Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 2 )

2019 ( 252 )

2018 ( 340 )

2017 ( 345 )

Custom range...

Search Results: 1 - 10 of 219439 matches for " John D. Lapek "
All listed articles are free for downloading (OA Articles)
Page 1 /219439
Display every page Item
Mitogen- and Stress-Activated Kinase 1 (MSK1) Regulates Cigarette Smoke-Induced Histone Modifications on NF-κB-dependent Genes
Isaac K. Sundar, Sangwoon Chung, Jae-woong Hwang, John D. Lapek, Michael Bulger, Alan E. Friedman, Hongwei Yao, James R. Davie, Irfan Rahman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031378
Abstract: Cigarette smoke (CS) causes sustained lung inflammation, which is an important event in the pathogenesis of chronic obstructive pulmonary disease (COPD). We have previously reported that IKKα (I kappaB kinase alpha) plays a key role in CS-induced pro-inflammatory gene transcription by chromatin modifications; however, the underlying role of downstream signaling kinase is not known. Mitogen- and stress-activated kinase 1 (MSK1) serves as a specific downstream NF-κB RelA/p65 kinase, mediating transcriptional activation of NF-κB-dependent pro-inflammatory genes. The role of MSK1 in nuclear signaling and chromatin modifications is not known, particularly in response to environmental stimuli. We hypothesized that MSK1 regulates chromatin modifications of pro-inflammatory gene promoters in response to CS. Here, we report that CS extract activates MSK1 in human lung epithelial (H292 and BEAS-2B) cell lines, human primary small airway epithelial cells (SAEC), and in mouse lung, resulting in phosphorylation of nuclear MSK1 (Thr581), phospho-acetylation of RelA/p65 at Ser276 and Lys310 respectively. This event was associated with phospho-acetylation of histone H3 (Ser10/Lys9) and acetylation of histone H4 (Lys12). MSK1 N- and C-terminal kinase-dead mutants, MSK1 siRNA-mediated knock-down in transiently transfected H292 cells, and MSK1 stable knock-down mouse embryonic fibroblasts significantly reduced CS extract-induced MSK1, NF-κB RelA/p65 activation, and posttranslational modifications of histones. CS extract/CS promotes the direct interaction of MSK1 with RelA/p65 and p300 in epithelial cells and in mouse lung. Furthermore, CS-mediated recruitment of MSK1 and its substrates to the promoters of NF-κB-dependent pro-inflammatory genes leads to transcriptional activation, as determined by chromatin immunoprecipitation. Thus, MSK1 is an important downstream kinase involved in CS-induced NF-κB activation and chromatin modifications, which have implications in pathogenesis of COPD.
Pseudomonas aeruginosa PA1006 Is a Persulfide-Modified Protein That Is Critical for Molybdenum Homeostasis
Gregory Tombline, Johanna M. Schwingel, John D. Lapek, Alan E. Friedman, Thomas Darrah, Michael Maguire, Nadine E. Van Alst, Melanie J. Filiatrault, Barbara H. Iglewski
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0055593
Abstract: A companion manuscript revealed that deletion of the Pseudomonas aeruginosa (Pae) PA1006 gene caused pleiotropic defects in metabolism including a loss of all nitrate reductase activities, biofilm maturation, and virulence. Herein, several complementary approaches indicate that PA1006 protein serves as a persulfide-modified protein that is critical for molybdenum homeostasis in Pae. Mutation of a highly conserved Cys22 to Ala or Ser resulted in a loss of PA1006 activity. Yeast-two-hybrid and a green-fluorescent protein fragment complementation assay (GFP-PFCA) in Pae itself revealed that PA1006 interacts with Pae PA3667/CsdA and PA3814/IscS Cys desulfurase enzymes. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) “top-down” analysis of PA1006 purified from Pae revealed that conserved Cys22 is post-translationally modified in vivo in the form a persulfide. Inductively-coupled-plasma (ICP)-MS analysis of ΔPA1006 mutant extracts revealed that the mutant cells contain significantly reduced levels of molybdenum compared to wild-type. GFP-PFCA also revealed that PA1006 interacts with several molybdenum cofactor (MoCo) biosynthesis proteins as well as nitrate reductase maturation factor NarJ and component NarH. These data indicate that a loss of PA1006 protein’s persulfide sulfur and a reduced availability of molybdenum contribute to the phenotype of a ΔPA1006 mutant.
End Stage Renal Disease Economics and the Balance of Treatment Modalities  [PDF]
John D. Sullivan
Journal of Service Science and Management (JSSM) , 2010, DOI: 10.4236/jssm.2010.31005
Abstract: Periodically, research articles emerge arguing the economic benefits of peritoneal dialysis, or PD, over the traditional in-center hemo dialysis for patients suffering from End Stage Renal Disease. Resulting conclusions indentify PD as the ideal therapy to reduce Medicare expenditures for this expensive treatment. However, despite this possible economic benefit to the United States taxpayer, the number of PD patients remains relatively flat with an increasing amount of patients being prescribed in-center hemo dialysis. A simplistic view of controlling the rising costs, on a per treatment basis, associated with the treatment of this disease would be to increase the number of patients from in-center hemo dialysis to peritoneal dialysis. This paper will argue why this shift is both unlikely and unrealistic, and why the resulting potential cost savings to this segment of the Medicare program is a myth.
Valuing European Put Options under Skewness and Increasing [Excess] Kurtosis  [PDF]
John-Peter D. Chateau
Journal of Mathematical Finance (JMF) , 2014, DOI: 10.4236/jmf.2014.43015

