CiteULike: Tag resistance

Overlapping ligand specificity of P-glycoprotein and serum alpha(1)-acid glycoprotein: evidences and potential implications.

F Zsila — 2008-03-01T00:32:58-00:00

Curr Drug Metab, Vol. 8, No. 6. (August 2007), pp. 563-593.

Plasma alpha(1)-acid glycoprotein (AGP) is an important modulator of drug disposition, since it binds and transports of a vast array of pharmaceutical agents. The ABC transporter efflux pump, P-glycoprotein (P-gp), also recognizes and binds a broad range of weakly basic and uncharged xenobiotics. Its efflux activity plays a key role in pharmacokinetics of drugs, and overexpression of P-gp in malignant cells confers multidrug resistance (MDR) to anticancer agents. Comparison of ligand specificities of AGP and P-gp revealed high similarity showing that both proteins interact with the same therapeutic classes of drugs (alpha/beta-blockers, anticancer agents, Ca(2+) antagonists, antipsychotics/neuroleptics, HIV protease inhibitors etc.) as well as with additional endo- and exogenous compounds (steroids, dyes, natural substances). A wealth of examples are presented to show the potential use of drug-AGP binding data to predict drug-P-gp interactions and vice versa. In addition, structural and functional similarities between AGP and P-gp have been highlighted. Based on these data, several proposals have been made: 1) AGP and P-gp might act synergistically in protecting cells from harmful xenobiotics; 2) An extensive shared list of their ligands allows prediction of mutual binding interactions; 3) Interaction of drugs and drug candidates, both with AGP and P-gp, should be considered to optimize pharmacotherapy and to delineate the causes of drug-drug interactions; 4) Structures of known AGP binders could be exploited in searching for novel scaffolds of P-gp modulators to overcome cancer MDR and efflux-mediated resistance in microorganisms and parasites; 5) Novel fluorescent probes for studying P-gp structure and function can be pre-selected among AGP binder agents.

Pretty in Punk: Girls' Gender Resistance in a Boys' Subculture

Lauraine Leblanc — 2005-05-15T17:34:35-00:00

(01 May 1999)

Cultural Resistance Reader

Duncombe Stephen — 2005-05-15T17:27:48-00:00

(24 May 2002)

Resistance Through Rituals: Youth Subcultures in Postwar Britain (Youth Subcultures in Post-war Britain)

Stuart Hall — 2005-05-15T17:14:50-00:00

(01 January 1995)

Weapons of the Weak : Everyday Forms of Peasant Resistance

James Scott — 2005-04-28T03:08:45-00:00

(10 September 1987)

Nation of Rebels : Why Counterculture Became Consumer Culture

Joseph Heath — 2005-05-15T16:59:20-00:00

(01 January 2005)

Resistance distance and Laplacian spectrum

Wenjun Xiao — 2007-12-13T00:24:00-00:00

Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta), Vol. 110, No. 4. (1 November 2003), pp. 284-289.

The resistance distance r ij between two vertices v i and v j of a (connected, molecular) graph G is equal to the resistance between the respective two points of an electrical network, constructed so as to correspond to G, such that the resistance of any two adjacent points is unity. We show how the matrix elements r ij can be expressed in terms of the Laplacian eigenvalues and eigenvectors of G. In addition, we determine certain properties of the resistance matrix R=|| r ij||.

Random Walks and Chemical Graph Theory

DJ Klein — 2008-01-28T00:24:33-00:00

J. Chem. Inf. Comput. Sci., Vol. 44, No. 5. (27 September 2004), pp. 1521-1525.

Abstract: Simple random walks probabilistically grown step by step on a graph are distinguished from walk enumerations and associated equipoise random walks. Substructure characteristics and graph invariants correspondingly defined for the two types of random walks are then also distinct, though there often are analogous relations. It is noted that the connectivity index as well as some resistance-distance-related invariants make natural appearances among the invariants defined from the simple random walks.

Computational Science and Engineering

Gilbert Strang — 2008-01-31T01:48:08-00:00

(01 November 2007)

This book presents the full range of computational science and engineering -- the equations, numerical methods, and algorithms with MATLAB® codes. The author has taught this material to thousands of engineers and scientists. The book is solution-based and not formula-based: it covers applied linear algebra and fast solvers, differential equations with finite differences and finite elements, Fourier analysis, optimization, and more. Contents Chapter 1: Applied Linear Algebra; Chapter 2: A Framework for Applied Mathematics; Chapter 3: Boundary Value Problems; Chapter 4: Fourier Series and Integrals; Chapter 5: Analytic Functions; Chapter 6: Initial Value Problems; Chapter 7: Solving Large Systems; Chapter 8: Optimization and Minimum Principles.

