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Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

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Astrodynamics 2024年第1期8卷 47-60页

作者： yuki Kubo Toshihiro Chujo Institute of Space and Astronautical Science Japan Aerospace Exploration AgencyKanagawa252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan

The solar sail is one of the most promising space exploration systems due to its theoretically infinite specific impulse achieved through solar radiation pressure(SRP).Recently,researchers have proposed“transformable spacecraft”capable of actively reconfiguring their body configurations using actuatable *** spacecraft,if used similarly to solar sails,are expected to significantly enhance orbit and attitude control capabilities owing to their high redundancy in control degrees of ***,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control *** study focuses on novel attitude control techniques for transformable spacecraft under *** developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle *** proposed methods are formulated in a general manner and can be applied to any transformable spacecraft comprising front faces that can predominantly receive the SRP on each *** validity of our proposed method is confirmed through numerical *** study contributes to making most of the high control redundancy of transformable spacecraft without the need for expendable propellants,thus significantly enhancing the orbit and attitude control capabilities.

关键词： solar sail transformable spacecraft attitude-joint coupled motion attitudestabilization

Laser-assisted direct roller imprinting of large-area microstructured optical surfaces

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Microsystems & Nanoengineering 2024年第1期10卷 257-266页

作者： Keisuke Nagato Ken Takahashi yuki Yajima Masayuki Nakao Department of Mechanical Engineering Graduate School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan

In this study,a high-throughput fabrication method called laser-assisted direct roller imprinting(LADRI)was developed to lower the cost of nanoimprinting large-area polymer films and to address problems associated with nanoimprinting,namely,microstructural damage and precision in flatness of entire *** LADRI,the laser directly heats the microstructured surface of the roller mold,which heats and melts the surface of a polymethyl methacrylate(PMMA)film to replicate the microstructures on the mold *** this study,the effects of laser power density,scanning speed,size of the microstructures,and contact pressure on the replication speed were investigated *** replication speed increased as the power and scanning speed ***,because the film required heating until it filled the entire depth of the microstructure,an appropriate replication speed was *** result was supported by simulation of the temperature distribution inside the mold and the PMMA using transient heat conduction *** demonstrate the applications of LADRI,two different optical surfaces were replicated:an antireflection(AR)structure with conical structures sized several hundred nanometers and a lightextraction structure with a microlens array(MLA)comprising 10μm lenses,for display and illumination,*** replication degree of the MLA was governed by the contact *** flow simulation indicated that the heat conduction and flow speeds of the melted PMMA surface were comparable within several tens of *** addition,the reflectivity of the AR structure decreased from 4 to 0.5%,and the light intensity of the light-extraction structure increased by a factor of 1.47.

关键词： microstructure roller conduction

Unroofing Technique for Anomalous Origin of the Left Coronary Artery from the Right Sinus of Valsalva: Report of a Case

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World Journal of Cardiovascular Surgery 2024年第6期14卷 69-77页

作者： Keisuke Morimoto Futoshi kobayashi Hiromu Horie yuki Sakaguchi Einosuke Mizuta Department of Cardiovascular Surgery Sanin Rosai Hospital Yonago Japan Department ofCardiology Sanin Rosai Hospital Yonago Japan

Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly higher risk of sudden cardiac death compared to those with an anomalous right coronary artery. The anomalous coronary artery traversing between the ascending aorta and the pulmonary artery markedly heightens the risk of myocardial ischemia, arrhythmia, and sudden death. Symptomatic patients often exhibit a longer intramural course of the coronary artery, which may necessitate earlier intervention or influence the choice of surgical repair method. Surgical intervention is advocated for patients with this anomaly, even in the absence of symptoms. For anomalous aortic origin of a coronary artery from the opposite sinus of Valsalva with an intramural course, coronary unroofing is the preferred revascularization procedure. This report presents a case of AOLCA originating from the right sinus of Valsalva, treated surgically using the unroofing technique for the aortic intramural segment of the anomalous coronary artery traversing between the great vessels. The unroofing technique is recommended for treating AOLCA with an extensive intramural course that does not involve the commissure.

