of several hundred microwatts for continuous-wave lasing have been realized. In particular, the threshold depends on the degree of confinement of the excitation light and the Raman scattering light in the two nanocavity modes. Here, we report lower threshold values for Raman silicon nanocavity lasers achieved by increasing the quality (Q) factors of the two cavity modes. By using an optimization method based on machine learning, we first increase the product of the two theoretical Q values by a factor of 17.0 compared to the conventional cavity. The experimental evaluation demonstrates that, on average, the actually achieved product is more than 2.5 times larger than that of the conventional cavity. The input–output characteristic of a Raman laser with a threshold of 90 nW is presented and the lowest threshold obtained in our experiments is 40 nW.

Asparaptine, a conjugate of L-arginine and asparagusic acid, was found in green asparagus (Asparagus officinalis) using ultrahigh-resolution metabolomics for sulfur-containing metabolites (S-metabolites), called S-omics. Asparaptine has been shown to inhibit the activity of angiotensin-converting enzyme. Larger amounts of this S-metabolite are therefore required for further analysis; however, there are limitations that asparagus is a perennial plant and its spears, wherein asparaptine accumulates, can be mainly harvested at the spring to summer season. In order to overcome these, we prepared a callus and suspension cell line from green asparagus. Untargeted metabolome analysis using liquid chromatography-tandem mass spectrometry was performed in the materials as well as spears and three calluses derived from wild type Asparagus. The analysis demonstrated that the amount of asparaptine in the callus derived from the green asparagus was more than the others per mg dry weight. The suspension cell line treated with methyljasmonate showed the induction of asparaptine, suggesting that the asparaptine production is modifiable under appropriate culture conditions. The described materials can be utilized for the production of asparaptine and in integrated metabolomics to study the biosynthesis of this S-metabolite, which is currently unknown.

In this paper, we review the history of 2-D photonic crystal slabs with a focus on point-defect cavities that can simultaneously realize ultrasmall modal volumes and ultrahigh quality factors. An important design concept to suppress radiation loss is introduced: the envelope of the cavity mode field should have no abrupt changes and should ideally follow a Gaussian function. Cubic-wavelength-order modal volumes, with experimental $\mathit {Q}$ factors exceeding 11000000, are obtained by tailoring the envelope functions using heterostructure nanocavities. We also discuss light/photon manipulation techniques, which are enabled by the emergence of high- $\mathit {Q}$ photonic crystal nanocavities, including ultracompact channel add/drop filters, ultralow-threshold silicon nanocavity Raman lasers, and strong coupling between distant nanocavities via the adiabatic transfer of photons.

We investigated the behavior of a Raman silicon laser based on a photonic-crystal nanocavity while it was irradiated with electrostatic charges from a static-electricity generator. Laser oscillation stopped after a few seconds of a weak irradiation and the time needed for the recovery of laser oscillation increased with irradiation time. We measured the resonance spectra of the nanocavity modes during irradiation. It indicates that such a lasing interruption can be caused by wavelength shifts of the nanocavity modes and absorption losses due to the electrostatic charges on the nanocavity surface. These results are useful for the sensing of electrostatic charges.

We report the first observation of spontaneous Raman scattering emission from a Raman silicon nanocavity laser excited by broadband light from a superluminescent diode.

The performance of a Raman silicon laser based on a high quality-factor nanocavity depends on the degree of free-carrier absorption, and this characteristic may be useful for certain applications. Here we demonstrate that laser oscillation in a Raman silicon nanocavity laser stops abruptly after an exposure to a weak flux of negatively ionized air for a few seconds. Spectral measurements reveal that the laser interruption is mainly caused by the transfer of extra electrons from the negatively ionized air molecules to the silicon nanocavity. These electrons affect the efficiency of the Raman laser by free carrier absorption. We find that the laser output gradually recovers as the extra electrons escape from the nanocavity and confirm that such a detection of ionized air is repeatable. These results show that a Raman silicon nanocavity laser can be used for the detection of ionized air with a high spatial resolution.

A complex of α-cyano-4-hydroxycinnamic acid (CHCA) and zeolite was used as the matrix for the analysis of drugs and their metabolites in urine by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). It was found that acetaminophen (AAP) and its metabolites could be detected in urine without any pretreatment or separation process. It was also found that the hydrolysis of one of the metabolites, glucuronide, was promoted when a mixture of urine and the developed matrix was heated at 343 K for 15 minutes. Because of the homogeneous distribution of CHCA on the zeolite surface, high reproducibility of the analyte peak intensity was achieved. By using isotope-labeled acetaminophen (D4-AAP) as the internal standard, quantitative analysis of AAP in urine from a donor who took 300 mg of AAP four hours before was performed, and 5.29 ± 0.19 mg of AAP was detected in 1.00 g of urine.

