Terahertz stretchable metamaterials with deformable dolmen resonators for uniaxial strain measurement

In this study, we propose a terahertz stretchable metamaterial that can measure uniaxial strain. Gold dolmen resonators formed on a sheet of polydimethylsiloxane (PDMS) is deformed by strain, and its resonance peak exhibits the gradual decrease in reflectance without a frequency shift, which is suitable for imaging applications at a single frequency. The metamaterial was designed by mechanical and electromagnetic simulations and fabricated by microfabrication including a transfer process of gold structures from a glass substrate to a PDMS sheet. By measuring the reflectance and observing the deformation under different strains, the reflectance decrease was obtained at 0.292 THz despite the appearance of wrinkles on gold structures. Linear response and repeatability up to 20% strain were also confirmed. Furthermore, the strain measurement through a sheet of paper was demonstrated, suggesting that our method can be applied even in situations where opaque obstacles in the visible region exist.

Tunable Fabry-Perot interferometer operated in the terahertz range based on an effective refractive index control using pitch-variable subwavelength gratings

We constructed a tunable Fabry-Perot interferometer (FPI) by controlling the effective refractive index of pitch-variable subwavelength gratings (PV-SWGs) that were incorporated into an FP cavity. The period of the PV-SWG can be varied to change the effective refractive index and shift the optical resonant frequency of the FPI. Compared with conventional methods that tune the optical resonance by adding fillers or deforming the cavity, the proposed FPI obtained a higher transmission and quality factor (Q-factor) for the transmittance peak, and its resonant frequency can be shifted by simply stretching the PV-SWG. A peak transmittance of 0.87, a Q-factor of 34, and a frequency shift of 17 GHz were obtained by the PV-SWG-based FPI for THz incomes around the frequency of 0.303 THz. As the effective refractive index and the working frequency can be tailored by altering the geometry design of the PV-SWG, the FPI holds significance for the development of THz communications and for applications at different wave bands.

Association between adverse childhood experience and unintended pregnancy among Japanese women: a large-scale cross-sectional study

Unintended pregnancy (UP) can negatively impact the health of mothers, children, and families. While Adverse Childhood Experiences (ACEs) are increasingly known to affect sexual health, the influence on pregnancy intention is not fully understood. This study examines the relationship between ACEs and UP and explores other related factors, using 5049 pregnant and postpartum women data from the Japan COVID-19 and Society Internet Survey (JACSIS). We measured participants' pregnancy intentions, ACEs, family functioning, and social network size. Logistic regression analysis provided odds ratios and 95% confidence intervals (CI). The prevalence of UP was approximately 16.5% (n = 893). Cumulative ACEs were consistently associated with UP, even after adjusting for intermediate variables in adulthood. The odds ratio for UP with a single ACE was 1.00 (CI: 0.82-1.21) but rose significantly with multiple ACEs: 1.39 (CI: 1.10-1.76) with double, 1.38 (CI: 1.02-2.86) with triple, and 1.81 (CI: 1.37-2.39) with more. Additionally, bad family functioning and lack of social networks emerged as contributors to UP. In conclusion, this study showed that ACEs are potentially correlated with UP. A deeper understanding of the transition from childhood experiences to UP is important for health interventions, necessitating further investigation.

Fabrication of functional metamaterials for applications in heat-shielding windows and 6G communications

Windows with passive multilayer coatings can allow less energy to be used when maintaining comfortable indoor temperatures. As a type of effective solar energy management, these coatings can prevent the generation of excessive heat inside buildings or vehicles by reflecting near-infrared solar radiation (750-2000 nm) while retaining visible light transmission (400-750 nm) over a large range of viewing angles. To prevent overheating, they must also reflect rather than absorb near-infrared radiation. A transparent heat-shielding window is numerically and experimentally demonstrated in this study. High visual transparency (77.2%), near-infrared reflectance (86.1%), and low infrared absorption (<20%) over a wide range of oblique incident angles were achieved using nanometer-scale cross-shaped metamaterials manufactured by electron beam lithography. Furthermore, high terahertz transmittance (up to 82%) was also achieved for 6G communication system applications.

Reconfigurable THz metamaterial based on microelectromechanical cantilever switches with a dimpled tip

We numerically and experimentally proposed a reconfigurable THz metamaterial (MM) by employing microelectromechanical cantilevers into a ladder-shaped MM (LS-MM). A fixed-free cantilever array with a dimpled tip behaved as Ohmic switches to reshape the LS-MM so as to actively regular the transmission response of THz waves. The cantilever tip was designed to be a concave dimple to improve the operational life without sacrificing the mechanical resonant frequency (fmr), and a fmr of 635 kHz was demonstrated. The device actively achieved a 115-GHz change in transmittance resonant frequency and a 1.82-rad difference in transmission phase shift, which can practically benefit advancing THz applications such as fast THz imaging and 6 G communications.

Micro-fabricated Si subwavelength grating for frequency-domain THz beam steering covering the 0.3-0.5 THz frequency band

We designed and fabricated beam steering subwavelength grating (BS-SWG) with high efficiency, wide angles, and broadband beam steering in the terahertz (THz) range. Beam steering technology in the THz range by a fixed structure and frequency sweep has to date lacked a device combining high efficiency and a wide beam steering angle. A subwavelength structure using float zone Si, a low-loss dielectric, could combine both of these aspects, but no experimental demonstration in the THz range has been performed to our knowledge. The BS-SWG was designed with an efficiency of 0.708 at 0.4 THz and beam steering angles of -72.1°--34.8° by sweeping the incident frequency from 0.3 THz to 0.5 THz including the Beyond 5 G/6 G communication bands. An efficiency of 0.354 at 0.400 THz and beam steering angles of -74°--34° were experimentally achieved, demonstrating the potential of high-efficiency, wide-angle beam steering for THz communications, imaging, and radar applications.

