Digital Commons Network^™

Friction Of Soft Elastomeric Surfaces With A Defect, Charles J. Rand, Alfred Crosby

Alfred Crosby

We consider a simple problem that provides insight into the building blocks of friction for topographically patternedsurfaces and fundamental understanding into the general friction of coatings. The problem focuses on the effect of a line defect, such as a pattern’s edge, on the lateral force of a sliding soft interface. The line defect presents a discontinuity in the stress at the sliding interface, changing the lateral stiffness and decreasing the sliding force. We relate the decrease in sliding shear force to the changes in lateral stiffness through relationships that account for contact splitting and lateral confinement effects.

Outcomes Of Care By Hospitalists, General Internists, And Family Physicians, Peter K. Lindenauer, Michael B. Rothberg, Penelope Susan Pekow, Christopher Kenwood, Evan M. Benjamin, Andrew D. Auerbach

Penelope Susan Pekow

Background: The hospitalist model is rapidly altering the landscape for inpatient care in the United States, yet evidence about the clinical and economic outcomes of care by hospitalists is derived from a small number of single-hospital studies examining the practices of a few physicians.

Methods: We conducted a retrospective cohort study of 76,926 patients 18 years of age or older who were hospitalized between September 2002 and June 2005 for pneumonia, heart failure, chest pain, ischemic stroke, urinary tract infection, acute exacerbation of chronic obstructive pulmonary disease, or acute myocardial infarction at 45 hospitals throughout the United States. We used …

The Editors' Corner, Rex E. Wallace

Rasenna: Journal of the Center for Etruscan Studies

No abstract provided.

Vector And Parameters For Targeted Transgenic Rna Interference In Drosophila Melanogaster, Jian Quan Ni, Michele Markstein, Richard Binari, Barret Pfeiffer, Lu Ping Liu, Christians Villalta, Matthew Booker, Lizabeth Perkins, Norbert Perrimon

Michele Markstein

The conditional expression of hairpin constructs in Drosophila melanogaster has emerged in recent years as a method of choice in functional genomic studies. To date, upstream activating site–driven RNA interference constructs have been inserted into the genome randomly using P-element–mediated transformation, which can result in false negatives due to variable expression. To avoid this problem, we have developed a transgenic RNA interference vector based on the phiC31 site-specific integration method.

Curriculum Vitae , Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

Requirements For Identification Of Low Dose And Non-Linear Mutagenic Responses To Ionising Radiation, Pamela J Sykes, Tanya K Day

Dose-Response: An International Journal

Cancer results from multiple changes in gene expression that can occur both genetically and epigenetically. High doses of radiation can lead to mutations and cancer. At high doses the number of mutations caused by radiation is essentially linear with dose. Low dose radiation induced protective responses observed for cancer in vivo and cellular transformation in vitro would predict that hormetic responses would also be observed in mutation assays. Although there are a large number of different mutation assays available, very few are able to detect changes in mutation frequency in response to very low doses of DNA damaging agents. The …

Effects Of Low Doses Of Radiation: Joint Statement From The Following Participants At The 15th Pacific Basin Nuclear Conference, Sessions Held In Sydney, Australia, Wednesday 18 October 2006, Dj Higson, Dr Boreham, Al Brooks, Y-C Luan, Re Mitchel, J Strzelczyk, Pj Sykes

Dose-Response: An International Journal

No abstract provided.

Rad-By-Rad (Bit-By-Bit): Triumph Of Evidence Over Activities Fostering Fear Of Radiogenic Cancers At Low Doses, J Strzelczyk, W Potter, Z Zdrojewicz

Dose-Response: An International Journal

Large segments of Western populations hold sciences in low esteem. This trend became particularly pervasive in the field of radiation sciences in recent decades. The resulting lack of knowledge, easily filled with fear that feeds on itself, makes people susceptible to prevailing dogmas. Decades-long moratorium on nuclear power in the US, resentment of “anything nuclear”, and delay/refusal to obtain medical radiation procedures are some of the societal consequences. The problem has been exacerbated by promulgation of the linear-no-threshold (LNT) dose response model by advisory bodies such as the ICRP, NCRP and others. This model assumes no safe level of radiation …

Special Issue Preface

Dose-Response: An International Journal

No abstract provided.

