217 research outputs found

    Robust regression for highly corrupted response by shifting outliers

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    Outlying observations are often disregarded at the sacrifice of degrees of freedom or downsized via robust loss functions (e.g., Huber's loss) to reduce the undesirable impact on data analysis. In this article, we treat the outlying status of each observation as a parameter and propose a penalization method to automatically adjust the outliers. The proposed method shifts the outliers towards the fitted values, while preserve the non-outlying observations. We also develop a generally applicable algorithm in the iterative fashion to estimate model parameters and demonstrate the connection with the maximum likelihood based estimation procedure in the case of least squares estimation. We establish asymptotic property of the resulting parameter estimators under the condition that the proportion of outliers does not vanish as sample size increases. We apply the proposed outlier adjustment method to ordinary least squares and lasso-type penalization procedure and demonstrate its empirical value via numeric studies. Furthermore, we study applicability of the proposed method to two robust estimators, Huber's robust estimator and Huberized lasso, and demonstrate its noticeable improvement of model fit in the presence of extremely large outliers

    The Korean Mistletoe (Viscum album coloratum) Extract Has an Antiobesity Effect and Protects against Hepatic Steatosis in Mice with High-Fat Diet-Induced Obesity

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    This study investigates the inhibitory effects of Korean mistletoe extract (KME) on adipogenic factors in 3T3-L1 cells and obesity and nonalcoholic fatty liver disease (NAFLD) in mice fed a high-fat diet. Male C57Bl/6 mice fed a high-fat diet were treated with KME (3ā€‰g/kg/day) for 15 weeks for the antiobesity and NAFLD experiments. Body weight and daily food intake were measured regularly during the experimental period. The epididymal pad was measured and liver histology was observed. The effects of KME on thermogenesis and endurance capacity were measured. The effects of KME on adipogenic factors were examined in 3T3-L1 cells. Body and epididymal fat pad weights were reduced in KME-treated mice, and histological examination showed an amelioration of fatty liver in KME-treated mice, without an effect on food consumption. KME potently induces mitochondrial activity by activating thermogenesis and improving endurance capacity. KME also inhibited adipogenic factors in vitro. These results demonstrate the inhibitory effects of KME on obesity and NAFLD in mice fed a high-fat diet. The effects appear to be mediated through an enhanced mitochondrial activity. Therefore, KME may be an effective therapeutic candidate for treating obesity and fatty liver caused by a high-fat diet

    Absorbable Plate as a Perpendicular Strut for Acute Saddle Nose Deformities

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    BackgroundNasal pyramid fractures accompanied by saddle nose deformities are not easily corrected by closed reduction. We used an absorbable plate as a perpendicular strut to support the collapsed "keystone area" and obtained good results.MethodsBetween September 2008 and June 2011, 18 patients who had nasal pyramid fractures with saddle nose deformities underwent surgery. Pre- and postoperative facial computed tomographic images and photographs were taken to estimate outcomes. The operative technique included the mucoperichondrial dissection of the nasal septum, insertion of an absorbable plate prepared to an appropriate length to support the "keystone area", and fixation of the absorbable plate strut to the cartilaginous septum.ResultsFunctional and esthetic outcomes were satisfactory in all patients. Eleven patients assessed the postoperative appearance of the external nose as 'markedly improved' and 7 patients as 'improved'. The 5 surgeons scored the results as a mean of 4.5 on a 5-point scale.ConclusionsThe use of an absorbable plate as a perpendicular strut requires no additional procedures because the plate is gradually absorbed. The mechanical strength provided by a buttress between the "keystone area" and the maxillary crest lasts for a long time before the strut is absorbed

    Rapid Clinical Course of Cerebral Metastatic Angiosarcoma from the Heart

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    We report here one case of rapid and aggressive course of cerebral metastatic angiosarcoma from the heart. A 36-year-old man presented with 10-days history of headache. Magnetic resonance imaging demonstrated subacute hemorrhage with a small region of enhancement in right parietal region and the pathological diagnosis was angiosarcoma. Transthoracic echocardiography demonstrated 3.2Ɨ3 cm sized mass on right atrial wall. Newly developed lesion was reoperated, three and four weeks later respectively, and whole brain radiotherapy of total 30 Gy was done. With the interval of two months, gamma knife surgery was done for new lesions two times, which were well controlled. Newly developed lesions rapidly happened even in the adjuvant treatment. He died 9 months after the diagnosis because of the aggravation of primary cancer. The cerebral metastatic angiosarcoma from the heart showed the rapid aggressive behavior and the closed follow-up could be needed for the adjuvant treatment

    Randomized Trial of Stents VersusĀ Bypass Surgery for Left Main Coronary Artery Disease 5-Year Outcomes of the PRECOMBAT Study