Fractal and Multifractal Scaling of Electrical Conduction in Random Resistor Networks

S Redner — 2007-10-08T11:42:20-00:00

(4 Oct 2007)

This article is a mini-review about electrical current flows in networks from the perspective of statistical physics. We briefly discuss analytical methods to solve the conductance of an arbitrary resistor network. We then turn to basic results related to percolation: namely, the conduction properties of a large random resistor network as the fraction of resistors is varied. We focus on how the conductance of such a network vanishes as the percolation threshold is approached from above. We also discuss the more microscopic current distribution within each resistor of a large network. At the percolation threshold, this distribution is multifractal in that all moments of this distribution have independent scaling properties. We will discuss the meaning of multifractal scaling and its implications for current flows in networks, especially the largest current in the network. Finally, we discuss the relation between resistor networks and random walks and show how the classic phenomena of recurrence and transience of random walks are simply related to the conductance of a corresponding electrical network.

Generalized matrix tree theorem for mixed graphs

Ravindra Bapat — 2008-02-13T09:54:57-00:00

Linear and Multilinear Algebra, Vol. 46, No. 4. (1999), pp. 299-312.

In this article we provide a combinatorial description of an arbitrary minor of the Laplacian matrix (L) of a mixed graph (a graph with some oriented and some unoriented edges). This is a generalized Matrix Tree Theorem. We also characterize the non-singular substructures of a mixed graph. The sign attached to a nonsingular substructure is described in terms of labeling and the number of unoriented edges included in certain paths. Nonsingular substructures may be viewed as generalized matchings, because in the case of disjoint vertex sets corresponding to the rows and columns of a minor of L, our generalized Matrix Tree Theorem provides a signed count over matchings between those vertex sets. A mixed graph is called quasi bipartite if it does not contain a non singular cycle (a cycle containing an odd number of un-oriented edges). We give several characterizations of quasi-bipartite graphs.

The electrical resistance of a graph captures its commute and cover times

AK Chandra — 2007-11-21T13:30:39-00:00

(1989), pp. 574-586.

. View an n-vertex, m-edge undirected graph as an electrical network with unit resistors as edges. We extend known relations between random walks and electrical networks by showing that resistance in this network is intimately connected with the lengths of random walks on the graph. For example, the commute time between two vertices s and t (the expected length of a random walk from s to t and back) is precisely characterized by the effective resistance R st between s and t: commute time =...

A Combinatorial Proof of the All Minors Matrix Tree Theorem

Seth Chaiken — 2008-02-13T09:46:02-00:00

SIAM Journal on Algebraic and Discrete Methods, Vol. 3, No. 3. (1982), pp. 319-329.

Random Walks and Electric Networks

Peter Doyle — 2007-12-09T08:53:41-00:00

(11 Jan 2000)

A popular account of the connection between random walks and electric networks.

Electric currents in infinite networks

Peter Doyle — 2008-02-06T08:16:26-00:00

(29 Mar 2007)

In this survey, we present the basic facts about conduction in infinite networks. This survey is based on the work of Flanders, Zemanian, and Thomassen, who developed the theory of infinite networks from scratch. Here we show how to get a more complete theory by paralleling the well-developed theory of conduction on open Riemann surfaces. Like Flanders and Thomassen, we take as a test case for the theory the problem of determining the resistance across an edge of a d-dimensional grid of 1-ohm resistors.

Spanning Trees on Hypercubic Lattices and Non-orientable Surfaces

WJ Tzeng — 2008-02-04T05:54:11-00:00

(27 Jan 2000)

We consider the problem of enumerating spanning trees on lattices. Closed-form expressions are obtained for the spanning tree generating function for a hypercubic lattice of size N_1 x N_2 x...x N_d in d dimensions under free, periodic, and a combination of free and periodic boundary conditions. Results are also obtained for a simple quartic net embedded on two non-orientable surfaces, a Moebius strip and the Klein bottle. Our results are based on the use of a formula expressing the spanning tree generating function in terms of the eigenvalues of an associated tree matrix. An elementary derivation of this formula is given.

Theory of resistor networks: The two-point resistance

FY Wu — 2007-08-31T18:09:27-00:00

(19 Feb 2004)

The resistance between arbitrary two nodes in a resistor network is obtained in terms of the eigenvalues and eigenfunctions of the Laplacian matrix associated with the network. Explicit formulas for two-point resistances are deduced for regular lattices in one, two, and three dimensions under various boundary conditions including that of a Moebius strip and a Klein bottle. The emphasis is on lattices of finite sizes. We also deduce summation and product identities which can be used to analyze large-size expansions of two-and-higher dimensional lattices.