Improvement of imaging performance of silicon micropore X-ray optics by ultra long-term annealing

We have been developing a light-weight X-ray telescope using micro electro mechanical systems technologies for future space missions. Micropores of 20 µm width are formed in a 4-inch Si wafer with deep reactive ion etching, and their sidewalls are used as X-ray reflection mirrors. The flatness of the sidewall is an important factor to determine the imaging performance, angular resolution. It is known that hydrogen annealing is effective to smooth a Si surface. We tested 150 hour annealing to achieve the ultimately smooth sidewalls. After 50 hour, 100 hour, and 150 hour annealing, the angular resolution improved 10.3, 4.0, and 2.6 arcmin in full width at half maximum (FWHM) and 17.0, 14.5, and 10.8 arcmin in half-power width (HPW). In spite of this improvement, the edge shapes of the sidewall were rounded. Therefore, both edges of the sidewall were ground and polished, and then the angular resolution was improved further to 3.2 arcmin (FWHM) and 5.4 arcmin (HPW).

Actively tunable THz filter based on an electromagnetically induced transparency analog hybridized with a MEMS metamaterial

Electromagnetically induced transparency (EIT) analogs in classical oscillator systems have been investigated due to their potential in optical applications such as nonlinear devices and the slow-light field. Metamaterials are good candidates that utilize EIT-like effects to regulate optical light. Here, an actively reconfigurable EIT metamaterial for controlling THz waves, which consists of a movable bar and a fixed wire pair, is numerically and experimentally proposed. By changing the distance between the bar and wire pair through microelectromechanical system (MEMS) technology, the metamaterial can controllably regulate the EIT behavior to manipulate the waves around 1.832 THz, serving as a dynamic filter. A high transmittance modulation rate of 38.8% is obtained by applying a drive voltage to the MEMS actuator. The dispersion properties and polarization of the metamaterial are also investigated. Since this filter is readily miniaturized and integrated by taking advantage of MEMS, it is expected to significantly promote the development of THz-related practical applications such as THz biological detection and THz communications.

Surface-plasmon-coupled optical force sensors based on metal-insulator-metal metamaterials with movable air gap

We proposed surface-plasmon-coupled optical force sensors based on metal–insulator–metal (MIM) metamaterials with a movable air gap as an insulator layer. The MIM metamaterial was composed of an air gap sandwiched by a metal nanodot array and a metal diaphragm, the resonant wavelength of which was red-shifted when the air gap was narrowed by applying a normal force. We designed and fabricated a prototype of the proposed sensor and confirmed that the MIM metamaterial could be used as a force sensor with larger sensitivity than a force sensor based on Fabry-Pérot interferometer (FPI).

P44 Impact of the distal radial artery approach in nursing service

Background

The distal transradial approach (dTRA) is a newly developed technique expected to reduce bleeding and other complications, such as occlusions, arising from the nature of the puncture site during transradial access. However, there is a paucity of data with regard to the nursing workload during or after achieving hemostasis. The present study aimed to evaluate the workload of the nursing service associated with dTRA in patients undergoing diagnostic coronary angiography (CAG).

Methods

 Two-hundred patients who underwent CAG using a 4-Fr sheath system in our hospital between October 2017 and September 2018 were enrolled in the study. Of the total, 100 patients underwent dTRA for CAG (dTRA group), and the other 100 patients underwent the conventional transradial approach (TRA) for CAG (TRA group). After CAG, continuous compression was performed for 3 hours in the TRA group using a TR Band™, which is a hemostasis device for TRA, to remove 2 ccs and 3 ccs of air at 30 and 120 minutes, respectively. If bleeding occurred, 1 to 2 ccs were replaced using the band, followed by a wait time of 15 minutes. Similarly, continuous compression was performed in the dTRA group usingSTEPTY™, a compression tape with a 6-mm-thick pad at the central portion, and the patient’s arm was wrapped in an elastic bandage for 2 hours after CAG. We compared the dTRA and TRA groups in terms of nursing workload associated with the achievement of hemostasis and the complications related to the puncture site.

Results

The nursing-service workload associated with the management of hemostasis, including the nursing hours, the time taken to measure vitals, and the recording times were found to be significantly shorter for the dTRA group compared to that of the TRA group (2.1 ± 0.5 vs 4.1 ± 0.7 times, p &lt; 0.001; 2.1 ± 0.4 vs 4.1 ± 0.7 times, p &lt; 0.001; 2.1 ± 0.4 vs 4.1 ± 0.6 times, p &lt; 0.001, respectively). Further, the number of cases requiring treatment for bleeding was fewer in the dTRA group than in the TRA group (3 vs 12 cases, p &lt; 0.05).

Conclusions

The workload of the nursing service associated with achieving hemostasis in the dTRA group was significantly lower compared to that in the TRA group. The introduction of dTRA for routine coronary catheterization possibly help in reducing the complications and the nursing workload in daily nursing practices.

Spectral and angular shaping of infrared radiation in a polymer resonator with molecular vibrational modes

We present a comprehensive approach for tailoring the spectral and angular properties of infrared thermal radiation by using a polymer resonator with molecular vibrational modes, consisting of a polymer thin film on a back-reflective substrate. To precisely design the resonator, we derived the infrared dielectric function of a poly(methyl methacrylate) (PMMA) thin film from the measured reflectance spectrum by fitting it with a Gaussian-convoluted Drude-Lorentz model while accounting for the inhomogeneous broadening caused by the disordered structure of polymers. Our experimental and numerical characterization confirms that the polymer resonator exhibits spectral shaping from quasi-broadband to narrowband due to the intrinsic molecular vibrational absorption of the polymer. The frequency-isolated and strong molecular vibrational absorption of the carbonyl stretching mode at 1730 cm^-1 enables the narrowband shaping of the PMMA resonator. In addition, we confirm that the angular-shaping characteristics of this polymer resonator can be tuned, from omnidirectional to strongly angular selective, by changing its polymer film thickness. Modal dispersion analysis reveals that the angle-selectivity of the polymer resonator at an angle of incidence of 80° comes from coupling between the molecular vibrational mode and leaky mode. The proposed infrared radiation management strategy based on molecular vibrational modes of polymers is cost-effective, scalable, and works well with terrestrial matter, including organic compounds and gas molecules, showing promise for applications such as optical gas sensing and radiative thermal management.