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    AbstractBackgroundIn a previous randomized trial, we found that percutaneous coronary intervention (PCI) was not inferior to coronary artery bypass grafting (CABG) for the treatment of unprotected left main coronary artery stenosis at 1 year.ObjectivesThis study sought to determine the 5-year outcomes of PCI compared with CABG for the treatment of unprotected left main coronary artery stenosis.MethodsWe randomly assigned 600 patients with unprotected left main coronary artery stenosis to undergo PCI withĀ a sirolimus-eluting stent (nĀ = 300) or CABG (nĀ = 300). The primary endpoint was a major adverse cardiac or cerebrovascular event (MACCE: a composite of death from any cause, myocardial infarction, stroke, or ischemia-driven target vessel revascularization) and compared on an intention-to-treat basis.ResultsAt 5 years, MACCE occurred in 52 patients in the PCI group and 42 patients in the CABG group (cumulative event rates of 17.5% and 14.3%, respectively; hazard ratio [HR]: 1.27; 95% confidence interval [CI]: 0.84 to 1.90; pĀ =Ā 0.26). The 2 groups did not differ significantly in terms of death from any cause, myocardial infarction, or stroke as well as their composite (8.4% and 9.6%; HR, 0.89; 95% CI, 0.52 to 1.52; pĀ = 0.66). Ischemia-driven target vessel revascularization occurred more frequently in the PCI group than in the CABG group (11.4% and 5.5%, respectively; HR:Ā 2.11; 95% CI: 1.16 to 3.84; pĀ = 0.012).ConclusionsDuring 5 years of follow-up, our study did not show significant difference regarding the rate ofĀ MACCE between patients who underwent PCI with a sirolimus-eluting stent and those who underwent CABG. However, considering the limited power of our study, our results should be interpreted with caution. (Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease [PRECOMBAT]; NCT00422968

    Strong Bathochromic Shift of Conjugated Polymer Nanowires Assembled with a Liquid Crystalline Alkyl Benzoic Acid via a Film Dispersion Process

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    We present aqueous dispersions of conjugated polymer nanowires (CPNWs) with improved light absorption properties aimed at aqueous-based applications. We assembled films of a donor???acceptor-type conjugated polymer and liquid crystalline 4-n-octylbenzoic acid by removing a cosolvent of their mixture solutions, followed by annealing of the films, and then formed aqueous-dispersed CPNWs with an aspect ratio >1000 by dispersing the films under ultrasonication at a basic pH. X-ray and spectroscopy studies showed that the polymer and liquid crystal molecules form independent domains in film assemblies and highly organized layer structures in CPNWs. Our ordered molecular assemblies in films and aqueous dispersions of CPNWs open up a new route to fabricate nanowires of low-band-gap linear conjugated polymers with the absorption maximum at 794 nm remarkably red-shifted from 666 nm of CPNWs prepared by an emulsion process. Our results suggest the presence of semicrystalline polymorphs ??1 and ??2 phases in CPNWs due to long-range ??????? stacking of conjugated backbones in compactly organized lamellar structures. The resulting delocalization with a reduced energy bang gap should be beneficial for enhancing charge transfer and energy-conversion efficiencies in aqueous-based applications such as photocatalysis

    Prediction of Specific Anxiety Symptoms and Virtual Reality Sickness Using In Situ Autonomic Physiological Signals During Virtual Reality Treatment in Patients With Social Anxiety Disorder: Mixed Methods Study

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    Background: Social anxiety disorder (SAD) is the fear of social situations where a person anticipates being evaluated negatively. Changes in autonomic response patterns are related to the expression of anxiety symptoms. Virtual reality (VR) sickness can inhibit VR experiences. Objective: This study aimed to predict the severity of specific anxiety symptoms and VR sickness in patients with SAD, using machine learning based on in situ autonomic physiological signals (heart rate and galvanic skin response) during VR treatment sessions. Methods: This study included 32 participants with SAD taking part in 6 VR sessions. During each VR session, the heart rate and galvanic skin response of all participants were measured in real time. We assessed specific anxiety symptoms using the Internalized Shame Scale (ISS) and the Post-Event Rumination Scale (PERS), and VR sickness using the Simulator Sickness Questionnaire (SSQ) during 4 VR sessions (#1, #2, #4, and #6). Logistic regression, random forest, and naive Bayes classification classified and predicted the severity groups in the ISS, PERS, and SSQ subdomains based on in situ autonomic physiological signal data. Results: The severity of SAD was predicted with 3 machine learning models. According to the F1 score, the highest prediction performance among each domain for severity was determined. The F1 score of the ISS mistake anxiety subdomain was 0.8421 using the logistic regression model, that of the PERS positive subdomain was 0.7619 using the naive Bayes classifier, and that of total VR sickness was 0.7059 using the random forest model. Conclusions: This study could predict specific anxiety symptoms and VR sickness during VR intervention by autonomic physiological signals alone in real time. Machine learning models can predict the severe and nonsevere psychological states of individuals based on in situ physiological signal data during VR interventions for real-time interactive services. These models can support the diagnosis of specific anxiety symptoms and VR sickness with minimal participant bias
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