Random Walks on Graphs: A Survey

László Lovász — 2007-08-31T18:06:43-00:00

this paper we'll formulate the results in terms of random walks, and mostly restrict our attention to the undirected case. 2 L. Lov'asz

On factor graphs and electrical networks

P Vontobel — 2008-01-28T07:20:54-00:00

(2003)

Factor graphs are graphical models with origins in coding theory. The sum-product and the max-product algorithms, which operate by message passing in a factor graph, subsume a great variety of algorithms in coding, signal processing, and artificial intelligence. In this paper, factor graphs are used to express a one-to-one correspondence (based on results by Dennis) between a class of static electrical circuits andmulti-variable probability distributions; these factor graphs may also be viewed...

Modern Graph Theory

Bela Bollobas — 2005-04-06T12:48:45-00:00

(01 July 1998)

Fundamentals 1 Electrical Networks 39 Flows, Connectivity and matching 67 Extremal Problems 103 Coloring Ramsey Theory 181 Random Graphs 215 Graphs, Groups and Matrices 253 Random walks on Graphs The Tutte Polynomial 335

Infinite electrical networks: a reprise

AH Zemanian — 2008-01-28T06:24:11-00:00

Circuits and Systems, IEEE Transactions on, Vol. 35, No. 11. (1988), pp. 1346-1358.

A tutorial on resistive infinite electrical networks at an undergraduate level is presented. Rather than presenting a comprehensive survey on the wide variety of results existing in this subject, the author introduces the basic ideas with several examples and puzzles, examines how the theory branches into two separate avenues of investigation, points out how infinite networks differ in their behavior from finite networks, and ends with a brief survey of the literature

The multivariate Tutte polynomial (alias Potts model) for graphs and matroids

Alan Sokal — 2005-03-28T15:25:20-00:00

(25 March 2005)

The multivariate Tutte polynomial (known to physicists as the Potts-model partition function) can be defined on an arbitrary finite graph G, or more generally on an arbitrary matroid M, and encodes much important combinatorial information about the graph (indeed, in the matroid case it encodes the full structure of the matroid). It contains as a special case the familiar two-variable Tutte polynomial -- and therefore also its one-variable specializations such as the chromatic polynomial, the flow polynomial and the reliability polynomial -- but is considerably more flexible. I begin by giving an introduction to all these problems, stressing the advantages of working with the multivariate version. I then discuss some questions concerning the complex zeros of the multivariate Tutte polynomial, along with their physical interpretations in statistical mechanics (in connection with the Yang--Lee approach to phase transitions) and electrical circuit theory. Along the way I mention numerous open problems. This survey is intended to be understandable to mathematicians with no prior knowledge of physics.

Pharmacokinetic/pharmacodynamic parameters: rationale for antibacterial dosing of mice and men.

WA Craig — 2006-04-10T05:18:59-00:00

Clin Infect Dis, Vol. 26, No. 1. (January 1998)

Investigations over the past 20 years have demonstrated that antibacterials can vary markedly in the time course of antimicrobial activity. These differences in pharmacodynamic activity have implications for optimal dosage regimens. The results of more recent studies suggest that the magnitude of the pharmacokinetic/pharmacodynamic parameters required for efficacy are relatively similar in animal infection models and in human infections. However, there is still much to learn. Additional studies are needed to further correlate pharmacokinetic/pharmacodynamic parameters for many antibacterials with therapeutic efficacy in a variety of animal infection models and in human infections. The potential value of using pharmacokinetic/pharmacodynamic parameters as guides for establishing optimal dosing regimens for new and old drugs and for new emerging pathogens and resistant organisms, for setting susceptibility breakpoints, and for reducing the cost of drug development should make the continuing search for the therapeutic rationale of antibacterial dosing of mice and men worthwhile.

A fresh look at the definition of susceptibility of Streptococcus pneumoniae to beta-lactam antibiotics.

DM Musher — 2006-04-10T05:00:13-00:00

Arch Intern Med, Vol. 161, No. 21. (26 November 2001), pp. 2538-2544.

Definitions for susceptibility or resistance of Streptococcus pneumoniae to penicillin were not developed until penicillin-resistant pneumococci appeared in South Africa in the late 1970s. The definition that was accepted (which still remains in use) and later definitions of resistance to most other beta-lactam antibiotics were derived from laboratory and clinical data relating to the treatment of meningitis, not otitis media, sinusitis, or pneumonia. An understanding of the origin of these definitions helps to resolve the apparent paradox that infections of the respiratory tract due to seemingly beta-lactam-resistant pneumococci may still respond well to standard doses of these drugs. A recently sanctioned change in the definition of susceptibility to amoxicillin is helpful in eliminating the paradox for this drug, but it may create further confusion by implying that, on a microgram basis, amoxicillin is substantially more effective than penicillin or third-generation cephalosporins. This article examines definitions of susceptibility and resistance of pneumococci, highlighting areas that have led to confusion and proposing a new way of understanding them.

