197 research outputs found

    Stable Process Approach to Analysis of Systems Under Heavy-Tailed Noise: Modeling and Stochastic Linearization

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    The Wiener process has provided a lot of practically useful mathematical tools to model stochastic noise in many applications. However, this framework is not enough for modeling extremal events, since many statistical properties of dynamical systems driven by the Wiener process are inevitably Gaussian. The goal of this work is to develop a framework that can represent a heavy-tailed distribution without losing the advantages of the Wiener process. To this end, we investigate models based on stable processes (this term “stable” has nothing to do with “dynamical stability”) and clarify their fundamental properties. In addition, we propose a method for stochastic linearization, which enables us to approximately linearize static nonlinearities in feedback systems under heavy-tailed noise, and analyze the resulting error theoretically. The proposed method is applied to assessing wind power fluctuation to show the practical usefulness

    Development of a system for the assessment of a dual-task performance based on a motion-capture device

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    The authors produced a dual task (DT) that provided a dynamic balance task and a cognitive task in a game system using motion sensors and virtual images. There had been no DT where a cognitive task needs a dynamic balance task that requires full-body motions. We developed and evaluated a game system to assess the performance of the DT. The DT was to solve a Sudoku puzzle using full-body motions like Tái Chi. An ability to perform a DT is intimately related to risk of falls. To evaluate the developed system, we compared the performance of elderly people and young people. Generally, elderly people are at a higher risk of falls. Twenty elderly community-dwelling adults (mean age, 73.0±6.2 years) and 16 young adults (mean age, 21.8±1.0 years) participated in this study. To compare the two groups, we applied an independent-samples t-test. The time taken for the elderly people was 60.6±43.2 s, whereas the time taken for the young people was 16.0±4.8 s. The difference is statistically significant (p<0.05). This result suggests that the developed game system is useful for the evaluation of the DT performance

    LPD after RHC for ascending colon cancer

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    Laparoscopic pancreaticoduodenectomy (LPD) has been widely adopted in institutions with sufficiently skilled practitioners. This technique requires attentive dissection around the superior mesenteric vein (SMV) and artery. Dissection around the SMV and Henle’s trunk is one of the key aspects of right hemicolectomy (RHC) ; adhesions and fibrosis around these vessels may impede LPD in patients with a history of RHC. We encountered three cases of periampullary tumors in patients with a history of RHC who were successfully treated with LPD. Cases 1, 2, and 3 were of 60-, 73-, and 74-year-old men with periampullary tumors. The operative durations in cases 1, 2, and 3 were 316, 267, and 265 min, respectively. The estimated blood loss volumes in cases 1, 2, and 3 were 20, 50, and 720 mL, respectively. The postoperative hospital stay durations in cases 1, 2, and 3 were of 13, 35, and 15 days, respectively. In conclusion, LPD following RHC may be safely completed with laparoscopy

    Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

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    <p>Abstract</p> <p>Background</p> <p>Chinchillas (<it>Chinchilla laniger</it>) are popular as pets and are often used as laboratory animals for various studies. <it>Pseudomonas aeruginosa </it>is a major infectious agent that causes otitis media, pneumonia, septicaemia enteritis, and sudden death in chinchillas. This bacterium is also a leading cause of nosocomial infections in humans. To prevent propagation of <it>P. aeruginosa </it>infection among humans and animals, detailed characteristics of the isolates, including antibiotic susceptibility and genetic features, are needed. In this study, we surveyed <it>P. aeruginosa </it>distribution in chinchillas bred as pets or laboratory animals. We also characterized the isolates from these chinchillas by testing for antibiotic susceptibility and by gene analysis.</p> <p>Results</p> <p><it>P. aeruginosa </it>was isolated from 41.8% of the 67 chinchillas included in the study. Slide agglutination and pulsed-field gel electrophoresis discriminated 5 serotypes and 7 unique patterns, respectively. For the antibiotic susceptibility test, 40.9% of isolates were susceptible to gentamicin, 77.3% to ciprofloxacin, 77.3% to imipenem, and 72.7% to ceftazidime. DNA analyses confirmed that none of the isolates contained the gene encoding extended-spectrum β-lactamases; however, 2 of the total 23 isolates were found to have a gene similar to the <it>pilL </it>gene that has been identified in the pathogenicity island of a clinical isolate of <it>P. aeruginosa</it>.</p> <p>Conclusions</p> <p><it>P. aeruginosa </it>is widely spread in chinchillas, including strains with reduced susceptibility to the antibiotics and highly virulent strains. The periodic monitoring should be performed to help prevent the propagation of this pathogen and reduce the risk of infection from chinchillas to humans.</p

    Low-fat Elemental Enteral Nutrition in the Management of Pediatric Acute Pancreatitis

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    Acute pancreatitis(AP)in childhood is rare, but is starting to be recognized more often. However, optimal enteral nutrition formulas for children with AP have not been determined. This report describes the successful management of AP, with low-fat elemental enteral nutrition, in a 5-year-old boy. The patient had been diagnosed with mild AP and started oral feeding after about 3 days of fasting, but his pancreatic enzyme levels subsequently became elevated. Therefore, to allow the pancreas to rest, total parenteral nutrition(TPN)was started. After starting TPN, there was no improvement in his pancreatic enzyme levels but, because his clinical symptoms were stable, a small amount of elemental diet was initiated. Elemental diet therapy was safely performed without return of any clinical symptoms and the patient’s pancreatic enzyme levels slowly improved. Elemental diet was both safe and beneficial, providing clinical remission and improvement in quality of life. Early elemental diet therapy may therefore be a useful treatment strategy for pediatric patients with AP