A method for producing Cu films with low resistivity, based on low temperature sintering, is demonstrated. The Cu inks for preparing conductive Cu films consisted of Cu particles that were coated with a decomposable polymer (poly(propylenecarbonate), PPC) as well as a self-reducible copper formate/1-amino-2- propanol (CuF-IPA) complex as an additive. The sintering temperature used in this study was as low as 100 degrees C. Following sintering at a temperature of 100 degrees C, the lowest reported resistivity (8.8 x 10(-7) Omega m) was achieved through the use of Cu-based metal-organic decomposition (MOD) inks. This was due to the dual promotional effects of the aminolysis of PPC with IPA and the pyrolysis of the CuF-IPA complex.

Thermophotovoltaic systems in principle enable utilization of heat that is usually regarded as wasted energy. However, the wavelength selectivity of the thermal emitter required for high efficiencies is rather difficult to control with conventional designs. Here, we design a thermophotovoltaic system comprising silicon rods as thermal emitter with a relatively narrow emission spectrum and a photovoltaic cell with a band gap corresponding to 1.76 $\mu$m, and verify efficient power generation. By accurately measuring the heat flux that enters the emitter, the emitter temperature, and the electrical output power of the photovoltaic cell, we find that the actual system efficiency (ratio of ingoing heat flux to output power) is 11.2% at an emitter temperature of 1338 K, and that the output power density footprint is 0.368 W/cm2. The obtained efficiency is relatively high, i.e., 1.65 times that of the previously reported record value (6.8%). Further efficiency improvements in the future may lead to development of distributed energy supplies using combustion heat., Comment: 19 pages, 6 figures

The ability of surface-assisted laser desorption/ionization mass spectroscopy (SALDI-MS) of low-molecular-weight compounds using six types of commercially available TiO2 nanoparticles (NPs) was exa...

We investigate the excitation wavelength dependence of the laser emission from a nanocavity-based Raman silicon laser with a technique called Raman-scattering-luminescence excitation. This technique provides an overview of the Raman gain including nonlinear optical losses.

Ferulic acid (FA), a phenolic phytochemical, has been reported to exert antioxidative and neuroprotective effects. In this study, we investigated the protective effects of FA against the dysfunction of the swallowing reflex induced by ligation of bilateral common carotid arteries (2VO) in rats. In 2VO rats, topical administration of water or citric acid to the pharyngolaryngeal region evoked a diminished number of swallowing events with prolonged latency compared to sham-operated control rats. 2VO rats had an increased level of superoxide anion radical, and decreased dopamine and tyrosine hydroxylase enzyme levels in the striatum, suggesting that 2VO augmented cerebral oxidative stress and impaired the striatal dopaminergic system. Furthermore, substance P (SP) expression in the laryngopharyngeal mucosa, which is believed to be positively regulated by dopaminergic signaling in the basal ganglia, was decreased in 2VO rats. Oral treatment with FA (30 mg/kg) for 3 weeks (from one week before 2VO to two weeks after) improved the swallowing reflex and maintained levels of striatal dopamine and laryngopharyngeal SP expression in 2VO rats. These results suggest that FA maintains the swallowing reflex by protecting the dopamine-SP system against ischemia-induced oxidative damage in 2VO rats.

Photonic nanocavities with high quality (Q) factors are essential components for integrated optical circuits. The use of crystalline silicon carbide (SiC) for such nanocavities enables the realization of devices with superior properties. We fabricate ultrahigh-Q SiC photonic crystal nanocavities by etching air holes into a 4H-SiC slab that is prepared without using hydrogen ion implantation, which usually causes higher absorption losses. In addition, compared to usual designs, a relatively thin slab is utilized to avoid losses through cross-polarized mode coupling induced by the tapered air holes. We obtain a heterostructure nanocavity with a high experimental Q factor of 6.3×105, which is 16 times larger than the highest Q among the previously reported values for nanocavities based on crystalline SiC. We also show that our nanocavity exhibits a high normalized second-harmonic conversion efficiency of 1900%/W.