In A Queer Time And Place: Transgender Bodies, Subcultural Lives (Sexual Cultures (Paperback))

Judith Halberstam — 2006-03-13T23:59:37-00:00

"Halberstam's marvelous new book combines fierce argumentation, vivid description, and astute as well as hilarious commentary. The author not only provides a powerful critique of common defenses and dismissals of 'postmodernism,' but offers a redefinition of 'identity politics' for the new millennium as well. —Lisa Duggan, author of Twilight of Equality?: Neoliberalism, Cultural Politics, and the Attack on Democracy In her first book since the critically acclaimed Female Masculinity, Judith Halberstam examines the significance of the transgender body in a provocative collection of essays on queer time and space. She presents a series of case studies focused on the meanings of masculinity in its dominant and alternative forms—especially female and trans-masculinities as they exist within subcultures, and are appropriated within mainstream culture. In a Queer Time and Place opens with a probing analysis of the life and death of Brandon Teena, a young transgender man who was brutally murdered in small-town Nebraska. After looking at mainstream representations of the transgender body as exhibited in the media frenzy surrounding this highly visible case and the Oscar-winning film based on Brandon's story, Boys Don't Cry, Halberstam turns her attention to the cultural and artistic production of queers themselves. She examines the "transgender gaze," as rendered in small art-house films like By Hook or By Crook, as well as figurations of ambiguous embodiment in the art of Del LaGrace Volcano, Jenny Saville, Eva Hesse, Shirin Neshat, and others. She then exposes the influence of lesbian drag king cultures upon hetero-male comic films, such as Austin Powers and The Full Monty, and, finally, points to dyke subcultures as one site for the development of queer counterpublics and queer temporalities. Considering the sudden visibility of the transgender body in the early twenty-first century against the backdrop of changing conceptions of space and time, In a Queer Time and Place is the first full-length study of transgender representations in art, fiction, film, video, and music. This pioneering book offers both a jumping off point for future analysis of transgenderism and an important new way to understand cultural constructions of time and place.

George Tooker, Surveillance, and Cold War Sexual Politics

Katherine Hauser — 2005-05-19T04:43:04-00:00

GLQ: A Journal of Lesbian and Gay Studies, Vol. 11, No. 3. (June 2005), pp. 391-426.

M-G-M's Greatest Musicals: The Arthur Freed Unit

Hugh Fordin — 2007-01-22T05:39:31-00:00

(30 September 1996)

Mapping Desire

David Bell — 2006-08-08T19:51:02-00:00

(24 April 1995)

Discover the truth about sex in the city (and the country). Mapping Desire explores the places and spaces of sexuality from body to community, from the "cottage" to the Barrio, from Boston to Jakarta, from home to cyberspace. Mapping Desire is the first book to explore sexualities from a geographical perspective. The nature of place and notions of space are of increasing centrality to cultural and social theory. Mapping Desires presents the rich and diverse world of contemporary sexuality, exploring how the heterosexed body has been appropriated and resisted on the individual, community and city scales. Editors David Bell and Gill Valentine have brought together contributors with a wealth of approaches to ways in which the spaces of sex and the sexes of space are being mapped out across contemporary culture. Among the many sexual geographies covered are: Lesbians at home and on the streets; gay men on fantasy islands; bisexual identities; The heterosexualization of the workplace; bachelor farmers and spinsters; surveillance and sexuality; prostitution; queer politics; sexual citizenship, and the transformation of intimacy. The book is divided into four sections: cartographies/identities; sexualized spaces: global/local; sexualized spaces: local/global; sites of resistance. Each section is separately introduced. Beyond the bibliography, an annotated guide to further reading is also provided to help the reader map their own way through the literature. Mapping Desire will be a valuable and accessible travelogue of information for anyone interested in social, cultural and political geography, lesbian and gay studies, cultural studies, or simply those who want to find out more about the sexual landscape of contemporary society. Contents: Part I: Cartographies/Identities; Resolving Riddles: The Sexed Body, Julia Cream; Locating Bisexual Identities: Discourses of Bisexuality and Contemporary Feminist Theory, Clare Hemmings; Of Moffies, Kaffiers and Perverts: Male Homosexuality and the Discourse of Moral Order in the Apartheid State, Glen Elder; Femme on the Streets, Butch in the Sheets (a Play on Whores), Alison Murray; Body Work: The Performance of Gendered and (Hetero)Sexualized Identities in City Workplaces, Linda McDowell; Part II: Sexualized Spaces: Global/Local; Whenever I Lay My Girlfriend That's My Home: The Performance and Surveillance of Lesbian Identities in Domestic Environments, Lynda Johnston and Gill Valentine; The Lesbian Flaneur, Sally Munt; Fantasy Islands: Popular Topographies of Marooned Masculinities, Gregory Woods; Sexuality and Urban Space: A Framework for Analysis, Lawrence Knopp; Part III: Sexualized Spaces: Local/Global; "And She Told Two Friends...": Lesbians Creating Urban Social Space, Tamar Rothenberg; Trading Places: Consumption, Sexuality and the Production of Queer Space, Jon Binnie; Bachelor Farmers and Spinsters: Gay and Lesbian Identities and Communities in Rural North Dakota, Jerry Lee Kramer; (Re)Constructing a Spanish Redlight District: Prostitution, Space and Power, Angie Hart; Part IV: Sites of Resistance; "Surveilliant Gays": HIV, Space and the Construction of Identities, David Woodhead; Sex, Scale and the "New Urban Politics": HIV-Prevention Strategies from Yaletown, Vancouver, Michael Brown; "Boom, Bye, Bye": Jamaican Ragga and Gay Resistance, Tracey Skelton; The Diversity of Queer Politics and the Redefinition of Sexual Identity and Community in Urban Space, Tim Davis; Perverse Dynamics, Sexual Citizenship and the Transformation of Intimacy, David Bell; Guide to Further Reading; Bibliography

