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Search Results: 1 - 10 of 233653 matches for " Jessica L Martin "
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Assessment of Risk of Carrier Waves in the Assisted Reproductive Laboratory  [PDF]
Samuel D. Prien, Jessica Smith, Christy Barron, Joseph Martin, Naghma Farooqi, Alita Loveless, Amy Van Gheem, Lindsay L. Penrose
Open Journal of Obstetrics and Gynecology (OJOG) , 2015, DOI: 10.4236/ojog.2015.510077
Abstract: Assisted reproductive technology (ART) laboratories represent the marriage of the most basic of biological activities with the most cutting edge technologies. While this association has worked well, the mixture of biology and technology can create risks to normal embryo development. Recently a significant amount of literature has explored the risks of manmade, electrically induced magnetic fields and carrier waves on reproduction, which some studies have suggested will lower functional gamete numbers in the males and potentially induce genetic issues in embryos. However, little is known about these phenomena within the ART laboratory, a laboratory filled with electronic equipment. The object of the present study was to explore the potential exposure of gametes and early stage embryos to two of the most prevalent fields and waves utilized in manmade technologies seen in the general environment, electromagnetic fields (EMF) and radio frequency waves (RF), and determine the effect varying levels of these energetic forces had on gamete function and embryo development. Results indicated that while extremely high concentrations of EMF (approximately 50-100X of laboratory background) caused negative outcomes in both gametes and embryos, levels consistent will the majority of lab equipment did not appear to impact growth, or function. Further, even extremely high RF appeared to have no impact cellular function. Results suggest few issues with EMF or RF on gamete and embryo function at normal laboratory levels for the relatively short exposure times seen in the ART laboratory.
Incorporating 16S Gene Copy Number Information Improves Estimates of Microbial Diversity and Abundance
Steven W. Kembel ,Martin Wu,Jonathan A. Eisen,Jessica L. Green
PLOS Computational Biology , 2012, DOI: 10.1371/journal.pcbi.1002743
Abstract: The abundance of different SSU rRNA (“16S”) gene sequences in environmental samples is widely used in studies of microbial ecology as a measure of microbial community structure and diversity. However, the genomic copy number of the 16S gene varies greatly – from one in many species to up to 15 in some bacteria and to hundreds in some microbial eukaryotes. As a result of this variation the relative abundance of 16S genes in environmental samples can be attributed both to variation in the relative abundance of different organisms, and to variation in genomic 16S copy number among those organisms. Despite this fact, many studies assume that the abundance of 16S gene sequences is a surrogate measure of the relative abundance of the organisms containing those sequences. Here we present a method that uses data on sequences and genomic copy number of 16S genes along with phylogenetic placement and ancestral state estimation to estimate organismal abundances from environmental DNA sequence data. We use theory and simulations to demonstrate that 16S genomic copy number can be accurately estimated from the short reads typically obtained from high-throughput environmental sequencing of the 16S gene, and that organismal abundances in microbial communities are more strongly correlated with estimated abundances obtained from our method than with gene abundances. We re-analyze several published empirical data sets and demonstrate that the use of gene abundance versus estimated organismal abundance can lead to different inferences about community diversity and structure and the identity of the dominant taxa in microbial communities. Our approach will allow microbial ecologists to make more accurate inferences about microbial diversity and abundance based on 16S sequence data.
Detection of Genetically Altered Copper Levels in Drosophila Tissues by Synchrotron X-Ray Fluorescence Microscopy
Jessica C. Lye, Joab E. C. Hwang, David Paterson, Martin D. de Jonge, Daryl L. Howard, Richard Burke
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026867
Abstract: Tissue-specific manipulation of known copper transport genes in Drosophila tissues results in phenotypes that are presumably due to an alteration in copper levels in the targeted cells. However direct confirmation of this has to date been technically challenging. Measures of cellular copper content such as expression levels of copper-responsive genes or cuproenzyme activity levels, while useful, are indirect. First-generation copper-sensitive fluorophores show promise but currently lack the sensitivity required to detect subtle changes in copper levels. Moreover such techniques do not provide information regarding other relevant biometals such as zinc or iron. Traditional techniques for measuring elemental composition such as inductively coupled plasma mass spectroscopy are not sensitive enough for use with the small tissue amounts available in Drosophila research. Here we present synchrotron x-ray fluorescence microscopy analysis of two different Drosophila tissues, the larval wing imaginal disc, and sectioned adult fly heads and show that this technique can be used to detect changes in tissue copper levels caused by targeted manipulation of known copper homeostasis genes.
