593 research outputs found

    Realizing Stabilized Landing for Computation-Limited Reusable Rockets: A Quantum Reinforcement Learning Approach

    Full text link
    The advent of reusable rockets has heralded a new era in space exploration, reducing the costs of launching satellites by a significant factor. Traditional rockets were disposable, but the design of reusable rockets for repeated use has revolutionized the financial dynamics of space missions. The most critical phase of reusable rockets is the landing stage, which involves managing the tremendous speed and attitude for safe recovery. The complexity of this task presents new challenges for control systems, specifically in terms of precision and adaptability. Classical control systems like the proportional-integral-derivative (PID) controller lack the flexibility to adapt to dynamic system changes, making them costly and time-consuming to redesign of controller. This paper explores the integration of quantum reinforcement learning into the control systems of reusable rockets as a promising alternative. Unlike classical reinforcement learning, quantum reinforcement learning uses quantum bits that can exist in superposition, allowing for more efficient information encoding and reducing the number of parameters required. This leads to increased computational efficiency, reduced memory requirements, and more stable and predictable performance. Due to the nature of reusable rockets, which must be light, heavy computers cannot fit into them. In the reusable rocket scenario, quantum reinforcement learning, which has reduced memory requirements due to fewer parameters, is a good solution.Comment: 5 pages, 5 figure

    Intratracheal inoculation of human varicella zoster virus (VZV; MAV strain) vaccine successfully induced VZV IgG antibodies in rhesus monkeys

    Get PDF
    Background The objective of this study was to investigate whether the use of live attenuated varicella zoster virus (VZV) MAV vaccination can efficiently induce VZV antibody production in naive rhesus monkeys as an approach to prevent simian varicella virus (SVV) reactivation in animals immunosuppressed for transplantation studies. Results Clinically available human VZV vaccine was used to induce the production of anti-VZV antibodies in rhesus monkeys. A vial of the vaccine was subcutaneously injected at 0 week, and the second and third vaccination was performed at 5 and 6 weeks by intratracheal inoculation. The titer of anti-VZV IgG was assessed at 0, 2, 4, 6, and 7 weeks. At 2 weeks, 3/16 were seropositive for VZV IgG. At 6 weeks, 9/16 were shown to be seropositive. At 7 weeks, 16/16 were found to be seropositive. Conclusions The VZV vaccine via intratrachael inoculation was shown to induce VZV IgG humoral immunity in rhesus monkeys and may be important immunosuppressed macaques for transplantation studies. Although the humoral immunity produced is an important finding, further studies will be necessary to confirm possible protection and it could protect probably against SVV infection in rhesus monkey.This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health & Welfare, Republic of Korea (Project No.HI13C0954), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (Grant No. NRF-2020R1A2C1004557 to Kim JM), and Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ01345302) Rural Development Administration, Republic of Korea

    Validity of gait parameters for hip flexor contracture in patients with cerebral palsy

    Get PDF
    Background: Psoas contracture is known to cause abnormal hip motion in patients with cerebral palsy. The authors investigated the clinical relevance of hip kinematic and kinetic parameters, and 3D modeled psoas length in terms of discriminant validty, convergent validity, and responsiveness. Methods: Twenty-four patients with cerebral palsy (mean age 6.9 years) and 28 normal children (mean age 7.6 years) were included. Kinematic and kinetic data were obtained by three dimensional gait analysis, and psoas lengths were determined using a musculoskeletal modeling technique. Validity of the hip parameters were evaluated. Results: In discriminant validity, maximum psoas length (effect size r = 0.740), maximum pelvic tilt (0.710), maximum hip flexion in late swing (0.728), maximum hip extension in stance (0.743), and hip flexor index (0.792) showed favorable discriminant ability between the normal controls and the patients. In convergent validity, maximum psoas length was not significantly correlated with maximum hip extension in stance in control group whereas it was correlated with maximum hip extension in stance (r = -0.933, p < 0.001) in the patients group. In responsiveness, maximum pelvic tilt (p = 0.008), maximum hip extension in stance (p = 0.001), maximum psoas length (p < 0.001), and hip flexor index (p < 0.001) showed significant improvement post-operatively. Conclusions: Maximum pelvic tilt, maximum psoas length, hip flexor index, and maximum hip extension in stance were found to be clinically relevant parameters in evaluating hip flexor contracture.Y