To capture the impact of skewness and increase kurtosis on Black’s [1] European put values, we first substitute a Gram-Charlier (GC) distribution and next a Johnson distribution for Black’s Gaussian one. We introduce next each distribution in the option payoff and develop until the closedform expression of each put is arrived at. Finally, we estimate by simulations GC, Johnson and Black put options, choosing the latter one as benchmark. Simulation estimates encompassing both skewness and kurtosis show that, for at-the-money (ATM) or slightly in-the-money put values, 1) Black’s overvaluation with respect to Johnson puts is very significant and 2) its undervaluation with respect to GC ones remains moderate. Yet, by using the same skewness values for both GC and Johnson puts, we highlight the differences induced by increasing kurtosis between the two models. In this case, the GC overvaluation for ATM values is explained by value differences in the put time component. Yet, while both Black and GC values exhibit significant time decay close to expiry, Johnson’s ones remain stable up to maturity.

Pricing the Credit-Risk Put Embedded in Borrowers’ Extendible Credit Commitments, with Its Application to Basel-3 Micro-Prudential Regulation  [PDF]
John-Peter D. Chateau
Journal of Mathematical Finance (JMF) , 2016, DOI: 10.4236/jmf.2016.65052
Abstract: This research makes two contributions: 1) use a term structure framework to price analytically the put option implicit in borrowers’ extendible credit commitments and 2) use the latter to compute in a ratings-based model the capital charge corresponding to the credit-risk exposure of such commitments. Since the term structure of interest rates is stochastic, the zero-coupon bonds in the put closed-form solution delink discounting factor from the credit and funding rates that define the credit spread appearing in the put payoff. By essence, extendible commitments straddle the term-based commitment classification of Basel-3 simplified approach. To improve this, we formulate a ratings-based model that combines extendible put values with new coefficients (forward funding proportion and exposure at funding) as well as a matrix that captures credit-ratings migration over time. Moreover, the combination is versatile enough to deal with a borrower’s credit downgrade and its attendant incremental Basel-3 capital charge.
Measurement of Arsenic Species in Infant Rice Cereals by Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry  [PDF]
John D. Brockman, John W. N. Brown IV
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.310091
Abstract: Infant rice cereals were analyzed for total arsenic, inorganic arsenic (i-As) and the organic arsenic species monomethylarsonoic acid (MMA) and dimethylarsinic acid (DMA) using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). Total arsenic concentrations in the samples ranged from 110 ng/gup to 420 ng/g. The i-As in the rice cereals accounted for 33% to 77% of the total arsenic. The observed variability between infant rice cereals makes a dietary survey approach to accessing arsenic exposures difficult.
Infection Prevalence of Borrelia burgdorferi in Ticks Collected from Songbirds in Far-Western Canada  [PDF]
John D. Scott, Lance A. Durden, John F. Anderson
Open Journal of Animal Sciences (OJAS) , 2015, DOI: 10.4236/ojas.2015.53027
Abstract: Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 species), which were collected from 21 species of birds in far-western Canada, to be infected with B. burgdorferi. Transstadial transmission of B. burgdorferi occurred from larva to nymph, plus nymph to adult, in the avian coastal tick, Ixodes auritulus, collected from songbirds in British Columbia (B.C). Collectively, all 3 motile life stages (larva, nymph, adult) of this tick had an infection prevalence of 31% for B. burgdorferi, which suggests vector competency. A Pacific Wren was highly infested with I. auritulus immatures, and 20 (44%) of 45 ticks (2 nymphs, 43 larvae) were infected with B. burgdorferi. This heavy infestation shows the high potential to initiate a new population of ticks and to disseminate Lyme spirochetes. Epidemiologically, B. burgdorferi-infected I. auritulus larvae collected from the Spotted Towhee, Swainson’s Thrush, Pacific Wren, and Fox Sparrow suggest that these avian hosts act as reservoirs for B. burgdorferi. In this study, the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis played a limited role in the enzootic transmission cycle of B. burgdorferi along coastal B.C. We document the first record of I. spinipalpis on a bird in Alberta. Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada.
Update of the Chronology of Natural Signals in the Near-Surface Mean Global Temperature Record and the Southern Oscillation Index  [PDF]
Chris R. de Freitas, John D. McLean
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.41A020