Breast cancer screening beliefs by practice location
Lisa M Santora, Martin C Mahoney, Silvana Lawvere, Jessica J Englert, Andrew B Symons, Amy L Mirand
BMC Public Health , 2003, DOI: 10.1186/1471-2458-3-9
Abstract: A cross-sectional survey design was used to examine approaches to breast cancer screening among physicians, nurse practitioners, and physician assistants involved in primary care practice. A summary index of beliefs about breast cancer screening was created by summing the total number of responses in agreement with each of four survey items; values for this summary variable ranged between zero and four. Respondents were classified into urban, rural and suburban categories based upon practise location.Among the 428 respondents, agreement with "correct" responses ranged from 50% to 71% for the individual survey items; overall, half agreed with three or more of the four breast cancer screening items. While no significant differences were noted by practice location, variation in responses were evident. Reported use of written breast cancer guidelines was less in both suburban (OR = 0.51) and urban areas (OR = 0.56) when compared to clinicians in rural areas.Development of an evidence-based consensus statement regarding breast cancer screening would support a single set of unambiguous guidelines for implementation in all primary care settings, thus decreasing variations in how breast cancer screening is approached across varied clinical settings.Breast cancer is the most common cancer (excluding non-malignant skin melanomas) and the second leading cause of cancer deaths among women in the US [1]. During the 1990s, the observed incidence of female breast cancers increased, and was accompanied by a significant decrease in breast cancer mortality [2]. Both trends may be due, in part, to the increased utilization of mammography [3]. From 1989 to 1997, the percentage of women aged = 40 years who reported "ever had a mammogram" increased from 63.9% to 84.8% [3,4]. However, there was a substantial difference between those who were ever screened and the proportion of women screened in the previous 2 years (84.8% v. 71.3% [1997]) [4].Relative to areas of higher population density
Perceived Obstacles of Colorectal Cancer Screening and Their Associated Factors among 10,078 Chinese Participants
Martin C. S. Wong, Jessica Y. L. Ching, Hoyee H. Hirai, Thomas Y. T. Lam, Sian M. Griffiths, Francis K. L. Chan, Joseph J. Y. Sung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070209
Abstract: Purpose to evaluate the proportion of self-referred screening participants having various psychological barriers and the factors associated with these barriers. Methods A territory-wide bowel cancer screening centre sent an invitation via the media to all Hong Kong residents aged 50–70 years who were asymptomatic of CRC to join a free screening programme. Upon attendance they were requested to complete self-administered surveys on their perceived barriers of screening. Binary logistic regression analyses were used to evaluate the factors associated with these barriers. Results From 10,078 consecutive screening participants (mean age 57.5 years; female 56.4%) completed the surveys between May 2008 to September 2012. There were high proportions who agreed or strongly agreed with the following barriers: financial difficulty (86.0%), limited service accessibility (58.2%), screening-induced bodily discomfort (55.2%), physical harm (44.4%), embarrassment (40.1%), apprehension (38.8%) and time constraints (13.9%). From regression models, older participants (aged ≥56) were less likely to have these barriers (Adjusted odds ratio [AOR] ranged from 0.738 to 0.952) but they encountered more difficulties to access to screening services (AOR ranged from 1.141 to 1.371). Female subjects were more likely to encounter most of these barriers (AOR ranged from 1.188 to 2.179). Participants who were uncertain of the necessity of CRC screening for people aged ≥50 were more likely to report these barriers (AOR ranged from 1.151 to 1.671). Conclusion The proportions of perceptual barriers of CRC screening were high among these participants. Those with these associated factors should receive more thorough explanation of the screening test procedures.