    Pig-to-Nonhuman Primate (NHP) Naked Islet Xenotransplantation

    Get PDF
    Islet transplantation is an established therapy for selected type 1 diabetes (T1D) patients with severe hypoglycemic unawareness and glycemic liability despite of insulin treatment. However, the donor organ is limited. Porcine islets are the best alternative source to overcome this limitation, and pig-to-nonhuman primate (NHP) naked islet xenotransplantation studies are being performed worldwide. Several studies including our own have presented successful proof-of-concept results based on immunosuppression regimen including the anti-CD154 monoclonal antibody. Particularly, long-term control of diabetes by adult porcine islet transplantation has been demonstrated in five consecutive monkeys, and the longest survival was ~1000 days after transplantation. Currently, pig-to-NHP islet xenotransplantation based on clinically applicable immunosuppression regimen is being pursued. In this chapter, we will describe all the procedures of pig-to-NHP naked islet xenotransplantation: (1) the porcine islet isolation from designated pathogen-free (DPF) miniature pigs, (2) diabetes induction in monkeys, (3) transplantation procedure via the portal vein, (4) immune monitoring comprising humoral and cellular immunity after porcine islet transplantation, and finally (5) liver biopsy and subsequent immunohistochemical procedure in detail

    Little Response of Cerebral Metastasis from Hepatocellular Carcinoma to Any Treatments

    Get PDF
    Objective : We retrospectively evaluated the survival outcome of patients with brain metastasis from hepatocellular carcinoma (HCC). Methods : Between 1991 and 2007, a total of 20 patients were diagnosed as having brain metastasis from HCC. The mean age of the patients was 55 +/- 13 years, and 17(85.0%) were men. Seventeen (85.0%) patients had already extracranial metastases. The median time from diagnosis of HCC to brain metastasis was 18.5 months. Fourteen (70.0%) patients had stroke-like presentation due to intracerebral hemorrhage (ICH). Ten (50.0%) patients had single or solitary brain metastasis. Among a total of 34 brain lesions, 31 (91.2%) lesions had the hemorrhagic components. Results : The median survival time was 8 weeks (95% Cl, 5.08-10.92), and the actuarial survival rates were 85.0%, 45.0%, 22.5%, and 8.4% at 4, 12, 24, and 54 weeks. Age < 60 years, treatment of the primary and/or extracranial lesions, and recurrent ICH were the possible prognostic factors (p = 0.044, p < 0.001, and p = 0.111, respectively). The median progression-free survival (PFS) time was 3 months (95% Cl, 0.95-5.05). Conclusion : The overall survival of the patients with brain metastasis from HCC was very poor with median survival time being only 8 weeks. However, the younger patients less than 60 years and/or no extracranial metastases seem to be a positive prognostic factor.Choi HJ, 2009, J NEURO-ONCOL, V91, P307, DOI 10.1007/s11060-008-9713-3Kim SR, 2006, WORLD J GASTROENTERO, V12, P6727Seinfeld J, 2006, J NEURO-ONCOL, V76, P93, DOI 10.1007/s11060-005-4175-3Cho DC, 2005, J CLIN NEUROSCI, V12, P699, DOI 10.1016/j.jocn.2004.08.026Chang L, 2004, SURG NEUROL, V62, P172, DOI 10.1016/j.surneu.2003.10.002Del Ben M, 2003, J EXP CLIN CANC RES, V22, P641El-Serag HB, 2002, J CLIN GASTROENTEROL, V35, pS72SALVATI M, 2002, J NEUROSURG SCI, V46, P77McIver JI, 2001, NEUROSURGERY, V49, P447Hayashi K, 2000, SURG NEUROL, V53, P379El-Serag HB, 1999, NEW ENGL J MED, V340, P745Peres MFP, 1998, ARQ NEURO-PSIQUIAT, V56, P658Deuffic S, 1998, LANCET, V351, P214Kim M, 1998, J NEURO-ONCOL, V36, P85TaylorRobinson SD, 1997, LANCET, V350, P1142Gaspar L, 1997, INT J RADIAT ONCOL, V37, P745LUCEY MR, 1997, LIVER TRANSPLANT SUR, V3, P628Murakami K, 1996, NEURORADIOLOGY, V38, pS31PATCHELL RA, 1990, NEW ENGL J MED, V322, P494OTSUKA S, 1987, NEUROL MED CHIR TOKY, V27, P654OKEN MM, 1982, AM J CLIN ONCOL-CANC, V5, P649PUGH RNH, 1973, BRIT J SURG, V60, P646

    Citrus aurantium flavonoids inhibit adipogenesis through the Akt signaling pathway in 3T3-L1 cells