Queers in Space: Communities, Public Places, Sites of Resistance

Gorden Ingram — 2006-08-08T19:48:18-00:00

(19 June 1997)

Moving beyond finding new ways to critique literature and philosophy, queer and postmodern theory delves into analyzing the concrete world. Aaron Betsky's Queer Space: Architecture and Same-Sex Desire and David Bell and Gill Valentine's Mapping Desire were groundbreaking studies, exploring how the material world shaped and was shaped by homosexual cultures and communities. In Queers in Space: Communities, Public Places, Sites of Resistance, Gordon Brent Ingram (along with Anne-Marie Bouthillette and Yolanda Retter) brings together more than 30 essays, meditations, studies, and fiction excerpts mapping how gay men and lesbians view, interpret, alter, and ultimately change the worlds in which they live. Writers as varied as Pat Califia, Sarah Schulman, David Bell, and Joan Nestle weigh in along with architects, geographers, and social scientists to delineate the relationship between gay people and the physical world. Weighing in at more than 500 pages, lavishly illustrated and beautifully produced, Queers in Space is a welcome addition to the growing literature of queer and urban studies. the gay/lesbian community in the urban environment

Queer Space: Architecture and Same-Sex Desire

Aaron Betsky — 2006-08-08T19:46:40-00:00

(02 April 1997)

Discussions of gay culture and gay politics traditionally have concerned "civil rights," "artistic influence," and "sexual freedom." Rarely has the concept of how gay people relate to material space been addressed. Aaron Betsky's Queer Space: Architecture and Same-Sex Desire is an important, ground-breaking book that examines how homosexual people live in physical space and how they are in the forefront of creating new concepts of space, for themselves as well as for the rest of the world. Queer Space is smart, well written, and filled with illustrations. Betsky's thesis--that "the purpose of queer space is ultimately sex"--is passionately argued and highly convincing. This is a major work of gay and social studies. In Building Sex, architecture critic and curator Aaron Betsky looked at how traditional gender roles have influenced architecture. In Queer Space, he examines how same-sex desire is creating an entirely new architecture. Gay men and women are in the forefront of architectural innovation, reclaiming abandoned neighborhoods, redefining urban spaces, and creating liberating interiors out of hostile environments. Queer spaces have arisen out of the experiences of homosexuals in a straight culture. Often forced to hide their true nature, gay men and women have turned inward, playing with the norms of interior space and creating environments of stagecraft and celebration where they can define themselves with out fear. Their experiments point the way to an architecture that can free us all from the imprisoning structures and spaces of the modern city.

beta-Lactam Resistance in Haemophilus parasuis Is Mediated by Plasmid pB1000 Bearing blaROB-1

Alvaro San Millan — 2007-10-09T15:01:12-00:00

Antimicrob. Agents Chemother., Vol. 51, No. 6. (1 June 2007), pp. 2260-2264.

beta-Lactam resistance in Haemophilus parasuis is an emerging phenomenon that has not yet been characterized from a molecular perspective. Clinical high-level beta-lactam-resistant isolates from Spain bore a novel plasmid, pB1000, expressing a functionally active ROB-1 beta-lactamase. Pulsed-field gel electrophoresis was applied for the first time to H. parasuis and showed that beta-lactam resistance is due to clonal spread of a resistant strain, BB1018, bearing pB1000. 10.1128/AAC.00242-07

Shear Stress Dependent Regulation of Vascular Resistance in Health and Disease: Role of Endothelium

Akos Koller — 2008-05-17T23:30:36-00:00

Endothelium, Vol. 4, No. 4. (1996), pp. 247-272.

