Dilations and Commutant Lifting for Jointly Isometric Operators—A Geometric Approach

AbstractA tuple of commuting contractionsT=(T1, T2, …, Tn) is called a joint-isometry if ∑T*jTj=I. We give a geometric proof that joint isometries have a regular unitary dilation and that its commutant lifts. We also show thatTis subnormal and that its minimal normal extension is also jointly isometric

Obtaining the Grobner Initialization for the Ground Flash Fraction Retrieval Algorithm

At optical wavelengths and from the vantage point of space, the multiple scattering cloud medium obscures one's view and prevents one from easily determining what flashes strike the ground. However, recent investigations have made some progress examining the (easier, but still difficult) problem of estimating the ground flash fraction in a set of N flashes observed from space In the study by Koshak, a Bayesian inversion method was introduced for retrieving the fraction of ground flashes in a set of flashes observed from a (low earth orbiting or geostationary) satellite lightning imager. The method employed a constrained mixed exponential distribution model to describe the lightning optical measurements. To obtain the optimum model parameters, a scalar function of three variables (one of which is the ground flash fraction) was minimized by a numerical method. This method has formed the basis of a Ground Flash Fraction Retrieval Algorithm (GoFFRA) that is being tested as part of GOES-R GLM risk reduction

Tests of the Grobner Basis Solution for Lightning Ground Flash Fraction Retrieval

Satellite lightning imagers such as the NASA Tropical Rainfall Measuring Mission Lightning Imaging Sensor (TRMM/LIS) and the future GOES-R Geostationary Lightning Mapper (GLM) are designed to detect total lightning (ground flashes + cloud flashes). However, there is a desire to discriminate ground flashes from cloud flashes from the vantage point of space since this would enhance the overall information content of the satellite lightning data and likely improve its operational and scientific applications (e.g., in severe weather warning, lightning nitrogen oxides studies, and global electric circuit analyses). A Bayesian inversion method was previously introduced for retrieving the fraction of ground flashes in a set of flashes observed from a satellite lightning imager. The method employed a constrained mixed exponential distribution model to describe the lightning optical measurements. To obtain the optimum model parameters (one of which is the ground flash fraction), a scalar function was minimized by a numerical method. In order to improve this optimization, a Grobner basis solution was introduced to obtain analytic representations of the model parameters that serve as a refined initialization scheme to the numerical optimization. In this study, we test the efficacy of the Grobner basis initialization using actual lightning imager measurements and ground flash truth derived from the national lightning network

Cytomorphologic features of metastatic urothelial carcinoma in serous effusions

Metastatic urothelial carcinoma (UC) to serous effusion (SE) is extremely rare and its cytomorphological features have only been described in case reports. In this study, we searched the pathology database at University of Michigan for SEs due to metastatic UC in the last 20 years. A total of 25 cases from 20 patients with clinically and pathologically confirmed metastatic UC in SEs were retrieved. The specimens consisted of 15 pleural, 8 peritoneal, and 2 pericardial effusions. Smears were reviewed and evaluated for the following features: cellularity, single cells, cell clusters or short cords, cell wrapping, “windows” between the cells, two‐tone cytoplasm, cytoplasmic vacuoles, signet ring cells, nuclear to cytoplasmic (N/C) ratio, nuclear hyperchromasia, irregular nuclear membrane, nuclear centricity, double or multiple nuclei, nucleoli, anaplastic cells and mitosis. Our results showed that UC manifested in SEs predominantly as a single cell population with or without clusters or short cords, and frequently exhibited the “cell wrapping” of two or more cells. Individual UC cell in SEs exhibited nuclear enlargement with increased N/C ratio, irregular nuclear membranes, hyperchromatic coarse chromatin and frequently prominent nucleoli. Double or multinucleated cells, cells with vacuolated cytoplasm or signet ring appearance were also frequently present. Our results demonstrated that while certain features could suggest the diagnosis of UC, the cytomorphological features are not specific and often overlap with those of reactive mesothelium, mesothelioma, metastatic adenocarcinoma, or squamous cell carcinoma in SEs. Accurate diagnosis of UC rests on the combination of clinical history, cytomorphologic features and appropriate immunohistochemical panel. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98804/1/22896_ftp.pd