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Obesity is a health hazard that is associated with a number of diseases and metabolic abnormalities, such as type-2 diabetes, hypertension, dyslipidemia, and coronary heart disease. In the current study, we investigated the effects of <it>Citrus aurantium </it>flavonoids (CAF) on the inhibition of adipogenesis and adipocyte differentiation in 3T3-L1 cells.</p> <p>Methods</p> <p>During adipocyte differentiation, 3T3-L1 cells were treated with 0, 10, and 50 μg/ml CAF, and then the mRNA and protein expression of adipogenesis-related genes was assayed. We examined the effect of CAF on level of phosphorylated Akt in 3T3-L1 cells treated with CAF at various concentrations during adipocyte differentiation.</p> <p>Results</p> <p>The insulin-induced expression of C/EBPβ and PPARγ mRNA and protein were significantly down-regulated in a dose-dependent manner following CAF treatment. CAF also dramatically decreased the expression of C/EBPα, which is essential for the acquisition of insulin sensitivity by adipocytes. Moreover, the expression of the aP2 and FAS genes, which are involved in lipid metabolism, decreased dramatically upon treatment with CAF. Interestingly, CAF diminished the insulin-stimulated serine phosphorylation of Akt (Ser473) and GSK3β (Ser9), which may reduce glucose uptake in response to insulin and lipid accumulation. Furthermore, CAF not only inhibited triglyceride accumulation during adipogenesis but also contributed to the lipolysis of adipocytes.</p> <p>Conclusions</p> <p>In the present study, we demonstrate that CAF suppressed adipogenesis in 3T3-L1 adipocytes. Our results indicated that CAF down-regulates the expression of C/EBPβ and subsequently inhibits the activation of PPARγ and C/EBPα. The anti-adipogenic activity of CAF was mediated by the inhibition of Akt activation and GSK3β phosphorylation, which induced the down-regulation of lipid accumulation and lipid metabolizing genes, ultimately inhibiting adipocyte differentiation.</p

    Primary Pulmonary T-Cell Lymphoma: a Case Report

    Get PDF
    Primary pulmonary T-cell lymphoma is an extremely rare malady, and we diagnosed this in a 52-year-old male who was admitted to our hospital with cough for the previous two weeks. The chest CT demonstrated multiple variable sized mass-like consolidations with low density central necrosis in the peripheral portion of both the upper and lower lobes. Positron emission tomography (PET) showed multiple areas of hypermetabolic fluorodeoxyglucose (FDG) uptake in both lungs with central metabolic defects, which correlated with central necrosis seen on CT. The histological sample showed peripheral T-cell lymphoma of the not otherwise specified form. The follow-up CT scan showed an increased extent of the multifocal consolidative lesions despite that the patient had undergone chemotherapy

    A Self-Regulatory Circuit of CIRCADIAN CLOCK-ASSOCIATED1 Underlies the Circadian Clock Regulation of Temperature Responses in Arabidopsis

    Full text link
    The circadian clock synchronizes biological processes to daily cycles of light and temperature. Clock components, including CIRCADIAN CLOCK-ASSOCIATED1 (CCA1), are also associated with cold acclimation. However, it is unknown how CCA1 activity is modulated in coordinating circadian rhythms and cold acclimation. Here, we report that self-regulation of Arabidopsis thaliana CCA1 activity by a splice variant, CCA1β, links the clock to cold acclimation. CCA1β interferes with the formation of CCA1α-CCA1α and LATE ELONGATED HYPOCOTYL (LHY)-LHY homodimers, as well as CCA1α-LHY heterodimers, by forming nonfunctional heterodimers with reduced DNA binding affinity. Accordingly, the periods of circadian rhythms were shortened in CCA1β-overexpressing transgenic plants (35S:CCA1β), as observed in the cca1 lhy double mutant. In addition, the elongated hypocotyl and leaf petiole phenotypes of CCA1α-overexpressing transgenic plants (35S:CCA1α) were repressed by CCA1β coexpression. Notably, low temperatures suppressed CCA1 alternative splicing and thus reduced CCA1β production. Consequently, whereas the 35S:CCA1α transgenic plants exhibited enhanced freezing tolerance, the 35S:CCA1β transgenic plants were sensitive to freezing, indicating that cold regulation of CCA1 alternative splicing contributes to freezing tolerance. On the basis of these findings, we propose that dynamic self-regulation of CCA1 underlies the clock regulation of temperature responses in Arabidopsis
    corecore