2,094 research outputs found
A Method of Intervals for the Study of Diffusion-Limited Annihilation, A + A --> 0
We introduce a method of intervals for the analysis of diffusion-limited
annihilation, A+A -> 0, on the line. The method leads to manageable diffusion
equations whose interpretation is intuitively clear. As an example, we treat
the following cases: (a) annihilation in the infinite line and in infinite
(discrete) chains; (b) annihilation with input of single particles, adjacent
particle pairs, and particle pairs separated by a given distance; (c)
annihilation, A+A -> 0, along with the birth reaction A -> 3A, on finite rings,
with and without diffusion.Comment: RevTeX, 13 pages, 4 figures, 1 table. References Added, and some
other minor changes, to conform with final for
Correlation Functions for Diffusion-Limited Annihilation, A + A -> 0
The full hierarchy of multiple-point correlation functions for
diffusion-limited annihilation, A + A -> 0, is obtained analytically and
explicitly, following the method of intervals. In the long time asymptotic
limit, the correlation functions of annihilation are identical to those of
coalescence, A + A -> A, despite differences between the two models in other
statistical measures, such as the interparticle distribution function
Fermi-surface topologies and low-temperature phases of the filled skutterudite compounds CeOs4Sb12 and NdOs4Sb12
MHz conductivity, torque magnetometer and magnetization measurements are reported on single crystals of CeOs4Sb12 and NdOs4Sb12 using temperatures down to 0.5 K and magnetic fields of up to 60 tesla. The field-orientation dependence of the de Haas-van Alphen and Shubnikov-de Haas oscillations is deduced by rotating the samples about the [010] and [0ÂŻ11] directions. The results indicate that NdOs4Sb12 has a similar Fermi surface topology to that of the unusual superconductor PrOs4Sb12, but with significantly smaller effective masses, supporting the importance of local phonon modes in contributing to the low-temperature heat capacity of NdOs4Sb12. By contrast, CeOs4Sb12 undergoes a field-induced transition from an unusual semimetal into a high-field, hightemperature state characterized by a single, almost spherical Fermi-surface section. The behavior of the phase boundary and comparisons with models of the bandstructure lead us to propose that the field-induced phase transition in CeOs4Sb12 is similar in origin to the well-known α â Îł transition in Ce and its alloys
Classification of TP53 mutations and HPV predict survival in advanced larynx cancer
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134126/1/lary25915-sup-0001-suppinfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134126/2/lary25915_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134126/3/lary25915.pd
Prevalence and predictive role of p16 and epidermal growth factor receptor in surgically treated oropharyngeal and oral cavity cancer
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 diseaseâspecific 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
Human papillomavirusârelated oropharyngeal cancer: HPV and p16 status in the recurrent versus parent tumor
Background Although typically associated with a favorable prognosis, a minority of human papillomavirus (HPV)ârelated (+) oropharyngeal cancers recur after chemoradiation. We postulated that a minor HPVânegative 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+/p16âpartial). One (3%) initially HPV+/p16+ patient developed an HPVânegative/p16ânegative lung squamous cell carcinoma (SCC), representing either a discordant oropharyngeal cancer metastasis or second primary tumor. Conclusion HPVârelated oropharyngeal cancers retain HPV+/p16+ expression at recurrence. Our results fail to provide evidence that a minor HPVânegative tumor subfraction is responsible for biologically aggressive behavior of HPV+ oropharyngeal cancer that recurs after chemoradiation. © 2014 Wiley Periodicals, Inc. Head Neck 37 : 8â11, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109811/1/hed23548.pd
Matted nodes: Poor prognostic marker in oropharyngeal squamous cell carcinoma independent of HPV and EGFR status
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 Seventyâeight previously untreated patients nested in a concurrent chemoradiation protocol were reviewed to correlate patterns of localâregional tumor extent to distant metastasis. Biomarker assessment was: HPV in situ hybridization and epidermal growth factor receptor (EGFR) immunointensity. Results The 3âyear diseaseâspecific 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 deâescalation of therapy. © 2012 Wiley Periodicals, Inc. Head Neck , 2012Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94456/1/21997_ftp.pd
Biomarkers in advanced larynx cancer
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102058/1/lary24245.pd
Analysis of blood and lymph vascularization patterns in tissue-engineered human dermo-epidermal skin analogs of different pigmentation
PURPOSE: Bioengineered dermo-epidermal skin analogs containing melanocytes represent a promising approach to cover large skin defects including restoration of the patient's own skin color. So far, little is known about the development of blood and lymphatic vessels in pigmented skin analogs after transplantation. In this experimental study, we analyzed the advancement and differences of host blood and lymphatic vessel ingrowth into light- and dark-pigmented human tissue-engineered skin analogs in a rat model.
METHODS: Keratinocytes, melanocytes, and fibroblasts from light- and dark-pigmented skin biopsies were isolated, cultured, and expanded. For each donor, melanocytes and keratinocytes were seeded in ratios of 1:1, 1:5, and 1:10 onto fibroblast-containing collagen gels. The skin analogs were subsequently transplanted onto full-thickness wounds of immuno-incompetent rats and quantitatively analyzed for vascular and lymphatic vessel density after 8 and 15Â weeks.
RESULTS: The skin analogs revealed a significant difference in vascularization patterns between light- and dark-pigmented constructs after 8Â weeks, with a higher amount of blood vessels in light compared to dark skin. In contrast, no obvious difference could be detected within the light- and dark-pigmented group when varying melanocyte/keratinocyte ratios were used. However, after 15Â weeks, the aforementioned difference in blood vessel density between light and dark constructs could no longer be detected. Regarding lymphatic vessels, light and dark analogs showed similar vessel density after 8 and 15Â weeks, while there were generally less lymphatic than blood vessels.
CONCLUSION: These data suggest that, at least during early skin maturation, keratinocytes, melanocytes, and fibroblasts from different skin color types used to construct pigmented dermo-epidermal skin analogs have distinct influences on the host tissue after transplantation. We speculate that different VEGF expression patterns might be involved in this disparate revascularization pattern observed
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