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"Hirose, Masaki"
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Low-Noise Propeller Design with Enlarged Blade Area for Drones
2025
The development of industrial drones is expected to expand in the future. In particular, applications such as delivery services are expected to drive demand for low-altitude flights. As drones become increasingly integrated into human environments, various challenges may arise, among which noise reduction represents a critical concern. To address this issue, a propeller design incorporating an enlarged blade area was investigated, wherein additional curved plates were attached to the trailing edges of the propellers to mitigate noise. The planar shape of the curved plates was designed using several parameters in a non-dimensional coordinate system. We introduced a relationship between the target noise reduction level and the second moment of area, subsequently used to scale the designed structure. The results of simultaneous force and noise measurements of a single propeller yielded significant noise reduction for all propellers with enlarged blade area. Strong correlations were observed between noise levels and the attachment length in the spanwise direction, as well as the inclination angle at the wing root side in the designed geometry. The in-flight test was performed using a six-rotor drone, achieving an overall noise reduction of 8.1 dBA compared to standard propellers, with significant reductions in the tonal noise specific to drones and in the high-frequency broadband noise, which causes discomfort to humans. These findings are expected to significantly inform future design guidelines for noise reduction in drones.
Journal Article
Effect of Bio-Inspired Cutout Shapes at the Leading Edge of Propellers on Noise and Flight Efficiency
2024
In recent years, the application of bio-inspired structures has garnered attention for enhancing the performance of fluid machinery. In this study, we experimentally investigated the effects of introducing a bio-inspired cutout structure to the propellers of drones, aiming to improve thrust efficiency and reduce noise levels. Our results demonstrated reductions in noise levels compared to conventional propellers. Parametric studies revealed that the roundness of the structure significantly influenced both flight efficiency and noise levels, suggesting its importance for replicating the inherent fluid characteristics found in nature. Additionally, optimal parameters for noise reduction, such as the length of the cutout, angle of incision relative to the flow direction, and the distance between the gap were identified. Although no improvements in flight efficiency were observed, most of the models investigated exhibited only around a 5% reduction in efficiency compared to the standard propellers, suggesting practical applicability for scenarios such as nighttime drone operations in urban areas. The noteworthy reduction in sound pressure levels in the mid- to high-frequency range achieved by the bio-inspired propellers in this study holds the potential to address the issue of drone noise pollution and encourage drone operations in urban areas. Moreover, the confirmed decrease in sound pressure at specific frequencies and the suggested controllability hint at the possibility of enhancing sound source localization performance using drones.
Journal Article
Clinical significance of serum anti-granulocyte–macrophage colony-stimulating factor autoantibodies in patients with sarcoidosis and hypersensitivity pneumonitis
2020
Background
Anti-granulocyte–macrophage colony-stimulating factor autoantibody (GMAb) has been recognized as a diagnostic biomarker for autoimmune pulmonary alveolar proteinosis (aPAP). The aims of this study were to know the incidence of increased level of serum GMAb in granulomatous lung diseases (sarcoidosis and hypersensitivity pneumonitis [HP]) and to clarify the role of GMAb. Consecutive individuals diagnosed with sarcoidosis (n = 92) and HP (n = 45) at National Hospital Organization Kinki-Chuo Chest Medical Center were retrospectively analyzed. We measured serum GMAb levels at the diagnosis. Cut-off values of GMAb discriminating aPAP (n = 110) from healthy controls (n = 31) were determined by receiver operating characteristic (ROC) curve analysis. We compared the clinical features of sarcoidosis and HP patients with GMAb levels above the cut-off value (“Elevated-GMAb”) with those of patients whose GMAb levels below the cut-off value (“Low-GMAb”). Radiological and pathological findings in elevated-GMAb patients were re-evaluated to elucidate the role of GMAb in granulomatous lung diseases.