Emission wavelength tuning of fluorescence by fine structural control of optical metamaterials with Fano resonance

We demonstrated fine emission wavelength tuning of quantum dot (QD) fluorescence by fine structural control of optical metamaterials with Fano resonance. An asymmetric-double-bar (ADB), which was composed of only two bars with slightly different bar lengths, was used to obtain Fano resonance in the optical region. By changing the short bar length of ADB structures with high dimensional accuracy in the order of 10 nm, resonant wavelengths of Fano resonance were controlled from 1296 to 1416 nm. Fluorescence of QDs embedded in a polymer layer on ADB metamaterials were modified due to coupling to Fano resonance and fine tuning from 1350 to 1376 nm was observed. Wavelength tuning of modified fluorescence was reproduced by analysis using absorption peaks of Fano resonance. Tuning range of modified fluorescence became narrow, which was interpreted by a simple Gaussian model and resulted from comparable FWHM in QD fluorescence and Fano resonant peaks. The results will help the design and fabrication of metamaterial devices with fluorophores such as light sources and biomarkers.

Demonstration of sharp multiple Fano resonances in optical metamaterials

We experimentally demonstrated multiple Fano resonances in optical metamaterials. By combination of two different sized asymmetric-double-bar (ADB) structures, triple Fano resonance was observed in the near-infrared region. In addition to Fano resonance due to anti-phase modes in isolated ADB structures, an anti-phase mode due to coupling among different sized ADBs was observed. Dependence of characteristics of resonances on size difference was also investigated. At specific conditions of size difference, quality factors of three Fano resonances were improved compared with ADB metamaterials consisting of one kind of ADBs. The results will help to realize applications using metamaterial resonators with multiple functionalities and high performance.

Reflection color filters of the three primary colors with wide viewing angles using common-thickness silicon subwavelength gratings

We fabricated reflection color filters of the three primary colors with wide viewing angles using silicon two-dimensional subwavelength gratings on the same quartz substrate. The grating periods were 400, 340, and 300 nm for red, green, and blue filters, respectively. All of the color filters had the same grating thickness of 100 nm, which enabled simple fabrication of a color filter array. Reflected colors from the red, green, and blue filters under s-polarized white-light irradiation appeared in the respective colors at incident angles from 0 to 50°. By rigorous coupled-wave analysis, the dimensions of each color filter were designed, and the calculated reflectivity was compared with the measured reflectivity.

Experimental demonstration of sharp Fano resonance in optical metamaterials composed of asymmetric double bars

We experimentally demonstrated Fano resonance in metamaterials composed of asymmetric double bars (ADBs) in the optical region. ADB metamaterials were fabricated by a lift-off method, and the optical spectra were measured. Around a wavelength of 1100 nm, measured optical spectra clearly showed sharp Fano resonance due to weak asymmetry of the ADB structures. The highest-quality factor (Q-factor) of the Fano resonance was 7.34. Calculated spectra showed the same tendency as the experimental spectra. Moreover, in a Fano resonant condition, out of phase of induced current flowing along each bar was revealed by electromagnetic field calculations. These antiphase currents decreased radiative loss of the Fano mode, resulting in a high Q-factor of the Fano resonance in ADB metamaterials. As the degree of asymmetry became small, the Q-factor decreased, and the Fano resonance disappeared because the effect of Joule loss became significant.

Comparison of electromagnetically induced transparency between silver, gold, and aluminum metamaterials at visible wavelengths

Electromagnetically induced transparency (EIT)-like effects in silver, gold, and aluminum metamaterials consisting of dipole resonators and quadrupole resonators were demonstrated at visible wavelengths. Optical characteristics of the metamaterials could be controlled by the gap distance between the two resonators. EIT-like effects were observed at wavelengths between 603 and 789 nm, 654 and 834 nm, and 462 and 693 nm for the silver, gold, and aluminum EIT metamaterials, respectively. At wavelengths longer than around 650 nm, the silver metamaterials had better EIT-like features. At wavelengths shorter than around 650 nm, on the other hand, the aluminum metamaterials showed promising EIT-like results.

Fabrication of antireflection subwavelength gratings at the tips of optical fibers using UV nanoimprint lithography

Antireflection (AR) layers at the tips of optical fibers are indispensable in high efficiency and low noise applications. We realized the AR structures with two-dimensional binary subwavelength gratings (SWGs) at the tips of optical fibers by using a dedicated UV nanoimprint machine. Using this technique, ideal AR structures with desired refractive indices can be realized at low cost in principle. The SWG with the period of 700 nm was fabricated at the tip of a single-mode optical fiber for optical communications system. The reflectance was decreased to less than 0.27% at measured wavelengths between 1460 nm and 1580 nm.

Minimally invasive removal of a recurrent lumbar herniated nucleus pulposus by the small incised microendoscopic discectomy interlaminar approach

In this report, we introduce two cases of recurrent herniated nucleus pulposus (HNP) at L5-S1 that were successfully removed using the small incised microendoscopic discectomy (sMED) technique, proposed by Dezawa and Sairyo in 2011. sMED was performed via the interlaminar approach with a percutaneous endoscope. The patients had previously underdone microendoscopic discectomy for HNP. For the recurrent HNP, the sMED interlaminar approach was selected because the HNP occurred at the level of L5-S1; the percutaneous endoscopic transforaminal approach was not possible for anatomical reasons. To perform sMED via the interlaminar approach, we employed new, specially made devices to enable us to use this technique. In conclusion, sMED is the most minimally invasive approach available for HNP, and its limitations have been gradually eliminated with the introduction specially made devices. In the near future, percutaneous endoscopic surgery could be the gold standard for minimally invasive disc surgery.

