112 research outputs found

    Size dependent disruption of tethered lipid bilayers by functionalized polystyrene nanoparticles

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    AbstractMolecular interactions between engineered nanomaterials (ENM) and biomembranes are not well understood. This study investigated the effects of particle size and surface functional group on polystyrene nanoparticles' (PNPs) potency for biomembrane disruption. Electrochemical impedance spectroscopy was used to measure changes in the electrical resistance (Rm) of a tethered bilayer lipid membrane BLM (tBLM) composed of 1,2-dioleoyl-sn-glycero-phosphocholine (DOPC) following PNP exposure. All PNPs tested triggered a decline in the Rm that could be described using an exponential-decay model. Statistical hierarchical clustering analysis of two model parameters (exponential rate constant and fractional loss of Rm) could distinguish between the PNPs based on both size and surface functional group. For COOH modified nanoparticles, 20nm PNPs were more potent in reducing Rm than 100nm PNP. However, for amidine modified nanoparticles, 120nm PNPs were more potent in reducing Rm than 23nm PNP. The COOH modified PNPs were more potent in reducing Rm than amidine modified PNP, which tended to aggregate following exposure to a tBLM. Ultra performance liquid chromatography–mass spectroscopy analysis suggested that the aggregation may have been triggered by DOPC that was removed from the tBLM by the amidine PNP

    Report on Archaeological Investigations Conducted at the St. Mary's Site (18AP45), 107 Duke of Gloucester Street, Annapolis, Maryland, 1987-1990

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    In celebration of the 250th anniversary of the birth of Charles Carroll of Carrollton, Archaeology in Annapolis was invited to excavate the Carroll House and garden on 107 Duke of Gloucester Street in Annapolis, Maryland. The site, named the St. Mary's Site (18AP45) for the Catholic church on the property, is currently owned by the Redemptorists, a Roman Catholic congregation of priests and brothers who have occupied the site since 1852. Prior to the Redemptorists' tenure, the site was owned by the Carroll family from 1701-1852 and is perhaps best known as the home of Charles Carroll of Carrollton (1737-1832), signer of the Declaration of Independence. Excavations at the site were conducted during four consecutive summer seasons from 1987-1990. The investigation focused on three research questions. The first line of inquiry were questions surrounding the dating, architectural configuration, and artifact deposits of the "frame house," a structure adjoining the west wall of the brick Carroll House via a "passage" and later a three story addition. The frame house was partially demolished in the mid-nineteenth century but the construction was thought to pre-date the brick portion of the house. The second research question was spurred by documentary research which indicated that the property might have been the location of Proctor's Tavern, a late 17th-century tavern which served as the meeting place of the Maryland Provincial Assembly. Archaeological testing hoped to determine its location and, if found, investigate Annapolis' early Euro-American occupation. The third research question focused on the landscape of the site as it was shaped by its occupants over the past three hundred years. The research questions included investigating the stratigraphy, geometry, and architectural and planting features of Charles Carroll of Carrollton's terraced garden built during the 1770s, and investigating the changes to the landscape made by the Redemptorists in the nineteenth and twentieth centuries. While no structural evidence associated with Proctor’s Tavern was uncovered during limited excavations along Spa Creek, the historic shore of Spa Creek was identified, buried beneath deep fill deposits laid down during construction of the Carroll Garden. Features and deposits associated with this period likely remain intact in a waterlogged environment along the southeastern sea wall at the St. Mary’s Site. Evidence of extensive earth moving by Carroll is present in the garden and was identified during excavation and coring. This strongly suggests that the garden landscape visible at the St. Mary’s Site is the intact Carroll Garden, which survives beneath contemporary and late nineteenth century strata. The extant surviving garden should be considered highly sensitive to ground-disturbing activities, and is also highly significant considering demonstrable associations with the Carroll family. Other garden-related features were also discovered, including planting holes, and a brick pavilion or parapet located along Spa Creek to the south of the site. The Duke of Gloucester Street wall was shown to be associated with the Carroll occupation of the site. Finally, intensive archaeological research was directed at the vicinity of a frame house constructed and occupied by the Carrolls to the east of the existing brick house, which was replaced by the Redemptorists in the nineteenth century with a greenhouse. These superimposed buildings were documented in detail and remain highly significant features at the St. Mary’s Site

    Ozone-CO Correlations Determined by the TES Satellite Instrument in Continental Outflow Regions

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    Collocated measurements of tropospheric ozone (O3) and carbon monoxide (CO) from the Tropospheric Emission Spectrometer (TES) aboard the EOS Aura satellite provide information on O3-CO correlations to test our understanding of global anthropogenic influence on O3. We examine the global distribution of TES O3-CO correlations in the middle troposphere (618 hPa) for July 2005 and compare to correlations generated with the GEOS-Chem chemical transport model and with ICARTT aircraft observations over the eastern United States (July 2004). The TES data show significant O3-CO correlations downwind of polluted continents, with dO3/dCO enhancement ratios in the range 0.4–1.0 mol mol−1 and consistent with ICARTT data. The GEOS-Chem model reproduces the O3-CO enhancement ratios observed in continental outflow, but model correlations are stronger and more extensive. We show that the discrepancy can be explained by spectral measurement errors in the TES data. These errors will decrease in future data releases, which should enable TES to provide better information on O3-CO correlations.Earth and Planetary SciencesEngineering and Applied Science