A Grobner Basis Solution for Lightning Ground Flash Fraction Retrieval

A Bayesian inversion method was previously introduced for retrieving the fraction of ground flashes in a set of flashes observed from a (low earth orbiting or geostationary) satellite lightning imager. The method employed a constrained mixed exponential distribution model to describe the lightning optical measurements. To obtain the optimum model parameters, a scalar function was minimized by a numerical method. In order to improve this optimization, we introduce a Grobner basis solution to obtain analytic representations of the model parameters that serve as a refined initialization scheme to the numerical optimization. Using the Grobner basis, we show that there are exactly 2 solutions involving the first 3 moments of the (exponentially distributed) data. When the mean of the ground flash optical characteristic (e.g., such as the Maximum Group Area, MGA) is larger than that for cloud flashes, then a unique solution can be obtained

Effect of North American Ginseng on 137Cs-induced Micronuclei in Human Lymphocytes

To explore the radioprotective effect of a standardized North American ginseng extract (NAGE) on human peripheral blood lymphocytes (PBL), a micronuclei (MN) assay was conducted in PBL obtained from 12 volunteers. NAGE (50â 1000 µg/mL) and WR-1065 (1 mm and 3 mm) were applied to PBL cultures at 0 h and 90 min post-irradiation. It was found that (1) the baseline MN yield of PBL ranged from 14.4 ± 1.5 to 15.9 ± 1.5 per 1000 binucleated cells (p > 0.05); after irradiation (1 Gy and 2 Gy), the MN yield increased sharply; (2) MN yields declined with increasing concentrations of NAGE and WR-1065. Even at 90 min post-irradiation of 1 Gy, the maximum level of MN reduction rate caused by NAGE and WR-1065 was 53.8% and 59.2%, respectively; after 2 Gy irradiation, it was 37.3% and 42%, respectively; (3) the MN distribution in PBL followed a non-Poisson distribution in all cases; and (4) both NAGE and WR-1065 showed no significant effect on the proliferation index of lymphocytes. The results indicate that NAGE is a relatively non-toxic natural product, which can be administered as a dietary supplement and has the potential to be a radiation countermeasure. Originally published Phytotherapy Research Vol. 22, No. 12 2008

Selected ginsenosides of the prptopanaxdiol series are novel positive allosteric modulators of P2X7 receptors

Background and Purpose The P2X7 receptor is an ATP-gated ion channel predominantly expressed in immune cells and plays a key role in inflammatory processes. Ginseng is a well-known Chinese herb with both pro- and anti-inflammatory properties and many of its actions have been ascribed to constituent ginsenosides. We screened a number of ginsenoside compounds for pharmacological activity at P2X7 receptors, that might contribute to the reported immunomodulatory actions of ginseng. Experimental Approach We used several assays to measure responses of P2X7 receptors, ATP-mediated dye uptake, intracellular calcium measurement and whole-cell patch-clamp recordings. HEK-293 cells stably expressing human P2X7 receptors were used in addition to mouse macrophages endogenously expressing P2X7 receptors. Key Results Four ginsenosides of the protopanaxdiol series, Rb1, Rh2, Rd and the metabolite compound K (CK) potentiated the dye uptake responses of P2X7 receptors, whereas other ginsenosides tested were ineffective (1–10 μM). The potentiation was rapid in onset, required a threshold concentration of ATP (>50 μM) and had an EC50 of 1.08 μM. CK markedly enhanced ATP-activated P2X7 currents, probably via an extracellular site of action. One of the consequences of this potentiation effect is a sustained rise in intracellular Ca2+ that could account for the decrease in cell viability in mouse macrophages after a combination of 500 μM ATP and 10 μM CK that are non-toxic when applied alone. Conclusions and Implications This study identifies selected ginsenosides as novel potent allosteric modulators of P2X7 channels that may account for some of the reported immune modulatory actions of protopanaxdiol ginsenosides in vivo

Ginseng on Hyperglycemia: Effects and Mechanisms

It has been reported that American ginseng attenuates hyperglycemia and may present itself as a supplement to diabetes therapy. However, the lack of standardization in the usage of ginseng root leads to inconclusive results when applied to diabetes treatment. The mechanisms of American ginseng root in the treatment of diabetes remains a mystery. This greatly limits the effective utilization of American ginseng in facilitating diabetic therapy. Initiating studies have shown that American ginseng increases insulin production and reduces cell death in pancreatic β-cells. Also, studies have revealed American ginseng's ability to decrease blood glucose in type II diabetes patients as well as in streptozotocin-induced diabetic animals (STZ-diabetic mice). These data suggest that effects of ginseng in improving hyperglycemia may alter mitochondrial function as well as apoptosis cascades to ensure cell viability in pancreatic islet cells. This review briefly summarizes current knowledge of ginseng components and clinical studies related to diabetes. Further research will be needed to explore and identify the component(s) of ginseng, which may be responsible for the beneficial effects observed in animal studies which could then be extrapolated to human islets