Results
Analysis of ROC indicated a sensitivity and specificity of 100% at GMAb level of 3.33 μg/mL for discriminating aPAP from healthy controls (area under curve = 1.000,
p
< 0.0001). The percentages of elevated-GMAb sarcoidosis and HP patients were 5.4% (n = 5) and 11.1% (n = 5), respectively. The number of comorbid sarcoidosis and HP patients with aPAP was two and one, respectively. Elevated-GMAb sarcoidosis patients presented with significantly higher serum levels of Krebs von den Lungen (KL)-6, surfactant protein-D (SP-D), lactate dehydrogenase, and the requirement of systemic corticosteroid therapy. Elevated-GMAb HP patients demonstrated older age, higher serum KL-6, SP-D, carcinoembryonic antigen, and cytokeratin fragment 21-1 levels, and a higher percentage of lymphocytes in bronchoalveolar lavage than low-GMAb patients. A subset of patients presented with radiological and pathological findings characteristic of aPAP.
Conclusions
We demonstrated the percentage of elevated-GMAb sarcoidosis and HP patients who presented with several features suggestive of aPAP. Elevated-GMAb sarcoidosis and HP patients without definitive aPAP diagnosis may have subclinical or early-stage aPAP and may not necessarily indicate false positives. Upon diagnosis of sarcoidosis or HP, measurement of GMAb may be useful in detecting possible comorbidity of subclinical or early-onset aPAP.
Journal Article
Atomic force microscopy identifies the alteration of rheological properties of the cardiac fibroblasts in idiopathic restrictive cardiomyopathy
by
Okajima, Takaharu
,
Matsumoto, Mizuki
,
Ozono, Keiichi
in
Actin
,
Actins
,
Atomic force microscopy
2022
Restrictive cardiomyopathy (RCM) is a rare disease characterized by increased ventricular stiffness and preserved ventricular contraction. Various sarcomere gene variants are known to cause RCM; however, more than a half of patients do not harbor such pathogenic variants. We recently demonstrated that cardiac fibroblasts (CFs) play important roles in inhibiting the diastolic function of cardiomyocytes via humoral factors and direct cell–cell contact regardless of sarcomere gene mutations. However, the mechanical properties of CFs that are crucial for intercellular communication and the cardiomyocyte microenvironment remain less understood. In this study, we evaluated the rheological properties of CFs derived from pediatric patients with RCM and healthy control CFs via atomic force microscopy. Then, we estimated the cellular modulus scale factor related to the cell stiffness, fluidity, and Newtonian viscosity of single cells based on the single power-law rheology model and analyzed the comprehensive gene expression profiles via RNA-sequencing. RCM-derived CFs showed significantly higher stiffness and viscosity and lower fluidity compared to healthy control CFs. Furthermore, RNA-sequencing revealed that the signaling pathways associated with cytoskeleton elements were affected in RCM CFs; specifically, cytoskeletal actin-associated genes ( ACTN1 , ACTA2 , and PALLD ) were highly expressed in RCM CFs, whereas several tubulin genes ( TUBB3 , TUBB , TUBA1C , and TUBA1B ) were down-regulated. These results implies that the signaling pathways associated with cytoskeletal elements alter the rheological properties of RCM CFs, particularly those related to CF–cardiomyocyte interactions, thereby leading to diastolic cardiac dysfunction in RCM.
Journal Article
Wide-bandgap GaN-based watt-class photonic-crystal lasers
by
Emoto, Kei
,
Ishizaki, Kenji
,
Togawa, Hiroyuki
in
639/624/1020/1093
,
639/624/399/1022
,
Brightness
2022
Short-wavelength (blue-violet-to-green) lasers with high power and high beam quality are required for various applications including the machining of difficult-to-process materials and high-brightness illuminations and displays. Promising light sources for such applications are wide-bandgap GaN-based photonic-crystal surface-emitting lasers (PCSELs), which are based on two-dimensional resonance in the photonic crystal. Developments of these devices have lagged behind those of longer-wavelength GaAs-based PCSELs, because device designs for achieving robust two-dimensional resonance and a nanofabrication process that avoids introducing disorders have remained elusive for wide-bandgap GaN-based materials. Here, we address these issues and successfully realize GaN-based PCSELs with high, watt-class (>1 W) output power and a circular, single-lobed beam with a very narrow (~0.2°) divergence angle at blue wavelengths. In addition, we demonstrate continuous-wave operation with a high output power (~320 mW) and a high beam quality (
M
2
~1). Our results will enable the use of GaN-based PCSELs in the above-mentioned applications.