    Human papillomavirus–related oropharyngeal cancer: HPV and p16 status in the recurrent versus parent tumor

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    Background Although typically associated with a favorable prognosis, a minority of human papillomavirus (HPV)‐related (+) oropharyngeal cancers recur after chemoradiation. We postulated that a minor HPV‐negative tumor subfraction may be responsible for recurrences of HPV+ oropharyngeal cancer. Methods Paired untreated primary and recurrent tumor specimens were identified for 37 patients with oropharyngeal cancer who received definitive chemoradiotherapy at our institution. Concordance in HPV/p16 expression between primary and recurrent tumors was assessed. Results Among 31 patients with HPV+/p16+ primary tumors, 30 (97%) retained evidence of both HPV and p16 expression at recurrence (27 HPV+/p16+; 3 HPV+/p16‐partial). One (3%) initially HPV+/p16+ patient developed an HPV‐negative/p16‐negative lung squamous cell carcinoma (SCC), representing either a discordant oropharyngeal cancer metastasis or second primary tumor. Conclusion HPV‐related oropharyngeal cancers retain HPV+/p16+ expression at recurrence. Our results fail to provide evidence that a minor HPV‐negative tumor subfraction is responsible for biologically aggressive behavior of HPV+ oropharyngeal cancer that recurs after chemoradiation. © 2014 Wiley Periodicals, Inc. Head Neck 37 : 8–11, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109811/1/hed23548.pd

    Chemotherapy alone for organ preservation in advanced laryngeal cancer

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    Background. For patients with advanced laryngeal cancer, a trial was designed to determine if chemotherapy alone, in patients achieving a complete histologic complete response after a single neoadjuvant cycle, was an effective treatment with less morbidity than concurrent chemoradiotherapy. Methods. Thirty-two patients with advanced laryngeal or hypopharyngeal cancer received 1 cycle of induction chemotherapy, and subsequent treatment was decided based on response. Results. A histologic complete response was achieved in 4 patients and were treated with chemotherapy alone. All 4 patients' cancer relapsed in the neck and required surgery and postoperative radiotherapy (RT). Twenty-five patients were treated with concomitant chemoradiation. Three patients were treated with surgery. Overall survival and disease-specific survival at 3 years were 68% and 78%, respectively. Conclusion. Chemotherapy alone is not feasible for long-term control of regional disease in patients with advanced laryngeal cancer even when they achieve a histologic complete response at the primary site. © 2009 Wiley Periodicals, Inc. Head Neck, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77508/1/21285_ftp.pd

    Matted nodes: Poor prognostic marker in oropharyngeal squamous cell carcinoma independent of HPV and EGFR status

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    Background Despite better prognosis, there is a group of oropharyngeal squamous cell carcinoma (SCC) human papillomavirus (HPV)+ patients who experience treatment failure and succumb to distant metastasis. Methods Seventy‐eight previously untreated patients nested in a concurrent chemoradiation protocol were reviewed to correlate patterns of local‐regional tumor extent to distant metastasis. Biomarker assessment was: HPV in situ hybridization and epidermal growth factor receptor (EGFR) immunointensity. Results The 3‐year disease‐specific survival (DSS) for patients presenting with and without matted nodes was 69% and 94%, respectively ( p = .003). Matted nodes were a poor prognostic factor independent of T classification, HPV, EGFR, and smoking status. For patients who were HPV+, 7 of 11 died of distant metastasis and 6 of 7 with distant metastasis had matted nodes. Conclusion Matted nodes are a novel marker of poor prognosis in oropharyngeal SCC independent of established prognostic factors. Matted nodes may identify patients at risk for the development of distant metastasis who could benefit from systemic therapy, whereas patients without matted nodes may be candidates for de‐escalation of therapy. © 2012 Wiley Periodicals, Inc. Head Neck , 2012Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94456/1/21997_ftp.pd

    Prevalence and predictive role of p16 and epidermal growth factor receptor in surgically treated oropharyngeal and oral cavity cancer

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    Background The purpose of this study was to describe the relationship of p16 and epidermal growth factor receptor (EGFR) expression with survival in surgically treated patients who had oropharyngeal or oral cavity squamous cell carcinoma (SCC). Methods Tissue from 36 patients with oropharyngeal SCC and 49 patients with oral cavity SCC treated between 1997 and 2001 was imbedded and immunostained using a tissue microarray. Results The p16 was positive in 57% and 13% of patients with oropharyngeal SCC and oral cavity SCC, respectively. EGFR was positive in 60% and 63% of patients with oropharyngeal SCC and oral cavity SCC, respectively. In patients with oropharyngeal SCC, p16 expression was associated with improved disease‐specific survival (DSS), overall survival (OS), and time to recurrence (TTR) ( p < .01, < .01, and <.01, respectively). EGFR expression was associated with poorer DSS, OS, and TTR ( p < .01, = .01, and < .01, respectively). For oropharyngeal SCC, when examining both p16 and EGFR expression as combined biomarkers, high p16 expression coupled with low EGFR expression was associated with improved DSS ( p p16 = .01; p EGFR = .01). Patients with oral cavity SCC showed no association between biomarker and outcome. Conclusions For patients with oropharyngeal SCC, high p16 and low EGFR were associated with improved outcome, suggesting a predictive role in surgically treated patients. © 2012 Wiley Periodicals, Inc. Head Neck, 2013Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99017/1/23087_ftp.pd
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