关键词： Unroofing Technique Anomaly of Coronary Artery Anomalous Origin of Left Coronary Artery

Controlling a peristaltic robot inspired by inchworms

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Biomimetic Intelligence & Robotics 2024年第1期4卷 88-96页

作者： Yanhong Peng Hiroyuki Nabae yuki Funabora Koichi Suzumori Department of Information and Communication Engineering Graduate School of EngineeringNagoya UniversityNagoya 464-8601Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan

This study presents an innovative approach in soft robotics,focusing on an inchworm-inspired robot designed for enhanced transport *** explore the impact of various parameters on the robot’s performance,including the number of activated sections,object size and material,supplied air pressure,and command execution *** a series of controlled experiments,we demonstrate that the robot can achieve a maximum transportation speed of 8.54 mm/s and handle loads exceeding 100 g,significantly outperforming existing models in both speed and load *** findings provide valuable insights into the optimization of soft robotic design for improved efficiency and adaptability in transport *** research not only contributes to the advancement of soft robotics but also opens new avenues for practical applications in areas requiring precise and efficient object *** study underscores the potential of biomimetic designs in robotics and sets a new benchmark for future developments in the field.

关键词： McKibben artificial muscles Bionics Soft robotics Soft actuator Bio-inspired robotics

Polarization Flipping of Even-Order Harmonics in Monolayer Transition-Metal Dichalcogenides

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Ultrafast Science 2021年第1期1卷 39-47页

作者： yuki kobayashi Christian Heide Hamed Koochaki Kelardeh Amalya Johnson Fang Liu Tony F.Heinz David A.Reis Shambhu Ghimire Stanford PULSE Institute SLAC National Accelerator LaboratoryMenlo ParkCA 94025USA Department of Applied Physics Stanford UniversityStanfordCA 94305USA Max Planck Institute for the Physics of Complex Systems Nöthnitzer Str.3801187 DresdenGermany Department of Materials Science and Engineering Stanford UniversityStanfordCA 94305USA Department of Chemistry Stanford UniversityStanfordCA 94305USA Department of Photon Science Stanford UniversityStanfordCA 94305USA

We present a systematic study of the crystal-orientation dependence of high-harmonic generation in monolayer transition-metal dichalcogenides,WS2 and MoSe2,subjected to intense linearly polarized midinfrared laser *** measured spectra consist of both odd-and even-order harmonics,with a high-energy cutoff extending beyond the 15th order for a laser-field strength around~1 V/*** WS2,we find that the polarization direction of the odd-order harmonics smoothly follows that of the laser field irrespective of the crystal orientation,whereas the direction of the even-order harmonics is fixed by the crystal mirror ***,the polarization of the even-order harmonics shows a flip in the course of crystal rotation when the laser field lies between two of the crystal mirror *** numerically solving the semiconductor Bloch equations for a gapped-graphene model,we qualitatively reproduce these experimental features and find the polarization flipping to be associated with a significant contribution from interband *** contrast,high-harmonic signals from MoSe2 exhibit deviations from the laser-field following of oddorder harmonics and crystal-mirror-plane following of even-order *** attribute these differences to the competing roles of the intraband and interband contributions,including the deflection of the electron-hole trajectories by nonparabolic crystal bands.

关键词： polarization harmonics mirror

Endoscopic hemostasis using self-expandable metal stent combinedwith PuraStat® for patient with high risk of post-endoscopicsphincterotomy bleeding (with video)

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 94-96页

作者： Takeshi Ogura yuki Uba Masahiro Yamamura Nobu Nishioka Hiroki Nishikawa 2nd Department of Internal Medicine Osaka Medical and Pharmaceutical UniversityOsakaJapan

To the Editor:Endoscopic sphincterotomy(EST)is an established technique for removal of bile duct stones and self-expandable metal stent(SEMS)***,bleeding can be considered an adverse event after EST,particularly for patients with high risk of bleeding such as those on *** the various techniques reported for obtaining endoscopic hemostasis[1-3].

