Efficient optimal design of mosaic-like PPDW devices for THz application using the adjoint variable method.

In the development of THz-wave circuits, parallel plate dielectric waveguide (PPDW) is a promising platform and recently some fundamental devices have been reported. In order to realize high performance PPDW devices, optimal design methods are crucial and as out-of-plane radiation does not occur in PPDW, mosaic-like optimal design appears to be appropriate for PPDW platform. In this paper, we present a novel and efficient mosaic-like design approach based on gradient method with adjoint variable method (AVM) to realize high performance PPDW devices for THz circuit applications. The design variables in the design of PPDW devices are efficiently optimized by utilizing the gradient method. The mosaic structure in the design region is expressed by using density method with an appropriate initial solution. In the optimization process, AVM is employed for an efficient sensitivity analysis. The usefulness of our mosaic-like design approach is confirmed by designing several PPDW devices, T-branch, three branch, mode splitting device, and THz bandpass filter. The proposed mosaic-like PPDW devices except bandpass filter achieved high transmission efficiencies at single frequency operation as well as at broadband operation. Furthermore, the designed THz bandpass filter achieved the desired flat top transmission property at the targeted frequency band.

[Multi-Center Joint Study on the Survey of Antiemetic Therapy for the Prevention of Nausea and Vomiting in Combination Therapy with a Mild Emetic Antineoplastic Drug].

While many studies have demonstrated the prevention of nausea and vomiting in patients receiving moderately or highly emetogenic anti-cancer agents, there are few reports of mildly emetogenic anti-cancer agents. In the present study, we performed a 2-year multi-center study to determine the types and efficacy of antiemetic therapy administered in a total of 77 cancer patients who received mildly emetogenic anti-cancer agents between September 2015 and August 2017. The effectiveness of antiemetic therapy was evaluated based on the frequency of nausea and vomiting and use of rescue medication. This information was reported by patients and collected every 24 hours for 120 hours after the administration of anti-cancer agents with a mild emetogenic risk. The combination of 5-HT3 receptor antagonist(1 or 3 mg granisetron, 0.75 mg palonosetron) and 6.6 mg dexamethasone was the most common antiemetic therapy used in our patient population. There was no significant difference in the effectiveness of all 5-HT3 receptor antagonists that were evaluated. Gemcitabine and nab-paclitaxel were the most commonly used with a total of 64 patients receiving a combination of these mildly emetogenic agents. Poor performance status was associated with failure to achieve total control(TC)of nausea and vomiting(p=0.0304), while habitual alcohol consumption was associated with TC of nausea and vomiting(p=0.0331).

Design of ultra-compact triplexer with function-expansion based topology optimization.

In this paper, in order to optimize wavelength selective photonic devices using the function-expansion-based topology optimization method, several expansion functions are considered and the influence on the optimized structure based on each expansion function was investigated. Although the Fourier series is conventionally used in the function-expansion-based method, the optimized structure sometimes has a complicated refractive index distribution. Therefore, we employed a sampling function and a pyramid function to obtain a simpler structure through the optimal design. A triplexer was designed by using our method, and the comparison between the optimized structures based on the three expansion functions was also discussed in detail.

Bending loss of elliptical-hole core circular-hole holey fibers bent in arbitrary bending directions.

A holey fiber having a core with an elliptical-hole lattice structure, which is referred to as an elliptical-hole core circular-hole holey fiber (EC-CHF), can be easily designed as a single-polarization fiber by using the fundamental space-filling modes of the core and cladding lattices. However, because the guided mode in an EC-CHF has a polarization that arises from the large geometric anisotropy of the core lattice, the influence of the bending direction on the bending loss is a crucial issue for the practical implementation of EC-CHFs. Here, the bending losses of an EC-CHF bent in arbitrary angular orientations with respect to the core cross section are calculated numerically using the equivalent anisotropic step-index circular fiber model for a real EC-CHF, and the influence of the bending direction of the fiber on the bending loss is discussed.

Squeezed lattice elliptical-hole holey fiber with extremely high birefringence.

A novel highly flat elliptical-hole holey fiber with a squeezed lattice is introduced for achieving extremely high birefringence. The fiber consists of two kinds of elliptical holes with the same major axis length and different minor axis lengths for the core and cladding regions. Numerical results demonstrate a modal birefringence exceeding 0.065.

Single-mode single-polarization holey fiber using anisotropic fundamental space-filling mode.

We present the single-mode single-polarization regime of a circular-hole holey fiber consisting of a core with large elliptical holes. The elliptical holes in the core, which produce large anisotropies, split the fundamental mode into two orthogonally polarized fundamental modes, often referred to as slow and fast modes. This fiber can guide only one polarization state of the fundamental mode when a fundamental space-filling mode index of the cladding region is designed to lie between these indices of the slow and fast modes of the core region. We demonstrate one design example of this fiber and show that the single-polarization regime can be achieved over a wide wavelength range.