Ultra-small silicon waveguide coupler switch using gap-variable mechanism

Submicron-wide silicon waveguide coupler with gap variable mechanism is proposed for a compact optical waveguide switch. Two freestanding silicon waveguides are placed parallel with a submicron gap. The gap is changed by electrostatic comb-drive micro-actuators to control the coupling coefficient of the coupler. The fabricated device consisted of the silicon waveguides of 400 nm in width and 260 nm in thickness. The total size of the switch was 100 μm wide and 150 μm long. Decreasing the gap between the waveguides to 110 nm, the output intensity at drop port became a maximum while the output intensity at through port became a minimum. The extension ratio of the switch output was 17 dB for the waveguide displacement of 300 nm.

Photoinduced change in the spin state of itinerant correlated electron systems

A photoinduced spin-state change in the itinerant correlated electron system is studied. A photon introduced in the low-spin band insulator induces a bound state of the high-spin state and a photoexcited hole. This bound state brings a characteristic peak in the pump-probe optical absorption spectra which are completely different from the spectra in thermal-excited states. The present results well explain the recent experiments of the ultrafast optical spectroscopy in perovskite cobaltites.

III-Nitride grating grown on freestanding HfO2 gratings

We report here the epitaxial growth of III-nitride material on freestanding HfO2 gratings by molecular beam epitaxy. Freestanding HfO2 gratings are fabricated by combining film evaporation, electron beam lithography, and fast atom beam etching of an HfO2 film by a front-side silicon process. The 60-μm long HfO2 grating beam can sustain the stress change during the epitaxial growth of a III-nitride material. Grating structures locally change the growth condition and vary indium composition in the InGaN/GaN quantum wells and thus, the photoluminescence spectra of epitaxial III-nitride grating are tuned. Guided mode resonances are experimentally demonstrated in fabricated III-nitride gratings, opening the possibility to achieve the interaction between the excited light and the grating structure through guided mode resonance.PACS: 78.55.Cr; 81.65.Cf; 81.15.Hi.

Pain in neuromyelitis optica and its effect on quality of life: a cross-sectional study

OBJECTIVE

To assess the features of pain and its impact on the health-related quality of life (HRQOL) in neuromyelitis optica (NMO).

METHODS

We analyzed 37 patients with NMO or NMO spectrum disorders seen at the Department of Neurology, Tohoku University Hospital, Sendai, Japan, during the period from November 2008 to February 2009. A total of 35 of them were aquaporin-4 antibody-positive. We used Short Form Brief Pain Inventory (BPI) to assess pain and Short Form 36-item (SF-36) health survey to evaluate the HRQOL. Fifty-one patients with multiple sclerosis (MS) were also studied for comparison.

RESULTS

Pain in NMO (83.8%) was far more common than in MS (47.1%). The Pain Severity Index score in BPI was significantly higher in NMO than in MS, and patients' daily life assessed by BPI was highly interfered by pain in NMO as compared with MS. Pain involving the trunk and both legs was much more frequent in NMO than in MS. SF-36 scores in NMO were lower than MS, especially in bodily pain.

CONCLUSION

Our study showed that pain in NMO is more frequent and severe than in MS and that pain has a grave impact on NMO patients' daily life and HRQOL. Therapy to relieve pain is expected to improve their HRQOL.

Freestanding HfO2 grating fabricated by fast atom beam etching

We report here the fabrication of freestanding HfO2 grating by combining fast atom beam etching (FAB) of HfO2 film with dry etching of silicon substrate. HfO2 film is deposited onto silicon substrate by electron beam evaporator. The grating patterns are then defined by electron beam lithography and transferred to HfO2 film by FAB etching. The silicon substrate beneath the HfO2 grating region is removed to make the HfO2 grating suspend in space. Period- and polarization-dependent optical responses of fabricated HfO2 gratings are experimentally characterized in the reflectance measurements. The simple process is feasible for fabricating freestanding HfO2 grating that is a potential candidate for single layer dielectric reflector.PACS: 73.40.Ty; 42.70.Qs; 81.65.Cf.

Investigation of strain sensing effect in modified single-defect photonic crystal nanocavity

This paper reports the theoretical and experimental investigations on the strain sensing effect of a two dimensions (2D) photonic crystal (PhC) nanocavity resonator. By using the finite element method (FEM) and finite difference time domain (FDTD) simulations, the strain sensitivity of a high quality factor PhC nanocavity was calculated. Linear relationships between the applied strain and the shift in the resonant wavelength of the cavity were obtained. A single-defect silicon (Si) PhC cavity was fabricated, and measurements of the strain sensitivity were performed. Good agreement between the experimental and simulation results was observed.

Endoscopic removal of herniated nucleus pulposus migrated dorsally to the dural sac

A herniated nucleus pulposus (HNP) migrated dorsally to the dural sac is a rare condition. Here, we present a case, in which the HNP was removed with minimally invasive spinal endoscopy. A 54-year-old man presented complaining of left leg pain and paresis. Neurologic findings and an MRI suggested an epidural tumor or a dorsally migrated HNP compressing the S1 nerve root and dural sac. With a spinal endoscope, careful laminotomy of caudal L5 and cranial S1 was made. En bloc flavectomy exposed a mass covered with a thin capsule. The mass was identified as a dorsally migrated HNP. After complete HNP fragment removal, the dural sac and S1 nerve root were decompressed. Immediately postoperative, the leg pain subsided and motor function normalized, although the patient complained of numbness at the S1 dermatome area. In summary, a large HNP that had migrated dorsally to the dural sac was successfully removed endoscopically.

