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Zero-mass metamaterials comprise an orifice and a thin film. The resonance between the film and the air mass of the orifice hole is caused by sound waves, which significantly decreases the transmission loss at a specific frequency. The study novelly incorporates acoustic metamaterials in the delay tube of an interference silencer. In this case, it is determined that an interference silencer and a “side-branch silencer with two different branch pipe lengths” can be realized in a single silencer. At certain frequencies, the acoustic mass of the acoustic metamaterial approaches zero, which results in an interference silencer with the full length of the delay tube applied. At other frequencies, the acoustic metamaterial acts as a rigid wall with high transmission loss, thereby reflecting sound waves at the zero-mass metamaterial location. In this case, it is a side-branch silencer with two different tube lengths, corresponding to the tube lengths from the entrance and exit of the delay tube to the zero-mass metamaterial, respectively. The incorporation of zero-mass metamaterial into an interference-type silencer can introduce the silencing effect of a side-branch silencer with two different branch tube lengths without increasing the volume of the interference-type silencer. Theoretical values were obtained using the transfer matrix. Consequently, the theoretical and experimental values were close, enabling us to predict the transmission loss of the proposed silencer. 相似文献
84.
Shuichi Ozono Naoko Maeda Jun Okamura Keiko Asami Tsuyako Iwai Kiyoko Kamibeppu Naoko Sakamoto Naoko Kakee Keizo Horibe 《Pediatrics international》2011,53(3):291-299
Background: Although more children with cancer continue to be cured, these survivors experience various late effects. Details of the medical visit behaviors of childhood cancer survivors (CCS) in adulthood remain to be elucidated. Methods: In order to examine medical visits in the past and future of CCS, we performed a cross‐sectional survey with self‐rating questionnaires on medical visits of CCS compared with control groups (their siblings and the general population). Results: Questionnaires were completed by 185 CCS, 72 of their siblings and 1000 subjects from the general population and the results were analyzed. Mean ages at this survey and the duration after therapy completions of CCS were 23 and 12 years, respectively. We found that the previous treatment hospitals (where CCS were treated for their cancer) were the most commonly visited medical facilities for the CCS group (74% for female patients and 64% for male patients) and more than half of the CCS preferred to continue visiting the previous treatment hospital with enough satisfaction in Japan. The multivariate analysis showed that female sex and relapse were significantly associated with the past visits to the previous treatment hospital and that the CCS with brain tumors or bone/soft tissue sarcomas and CCS with any late effects tended to continue the relationships with the hospital. In addition female sex was also significantly associated with desired future visits to the previous treatment hospital. On the other hand, the married CCS tended to be disinclined to visit the hospital it in the future. Conclusions: In order to optimize risk‐based care and promote health for CCS after adulthood, we should discuss the medical transition with CCS and their parents. 相似文献
85.
The present investigation focused on the transepithelial flux of liquiritigenin (LG), davidigenin (DG), liquiritin (LQ), and liquiritin apioside (LA) using the human colonic cell line Caco-2 as a model of human intestinal absorption. Apparent permeability coefficients (Papp) for the apical to basolateral flux of LG and DG were (16.0 +/- 0.727) x 10(-6) cm/s and (18.2 +/- 1.67) x 10(-6) cm/s, respectively. These Papp were higher than that of the transcellular transport marker propranolol (13.5 +/- 0.34) x 10(-6) cm/s (P < 0.01). Papp for the apical to basolateral flux of LQ and LA were (0.26 +/- 0.12) x 10(-6) cm/s and (0.075 +/- 0.005) x 10(-6) cm/s, respectively. These Papp were lower than that of the paracellular transport marker mannitol (0.64 +/- 0.04) x 10(-6) cm/s (LG, P < 0.01; LA, P < 0.001). These data suggested excellent absorption of LG and DG through the human intestinal epithelial cell line. On the contrary, poor absorption of LQ and LA was expected due to the little transepithelial flux of these compounds in the human colonic cell line Caco-2. 相似文献
86.
In this study, the sound absorption properties of randomly packed granular materials were estimated. Generally, it is difficult to construct a general mathematical model for the arrangement of randomly packed granular materials. Therefore, in this study, an attempt was made to estimate the sound absorption coefficient using a theoretical analysis by introducing data from computed tomography (CT) scans, as the tomographic images of CT scans correspond to the slicing and elemental division of packing structures. In the theoretical analysis, the propagation constants and characteristic impedances in the voids were obtained by approximating each tomographic image as a void between two parallel planes. The derived propagation constants and characteristic impedances were then treated as a one-dimensional transfer matrix in the propagation of sound waves, and the transfer matrix method was used to calculate the normal incident sound absorption coefficient. The theoretical value of the sound absorption coefficient was derived using the effective density to which the measured tortuosity was applied. As a result, for the theoretical values considering the tortuosity, in many cases, the theoretical values were close to the measured values. For the theoretical values, when both the surface area and tortuosity were considered, the peak sound absorption frequency moved to a lower frequency and was in general agreement with the measured values. 相似文献
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88.
Pradipta Mukherjee Shinichi Fukuda Donny Lukmanto Toshiharu Yamashita Kosuke Okada Shuichi Makita Ibrahim Abd El-Sadek Arata Miyazawa Lida Zhu Rion Morishita Antonia Lichtenegger Tetsuro Oshika Yoshiaki Yasuno 《Biomedical optics express》2022,13(7):4071
Label-free metabolic imaging of non-alcoholic fatty liver disease (NAFLD) mouse liver is demonstrated ex vivo by dynamic optical coherence tomography (OCT). The NAFLD mouse is a methionine choline-deficient (MCD)-diet model, and two mice fed the MCD diet for 1 and 2 weeks are involved in addition to a normal-diet mouse. The dynamic OCT is based on repeating raster scan and logarithmic intensity variance (LIV) analysis that enables volumetric metabolic imaging with a standard-speed (50,000 A-lines/s) OCT system. Metabolic domains associated with lipid droplet accumulation and inflammation are clearly visualized three-dimensionally. Particularly, the normal-diet liver exhibits highly metabolic vessel-like structures of peri-vascular hepatic zones. The 1-week MCD-diet liver shows ring-shaped highly metabolic structures formed with lipid droplets. The 2-week MCD-diet liver exhibits fragmented vessel-like structures associated with inflammation. These results imply that volumetric LIV imaging is useful for visualizing and assessing NAFLD abnormalities. 相似文献
89.
90.
Kazuyuki Enomoto Shuichi Takahashi Yasunari Maekawa 《Macromolecular chemistry and physics.》2012,213(1):72-78
Most polymer grafts in grafted polymer films obtained by radiation‐induced solid graft polymerization are not analyzed in detail due to difficulties in isolation of the grafts without structural decomposition. Herein, a novel structural and molecular weight characterization method is reported for polymer grafts that are chemically attached to thermally and chemically stable polymer substrates, based on a swelling‐induced graft detachment in hot water. Polymer grafts prepared by the radiation‐induced polymerization of alkyl acrylate into poly(ethylene‐co‐tetrafluoroethylene) (ETFE) followed by a sulfonation reaction are found to have a ternary copolymer structure whose monomer units contain –COOH or –SO3H groups, or both. 相似文献