252 research outputs found
Improved Probability Method for Estimating Signal in the Presence of Background
A suggestion is made for improving the Feldman Cousins method of estimating
signal counts in the presence of background. The method concentrates on finding
essential information about the signal and ignoring extraneous information
about background. An appropriate method is found which uses the condition that
the number of background events obtained does not exceed the total number of
events obtained. Several alternative approaches are explored.Comment: Modified 12/21 for singlespace to save trees, 9 pages, 1 figure.
Modified 8/11/99 to add small modifications made for the Phys. Rev. articl
Molecular engineering strategies for expanding the capabilities of fluorescent zinc (II) sensors
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.Vita.Includes bibliographical references.(cont.) affords the two fluorophores, such that excitation of the coumarin at 445 nm and measurement of the emission at 488 nm affords information of the amount of sensor present, while excitation of the fluorescein at 505 nm and measurement of the emission at 535 nm indicates the amount of sensor in the zinc(II)-bound form. This system has been characterized and applied to the study of exogenous zinc(II) fluxes in HeLa cells. Chapter 4: Unimolecular Two-Fluorophore Ratiometric Zn²⁺ Sensing Systems. Dichlorofluorescein compounds covalently bound to zinc(II)-insensitive reporter fluorophores via a rigid cyclohexyl linker have been prepared and characterized. Based on favorable photophysical properties, a Zinpyr-1 species covalently bound to coumarin 343 has been prepared and shown to afford a ratiometric response to excess zinc(II). Chapter 5: ZPI Synthons for Functionalization of Biological Targets. Installation of a functional group prior to Mannich reaction is impractical in many cases. This chapter describes the preparation of reactive ZP1 synthons for direct functionalization of biological targets containing an amine or azide, and reports applications to the synthesis of ZPI conjugates. Appendix 1: Synthetic Approaches to Other Isomerically Pure Functionalizable Fluorophores. Crystallization approaches have been applied to separate fluorescein 5- and 6-sulfonic acid, and subsequent generation of the sulfonyl chlorides is discussed. A dibromofluoran approach to isomerically pure rhodamine carboxylates is based on a similar separation. Basic hydrolysis of the previously described 2',7'-dichlorofluorescein ...Chapter 1: The Development and Use of Fluorescent Sensors in the Imaging of Physiological Zinc(II): A Review This chapter presents an overview of fluorescent techniques used to image chelatable zinc(II) in vivo. Many intensity-based sensors take advantage of photoinduced electron transfer quenching pathways. Peptide- and protein-based sensors offer excellent selectivity but are poorly suited to intracellular applications. Recently, ratiometric sensors in which the zinc(II) binding event interrupts or alters conjugation within the fluorophore have been described. Chapter 2: Carboxylate-Functionalized Zinpyr-1 Sensors: Synthesis, Characterization, and In Vivo Staining Patterns. A class of Zinpyr-1 sensors containing a carboxylic acid or ester at the 5- or 6-position of the fluorescein has been prepared. These sensors offer decreased background fluorescence and enhanced fluorescence response compared to the parent Zinpyr-1. The acid-functionalized sensors bear a negative charge at physiological pH, rendering them cell-impermeable. The esterified sensors are cell-permeable, but are hydrolyzed in vivo by intracellular esterases, affording a clear delineation of zinc(II)-containing damaged neurons in mechanically-injured or seizure-induced rats, rather than the punctate staining pattern obtained with Zinpyr-1. Chapter 3: Esterase-Dependent Two-Fluorophore Ratiometric Sensing of Zinc(II). This chapter describes a new approach to ratiometric sensing in which a zinc(II)-sensitive fluorescein fluorophore based on Zinpyr-1 is functionalized with a zinc(lI)-insensitive coumarin fluorophore via a flexible ester linker. The flexible linker enables intramolecular quenching of the two fluorophores. Esterase hydrolysis of the linkerby Carolyn C. Woodroofe.Ph.D
Inference for bounded parameters
The estimation of signal frequency count in the presence of background noise
has had much discussion in the recent physics literature, and Mandelkern [1]
brings the central issues to the statistical community, leading in turn to
extensive discussion by statisticians. The primary focus however in [1] and the
accompanying discussion is on the construction of a confidence interval. We
argue that the likelihood function and -value function provide a
comprehensive presentation of the information available from the model and the
data. This is illustrated for Gaussian and Poisson models with lower bounds for
the mean parameter
On the future of astrostatistics: statistical foundations and statistical practice
This paper summarizes a presentation for a panel discussion on "The Future of
Astrostatistics" held at the Statistical Challenges in Modern Astronomy V
conference at Pennsylvania State University in June 2011. I argue that the
emerging needs of astrostatistics may both motivate and benefit from
fundamental developments in statistics. I highlight some recent work within
statistics on fundamental topics relevant to astrostatistical practice,
including the Bayesian/frequentist debate (and ideas for a synthesis),
multilevel models, and multiple testing. As an important direction for future
work in statistics, I emphasize that astronomers need a statistical framework
that explicitly supports unfolding chains of discovery, with acquisition,
cataloging, and modeling of data not seen as isolated tasks, but rather as
parts of an ongoing, integrated sequence of analyses, with information and
uncertainty propagating forward and backward through the chain. A prototypical
example is surveying of astronomical populations, where source detection,
demographic modeling, and the design of survey instruments and strategies all