Structural analyses of high-pressure and high-temperature treated double-walled carbon nanotubes

This paper reports the structural properties of the high-pressure and high-temperature (HPHT) treated double-walled carbon nanotubes (DWCNTs) based on Raman, XRD and TEM experiments. It was found that the DWCNTs are more stable toward HPHT treatment than the single-walled carbon nanotubes (SWCNTs). We propose that this is probably because the DWCNTs tend not to be deformed by compression and thereby they are less reactive under pressure compared to SWCNTs.

Phase-shifter using submicron silicon waveguide couplers with ultra-small electro-mechanical actuator

Phase shifter is an important part of optical waveguide circuits as used in interferometer. However, it is not always easy to generate a large phase shift in a small region. Here, a variable phase-shifter operating as delay-line of silicon waveguide was designed and fabricated by silicon micromachining. The proposed phase-shifter consists of a freestanding submicron-wide silicon waveguide with two waveguide couplers and an ultrasmall silicon comb-drive actuator. The position of the freestanding waveguide is moved by the actuator to vary the total optical path. Phase-shift was measured in a Mach-Zehnder interferometer to be 3.0pi at the displacement of 1.0 mum at the voltage of 31 V. The dimension of the fabricated device is 50microm wide and 85microm long.

Large area, freestanding GaN nanocolumn membrane with bottom subwavelength nanostructure

We propose, fabricate and characterize the freestanding GaN nanocolumn membrane with bottom subwavelength nanostructures. The GaN nanocolumns are epitaxially grown on freestanding nanostructured silicon substrate that is achieved by a combination of self-assemble technique and silicon-on-insulator (SOI) technology. Optical reflection is greatly suppressed in the visible range due to the graded refractive index effect of subwavelength nanostructures. The freestanding GaN nanocolumn membrane is realized by removing silicon substrate from the backside, eliminating the silicon absorption of the emitted light and leading to a strong blue emission from the bottom side. The obtained structures also demonstrate the potential application for anti-reflective (AR) coating and GaN-Si hybrid microelectromechanical system (MEMS).

Fabrication and characterization of subwavelength nanostructures on freestanding GaN slab

We develop a novel way to fabricate subwavelength nanostructures on the freestanding GaN slab using a GaN-on-silicon system by combining self-assemble technique and backside thinning method. Silicon substrate beneath the GaN slab is removed by bulk silicon micromachining, generating the freestanding GaN slab and eliminating silicon absorption of the emitted light. Fast atom beam (FAB) etching is conducted to thin the freestanding GaN slab from the backside, reducing the number of confined modes inside the GaN slab. With self-assembled silica nanospheres acting as an etching mask, subwavelength nanostructures are realized on the GaN surface by FAB etching. The reflection losses at the GaN interfaces are thus suppressed. When the InGaN/GaN multiple quantum wells (MQWs) active layers are excited, the light extraction efficiency is significantly improved for the freestanding nanostructured GaN slab. This work provides a very practical approach to fabricate freestanding nanostructures on the GaN-on-silicon system for further improving the light extraction efficiency.

Dynamical coupling and separation of multiple degrees of freedom in a photoexcited double-exchange system

We present a theory of ultrafast photoinduced dynamics in a spin-charge coupled system, motivated by pump-probe experiments in perovskite manganites. A microscopic picture for multiple dynamics in spin and charge degrees is examined. Real-time simulations are carried out by two complimentary methods. Our calculation demonstrates that electron motion governs a short-time scale where charge and spin dynamics are combined strongly, while, in a long-time scale controlled by spin relaxation, the charge sector does not follow the remarkable change in the spin sector. The present results are in contrast to a conventional double-exchange picture in equilibrium states.

Fabrication and characterization of nanoscale resonant gratings on thin silicon membrane

We report the design and fabrication of nanoscale resonant gratings which is of interest for narrow bandwidth filtering application. The linear/circular grating structures, of which the grating width is 200nm and the grating height is 260nm, are generated on silicon-on-insulator wafer. Nanoscale gratings are fabricated on the silicon device layer by a combination of electron beam lithography and fast atom beam etching. The silicon handle layer under grating region is removed by deep reactive ion etching, and the buried oxide layer is kept. The reflectance measurements are performed to characterize the optical response of fabricated freestanding nanoscale gratings. The resonant behavior of linear gratings agrees with the theoretical predication, and the polarization-independent responses of circular gratings are also experimentally demonstrated.

Pitch-variable blazed grating consisting of freestanding silicon beams

Theoretical analysis is presented for a pitch-variable blazed grating which consists of freestanding silicon beams. The pitch-variable blazed grating is implemented by combining silicon-on-insulator (SOI) technology with microelectronicmechanical system (MEMS) technology. The whole device is fabricated on a 10 microm silicon device layer to guarantee sufficient stiffness. The 4-level blazed surface profile is realized by combining a two-mask process with fast atom beam etching. Electrostatic combdrive microactuators with double folded springs are proposed to stretch the freestanding grating beams. In association with reactive ion etching and vapor HF release, the freestanding grating beams and the microactuators are obtained, and a Cr/Au film is deposited onto the blazed grating surfaces by a protective mask process to improve the diffracted power. Mechanical response and diffraction efficiency of fabricated devices are characterized and the experimental results indicate that the fabricated 4- level blazed gratings extend both the tuning range and the diffraction efficiency of the 1st diffraction order of present MEMS diffraction gratings.