Impacts Of Low-Dose Gamma-Radiation On Genotoxic Risk In Aquatic Ecosystems, Cheryl L Cassidy, Jennifer A Lemon, Douglas R Boreham

Dose-Response: An International Journal

Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might alter the consequences of radiation exposures to high doses of radiation (adaptive response). The cells adapted but only at doses which were above levels that might be expected environmentally. The “adaptive response” endpoint was useful to show biological responses to exposure, however, under these conditions it might not help in …

The Australasian Radiation Protection Society’S Position Statement On Risks From Low Levels Of Ionizing Radiation, Donald Higson

Dose-Response: An International Journal

Controversy continues on whether or not ionizing radiation is harmful at low doses, with unresolved scientific uncertainty about effects below a few tens of millisieverts. To settle what regulatory controls should apply in this dose region, an assumption has to be made relating dose to the possibility of harm or benefit. The position of the Australasian Radiation Protection Society on this matter is set out in a statement adopted by the Society in 2005. Its salient features are:

• There is insufficient evidence to establish a dose-effect relationship for doses that are less than a few tens of millisieverts in …

Very Large Amounts Of Radiation Are Required To Produce Cancer, Antone L Brooks, Edmond Hui, Lezlie A Couch

Dose-Response: An International Journal

The public fear of radiation is in part driven by the Linear No Threshold Hypothesis (LNTH), or the concept that each and every ionization increases the risk for cancer. Even if this were true, it is important to recognize that the increased risk is very small at low doses and cannot be detected. This paper demonstrates the large number of assumptions and extrapolations needed when using the LNTH to estimate low-dose cancer risk. The manuscript provides information at every level of biological organization suggesting that many of these linear assumptions do not hold. While the initial damage may be produced …

Cancer And Low Dose Responses In Vivo: Implications For Radiation Protection, Rej Mitchel

Dose-Response: An International Journal

The Linear No Threshold (LNT) hypothesis states that ionizing radiation risk is directly proportional to dose, without a threshold. This hypothesis, along with a number of additional derived or auxiliary concepts such as radiation and tissue type weighting factors, and dose rate reduction factors, are used to calculate radiation risk estimates for humans, and are therefore fundamental for radiation protection practices. This system is based mainly on epidemiological data of cancer risk in human populations exposed to relatively high doses (above 100 mSv), with the results linearly extrapolated back to the low doses typical of current exposures. The system therefore …

Extremely Low Doses Of X-Radiation Can Induce Adaptive Responses In Mouse Prostate, Tanya K Day, Guoxin Zeng, Antony M Hooker, Madhava Bhat, David R Turner, Pamela J Sykes

Dose-Response: An International Journal

The pKZ1 mouse chromosomal inversion assay is the only assay that has detected modulation of a mutagenic endpoint after single whole body X-irradiation with doses lower than 1 mGy. A non-linear dose response for chromosomal inversion has been observed in spleen and prostate between 0.001 mGy and 10 mGy, with doses between 0.005-0.01 mGy causing an increase in inversions and doses between 1–10 mGy causing a reduction below spontaneous inversion frequency. An adaptive response is a decreased biological effect induced by a low radiation dose. Adaptive responses contradict the linear-no-threshold model of risk estimation. We demonstrated that very low (0.001 …

Individual Radiosensitivity And Its Relevance To Health Physics, Kara Schnarr, Ian Dayes, Jinka Sathya, Douglas Boreham

Dose-Response: An International Journal

Radiation protection regulations have been established to reduce exposure of individuals to acceptable safe levels. These limits assume that people have similar responses to ionizing radiation and that there is no variation in individual radiation risk. The purpose of this research was to determine if apoptosis in lymphocytes can be used to assess individual sensitivity to ionizing radiation. Blood samples were taken from 54 males ranging in age from 19–85 years. Apoptosis was measured using modified flow cytometry based Annexin-FITC/7AAD and DiOC₆/7AAD assays in different populations of lymphocytes (total mixed lymphocyte population, subset CD4+ or CD8+ lymphocytes) after …

Health Effects Of Low Level Radiation: When Will We Acknowledge The Reality?, Jm Cuttler