interact.Comment: 8 pp, 2 figures. To appear in "Statistical Challenges in Modern
Astronomy V," (Lecture Notes in Statistics, Vol. 209), ed. Eric D. Feigelson
and G. Jogesh Babu; publication planned for Sep 2012; see
http://www.springer.com/statistics/book/978-1-4614-3519-
Transcriptome analysis suggests a role for the differential expression of cerebral aquaporins and the MAPK signalling pathway in human temporal lobe epilepsy
Epilepsies are common disorders of the central nervous system (CNS), affecting up to 2% of the global population. Pharmaco-resistance is a major clinical challenge affecting about 30% of temporal lobe epilepsy (TLE) patients. Water homeostasis has been shown crucial for regulation of neuronal excitability. The control of water movement is achieved through a family of small integral membrane channel proteins called aquaporins (AQPs). Despite the fact that changes in water homeostasis occur in sclerotic hippocampi of people with TLE, the expression of AQPs in the epileptic brain is not fully characterised. This study uses microarray and ELISA methods to analyse the mRNA and protein expression of the human cerebral AQPs in sclerotic hippocampi (TLE-HS) and adjacent neocortex tissue (TLE-NC) of TLE patients. The expression of AQP1 and AQP4 transcripts was significantly increased, while that of the AQP9 transcript was significantly reduced in TLE-HS compared to TLE-NC. AQP4 protein expression was also increased while expression of AQP1 protein remained unchanged, and AQP9 was undetected. Microarray data analysis identified 3,333 differentially regulated genes and suggested the involvement of the MAPK signalling pathway in TLE pathogenesis. Proteome array data validated the translational profile for 26 genes and within the MAPK pathway (e.g. p38, JNK) that were identified as differentially expressed from microarray analysis. ELISA data showed that p38 and JNK inhibitors decrease AQP4 protein levels in cultured human primary cortical astrocytes. Elucidating the mechanism of selective regulation of different AQPs and associated regulatory proteins may provide a new therapeutic approach to epilepsy treatment. This article is protected by copyright. All rights reserved
Click beetle luciferase mutant and near infrared naphthyl-luciferins for improved bioluminescence imaging
The sensitivity of bioluminescence imaging in animals is primarily dependent on the amount of photons emitted by the luciferase enzyme at wavelengths greater than 620 nm where tissue penetration is high. This area of work has been dominated by firefly luciferase and its substrate, D-luciferin, due to the system's peak emission (~ 600 nm), high signal to noise ratio, and generally favorable biodistribution of D-luciferin in mice. Here we report on the development of a codon optimized mutant of click beetle red luciferase that produces substantially more light output than firefly luciferase when the two enzymes are compared in transplanted cells within the skin of black fur mice or in deep brain. The mutant enzyme utilizes two new naphthyl-luciferin substrates to produce near infrared emission (730 nm and 743 nm). The stable luminescence signal and near infrared emission enable unprecedented sensitivity and accuracy for performing deep tissue multispectral tomography in mice
Expression of costimulatory molecules B7-1 (CD80), B7-2 (CD86), and interleukin 12 cytokine in multiple sclerosis lesions.
Click beetle luciferase mutant and near infrared naphthyl-luciferins for improved bioluminescence imaging
Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
Click beetle luciferase mutant and near infrared naphthyl-luciferins for improved bioluminescence imaging
Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment
Background
Breast cancer survivors often encounter physiological and psychological problems related to their diagnosis and treatment that can influence long-term prognosis. The aim of this research is to investigate the effects of a lifestyle intervention on body weight and psychological well-being in women recovering from breast cancer treatment, and to determine the relationship between changes in these variables and biomarkers associated with disease recurrence and survival.
Methods/design
Following ethical approval, a total of 100 patients will be randomly assigned to a lifestyle intervention (incorporating dietary energy restriction in conjunction with aerobic exercise training) or normal care control group. Patients randomised to the dietary and exercise intervention will be given individualised healthy eating dietary advice and written information and attend moderate intensity aerobic exercise sessions on three to five days per week for a period of 24 weeks. The aim of this strategy is to induce a steady weight loss of up to 0.5 Kg each week. In addition, the overall quality of the diet will be examined with a view to (i) reducing the dietary intake of fat to ~25% of the total calories, (ii) eating at least 5 portions of fruit and vegetables a day, (iii) increasing the intake of fibre and reducing refined carbohydrates, and (iv) taking moderate amounts of alcohol. Outcome measures will include body weight and body composition, psychological health status (stress and depression), cardiorespiratory fitness and quality of life. In addition, biomarkers associated with disease recurrence, including stress hormones, estrogen status, inflammatory markers and indices of innate and adaptive immune function will be monitored.
Discussion
This research will provide valuable information on the effectiveness of a practical, easily implemented lifestyle intervention for evoking positive effects on body weight and psychological well-being, two important factors that can influence long-term prognosis in breast cancer survivors. However, the added value of the study is that it will also evaluate the effects of the lifestyle intervention on a range of biomarkers associated with disease recurrence and survival. Considered together, the results should improve our understanding of the potential role that lifestyle-modifiable factors could play in saving or prolonging lives
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