A wavelength-selective add-drop switch using silicon microring resonator with a submicron-comb electrostatic actuator

Electrostatic comb-drive micro actuator with submicron comb fingers was connected to silicon microring resonator to consist a wavelength-selective add-drop switch at 1.5 microm wavelength with variable coupling mechanism. A 500 nm wide 260 nm thick 63.4 microm long silicon microring waveguide was suspended in air with low-loss suspension arms. The air gap between the microring and the input/output waveguides was adjusted by the voltage applied to the comb actuator to vary the coupling efficiency. Transmittance from the input port to a drop port was varied 32.9dB by applying the voltages from 0V to 28.2V. At 28.2V, transmittance from the input port to a through port decreased by 7.83 dB from that at 0V, and 55% of the intensity was transmitted to the drop port. The full-width-half-maximum bandwidth of the dropped light was 0.5 nm, corresponding to a Q-value of 3150.

Expression of hypoxia-inducible factor 1alpha gene affects the outcome in patients with ovarian cancer

We conducted study to determine whether and how the expression of the hypoxia-inducible factor 1alpha (HIF-1alpha) gene relates to outcome in patients with epithelial ovarian cancer. A total of 66 patients with epithelial ovarian cancer, who underwent primary surgery followed by platinum-based chemotherapy, were entered into this study. We confirmed the expression of HIF-1alpha and the vascular endothelial growth factor (VEGF) by immunohistochemistry. To determine the quantity of HIF-1alpha and VEGF expression, messenger RNA of each gene was measured by real-time reverse transcription-polymerase chain reaction. The cutoff values were determined by the receiver-operating characteristic curve according to survival. The protein expressions of HIF-1alpha and VEGF were strongly observed in the cancer cells. The cutoff value of HIF-1alpha and VEGF gene expression was 6.0 and 3.0, respectively. The expression of HIF-1alpha did not relate to clinical stage, but tumor with low VEGF expression was observed more frequently in stage I patients. The response rate to chemotherapy did not differ between high and low expression of both genes. The overall survival for patients with high expression of HIF-1alpha was significantly lower, but disease-free survival did not differ between high and low expression of HIF-1alpha, whereas both overall and disease-free survival for patients with high expression of VEGF were significantly lower. Multivariate analysis revealed that FIGO stage and HIF-1alpha expression were independent prognostic factors but that VEGF was not. The present study suggested that the expression level of HIF-1alpha could be an independent prognostic factor in epithelial ovarian cancer.

A 100 nm thick InGaN/GaN multiple quantum-well column-crystallized thin film deposited on Si(111) substrate and its micromachining

A 100 nm thick InGaN/GaN multiple quantum-well column-crystallized thin film was deposited on Si(111) substrate, with InN as the interlayer, by molecular beam epitaxy. The diameter of the column crystal is about 40 nm. Transmission electron microscopy images showed clear five-period well layers. Photoluminescence measurements demonstrated a wide emission wavelength from about 500 to 800 nm with the full width at half maximum of 107 nm at room temperature. An unusual photoluminescence peak position shift was observed from the optical measurement. The selected area electron diffraction image demonstrated the hexagonal wurtzite structure of the column crystal. A self-supported GaN-based active subwavelength grating was proposed, and the active subwavelength grating structure was fabricated from the InGaN/GaN quantum-well thin film by a Si micromachining process.

Effect of simultaneous inhibition of MEK and PI3K/Akt pathways on paclitaxel sensitivity in ovarian cancer

16046

Background: Paclitaxel (PTX) is one of the key drugs for ovarian cancer treatment. PTX activates the Raf-mitogen-activated protein kinase kinase (MEK) and phosphatidylinositol 3’-kinase (PI3K) pathways that lead to cell survival pathways. The purpose of this study was to clarify whether and how the inhibitors of MEK and/or PI3K affect the sensitivity to PTX in ovarian cancer cells. Methods: We treated five ovarian cancer cell lines in combination with PTX and MEK- [PD98059 (PD)] and/or PI3K-inhibitor [LY294002 (LY)] and assessed cell viability, apoptosis, and the expression of phosphorylated (p) MEK and pAkt. The sensitivity of the cell lines to PTX was determined by 3-(4,5- dimethylthiazol-2-yl) -2,5-dyphenyltetrazolium bromide (MTT) assay. The level of protein expression was analyzed by western blot analysis. The drug-induced apoptosis was assessed by Annexin V-FITC staining. Additionally, KOC-2S was injected to intraperitoneal cavity of nude mouse. The effect of combined treatment on the survival in xenograft model was investigated. Results: The levels of pMEK and pAkt protein expression were higher in PTX resistant cell lines (KOC-2S and KFTx) than that in sensitive cell lines (KF, SHIN-3, SK-OV-3). Treatment of PTX induced MEK activation in all five ovarian cancer cell lines. The combination of PTX with either PD or LY led to additive effect on cell growth inhibition. In contrast, synergistic effect was observed in the combination of PTX with PD and LY. Furthermore, apoptotic cells were significantly increased after exposure to PTX and both inhibitors in comparison with other treatment conditions, such as PTX alone, PTX with either PD or LY. The level of pMEK induced by PTX was down-regulated by PD. Interestingly, the level of pAkt was up-regulated by the combination of PTX with PD, which was reduced by LY. Treatment with PTX, PD, and LY prolonged survival in an ovarian cancer xenograft model (p < 0.01). Conclusions: The present study suggests that simultaneous inhibition of MEK and PI3K/Akt pathways enhances the sensitivity to PTX in ovarian cancer. The combination of PTX with MEK- and PI3K-inhibitor may be a new treatment strategy for ovarian cancer.

No significant financial relationships to disclose.