Short-wavelength lasers based on wide-bandgap GaN photonic crystals are promising for high-brightness illumination and materials processing. Here, the authors develop a nano-fabrication method for GaN/air photonic crystals, achieving high lasing operation performance in terms of output power, beam quality, and low threshold current.
Journal Article
Use of drug-coated balloon instead of drug-eluting stent for pediatric cardiac allograft vasculopathy
by
Masaki Hirose
,
Kazuhisa Hashimoto
,
Jun Narita
in
Balloon dilatation
,
cardiac allograft vasculopathy
,
Care and treatment
2023
ABSTRACT
Cardiac allograft vasculopathy (CAV) sometimes leads to restenosis, even after percutaneous transcatheter intervention. Recently, drug-coated balloons (DCBs) have been successfully used to treat coronary artery disease, especially CAVs, in adults. However, no studies have used DCBs in pediatric CAVs. We encountered a patient with CAV who underwent cardiac transplantation for restrictive cardiomyopathy at the age of 2 years. Nine years after the transplantation, severe stenosis of the proximal left anterior descending branch was observed. Considering the patient's young age and the possibility of restenosis, we performed an intervention with DCB. Follow-up conducted 7 months after the intervention showed no restenosis. Cardiac coronary artery lesions following transplantation are more likely to result in restenosis earlier than arteriosclerotic lesions. In pediatric patients, restenosis might require multiple stents and prolonged antiplatelet therapy. Our findings provide evidence supporting the possibility of an effective treatment of CAV in children.
Journal Article
Trans-subclavian approach for Impella CP implantation using the chimney graft in a pediatric patient with fulminant myocarditis during extracorporeal support
2023
Impella is a device effective for the treatment of cardiogenic shock. However, among small children, its application has limitations due to left ventricle size and vasculature and the turning diameter of the aortic arch. Herein, we report an 11-year-old girl with fulminant myocarditis who was successfully managed with Impella CP implantation via the right subclavian artery using a polyethylene terephthalate chimney graft. Compared with insertion via the femoral artery, this method has several advantages. That is, it can address limitations in aortic arch diameter and facilitate equable fixation of the Impella device in small pediatric patients.
Journal Article
Effectiveness of a 5-Hydroxytryptamine Type 3 Receptor Antagonist for Treating Nintedanib-Induced Diarrhea: A Prospective Observational Study
2025
Background/Objectives: Idiopathic pulmonary fibrosis (IPF) is a fibrotic interstitial lung disease (ILD) with a poor prognosis. The prognosis of ILDs showing progressive pulmonary fibrosis (PPF) is poor, similar to that of IPF. Diarrhea is the most frequently observed adverse event in ILDs treated with nintedanib. Managing diarrhea is important for maintaining nintedanib use and improving the prognosis of ILDs. Methods: Between October 2022 and March 2025, we enrolled patients with severe nintedanib-induced diarrhea that was uncontrolled by loperamide and/or probiotics. Other drugs were administered to control diarrhea, and the patients were prospectively observed to evaluate stool frequency, stool form score (scores 3, 2, and 1 for watery stool, soft stool without form, and soft stool with form, respectively), quality of life (QOL) using the Japanese version of the irritable bowel syndrome (IBS)-QOL questionnaire, adverse events, and laboratory findings. Results: Eleven patients (IPF, n = 5; PPF, n = 6) were enrolled, and all patients were treated with ramosetron, a 5-hydroxytryptamine type 3 receptor (5-HT3) antagonist. Ramosetron was terminated within 3 weeks, before sufficient evaluation, because of insufficient efficacy (n = 1) and the discontinuation of nintedanib due to pneumothorax (n = 1). Stool frequency and stool form scores decreased significantly after the initiation of ramosetron therapy; however, IBS-QOL did not improve significantly. IBS-QOL correlated with shortness of breath scores but not with stool frequency. No prominent adverse events were associated with ramosetron administration. Conclusions: Ramosetron, a 5-HT3 antagonist, improved stool frequency and stool form in patients with severe nintedanib-induced diarrhea.