Above and Below Ground Interactions in Monoculture and Intercropping of Onion and Lettuce in Greenhouse Conditions  [PDF]
Jessica L. de Haan, Liette Vasseur
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.521347
Abstract: Intercropping has been seen as an advantageous strategy in sustainable agriculture. Plants however interact with one another both above and below ground with members of the same species (intraspecific) or members of a different species (interspecific) for nutrients, water and light. It is therefore essential to understand these interactions when intercropped. The objective was to examine the above and below ground interactions between onion and lettuce in monocrop and intercrop systems. We examined the various possible interactions (no competition, above ground, below ground, or full) using a full factorial randomized design under greenhouse conditions. Onion yield was highest in intraspecific above ground competition and lowest in below ground and full interspecific competition with lettuce. Dry weight of onions in above ground competition with lettuce was significantly greater than that of the control group. Fresh weight of lettuce leaves were highest in below ground and full interspecific competition treatments. The hectare model and yield results suggest that there is strong below ground competitive effect between onion and lettuce in intercrop. Asymetric interspecific facilitation was found: facilitation by onion led to increased lettuce yield but a negative effect of lettuce on onion yield was observed. Knowledge of competitive interactions between component crops can have several applications in sustainable agricultural as it helps to match the most efficient species under specific conditions.
An Approximate L p Difference Algorithm for Massive Data Streams
Jessica H. Fong,Martin Strauss
Discrete Mathematics & Theoretical Computer Science , 2001,
Abstract: Several recent papers have shown how to approximate the difference ∑ i |a i-b i | or ∑|a i-b i | 2 between two functions, when the function values a i and b i are given in a data stream, and their order is chosen by an adversary. These algorithms use little space (much less than would be needed to store the entire stream) and little time to process each item in the stream. They approximate with small relative error. Using different techniques, we show how to approximate the L p-difference ∑ i |a i-b i | p for any rational-valued p∈(0,2], with comparable efficiency and error. We also show how to approximate ∑ i |a i-b i | p for larger values of p but with a worse error guarantee. Our results fill in gaps left by recent work, by providing an algorithm that is precisely tunable for the application at hand. These results can be used to assess the difference between two chronologically or physically separated massive data sets, making one quick pass over each data set, without buffering the data or requiring the data source to pause. For example, one can use our techniques to judge whether the traffic on two remote network routers are similar without requiring either router to transmit a copy of its traffic. A web search engine could use such algorithms to construct a library of small ``sketches,'' one for each distinct page on the web; one can approximate the extent to which new web pages duplicate old ones by comparing the sketches of the web pages. Such techniques will become increasingly important as the enormous scale, distributional nature, and one-pass processing requirements of data sets become more commonplace.
Inactivation of [Fe-S] Metalloproteins Mediates Nitric Oxide-Dependent Killing of Burkholderia mallei
Jessica Jones-Carson, James Laughlin, Mohammed A. Hamad, Amanda L. Stewart, Martin I. Voskuil, Andrés Vázquez-Torres
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001976
Abstract: Background Much remains to be known about the mechanisms by which O2-dependent host defenses mediate broad antimicrobial activity. Methodology/Principal Findings We show herein that reactive nitrogen species (RNS) generated by inducible nitric oxide (NO) synthase (iNOS) account for the anti-Burkholderia mallei activity of IFNγ-primed macrophages. Inducible NOS-mediated intracellular killing may represent direct bactericidal activity, because B. mallei showed an exquisite sensitivity to NO generated chemically. Exposure of B. mallei to sublethal concentrations of NO upregulated transcription of [Fe-S] cluster repair genes, while damaging the enzymatic activity of the [Fe-S] protein aconitase. To test whether [Fe-S] clusters are critical targets for RNS-dependent killing of B. mallei, a mutation was constructed in the NO-induced, [Fe-S] cluster repair regulator iscR. Not only was the iscR mutant hypersusceptible to iNOS-mediated killing, but its aconitase pool was readily oxidized by NO donors as compared to wild-type controls. Although killed by authentic H2O2, which also oxidizes [Fe-S] clusters, B. mallei appear to be resilient to NADPH oxidase-mediated cytotoxicity. The poor respiratory burst elicited by this bacterium likely explains why the NADPH oxidase is nonessential to the killing of B. mallei while it is still confined within phagosomes. Conclusions/Significance Collectively, these findings have revealed a disparate role for NADPH oxidase and iNOS in the innate macrophage response against the strict aerobe B. mallei. To the best of our knowledge, this is the first instance in which disruption of [Fe-S] clusters is demonstrated as cause of the bactericidal activity of NO congeners.