By using 2,4,6-trihydroxyacetophenone adsorbed to cation-substituted zeolite, laser desorption/ionization mass spectrometry for six kinds of bioactive substances was carried out. The compounds, which were usually difficult to observe by conventional matrix-assisted laser desorption/ionization mass spectrometry, were ionized by cation adduction from the zeolite surface.

Silicon carbide (SiC) is a promising optical material for stable and broadband nanophotonics. To date, thin crystalline SiC layers for nanophotonic platforms have been created by ion implantation or growth on other materials, which may cause optical absorption in the SiC layer. We fabricated SiC nanobeam photonic crystal cavities directly from a crystalline (4H) SiC bulk wafer using oblique plasma etching to avoid material-based optical absorptions. The measured quality (Q) factor of the nanobeam photonic crystal cavity reaches 4 × 104, which is the highest recorded Q factor in crystalline SiC cavities. Furthermore, we investigated theoretical Q factors by taking into account structural imperfections unique to this fabrication process and compared them with the experimental results.

Camptothecin is a monoterpenoid indole alkaloid that exhibits anti-tumor activity. In Ophiorrhiza pumila, production of camptothecin and its related alkaloids was high in the hairy roots, but not in the cell suspension culture derived from hairy roots. To identify the intermediates in camptothecin biosynthesis, expression of genes encoding tryptophan decarboxylase (TDC) and secologanin synthase (SLS), the two enzymes catalyzing the early steps in camptothecin biosynthesis, were suppressed in the hairy roots of O. pumila by RNA interference (RNAi), and metabolite changes were investigated. In most TDC- and SLS-suppressed lines, accumulation of camptothecin and related alkaloids, strictosidine, strictosamide, pumiloside, and deoxypumiloside was reduced. The accumulation levels of secologanin exhibited a strong negative correlation with the expression level of TDC, and that of loganin exhibited a negative correlation with the expression level of SLS. Some hairy root-specific chromatographic peaks detected by liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR-MS) exhibited positive or negative correlation with TDC expression, suggesting their possible involvement in camptothecin biosynthesis.

A mass measurement technique for detecting low-molecular-weight drugs with a cyclodextrin-supported organic matrix was investigated. By using cyclodextrin-supported 2,4,6-trihydroxyacetophenone (THAP), the matrix-related peaks of drugs were suppressed. The peaks of protonated molecules of the sample and THAP were mainly observed, and small fragments were detected in a few cases. Despite the Na+ and K+ peaks were observed in the spectrum, Na+ or K+ adduct sample molecules were undetected, owing to the sugar units of cyclodextrin. The advantages of MALDI-MS with cyclodextrin-supported matrices as an analytical tool for forensic samples are discussed. The suppression of alkali adducted molecules and desorption process are also discussed.

An efficient matrix for matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) has been developed. The use of 2,4,6-trihydroxyacetophenone (THAP) on lithium-substituted zeolite has enabled ionization of low-molecular-weight compounds that are not detectable by conventional MALDI-MS. IR measurements and quantum-chemical calculations have also been carried out to understand the adsorption structure of THAP on zeolite. The mechanism of Li+ adduction from zeolite to THAP is also discussed. The important role of the water molecules adsorbed on the zeolite surface for the Li+ adduction from zeolite to THAP has been clarified.

We achieved the reduced the surface roughness of poly[9,9-dioctylfluorenyl-2,7-diyl]-co-1,4-benzo-(2,1,3)-thiadiazole (F8BT) thin film fabricated by the electrospray deposition technique, using two organic solvents. The root mean square (RMS) roughness of the F8BT thin film was reduced by the addition of dimethyl sulfoxide (DMSO) in tetrahydrofuran (THF). A minimum RMS roughness of 23 nm was obtained by optimizing the ratio of DMSO in THF. We found that the low evaporation pressure of the additional organic solvent is an important factor in attaining a smooth surface for F8BT thin film. The current density-voltage-luminance characteristics of the organic lightemitting diode was improved by reducing the surface roughness of the F8BT layer. A maximum luminance of 36.7 cd/cm2 was obtained, and it was more than 14 times higher than the reference device fabricated by the conventional single organic solvent technique., NOTICE: this is the author's version of a work that was accepted for publication in Thin Solid Films. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Thin Solid Films, [VOL 520, ISSUE 1, (2011)] DOI : 10.1016/j.tsf.2011.07.048.