Galectin-3 may contribute to Cisplatin resistance in clear cell carcinoma of the ovary

Our previous findings suggested that lower cell proliferation of clear cell carcinoma (CCC) of the ovary may contribute to its resistance to chemotherapy. We conducted the present study to find the gene that regulates cell proliferation of CCC and to elucidate whether it contributes to cisplatin (CDDP) resistance. Complementary DNA microarray analysis revealed that the gene expression level of galectin-3 of CCC cell lines (KK, RMG-I, HAC-2) was over threefold higher than that of ovarian serous adenocarcinoma (SAC) cell lines (HRA, KF). S-phase fraction increased after knocking down galectin-3 using small interfering RNA in RMG-I, KK, and HAC-2 cells. The protein expression of p27 decreased after knocking down galectin-3. CDDP-induced apoptosis was increased after knocking down galectin-3, and this cytotoxic effect was canceled by roscovitine. Immunohistochemical staining showed that galectin-3 expression in tumors of 20 CCC was significantly more frequent than that of 20 SAC (70.0% vs 15.0%, P = 0.0004). The present study showed that the expression of galectin-3 in CCC might contribute to its lower cell proliferation and lead to CDDP resistance.

Genetic diagnosis for chemosensitivity with drug-resistance genes in epithelial ovarian cancer

We conducted the present study to investigate whether and how chemosensitivity can be determined by means of genetic diagnosis using drug-resistance genes in patients with epithelial ovarian cancer. A total of 75 patients who had epithelial ovarian cancer with measurable lesions were entered into this study. Thirty-three patients received first-line chemotherapy, consisting of paclitaxel and carboplatin (TJ). Forty-two patients received second-line chemotherapy, 22 received EP therapy consisting of etoposide and cisplatin (CDDP), and 20 received irinotecan (CPT-11) and CDDP (CPT-11/CDDP) therapy. Tumor samples were obtained before chemotherapy. MessengerRNA expressions of the multidrug-resistance (MDR)-1 gene, MDR-associated protein-1 (MRP-1), topoisomerase (topo) I, and topo IIalpha were measured by real-time reverse transcription-polymerase chain reaction. The cutoff values of each gene were determined by the receiver operating characteristic curve. MDR-1 expression was significantly higher in patients who did not respond to TJ therapy. The expression of topo IIalpha was significantly higher in patients who did respond to EP therapy. The expression of topo I was significantly higher in patients who did respond to CPT-11/CDDP. MRP-1 expression did not differ between responders and nonresponders in all regimens. The cutoff value was 80 for MDR-1, 90 for topo IIalpha, and 200 for topo I. Next, to evaluate genetic diagnosis, 31 patients were newly added. The accuracy of this genetic diagnosis for chemosensitivity was 85.7% for TJ, 77.8% for EP, and 100.0% for CPT-11/CDDP therapy. The present study suggests that genetic diagnosis may be useful to determine chemosensitivity in patients with epithelial ovarian cancer.

Feasibility study comparing docetaxel-cisplatin versus docetaxel-carboplatin as first-line chemotherapy for ovarian cancer

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Background: The carboplatin-paclitaxel combination therapy is a gold standard regimen for patients with ovarian cancer. However, combination chemotherapy continues to produce significant neurotoxicity, a serious adverse effect. We conducted the present study to determine the feasibility of docetaxel-cisplatin combination therapy compared with docetaxel-carboplatin combination therapy as first-line chemotherapy for patients with ovarian cancer. Methods: Fifty patients with International Federation of Gynecology and Obstetrics stage Ic-IV ovarian cancer who underwent primary surgery were randomly assigned to receive treatment with docetaxel-cisplatin (n = 23) or docetaxel-carboplatin (n = 27). Docetaxel 70 mg/m2 and cisplatin 60 mg/m2 or carboplatin to an area under the curve = of 5 were administered consecutively on Day 1 of a 3-week cycle, for 3 cycles in patients with stage Ic-II cancer and for over 5 cycles in patients with stage III-IV cancer. Patients were evaluated for treatment-related toxicity in each cycle using the National Cancer Institute Common Toxicity Criteria version 2.0. Results: Five patients (2 in the docetaxel-cisplatin arm and 3 in the docetaxel-carboplatin arm) discontinued the treatment at the end of the second course of chemotherapy because of apparent disease progression; however, no patients came off the protocol therapy because of treatment-related toxicity. Overall, 103 cycles of docetaxel-cisplatin treatment and 130 cycles of docetaxel-carboplatin treatment were delivered. The major toxicity was neutropenia in both regimens. The total incidence of grades 3 and 4 neutropenia was 83% (19/23) in the docetaxel-cisplatin arm and 96% (26/27) in the docetaxel-carboplatin arm. The incidence of grade 4 neutropenia was significantly lower in the docetaxel-cisplatin arm [39% (9/23) vs. 74% (20/27)]. Conclusions: Docetaxel-cisplatin combination therapy may be feasible as first-line chemotherapy for patients with ovarian cancer.

No significant financial relationships to disclose.

Outcome of patients with early ovarian cancer undergoing three courses of adjuvant chemotherapy following complete surgical staging

We conducted the present study to determine the outcome of patients with early ovarian cancer who underwent three courses of adjuvant chemotherapy after complete surgical staging. One hundred consecutive patients with stage I-II epithelial ovarian cancer who had undergone complete surgical staging and received three courses of platinum-based chemotherapy were entered in this study. Twenty-one patients were low risk, defined as stage IA-B, grade 1 and histologic types except for clear cell adenocarcinoma, and remaining 79 were high risk. All patients with stage IA or IB, whatever histologic type and histopathologic grade, were alive without disease. The 5-year survival rate was 89.4% for patients with stage IC and 76.2% for those with stage II. The 5-year survival rate for low- and high-risk patients was 100% and 89.4%, respectively. The survival rate for grade 1 was significantly better than that for grade 2 or 3. Multivariate analysis revealed that histologic grade was an independent prognostic factor in stage IC-II ovarian cancer. The outcome of patients with early ovarian cancer undergoing three courses of chemotherapy after complete surgical staging was favorable even in high-risk patients.