For a long time, locally released metabolic factors from parenchymal cells and the myo-genic response of vascular smooth muscle were considered to be the two main peripheral regulatory mechanisms to control vascular resistance and thereby determining the distribution of blood flow and pressure within vascular networks of various organs of the body. However, not every change in blood flow could be satisfactorily explained by these two mechanisms. The flow-dependent responses of blood vessels, namely, an increase in blood flow in arteries followed by their dilation had already been observed at the beginning of this century, and perhaps even earlier, yet the nature and importance of this phenomenon in blood flow regulation was not delineated until recently. In the last two decades, especially following the recognition of the role of endothelium in the production of vasoactive factors, much new experimental evidence was gathered that suggests the general presence and importance of flow (shear stress)-dependent vascular reactivity in the regulation of organ blood flow. In this review we make an attempt to summarize the exponentially growing experimental results obtained in vitro and in vivo, suggesting that a change in wall shear stress is the underlying stimulus of flow dependent vascular phenomena, and some of the theoretical aspects and consequences of acute, shear stress-dependent changes in resistance in the circulation. The possible physiological and pathophysiological roles of shear stress-dependent vascular regulatory mechanisms as well as the effects of chronic increases in blood flow (shear stress) on the adaptation of blood vessels are also discussed.

Oseltamivir resistance during treatment of influenza A (H5N1) infection.

MD de Jong — 2006-01-13T20:39:48-00:00

N Engl J Med, Vol. 353, No. 25. (22 December 2005), pp. 2667-2672.

Influenza A (H5N1) virus with an amino acid substitution in neuraminidase conferring high-level resistance to oseltamivir was isolated from two of eight Vietnamese patients during oseltamivir treatment. Both patients died of influenza A (H5N1) virus infection, despite early initiation of treatment in one patient. Surviving patients had rapid declines in the viral load to undetectable levels during treatment. These observations suggest that resistance can emerge during the currently recommended regimen of oseltamivir therapy and may be associated with clinical deterioration and that the strategy for the treatment of influenza A (H5N1) virus infection should include additional antiviral agents.

Parasite infectivity to hybridising host species: a link between hybrid resistance and allopolyploid speciation?

JA Jackson — 2007-01-02T13:25:03-00:00

Int J Parasitol, Vol. 33, No. 2. (February 2003), pp. 137-144.

Variation in host-specific infectivity was studied in monogenean polystome parasites (Protopolystoma spp.) of the interfertile, parapatric anurans Xenopus laevis laevis and Xenopus muelleri. Laboratory-raised host F1 hybrids were resistant to parasites respectively specific to each parent taxon in nature. This resistance occurred against parasite isolates from both inside and outside a host hybrid/sympatric zone (and no isolate was compatible with the foreign host species under experimental conditions). Geographical Protopolystoma xenopodis isolates showed variable infectivity to a single full-sib group of their usual host, X. l. laevis, and strains with high or low infectivity to these sibs co-occurred in spatially distant local areas (separated by 1,700 km). The host compatibility of P. xenopodis was also subject to host genotypexparasite genotype interactions. Refractoriness to some parasites or pathogens, as a consequence of hybridisation, may have conferred a selective advantage on the allopolyploid pathway by which most Xenopus spp. are believed to have evolved.

Evolutionary dynamics of pathogen resistance and tolerance.

BA Roy — 2007-01-03T10:40:48-00:00

Evolution Int J Org Evolution, Vol. 54, No. 1. (February 2000), pp. 51-63.

Host organisms can respond to the threat of disease either through resistance defenses (which inhibit or limit infection) or through tolerance strategies (which do not limit infection, but reduce or offset its fitness consequences). Here we show that resistance and tolerance can have fundamentally different evolutionary outcomes, even when they have equivalent short-term benefit for the host. As a gene conferring disease resistance spreads through a population, the incidence of infection declines, reducing the fitness advantage of carrying the resistance gene. Thus genes conferring complete resistance cannot become fixed (i.e., universal) by selection in a host population, and diseases cannot be eliminated solely by natural selection for host resistance. By contrast, as a gene conferring disease tolerance spreads through a population, disease incidence rises, increasing the evolutionary advantage of carrying the tolerance gene. Therefore, any tolerance gene that can invade a host population will tend to be driven to fixation by selection. As predicted, field studies of diverse plant species infected by rust fungi confirm that resistance traits tend to be polymorphic and tolerance traits tend to be fixed. These observations suggest a new mechanism for the evolution of mutualism from parasitism, and they help to explain the ubiquity of disease.

Substances involved in the natural resistance of fish to infection-A review

GA Ingram — 2007-04-02T08:21:28-00:00

Journal of Fish Biology, Vol. 16, No. 1. (1980), pp. 23-60.