M. tuberculosis genotypic diversity and drug susceptibility pattern in HIV- infected and non-HIV-infected patients in northern Tanzania
Gibson S Kibiki, Bert Mulder, Wil MV Dolmans, Jessica L de Beer, Martin Boeree, Noel Sam, Dick van Soolingen, Christophe Sola, Adri GM van der Zanden
BMC Microbiology , 2007, DOI: 10.1186/1471-2180-7-51
Abstract: TB positive culture, BAL fluid or sputum samples from 130 patients were collected and genotyped. The spoligotypes were correlated with anti-tuberculous drug susceptibility in HIV-infected and non-HIV patients from Tanzania.One-third of patients were TB/HIV co-infected. Forty-seven spoligotypes were identified.Fourteen isolates (10.8%) had new and unique spoligotypes while 116 isolates (89.2%) belonged to 33 known spoligotypes. The major spoligotypes contained nine clusters: CAS1-Kili 30.0%, LAM11- ZWE 14.6%, ND 9.2%, EAI 6.2%, Beijing 5.4%, T-undefined 4.6%, CAS1-Delhi 3.8%, T1 3.8% and LAM9 3.8%. Twelve (10.8%) of the 111 phenotypically tested strains were resistant to anti-TB drugs. Eight (7.2%) were monoresistant strains: 7 to isoniazid (INH) and one to streptomycin. Four strains (3.5%) were resistant to multiple drugs: one (0.9%) was resistant to INH and streptomycin and the other three (2.7%) were MDR strains: one was resistant to INH, rifampicin and ethambutol and two were resistant to all four anti-TB drugs. Mutation in the katG gene codon 315 and the rpoB hotspot region showed a low and high sensitivity, respectively, as predictor of phenotypic drug resistance.CAS1-Kili and LAM11-ZWE were the most common families. Strains of the Beijing family and CAS1-Kili were not or least often associated with resistance, respectively. HIV status was not associated with spoligotypes, resistance or previous TB treatment.Tuberculosis (TB) persists as a major cause of morbidity and mortality, affecting almost a third of the world's population [1]. Inadequate detection and cure rates have been identified as reasons for a mounting global tuberculosis burden [2]. Human immunodeficiency virus (HIV) is by far the major cause of the current increase in tuberculosis infection. The presence of HIV increases the risk of reactivation of a latent Mycobacterium tuberculosis (MTB) infection [3] and rapid thus progression of the infection [4]; HIV also increases MTB transmission rates at
Parental Smoking and Risk of Childhood Brain Tumors by Functional Polymorphisms in Polycyclic Aromatic Hydrocarbon Metabolism Genes
Jessica L. Barrington-Trimis, Susan Searles Nielsen, Susan Preston-Martin, W. James Gauderman, Elizabeth A. Holly, Federico M. Farin, Beth A. Mueller, Roberta McKean-Cowdin
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079110
Abstract: Background A recent meta-analysis suggested an association between exposure to paternal smoking during pregnancy and childhood brain tumor risk, but no studies have evaluated whether this association differs by polymorphisms in genes that metabolize tobacco-smoke chemicals. Methods We assessed 9 functional polymorphisms in 6 genes that affect the metabolism of polycyclic aromatic hydrocarbons (PAH) to evaluate potential interactions with parental smoking during pregnancy in a population-based case-control study of childhood brain tumors. Cases (N = 202) were ≤10 years old, diagnosed from 1984–1991 and identified in three Surveillance, Epidemiology, and End Results (SEER) registries in the western U.S. Controls in the same regions (N = 286) were frequency matched by age, sex, and study center. DNA for genotyping was obtained from archived newborn dried blood spots. Results We found positive interaction odds ratios (ORs) for both maternal and paternal smoking during pregnancy, EPHX1 H139R, and childhood brain tumors (Pinteraction = 0.02; 0.10), such that children with the high-risk (greater PAH activation) genotype were at a higher risk of brain tumors relative to children with the low-risk genotype when exposed to tobacco smoke during pregnancy. A dose-response pattern for paternal smoking was observed among children with the EPHX1 H139R high-risk genotype only (ORno exposure = 1.0; OR≤3 hours/day = 1.32, 95% CI: 0.52–3.34; OR>3hours/day = 3.18, 95% CI: 0.92–11.0; Ptrend = 0.07). Conclusion Parental smoking during pregnancy may be a risk factor for childhood brain tumors among genetically susceptible children who more rapidly activate PAH in tobacco smoke.
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