关键词： bleeding stasis endoscopic

Which characteristics are associated with changes in medication status for lower urinary tract symptoms among patients with prostate cancer receiving external beam radiotherapy?

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Current Urology 2024年第2期18卷 122-127页

作者： yuki Kyoda Kohei Hashimoto Atsushi Takahashi TakeshiMaehana Kimihito Tachikawa Takashi Muranaka Shuichi Kato Tomoyo Kurisug Fumimasa Fukuta Takahiro Kirisawa Manabu Okada Ko kobayashi Toshiaki Tanaka Shiro Hinotsu Naoya Masumoria Department of Urology SapporoMedical University School of MedicineSapporoJapan Department of Urology Hakodate Goryoukaku HospitalHakodateJapan Department of Urology Muroran City General HospitalMuroranJapan Department of Urology NTT-East Sapporo HospitalSapporoJapan Department of Urology Sunagawa City Medical CenterSunagawaJapan Department of Urology Oji General HospitalTomakomaiJapan Department of Urology Steel Memorial Muroran HospitalMuroranJapan Department of Urology Obihiro Kyokai HospitalObihiroJapan Department of Medical Statistics Sapporo Medical University School of MedicineSapporoJapan

Background:We clarified the predictive factors for changes in the status ofmedications for lower urinary tract symptoms(LUTS)2 years after local radiotherapy for nonmetastatic prostate *** and methods:We retrospectively included patients who underwent local external radiotherapy for nonmetastatic prostate cancer in 8 institutions between April 2001 and March *** were divided into themedication and no-medication group based on the use of drugs for LUTS before *** defined improvement of LUTS as when the patient did not require medication for LUTS at 24 months after radiotherapy in the medication group and as deterioration whenmedication was required in the no-medication *** regression analysis was used to evaluate predictive factors for changes in medication ***:Altogether,505 patients were divided into a no-medication group(n=352)and a medication group(n=153).The number of patients with deterioration and improvement in LUTS was 49(14%)and 36(23%),*** the multivariate analysis,the predictive variables for deterioration were the International Prostate SymptomScore(≥8;odds ratio[OR],2.21;p=0.014)and the biopsy Gleason score(≤3+4=7;OR,2.430;p=0.008)in the no-medication group,whereas those for improvement were age(<75 years old;OR,5.81;p=0.002),the quality of life score(<3;OR,3.15;p=0.028),and a positive biopsy core rate(≥50%;OR,2.530;p=0.027)in the medication ***:These predictive factors for changes in the status ofmedications for LUTS at 2 years after external radiotherapymay help determine the definitive therapy for nonmetastatic prostate cancer.

关键词： Prostate cancer Radiotherapy Lower urinary tract symptoms Medications

Low skeletal muscle mass and high visceral adiposity are associated with recurrence of acute cholecystitis after conservative management:A propensity score-matched cohort study

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 64-70页

作者： Yudai Koya Michihiko Shibata yuki Maruno Yoshitaka Sakamoto Shinji Oe Koichiro Miyagawa Yuichi Honma Masaru Harada Department of Gastroenterology Kyushu Rosai HospitalMoji Medical Center3-1 HigashiminatomachiMoji-kuKitakyushu 801-8502Japan Third Department of Internal Medicine School of MedicineUniversity of Occupational and Environmental HealthKitakyushu 807-8555Japan Department of Surgery Kyushu Rosai Hospital Moji Medical CenterKitakyushu 801-8502Japan