Natural'antibodies'are substances found in the blood of animals that have not been immunised against infective agents. However, exposure to these agents or to cross-reacting antigens may well have taken place. Fish contain naturally-occurring, relatively nonspecific, lectin-like proteins or glycoproteins, which are distinct from immunoglobulins, and which react with a wide variety of antigens and may confer some degree of immunity against natural infection. In most cases the cause of the antigenic stimulus is not obvious although the formation of these'antibodies'may have been brought about by exposure to various micro-organisms. Many of these antibody-like molecules behave in a similar manner to immune antibodies or immunoglobulins and cross-react with specific carbohydrate moieties on the cell walls of bacteria, erythrocytes and certain other cellular antigens, due to the presence of similar antigenic determinants. It is difficult to ascribe an appropriate definition to the term'natural antibody'. In fish, these'antibodies'have been so designated on the basis of functional rather than structural criteria. Such naturally-occurring, low grade, antibody-like'immune'substances include'acute phase'proteins, lysozyme and chitinase, interferon, agglutinins, lysins, complement and properdin, precipitins, and non-immunoglobulin, lectin-like molecules. In addition to the above non-immunoglobulin materials, natural immunoglobulins identifiable as IgM have also been reported in fish. Furthermore, mucus contains many biochemical agents capable of reaction against infective organisms and thus providing the host with an immediate or a first line of defence mechanism. This review compiles some of the relevant information in the literature concerned with natural'immune'substances, present in the serum and mucus of fish, involved in protection against pathogens. Wherever possible the basic physicochemical properties of these substances are indicated and their potential immunobiological functions discussed.

Selection of Antifolate-Resistant Plasmodium falciparum by Sulfadoxine-Pyrimethamine Treatment and Infectivity to Anopheles Mosquitoes

Fabian Mendez — 2007-10-10T11:59:44-00:00

Am J Trop Med Hyg, Vol. 77, No. 3. (1 September 2007), pp. 438-443.

Resistance-conferring mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) in Plasmodium falciparum are selected by treatment with sulfadoxine pyrimethamine (SP). We assessed the association between these mutations and transmission capacity of parasites to Anopheles mosquitoes on the Pacific coast of Colombia. Patients with uncomplicated P. falciparum malaria received SP treatment and were followed-up to compare the prevalence of DHFR and DHPS mutations before and after SP treatment. Membrane feeding assays were used to measure infectivity to mosquitoes of post-treatment gametocytes with and without these mutations. Per-protocol treatment efficacy was 95.0% (132 of 139). Gametocytes carrying resistance-conferring mutations were selected after SP treatment and were infective to mosquitoes. Seven days after treatment, infections with two DHFR mutations had a 10-fold higher probability of infecting mosquitoes than infections with no DHFR mutations (odds ratio = 10.23, P < 0.05). Low-level drug resistance mutations have the potential to enhance transmission of P. falciparum and spread resistant parasites.

Skin Effect Modeling Based on a Differential Surface Admittance Operator

D De Zutter — 2007-06-25T13:20:50-00:00

IEEE Trans. Microw. Theory Tech., Vol. 53, No. 8. (2005), pp. 2526-2538.

An important issue in high-frequency signal integrity prediction is the modeling of the skin effect of thick conductors. A new differential surface admittance concept is put forward allowing to replace the conductor by equivalent electric surface currents and to replace the material of the conductor by the material of the background medium the conductor is embedded in. This new concept is studied in detail for the two-dimensional TM case starting from the Dirichlet eigenfunctions of the cross section. Detailed expressions are derived for the important practical case of a rectangular cross section. Next, the differential surface admittance operator is exploited to determine the resistance and inductance matrices of a set of multiconductor lines. A first set of numerical results provides the reader with some insight into the behavior of the surface admittance matrix. A second set of results demonstrates the correctness and versatility of the new approach to determine inductance and resistance matrices.

Bear Bodies, Bear Masculinity: Recuperation, Resistance, or Retreat?

Peter Hennen — 2004-12-28T17:33:49-00:00

Gender & Society, Vol. 19, No. 1., 25.

The Remaking of a Model Minority Perverse Projectiles under the Specter of (Counter)Terrorism

Jasbir Puar — 2007-06-20T21:38:44-00:00

Social Text, Vol. 22, No. 3. (2004), pp. 75-104.

The New Privacy [Overseers of the Poor: Surveillance, Resistance and the Limits of Privacy (John Gilliom)]

Paul Schwartz — 2007-09-18T21:52:44-00:00

Michigan Law Review, Vol. 101, No. 6. (2003), pp. 2163-2184.

Organization, Surveillance and the Body: Towards a Politics of Resistance

Kirstie Ball — 2007-06-20T20:43:55-00:00

Organization, Vol. 12, No. 1. (1 January 2005), pp. 89-108.

This paper examines the problematic of embodied resistance to biometric surveillance practices. After establishing that surveillance is becoming more widespread, the paper draws on the multidisciplinary areas of organization theory, surveillance theory, and body and feminist sociology. It is argued that current theoretical resources available to organization theorists are inadequate for analysing resistance to these technologies. After an investigation of recent developments in the sociology of the body and in surveillance theory, resistance is conceptualized at the interface of bodies and technologies, and is antagonistic towards categorizations and fixities produced by biometrics. A number of resistance strategies are distilled, using feminist and post-structuralist sociology. Although it is acknowledged that the paper's arguments do not address questions of agency and an ethics of the self, resistance arguments that challenge the totalizing impulse of surveillance practice are welcome in the face of government and private sector rhetoric about its desirability. 10.1177/1350508405048578

Counter-surveillance as Political Intervention?