Journal Article
Serum vascular endothelial growth factor-D as a diagnostic and therapeutic biomarker for lymphangioleiomyomatosis
2019
In lymphangioleiomyomatosis (LAM), tuberous sclerosis gene mutations activate the mechanistic target of the rapamycin pathway, resulting in vascular endothelial growth factor-D (VEGF-D) overproduction. While the utility of serum VEGF-D testing for the diagnosis of LAM is outlined in ATS/JRS LAM Guidelines, the assay has not been fully validated for Asian populations. Our aims were to validate serum VEGF-D testing in Japan, by directly comparing measurements in Japan and the U.S., determining the diagnostic cut-off for serum VEGF-D levels among the Japanese women with typical thin walled cystic change on CT, and determining the performance of VEGF-D as a prognostic biomarker.
We determined serum VEGF-D levels from 108 LAM patients, 14 disease controls, and 51 healthy volunteers from the Japanese population. Measurements of 61 LAM patients were compared to those from the principal VEGF-D laboratory in the U.S at Cincinnati Children's Hospital Medical Center. We correlated baseline serum VEGF-D levels with baseline and longitudinal clinical data to determine how pregnancy, sirolimus or gonadotrophin-releasing hormone (GnRH) agonists influence serum VEGF-D levels.
Serum VEGF-D measurements in Japan and the U.S. were very similar. Baseline serum VEGF-D levels effectively distinguished LAM from other diseases and healthy volunteers at a cut-off level of 645 pg/ml and were diagnostically specific at 800 pg/ml, consistent with the recommendations of the ATS/JRS LAM Guidelines. Baseline serum VEGF-D correlated negatively with the DLco baseline % predicted and with the annual decrease in DLco % predicted. There was no significant association between baseline serum VEGF-D level and the outcomes of death or transplant. Serum VEGF-D levels markedly decreased during treatment with sirolimus, but not with GnRH analogues. Serum VEGF-D levels of most LAM patients did not increase over time, and neither pregnancy nor menopause significantly modulated serum VEGF-D levels.
Serum VEGF-D is a useful diagnostic and therapeutic biomarker for LAM. Satisfactory precision and international inter-laboratory agreement of the clinical assay support VEGF-D recommendations in the ATS/JRS LAM Guidelines for the Japanese population.
Journal Article
Atomic force microscopy identifies the alteration of rheological properties of the cardiac fibroblasts in idiopathic restrictive cardiomyopathy
2022
Restrictive cardiomyopathy (RCM) is a rare disease characterized by increased ventricular stiffness and preserved ventricular contraction. Various sarcomere gene variants are known to cause RCM; however, more than a half of patients do not harbor such pathogenic variants. We recently demonstrated that cardiac fibroblasts (CFs) play important roles in inhibiting the diastolic function of cardiomyocytes via humoral factors and direct cell-cell contact regardless of sarcomere gene mutations. However, the mechanical properties of CFs that are crucial for intercellular communication and the cardiomyocyte microenvironment remain less understood. In this study, we evaluated the rheological properties of CFs derived from pediatric patients with RCM and healthy control CFs via atomic force microscopy. Then, we estimated the cellular modulus scale factor related to the cell stiffness, fluidity, and Newtonian viscosity of single cells based on the single power-law rheology model and analyzed the comprehensive gene expression profiles via RNA-sequencing. RCM-derived CFs showed significantly higher stiffness and viscosity and lower fluidity compared to healthy control CFs. Furthermore, RNA-sequencing revealed that the signaling pathways associated with cytoskeleton elements were affected in RCM CFs; specifically, cytoskeletal actin-associated genes (ACTN1, ACTA2, and PALLD) were highly expressed in RCM CFs, whereas several tubulin genes (TUBB3, TUBB, TUBA1C, and TUBA1B) were down-regulated. These results implies that the signaling pathways associated with cytoskeletal elements alter the rheological properties of RCM CFs, particularly those related to CF-cardiomyocyte interactions, thereby leading to diastolic cardiac dysfunction in RCM.
Journal Article