79 research outputs found
Entropy fluctuation formulas of fermionic Gaussian states
We study the statistical behaviour of quantum entanglement in bipartite
systems over fermionic Gaussian states as measured by von Neumann entropy. The
formulas of average von Neumann entropy with and without particle number
constrains have been recently obtained, whereas the main results of this work
are the exact yet explicit formulas of variances for both cases. For the latter
case of no particle number constrain, the results resolve a recent conjecture
on the corresponding variance. Different than existing methods in computing
variances over other generic state models, the key ingredient in proving the
results of this work relies on a new simplification framework. The framework
consists of a set of new tools in simplifying finite summations of what we
refer to as dummy summation and re-summation techniques. As a byproduct, the
proposed framework leads to various new transformation formulas of
hypergeometric functions.Comment: 64 pages, 3 figure
Saikosaponins induced hepatotoxicity in mice via lipid metabolism dysregulation and oxidative stress: a proteomic study
Background Radix Bupleuri (RB) has been popularly used for treating many liver diseases such as chronic hepatic inflammation and viral Hepatitis in China. Increasing clinical and experimental evidence indicates the potential hepatotoxicity of RB or prescriptions containing RB. Recently, Saikosaponins (SS) have been identified as major bioactive compounds isolated from RB, which may be also responsible for RB-induced liver injury. Methods Serum AST, ALT and LDH levels were determined to evaluate SS-induced liver injury in mice. Serum and liver total triglyceride and cholesterol were used to indicate lipid metabolism homeostasis. Liver ROS, GSH, MDA and iNOS were used to examine the oxidative stress level after SS administration. Western blot was used to detect CYP2E1 expression. A 8-Plex iTRAQ Labeling Coupled with 2D LC - MS/MS technique was applied to analyze the protein expression profiles in livers of mice administered with different doses of SS for different time periods. Gene ontology analysis, cluster and enrichment analysis were employed to elucidate potential mechanism involved. HepG2 cells were used to identify our findings in vitro. Results SS dose- and time-dependently induced liver injury in mice, indicated by increased serum AST, ALT and LDH levels. According to proteomic analysis, 487 differentially expressed proteins were identified in mice administrated with different dose of SS for different time periods. Altered proteins were enriched in pathways such as lipid metabolism, protein metabolism, macro molecular transportation, cytoskeleton structure and response to stress. SS enhanced CYP2E1 expression in a time and dose dependent manner, and induced oxidative stress both in vivo and in vitro. Conclusion Our results identified hepatotoxicity and established dose-time course-liver toxicity relationship in mice model of SS administration and suggested potential mechanisms, including impaired lipid and protein metabolism and oxidative stress. The current study provides experimental evidence for clinical safe use of RB, and also new insights into understanding the mechanism by which SS and RB induced liver injury
α1A-Adrenergic Receptor Induces Activation of Extracellular Signal-Regulated Kinase 1/2 through Endocytic Pathway
G protein-coupled receptors (GPCRs) activate mitogen-activated protein kinases through a number of distinct pathways in cells. Increasing evidence has suggested that endosomal signaling has an important role in receptor signal transduction. Here we investigated the involvement of endocytosis in α1A-adrenergic receptor (α1A-AR)-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Agonist-mediated endocytic traffic of α1A-AR was assessed by real-time imaging of living, stably transfected human embryonic kidney 293A cells (HEK-293A). α1A-AR was internalized dynamically in cells with agonist stimulation, and actin filaments regulated the initial trafficking of α1A-AR. α1A-AR-induced activation of ERK1/2 but not p38 MAPK was sensitive to disruption of endocytosis, as demonstrated by 4°C chilling, dynamin mutation and treatment with cytochalasin D (actin depolymerizing agent). Activation of protein kinase C (PKC) and C-Raf by α1A-AR was not affected by 4°C chilling or cytochalasin D treatment. U73122 (a phospholipase C [PLC] inhibitor) and Ro 31–8220 (a PKC inhibitor) inhibited α1B-AR- but not α1A-AR-induced ERK1/2 activation. These data suggest that the endocytic pathway is involved in α1A-AR-induced ERK1/2 activation, which is independent of Gq/PLC/PKC signaling
Machine Learning Applications in Head and Neck Radiation Oncology: Lessons From Open-Source Radiomics Challenges