Time series for the Southern Oscillation Index and mean global near surface temperature anomalies are compared for the 1950 to 2012 period using recently released HadCRU4 data. The method avoids a focused statistical analysis of the data, in part because the study deals with smoothed data, which means there is the danger of spurious correlations, and in part because the El Ni?o Southern Oscillation is a cyclical phenomenon of irregular period. In these situations the results of regression analysis or similar statistical evaluation can be misleading. With the potential controversy arising over a particular statistical analysis removed, the findings indicate that El Nino-Southern Oscillation exercises a major influence on mean global temperature. The results show the potential of natural forcing mechanisms to account for mean global temperature variation, although the extent of the influence is difficult to quantify from among the variability of short-term influences.

Classification of River Reaches on the Little Disturbed East Alligator River, Northern Australia  [PDF]
Michael John Saynor, Wayne D. Erskine
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.46A2007

The East Alligator River drains a 7000 km2 catchment in northern Australia comprised largely of Aboriginal land and has a very low average population density of about 0.15 persons per km2. River reaches were classified according to geomorphic features on both the East Alligator River and its major tributary, Magela Creek, next to which is located the Ranger uranium mine. Sixteen reaches were described for the 241.4 km of the East Alligator River and ten reaches were described for the 118.8 km of Magela Creek. The dominant river types on the East Alligator River were various types of anabranching rivers, sandstone gorges and cuspate tidal meanders. On Magela Creek the dominant river types were wetlands and channel billabongs, island anabranching and sandstone gorges. It is unusual for anabranching rivers and gorges to be so dominant. Current river classification schemes could not accommodate all the various river types and need to be modified so that tidal channels are covered in more detail and so that the classification of anabranching rivers recognises that sand-bed varieties occur in partly confined valley settings.

Selling Politics? How the Traits of Salespeople Manifest Themselves in Irish Politicians  [PDF]
Dónal ó Mearáin, Roger Sherlock, John Hogan
Open Journal of Political Science (OJPS) , 2013, DOI: 10.4236/ojps.2013.34024

This article seeks to uncover if some of the traits most associated with salespeople manifested themselves in the activities of candidates in the constituency of Dún Laoghaire during the 2007 Irish general election. Such a finding would suggest that just as political parties have looked to the marketing profession for their lead in developing political marketing, politicians are looking to, and adopting the traits of those in the sales profession. This would point to the traits that the modern politician must possess in order to get and remain elected. It would also raise significant questions in terms of how candidates present themselves to the electorate, as well as how they go about campaigning and formulating policy.

Page 1 /219439
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.