Dose-Response: An International Journal

The 1986 April 26th Chernobyl event was the worst nuclear power accident—it killed 31 people. Its significance was exaggerated immensely because of the pervasive fear of ionizing radiation that has been indoctrinated in all of humanity. In reality, our environment includes radiation from natural sources, varying widely in intensity, to which all living things have adapted. The effect of radiation on organisms is primarily on their damage control biosystem, which prevents, repairs and removes cell damage. Low doses stimulate this system, while high doses inhibit it. So low doses decrease the incidences of cancer and congenital malformations; high doses have …

Whole-Body Low Dose Irradiation Promotes The Efficacy Of Conventional Radiotherapy For Cancer And Possible Mechanisms, Sz Jin, Xn Pan, N Wu, Gh Jin, Sz Liu

Dose-Response: An International Journal

The purpose of the present study was to explore the possibility of establishing cancer radiotherapy protocols that could promote treatment efficacy at a reduced radiation dose. Mouse models of melanoma (B16) and Lewis lung carcinoma (LLC) were used in the experiments. Conventional local radiotherapy was combined with low dose whole-body irradiation (LDWBI) in the presence or absence of gene therapy by intratumor injection of a recombinant plasmid Egr-mIL-18-B7.1 (E18B). After a number of trials with different combinations it was found that a protocol of 2-week treatment with 2 x (E18B + 2 Gy + 0.075 Gy x 2) was found …

Manifesto For Voice, Elizabeth L. Krause

Selected Publications of EFS Faculty, Students, and Alumni

No abstract provided.

Identifying Success And Abandonment Of Free/Libre And Open Source (Floss) Commons: A Preliminary Classification Of Sourceforge.Net Projects, Charles M. Schweik, Robert English

Schweik Open Source Project

Free/Libre and Open Source Software (FLOSS) projects are a form of commons where individuals work collectively to produce software that is a public, rather than a private, good. The famous phrase “Tragedy of the Commons” describes a situation where a natural resource commons, such as a pasture, or a water supply, gets depleted because of overuse. The tragedy in FLOSS commons is distinctly different -- it occurs when collective action is abandoned before a software product is produced or reaches its full potential. This paper builds on previous work about defining success in FLOSS projects by taking a collective action …

Multivalent Symbols Of An Enclosing Hand, Christopher Fennell

African Diaspora Archaeology Newsletter

No abstract provided.

Teaching The Archaeology Of The African Diaspora And Its Consequences: Thoughts About Entangling Education, Timothy James Scarlett

African Diaspora Archaeology Newsletter

No abstract provided.

The Fifth Annual Herman C. Hudson Symposium

African Diaspora Archaeology Newsletter

No abstract provided.

History Of The Urhobo People Of Niger Delta, Peter P. Ekeh

African Diaspora Archaeology Newsletter

No abstract provided.

Editor's Note On Book Reviews

African Diaspora Archaeology Newsletter

No abstract provided.

Coplanar Constant Mean Curvature Surfaces, Karsten Grosse-Brauckmann, Robert Kusner, John M. Sullivan

Robert Kusner

We consider constant mean curvature surfaces with finite topology, properly embedded in three-space in the sense of Alexandrov. Such surfaces with three ends and genus zero were constructed and completely classified by the authors. Here we extend the arguments to the case of an arbitrary number of ends, under the assumption that the asymptotic axes of the ends lie in a common plane: we construct and classify the entire family of these genus-zero, coplanar constant mean curvature surfaces.

Curriculum Vitae , Otto Vogl

Otto Vogl

No abstract provided.

Manifesto For Voice, Elizabeth L. Krause

Elizabeth L. Krause

No abstract provided.

Nelig Meeting - November 30, 2007, New England Library Instruction Group

New England Library Instruction Group

NELIG quarterly meeting, co-sponsored by ITIG, Get to Know Library 2.0.

How To Keep Your Author Rights (And Influence People), Marilyn S. Billings

Marilyn S. Billings

This presentation was part of the “Got Rights” UMass Amherst Science Faculty Colloquy, November 29, 2007.

How To Keep Your Author Rights (And Influence People), Marilyn S. Billings

University Libraries Publication Series

No abstract provided.