Radiomics leverages existing image datasets to provide non-visible data extraction via image post-processing, with the aim of identifying prognostic, and predictive imaging features at a sub-region of interest level. However, the application of radiomics is hampered by several challenges such as lack of image acquisition/analysis method standardization, impeding generalizability. As of yet, radiomics remains intriguing, but not clinically validated. We aimed to test the feasibility of a non-custom-constructed platform for disseminating existing large, standardized databases across institutions for promoting radiomics studies. Hence, University of Texas MD Anderson Cancer Center organized two public radiomics challenges in head and neck radiation oncology domain. This was done in conjunction with MICCAI 2016 satellite symposium using Kaggle-in-Class, a machine-learning and predictive analytics platform. We drew on clinical data matched to radiomics data derived from diagnostic contrast-enhanced computed tomography (CECT) images in a dataset of 315 patients with oropharyngeal cancer. Contestants were tasked to develop models for (i) classifying patients according to their human papillomavirus status, or (ii) predicting local tumor recurrence, following radiotherapy. Data were split into training, and test sets. Seventeen teams from various professional domains participated in one or both of the challenges. This review paper was based on the contestants' feedback; provided by 8 contestants only (47%). Six contestants (75%) incorporated extracted radiomics features into their predictive model building, either alone (n = 5; 62.5%), as was the case with the winner of the “HPV” challenge, or in conjunction with matched clinical attributes (n = 2; 25%). Only 23% of contestants, notably, including the winner of the “local recurrence” challenge, built their model relying solely on clinical data. In addition to the value of the integration of machine learning into clinical decision-making, our experience sheds light on challenges in sharing and directing existing datasets toward clinical applications of radiomics, including hyper-dimensionality of the clinical/imaging data attributes. Our experience may help guide researchers to create a framework for sharing and reuse of already published data that we believe will ultimately accelerate the pace of clinical applications of radiomics; both in challenge or clinical settings
Development of low-temperature fusion using ammonium hydrogen fluoride for rapid determination of actinides in environmental and nuclear decommissioning samples
In this study, a green and rapid analytical method was developed for determination of 237Np and Pu isotopes in environmental and nuclear decommissioning samples, such as soil, marine sediment and concrete samples. The methods consisted of NH4HF2 fusion incorporated with procedure for CaF2/LaF3 co-precipitation, extraction chromatography or anion-exchange chromatography and ICP-MS measurement. ICP-MS, as an atom-counting approach that counts the atoms themselves, irrespective of their decay mode, specific activity, or half-life, is gradually replacing/has replaced conventional radiometric methods, for ultra-sensitive analysis of actinides. The fusion procedure was done at 250oC on a portable hot plate instead of in a cumbersome muffle furnace and took only 15 min. Chemical recoveries of 237Np and Pu after completing the NH4HF2 fusion method and chromatographic separation for 0.5-1 g sample were approximately 70-90%. The NH4HF2 fusion was capable of completely releasing actinides from samples that were pre-ignited at temperatures over 450 oC to 1000 oC, which was comparable to releases obtained by the hazardous and time-consuming HNO3-HF digestion. Additionally, because HF is not used in any procedure of the NH4HF2 fusion, a safer and greener alternative to HNO3-HF digestion is realized for rapid 237Np and Pu isotopes determination in soil, marine sediment and concrete samples. It takes approximately one day for 10 sample analysis (NH4HF2 fusion and sample transferring, 0.5 h; CaF2/LaF3 coprecipitation and filtration, 1.5 h; chromatographic separation and sample preparation, 5.5 h; ICP-MS measurement, 0.5 h) which is less than the conventional acid digestion methods.日本分析化学会第68年
Low-temperature fusion using NH4HF2 for rapid determination of Pu isotopes by ICP-MS/MS: application for marine sediments collected in Japanese coast
ICP-MS, as an atom-counting approach that counts the atoms themselves, irrespective of their decay mode, specific activity, or half-life, is gradually replacing/has replaced conventional radiometric methods, especially, due to its high abundance sensitivity and the ability of removal of polyatomic interference via ion-molecular reaction in the reaction cell, the triple quadrupole ICP-MS (ICP-MS/MS) showed great potential for ultra-sensitive analysis of actinides. Sample decomposition is an early and critical part of the analytical procedures which transform Pu into solute form so as to realize subsequent chemical purification before measurement. There are roughly two broad categories of sample decomposition strategies, i.e. acid digestion and fusion. Acid digestion is accomplished using a single acid such as HNO3 or mixed acids such as HNO3-HCl, HNO3-HF and HNO3-HF-HClO4. Fusion is a useful sample decomposition strategy which is accomplished by heating a mixture of sample and flux to a temperature above the flux melting point. Compared with the conventional acid digestion methods, the times required for fusion