Kinetic spectroscopic ellipsometry have been used to study the initial growth stage of poly(3,4-polyethylene dioxythiophene):poly(styrenesulfonic acid)(PEDOT:PSS) films by the electrospray deposition (ESD) method. The real-time spectra analysis revealed that the surface overlayer decreased in thickness once the first bulk layer monolayer was formed, indicating a smoothening effect as the nucleation-related microstructure coalesced into the bulk layer. Once the coalescence was completed and the nucleation-induced surface roughness layer was stabilized, the underlying bulk layer increased linearly with time. These results originate from the degrees of the evaporation of solvent material during the transferring the precursors to the surface and/or of the diffusion of deposition precursors after sticking at the growing surface.

application/pdf, Optica. 2018, 5 (10), P.1256-1263

We propose a scheme for near-field thermophotovoltaic (TPV) energy conversion, where thermal emission from an emitter is extracted by an intermediate transparent substrate attached to the top of a photovoltaic (PV) cell. The addition of an intermediate transparent substrate suppresses the unwanted heat transfer from the emitter to the PV cell due to the surface modes on the PV cell while maintaining the enhancement in the interband absorption. We confirm that our scheme is applicable for near-field TPV systems using a silicon (Si) or tungsten (W) emitter. As a specific example, we designed a near-field TPV system composed of a one-dimensional Si photonic crystal thermal emitter, an InGaAs PV cell, and an intermediate Si substrate, and displayed that our scheme could realize both high power density (>5 × 104 W/m2) and high power conversion efficiency (>40%) at a 50-nm gap between the emitter and the intermediate substrate.

Supporting substrates for Si rod-type photonic crystals (PCs) are investigated for realizing highly wavelength-selective near-infrared thermal emitters. Three materials—SiO2, Al2O3, and MgO—are considered for their low infrared emission (transparency) and remarkable heat resistance. Theoretical calculations of the emissivity spectra of Si-rod PCs (rod height = 500 nm, rod diameter = 300 nm, and lattice constant = 600 nm) on 50 μm-thick supporting substrates at 1400 K indicate that the long-wavelength (>3 μm) emission power from the emitter using MgO is less than 1/10 of that of the other two materials. Fabrication of the Si-rod PCs on the 50 μm-thick MgO substrate requires the insertion of a thin (30 nm) HfO2 film between MgO and Si to improve the stability at high temperatures (>1400 K). Experimental results of the fabricated structure show that at 1400 K, the ratio of emissive power at wavelengths 3 μm) emission power from the emitter using MgO is less than 1/10 of that of the other two materials. Fabrication of the Si-rod PCs on the 50 μm-thick MgO substrate requires the insertion of a thin (30 nm) HfO2 film between MgO and Si to improve the stability at high temperatures (>1400 K). Experimental results of the fabricated structure show that at 1400 K, the ratio of emissive power at wavelengths

Camptothecin is one of the clinically used anticancer compounds derived from plants. We have established a hairy root culture Ophiorrhiza pumila, which efficiently produces camptothecin. The strictosidine synthase cDNA was obtained from O. pumila, and its properties were characterized using recombinant protein expressed in Escherichia coli. The mechanisms of camptothecin transport and self-resistance of producing plant cells have also been investigated. These studies offer a basis for pathway engineering of camptothecin in the future.

We studied cement-like solidification process for low-level liquid waste with relatively high levels of radioactivity that contains a high concentration of sodium sulfate. For this type waste, it is important that the sulfate ion should not dissolve from the solid waste because it forms ettringite on reaction with minerals in the concrete of the planned repository, and this leads to cracking during repository storage. It is also preferable that the pH of the pore water of the solid waste be low, because the bentonite of the repository changes in quality on exposure to alkaline solution. Therefore, the present solidification process has two procedures: conversion into insoluble sulfate from sodium sulfate (CIS) and formation of low pH cement-like solid (FLS). In the CIS procedure, BaSO4 precipitation occurs with addition of Ba(OH)2•8H2O to the liquid waste. In the FLS procedure, silica fume and blast furnace slag are added to the liquid waste containing BaSO4 precipitate. We show the range of appropriate Ba/SO4 molar ratio is from 1.1 to 1.5 in the present solidification process by leaching tests for some kinds of solid waste samples. The CIS reaction yield is over 98% at a typical CIS condition, i.e. Ba/SO4 molar ratio=1.3, reaction temperature=60°C, and time=3 hr.