    Role of neurosteroid allopregnanolone on age-related differences in exercise-induced hypoalgesia in rats

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    The beneficial effects of physical activity for pain are denominated exercise-induced hypoalgesia (EIH). Here, we examined the age-related change and potential role of the neurosteroid allopregnanolone (ALLO) on EIH in rats. Adult and aged rats were randomly divided into one of three groups; non-exercise control, Low-exercise, and High-exercise. The animals in the Low- and High-exercise groups were subjected to a 10-minute treadmill workout at 40% and 80% maximum oxygen intake intensity, respectively. In the Low-exercise groups, a significant EIH response was observed in aged but not in adult rats. The pre-treatment with ALLO synthesis inhibitor finasteride, but not opioid-receptor antagonist naloxone, inhibited the Low-exercise induced EIH response in aged rats. Furthermore, the Low-exercise increased brain ALLO levels in aged animals compared with controls, which was correlated with the mechanical pain sensitivity. On the other hand, High-exercise could induce EIH response in both adult and aged animals, but it was more effective in adult rats. The pre-treatment with naloxone, but not finasteride, reduced the EIH observed after High-exercise in both adult and aged rats. Our findings demonstrated that effective EIH can be achieved even by mild-intensity exercise in aged animals via an increase of the brain ALLO levels

    Resveratrol-loaded nanoemulsion prevents cognitive decline after abdominal surgery in aged rats

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    The maladaptive response of aged microglia to surgery and consequent neuroinflammation plays a key pathogenic role in postoperative cognitive dysfunction (POCD). Here, we assessed the preventive effect of resveratrol (RESV) for POCD in aged rats. The emulsified form of RESV (e-RESV) was selected to improve its oral and brain bioavailability. Animals were assigned to one of four groups: e-RESV (80 mg/kg) versus vehicle treatment by abdominal surgery versus isoflurane anesthesia alone (n = 8 in each group). The dose-dependent effects of e-RESV were also assessed in dose range of 0e60 mg/kg. Either vehicle or e-RESV was administered intragastrically 24 h before surgery. Seven days after procedure, cognitive function was evaluated using a novel object recognition test, followed by measurement of hippocampal pro-inflammatory cytokine levels. Our results showed that pre-treatment with e-RESV attenuated the surgery-induced cognitive impairment and related hippocampal neuroinflammation at 40 mg/kg or higher doses. Additionally, the ex-vivo experiments revealed that the preemptive e-RESV regimen reduced the hippocampal microglial immune reactivity to lipopolysaccharide. Furthermore, e-RESV induced neuroprotective benefits were inhibited by the concomitant administration of sirtinol, a specific SIRT1 inhibitor. Our findings imply the preventive potential of e-RESV for POCD via the SIRT1 signaling pathway

    Evaluation of Setup Errors at the Skin Surface Position for Whole Breast Radiotherapy of Breast Cancer Patients

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    We used image-processing software to analyze the setup errors at the skin surface position of breast cancer patients (n=66) who underwent post-operative whole breast irradiation at our hospital in 2014-2015. The sixty-six digital reconstructed radiographs (DRR) were created at the treatment planning for each patient. The lineacgraphies (n=377) were taken after the patients’ setup during radiotherapy. The lineacgraphies and DRR were superimposed at the skin surface position for each patient with the image-processing software. We measured the deviations of the isocenters for the nipple-lung (X) direction and craniocaudal (Y) direction and the deviation of the rotation angle of the XY axes between the lineacgraphy and DRR on the superimposed images. The systematic error (μ, Σ) and random error (σ) were calculated from the X and Y deviations and rotation angle deviation. The μ of X, Y, and rotation angle were 0.01 mm, −1.2 mm, and 0.05°, respectively. The Σ of X, Y, and rotation angle were 1.8 mm, 1.5 mm, and 0.9°, respectively. The σ of X, Y, and rotation angle were 2.0 mm, 1.5 mm, and 1.0°, respectively. Our analyses thus revealed that evaluations using image-processing software at the skin surface position in routine breast radiotherapy result in sufficiently small setup errors

    Jiadifenolide induces the expression of cellular communication network factor (CCN) genes, and CCN2 exhibits neurotrophic activity in neuronal precursor cells derived from human induced pluripotent stem cells

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    Jiadifenolide has been reported to have neurotrophin-like activity in primary rat cortical neurons, and also possesses neurotrophic effects in neuronal precursor cells derived from human induced pluripotent stem cells (hiPSCs), as we have previously reported. However, the molecular mechanisms by which jiadifenolide exerts its neurotrophic effects in rat and human neurons are unknown. Thus, we aimed to investigate the molecular mechanisms and pathways by which jiadifenolide promotes neurotrophic effects. Here, we found that jiadifenolide activated cellular communication network factor (CCN) signaling pathways by up-regulating mRNA level expression of CCN genes in human neuronal cells. We also found that CCN2 (also known as connective tissue growth factor, CTGF) protein promotes neurotrophic effects through activation of the p44/42 mitogen-activated protein kinase signaling pathway. This is the first discovery which links neurotrophic activity with CCN signaling
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