methods are reduced to various extents. Additionally, a thorough dissolution of Pu from samples is realizable via a complete decomposition of the sample by fusion with properly selected fluxes. However, due to the high melting point of the commonly used fluxes, most fusion methods in the literature are done in furnaces at high temperatures. In this study, a green and rapid analytical method was developed for determination of Pu isotopes in marine sediment samples. The methods consisted of NH4HF2 fusion incorporated with procedure for CaF2/LaF3 co-precipitation, extraction chromatography and ICP-MS/MS measurement. The fusion procedure was done at 250oC on a portable hot plate instead of in a cumbersome muffle furnace and took only 15 min. Chemical recoveries of Pu after completing the NH4HF2 fusion method and chromatographic separation for 0.5-1 g sample were approximately 90%. The NH4HF2 fusion was capable of completely releasing Pu from samples that were pre-ignited at temperatures over 450 oC to 1000 oC, which was comparable to releases obtained by the hazardous and time-consuming HNO3-HF digestion. Additionally, because HF is not used in any procedure of the NH4HF2 fusion, a safer and greener alternative to HNO3-HF digestion is realized for rapid Pu determination in marine sediments collected in Japanese coast after the Fukushima nuclear accident. It takes approximately 8 h for 10 sample analysis (NH4HF2 fusion and sample transferring, 0.5 h; CaF2/LaF3 coprecipitation and filtration, 1.5 h; extraction chromatography and sample preparation, 5.5 h; ICP-MS/MS measurement, 0.5 h) which is less than the conventional acid digestion methods. Acknowledgements: This work was supported by the Grant of Fukushima Prefecture related to Research and Development in Radiological Sciences, and the JSPS KAKENHI (Grant number JP17k00537).The The 20th KEK Symposium on Environmental Radioactivit
Line of Sight and Image Motion Compensation for Step and Stare Imaging System
In recent years, applications such as marine search and rescue, border patrol, etc. require electro-optical equipment to have both high resolution and precise geographic positioning abilities. The step and stare working based on a composite control system is a preferred solution. This paper proposed a step and stare system composed of two single-axis fast steering mirrors and a two-axis gimbal. The fast steering mirrors (FSMs) realize image motion compensation and the gimbal completes pointing control. The working principle and the working mode of the system are described first. According to the imaging optical path, the algorithm and control flow of the line of sight (LOS) and image motion compensation are developed. The proposed method is verified through ground imaging and flight tests. Under the condition of flight, the pointing accuracy of the target can be controlled within 15 m. The proposed algorithm can achieve effective motion compensation and get high-resolution images. This achieves high resolution and accurate LOS simultaneously
chngpt: threshold regression model estimation and inference
Abstract Background Threshold regression models are a diverse set of non-regular regression models that all depend on change points or thresholds. They provide a simple but elegant and interpretable way to model certain kinds of nonlinear relationships between the outcome and a predictor. Results The R package chngpt provides both estimation and hypothesis testing functionalities for four common variants of threshold regression models. All allow for adjustment of additional covariates not subjected to thresholding. We demonstrate the consistency of the estimating procedures and the type 1 error rates of the testing procedures by Monte Carlo studies, and illustrate their practical uses using an example from the study of immune response biomarkers in the context of Mother-To-Child-Transmission of HIV-1 viruses. Conclusion chngpt makes several unique contributions to the software for threshold regression models and will make these models more accessible to practitioners interested in modeling threshold effects
Low-temperature fusion using NH4HF2 for rapid determination of Pu isotopes by ICP-MS/MS: application for marine sediments collected in Japanese coast.
In this study, a green and rapid analytical method was developed for determination of Pu isotopes in marine sediment samples. The methods consisted of low temperature NH4HF2 fusion incorporated with procedure for CaF2/LaF3 co-precipitation, extraction chromatography and ICP-MS/MS measurement. The fusion procedure was done at 250oC on a portable hot plate instead of in a cumbersome muffle furnace and took only 15 min. Chemical recoveries of Pu after completing the NH4HF2 fusion method and chromatographic separation for 0.5-1 g sample were approximately 90%. This fusion method was capable of releasing refractory Pu from samples. Additionally, because HF is not used in the NH4HF2 fusion method, a safer and greener alternative to HNO3-HF digestion is realized for rapid Pu determination in marine sediments collected in Japanese coast after the Fukushima nuclear accident
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