Numerical study on spectral properties of tungsten one-dimensional surface-relief gratings for spectrally selective devices

Spectral properties of one-dimensional tungsten gratings with various depths and widths of grooves were investigated by means of finite-difference time-domain simulation with a multi-Lorentz model. Shallow gratings showed a strong absorption peak due to surface plasmon polaritons when the oscillation of the electric field was parallel to the grating vector. On the other hand, deep gratings with wide grooves showed a different absorption attributed to the microcavity effect when the oscillation of the electric field was perpendicular to the grating vector. With narrowed grooves, another absorption with d-dependence occurred, which was probably due to vertically oscillating surface plasmons to the grooves.

Outcome of patients with early ovarian cancer undergoing three courses of adjuvant chemotherapy following complete surgical staging

We conducted the present study to determine the outcome of patients with early ovarian cancer who underwent three courses of adjuvant chemotherapy after complete surgical staging. One hundred consecutive patients with stage I–II epithelial ovarian cancer who had undergone complete surgical staging and received three courses of platinum-based chemotherapy were entered in this study. Twenty-one patients were low risk, defined as stage IA–B, grade 1 and histologic types except for clear cell adenocarcinoma, and remaining 79 were high risk. All patients with stage IA or IB, whatever histologic type and histopathologic grade, were alive without disease. The 5-year survival rate was 89.4% for patients with stage IC and 76.2% for those with stage II. The 5-year survival rate for low- and high-risk patients was 100% and 89.4%, respectively. The survival rate for grade 1 was significantly better than that for grade 2 or 3. Multivariate analysis revealed that histologic grade was an independent prognostic factor in stage IC–II ovarian cancer. The outcome of patients with early ovarian cancer undergoing three courses of chemotherapy after complete surgical staging was favorable even in high-risk patients

Hormonal control of a metamorphosis-specific transcriptional factor Broad-Complex in silkworm

Insect metamorphosis is induced by the steroid 20-hydroxyecdysone (20E) in the absence of sesquiterpenoid juvenile hormone (JH). In Drosophila melanogaster, the Broad-Complex (BR-C) transcriptional factor plays critical roles during metamorphosis. We isolated cDNAs encoding BR-C in the silkworm Bombyx mori and examined their mRNA expression. cDNAs for three BR-C isoforms with zinc finger pairs (Z1, Z2 and Z4) and four isoforms lacking them were cloned. Their mRNAs were expressed in multiple tissues at the larval-pupal metamorphosis. In the anterior silk gland, BR-C mRNAs were expressed at the end of the last larval instar but not expressed during the penultimate instar. 20E administration induced BR-C mRNA expression and JH suppressed 20E-induced BR-C expression in this tissue both in vivo and in vitro. Thus, BR-C mRNAs are inducible by 20E only in the absence of JH, a finding that explains their metamorphosis-specific expression.

Anterior decompression and fusion for multiple thoracic disc herniation

Multiple thoracic disc herniations are rare and there are few reports in the literature. Between December 1998 and July 2002, we operated on 12 patients with multiple thoracic disc herniations. All underwent an anterior decompression and fusion through a transthoracic approach. The clinical outcomes were assessed using the Frankel neurological classification and the Japanese Orthopaedic Association (JOA) score. Under the Frankel classification, two patients improved by two grades (C to E), one patient improved by one grade (C to D), while nine patients who had been classified as grade D did not change. The JOA scores improved significantly after surgery with a mean recovery rate of 44.8% +/- 24.5%. Overall, clinical outcomes were excellent in two patients, good in two, fair in six and unchanged in two. Our results indicate that anterior decompression and fusion for multiple thoracic disc herniations through a transthoracic approach can provide satisfactory results.

Vascular-pedicled costal cartilage graft for the treatment of subglottic and upper tracheal stenosis

BACKGROUND/PURPOSE

Free costal cartilage graft for the treatment of subglottic and tracheal stenosis is widely used, but postoperative granulation formation is a problem. To reduce the risk of granulation formation after free costal graft, a new operation of costal cartilage graft with vascular pedicle was introduced.

METHODS

A vascular pedicled fifth costal cartilage graft is prepared using internal thoracic artery and vein and intercostal artery and vein as a vascular pedicle. The prepared graft is brought to the upper trachea. The anterior wall of cricoid is split, and the costal cartilage graft is implanted to the split part and tracheostomy. Extubation on the next day is possible if the general condition of the patient permits.

RESULTS

In 3 cases of subglottic or upper tracheal stenosis, this operation was performed. All the patients had tracheostomy made during early infancy. The postoperative course was uneventful, and all the patients were extubated soon after the operation. No granulation tissue was observed by postoperative bronchoscopic examinations.

CONCLUSIONS

Costal cartilage graft with vascular pedicle is a safe and useful new operation for the treatment of subglottic and upper tracheal stenosis. There also is a possibility of using this procedure for the treatment of long segment tracheal stenosis.

[Aortic valve papillary fibroelastoma found at reoperation after open mitral commissurotomy; report of a case]

In 1982, a 63-year-old woman underwent open mitral commissurotomy for rheumatic mitral stenosis. She was referred to our hospital for surgical treatment of mitral restenosis in 2003. Preoperative echocardiography showed rheumatic mitral valve restenosis and demonstrated a mobile mass of the aortic valve. During the operation, a mitral valve replacement was performed using prosthetic valve (SJM 29 mm) and a tricuspid valve was repaired by annuroplasty (De Vega). Through the aortotomy, a multiple frond-like tumor, measuring 5 mm, was found attached to the free-edge of the left-coronary cusp of the aortic valve. The resection of the tumor was performed without valve replacement. The histopathologic diagnosis was papillary fibroelastoma. The postoperative course was uneventful. In the pathogenesis of this case, the iatrogenic factor may have played a role in tumor development.