Experimental and numerical analysis of methanol steam reforming for fuel cell have been carried out. The reforming catalyst was supported by metal honeycomb to decrease the heat capacity. Conversion performances were improved by segmenting the catalyst into several blocks due to the enhancement of mixing of gases and heat transfer at the front edges of the segmenting catalyst. Numerical simulation model for methanol steam reforming catalyst was developed by changing chemical reactions in the model for exhaust catalyst of internal combustion engine and using a smaller mass transfer coefficient for methanol steam reforming. The calculated results for plate type methanol steam reformer which generates hydrogen of 7 kW (LHV) were also in good agreement with the measurements. It was found that the pattern of heat supply to catalyst and the reformer configuration affected the steam reforming performance. It was predicted that the optimized methanol steam reformer for 50 kW size fuel cell vehicle had a sufficient compactness.

We have investigated the subcellular accumulation and transport of camptothecin (CPT), a monoterpene indole alkaloid, in hairy roots of Ophiorrhiza pumila. This hairy root produces high amounts of CPT and excretes it into the culture medium. When the hairy roots were exposed to UV radiation, autofluorescence emitted from CPT showed subcellular localization of CPT in the vacuole. Treatment with several inhibitors suggested that CPT excretion is a transporter-independent passive transport controlled by the concentration gradient of the compound. Interestingly, the hairy roots treated with brefeldin A, a vesicle transport inhibitor, showed increased CPT excretion. This could be explained by an increased transport rate of CPT from the endoplasmic reticulum (ER) to the cytoplasm when transport of CPT to the vacuole is blocked. The much higher concentration of CPT in the cytoplasm resulted in the increased excretion rate. This result indicates that CPT is biosynthesized at the ER and transported to accumulate in the vacuole by the same machinery that is used for vacuolar protein sorting. How O. pumila is insensitive to CPT is discussed.

A new mouthguard material, polyolefin, was recently developed. To date, no studies have compared ethylene vinyl acetate (EVA) and polyolefin mouthguards. The aim of this study was to evaluate the physical properties of polyolefin, relative to those of EVA. Two polyolefin materials, hard and regular, were used, in addition to EVA. Hardness, tensile strength, tear strength, elongation, and water absorption were analyzed, as well as the adhesive strength of the materials in laminated mouthguards. Hard polyolefin (MG-H) and EVA were significantly harder than regular polyolefin (MG-R) (p

We develop a nanocavity Raman Si laser with a sub-microwatt threshold of 0.52 μW by accurately matching a frequency spacing of the two nanocavity modes to the Raman shift of Si nanocavity.

We have precisely measured the Raman shift of photonic crystal silicon heterostructure nanocavities for Raman laser applications. We utilized a near-infrared excitation laser of wavelength 1.42 μm in order to avoid local sample heating and exploited two high-Q nanocavity modes to calibrate the Raman frequency. The measured Raman shift was 15.606 THz (520.71 cm(-1)) with a small uncertainty of 1.0 × 10(-3) THz. In addition, we investigated the compressive stress generated in a photonic crystal slab in which a ~5.1 × 10(-3) THz blue shift of the Raman peak and a slight warpage of the slab were observed. We also demonstrated that the stress could be eliminated by using a cantilever structure.

The two-dimensional photonic crystal cavities employing local three-dimensional structures are investigated. Donor-type cavities with small and shallow holes are examined as examples of cavities with a local three-dimensional structure. It is shown that both the far-field and near-field patterns of the cavities can be controlled by the addition of small and shallow holes. The fabrication of such structures using a focused ion beam is proposed and investigated. Residual gallium ions, used in fabrication with a focused ion beam, lead to optical absorption; these gallium ions can be removed by heat treatment at 800 °C. The near-field pattern of a fabricated three-dimensional cavity is measured, and is shown to be consistent with a theoretical analysis.

Desulfurization and deoxidation of molten iron with magnesium vapor produced in-situ by aluminothermic reduction of magnesium oxide has been developed. In the present study, the mechanism of aluminothermic reduction of magnesium oxide by use of pellets composed of magnesium oxide and aluminum powders was discussed. SEM observation of the pellets at different reduction stages for various temperatures showed that fracture and disappearance of the alumina films on the aluminum particles were stimulated above 1 473 K, and thus the reduction of magnesium oxide was greatly accelerated.From in-situ observation of the aluminothermic reduction of magnesium oxide using a high temperature optical microscope (HTOM), it was found that the reduction proceeded after the penetration of molten aluminum into the magnesium oxide phase. The penetration began at 1 273 K and it was accelerated above 1 373 K. The reduction took place violently at 1 473 K. SEM observation and EDS analysis of the cooled sample revealed that the penetration took place only through cracks of the alumina film.In-situ observation of the melting process of aluminum particles together with SEM observation of the cooled sample showed that the thermal stress and the stress formed during phase transformation could break up the alumina film and the outflow of molten aluminum did take place at the elevated temperature.