Background:Recurrent acute cholecystitis(RAC)can occur after non-surgical treatment for acute cholecystitis(AC),and can be more severe in comparison to the first episode of *** skeletal muscle mass or adiposity have various effects in several *** aimed to clarify the relationship between RAC and body ***:Patients with AC who were treated at our hospital between January 2011 and March 2022 were *** psoas muscle mass and adipose tissue area at the third lumbar level were measured using computed tomography at the first episode of *** areas were divided by height to obtain the psoas muscle mass index(PMI)and subcutaneous/visceral adipose tissue index(SATI/VATI).According to median VATI,SATI and PMI values by sex,patients were divided into the high and low PMI *** performed propensity score matching to eliminate the baseline differences between the high PMI and low PMI groups and analyzed the cumulative incidence and predictors of ***:The entire cohort was divided into the high PMI(n=81)and low PMI(n=80)*** the propensity score-matched cohort there were 57 patients in each *** Kaplan-Meier analysis,the low PMI group and the high VATI group had a significantly higher cumulative incidence of RAC than their counterparts(log-rank P=0.001 and 0.015,respectively).In a multivariate Cox regression analysis,the hazard ratios of low PMI and low VATI for RAC were 5.250(95%confidence interval 1.083-25.450,P=0.039)and 0.158(95%confidence interval:0.026-0.937,P=0.042),***:Low skeletal muscle mass and high visceral adiposity were independent risk factors for RAC.

关键词： Acute cholecystitis Low skeletal muscle mass Recurrent acute cholecystitis Sarcopenia Visceral adiposity

Tannins from Acacia mangium Bark as Natural Dyes for Textiles:Characteristics and Applications

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Journal of Renewable Materials 2024年第9期12卷 1625-1637页

作者： Maya Ismayati Nissa Nurfajrin Solihat Fifi Melinda Setiawati Wasrin Syafii yuki Tobimatsu Deni Zulfiana Research Center for Biomass and Bioproducts Research Organization for Life Sciences and EnvironmentNational Research and Innovation Agency(BRIN)Jl.Raya Bogor KM 46CibinongBogor16911Indonesia Department of Forest Product Technology Faculty of ForestryIPB UniversityBogor16680Indonesia Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyoto611-0011Japan Research Center for Applied Microbiology Research Organization for Life Sciences and EnvironmentNational Research and Innovation Agency(BRIN)Jl.Raya Bogor KM 46CibinongBogor16911Indonesia

Tannins are capable of producing natural dyes with antioxidant and antibacterial propertis,while synthetic dyes are commonly used in the textile industry,causing environmental issues like water *** research aims to utilize waste tannins as natural dyes as an alternative to synthetic *** study examined the effect of the extraction method on tannin properties such as phenolic content,antioxidants,and antibacterial *** addition,Pyrolysis Gas Chromatography‒Mass Spectrometry(Py-GCMS)analysis was used to identify the effect of extraction temperature on the chemical elucidation of *** effect of tannin concentration was evaluated against four bacteria that are usually found on human skin:Staphylococcus epidermidis,Bacillus subtilis,Propionibacterium acnes,and Staphylococcus *** temperature significantly influences the chemical composition of tannin,which leads to different antioxidant *** maximum antibacterial properties of tannin were obtained at 90℃with the inhibition zone in the range of 0.9–1.0 mm against four bacteria,tannin yield of 26.59%,Gallic Acid Equivalents or total phenolic content(GAE)of 40.30 mg/g,and Radical Scavenging Activity or antioxidant activity(RSA)of 89.88%.Moreover,the concentration of tannin was significantly linear with its antibacterial *** was successfully applied to the textile by using alum as a mordanting agent to create an antibacterial *** textile’s bacterial structure damage was analyzed under Field Emission Scanning Electron Microscopy(FESEM).After 50 washings,tannin-textiles with alum-modified properties remained stable compared to those without alum,with *** and *** being the most vulnerable bacteria,as confirmed by FESEM ***,tannin is a feasible alternative to harmful and nondegradable synthetic dyes and antibacterial agents.

关键词： Acacia mangium tannin antibacterial antioxidant different temperature extraction dyes