The main ingredient of grape seed proanthocyanidin extract (GSPE), is proanthocyanidin, a kind of flavonoid. Proanthocyanidins are known to have a variety of biological regulatory activities, such as antioxidant effects; however, little is known the effects on bone. In the present study, we performed mechanical analysis using three-dimensional peripheral quantitative computed tomography (pQCT), bone strength tests and quantitative analysis of a combination therapy composed of high-calcium diet and GSPE fed to rats during their growth. Forty male Wistar rats, 5 weeks old, were divided randomly into control (A), low-calcium diet (B), low-calcium/high-calcium diet (C) and low-calcium/high-calcium diet with supplementary GSPE (D) groups. After 6 weeks, the tibias were removed and cortical bone density, cross-sectional area, mineral content, cortical bone thickness, periosteal perimeters, endosteal perimeters, and stress strain index (SSI) were measured. Invasive three-point bending tests, and quantitative analysis of Ca, P, Mg and Zn using inductively coupled plasma (ICP) spectral analysis were performed. Body weights were not significantly different in the 4 groups. Cortical bone density and mineral content in group D were significantly higher than those in group C ( P P P

Camptothecin-derived compounds are widely used for clinical treatment of human cancer. They are synthesized from natural camptothecin, which is obtained by extraction from intact plants. For the feasible production of camptothecin, tissue cultures of Ophiorrhiza liukiuensis and O. kuroiwai, an interspecies hybrid of O. liukiuensis and O. pumila, have been investigated. The aseptic plants and hairy roots of O. liukiuensis and O. kuroiwai were established in addition to the previously-established O. pumila. The camptothecin production by O. kuroiwai was better than that by O. liukiuensis. 10-Methoxycamptothecin was accumulated in tissue cultures of O. liukiuensis and O. kuroiwai but not in O. pumila. Methyl jasmonic acid slightly enhanced the production of camptothecin in the O. liukiuensis hairy roots. These results indicate that the tissue cultures of O. liukiuensis and O. kuroiwai would be the feasible ways for production of camptothecin and related alkaloids.

We improve design quality factors of slotted photonic crystal nanocavities embedded in electro-optic polymers (EOPs), which enables control of resonant wavelengths without the use of light-absorbing free carriers. We form nanocavities by modifying single- and double-slotted line-defect waveguides with lattice-constant modulations analytically determined based on dispersions of the waveguides. A double-slotted nanocavity achieves a fourfold increase in Q factor (36 million) compared to a single-slotted nanocavity with similar modulation of lattice constants. Both structures can realize large concentration of light in the EOP region (50%), and resonant wavelength modulations of ~0.01% are expected with applied voltage of 2 V.

application/pdf, Article, Optics Express. 2017, 25 (3), p.1769-1777

A high-efficiency bulk heterojunction organic photovoltaic cell (OPV) was achieved by the electrospray deposition method. The surface roughness of the P3HT:PCBM thin film can be reduced using the mixed solvent consisting of o-dichlorobenzene (o-DCB) and acetone. The effect of acetone concentration is related to its dielectric constant. Under an optimized concentration of acetone in o-DCB (20 vol%), the P3HT/PCBM active layer with a smooth surface can be formed, and the power conversion efficiency of the OPV was 1.9%. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

When a heterostructure is created at the center of a photonic crystal line-defect cavity to form a nanocavity, the photonic band gap contains several high-quality ($Q$) factor resonant modes. We have studied the optical properties of these modes to examine their applicability to Raman silicon lasers, which require two high-$Q$ resonant modes with a frequency spacing of 15.6 THz. Our experimental and numerical analyses reveal four types of resonant modes. We demonstrate that pairing the resonant mode originating from the first-order propagation mode with that arising from the second-order propagation mode is the most promising approach toward the realization of Raman silicon lasers.

This report quantum mechanically analyses a system composed of a two-level system, a single mode cavity, and free space photon modes, which are coupled to each other. The analytical solution in the intermediate regime between the strong and weak coupling regimes is successfully obtained. It is found that the emission rate reaches its maximum when the cavity photon lifetime τcav satisfy 1/τcav = 4|g |, where 2|g | is the vacuum Rabi frequency. Also, Fano resonance is shown to occur under certain conditions. These results can be useful for high-speed single photon sources and for fundamental understanding of the interaction between a quantum dot and a cavity mode. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)