Torin Monahan — 2007-06-20T19:01:49-00:00

Social Semiotics, Vol. 16, No. 4. (2006), pp. 515-534.

This paper analyzes practices of counter-surveillance—particularly against closed-circuit television systems in urban areas—and theorizes their political implications. Counter-surveillance is defined as intentional, tactical uses, or disruptions of surveillance technologies to challenge institutional power asymmetries. Such activities can include disabling or destroying surveillance cameras, mapping paths of least surveillance and disseminating that information over the Internet, employing video cameras to monitor sanctioned surveillance systems and their personnel, or staging public plays to draw attention to the prevalence of surveillance in society. The main argument is that current modes of activism tend to individualize surveillance problems and methods of resistance, leaving the institutions, policies, and cultural assumptions that support public surveillance relatively insulated from attack.

We Know You Are Watching: Surveillance Camera Players 1996-2006

Surveillance Players — 2007-11-29T18:35:50-00:00

The Cytochrome P450 Lanosterol 14alpha-Demethylase Gene Is a Demethylation Inhibitor Fungicide Resistance Determinant in Monilinia fructicola Field Isolates from Georgia

Chao-Xi Luo — 2008-01-09T23:14:22-00:00

Appl. Environ. Microbiol., Vol. 74, No. 2. (15 January 2008), pp. 359-366.

Resistance in Monilinia fructicola to demethylation inhibitor (DMI) fungicides is beginning to emerge in North America, but its molecular basis is unknown. Two potential genetic determinants of DMI fungicide resistance including the 14alpha-demethylase gene (MfCYP51) and the ATP-binding cassette transporter gene MfABC1, were investigated in six resistant (DMI-R) and six sensitive (DMI-S) field isolates. No point mutations leading to an amino acid change were found in the MfCYP51 gene. The constitutive expression of the MfCYP51 gene in DMI-R isolates was significantly higher compared to DMI-S isolates. Gene expression was not induced in mycelium of DMI-R or DMI-S isolates treated with 0.3 microg of propiconazole/ml. A slightly higher average MfCYP51 copy number value was detected in DMI-R isolates (1.35) compared to DMI-S isolates (1.13); however, this difference could not be verified in Southern hybridization experiments or explain the up to 11-fold-increased MfCYP51 mRNA levels in DMI-R isolates. Analysis of the upstream nucleotide sequence of the MfCYP51 gene revealed a unique 65-bp repetitive element at base pair position 117 from the translational start site in DMI-R isolates but not in DMI-S isolates. This repetitive element contained a putative promoter and was named Mona. The link between Mona and the DMI resistance phenotype became even more apparent after studying the genetic diversity between the isolates. In contrast to DMI-S isolates, DMI-R isolates contained an MfCYP51 gene of identical nucleotide sequence associated with Mona. Still, DMI-R isolates were not genetically identical as revealed by Microsatellite-PCR analysis. Also, real-time PCR analysis of genomic DNA indicated that the relative copy number of Mona among DMI-S and DMI-R isolates varied, suggesting its potential for mobility. Interestingly, constitutive expression of the MfABC1 gene in DMI-R isolates was slightly lower than that of DMI-S isolates, but expression of the MfABC1 gene in DMI-R isolates was induced in mycelium after propiconazole treatment. Therefore, the MfABC1 gene may play a minor role in DMI fungicide resistance in M. fructicola. Our results strongly suggest that overexpression of the MfCYP51 gene is an important mechanism in conferring DMI fungicide resistance in M. fructicola field isolates from Georgia and that this overexpression is correlated with Mona located upstream of the MfCYP51 gene. 10.1128/AEM.02159-07

Comparison of three advanced hard coatings for stamping applications

XT Zeng — 2007-05-19T09:52:50-00:00

pp. 38-42.

Three advanced hard coatings, CrTiN alloy, TiN/NbN multilayer and a multilayered C-composite, were field-tested and compared for their stamping wear resistance. All coatings were deposited onto SKH51 steel punches using an unbalanced magnetron sputtering system. Parametric studies of substrate bias, deposition pressure, composition, and structure effects on the coatings' performance were conducted to determine the optimum deposition conditions. A 25-ton open-frame stamping machine was used for the stamping test on cold rolled carbon steel. Wear characteristics of the coated and uncoated punches were analysed using shearing and stripping force diagrams and optical microscopy. The results showed that: (1) all three coatings significantly improved the wear resistance and stamping performance; and (2) CrTiN coating out-performed the other two, owing to its high hardness, good adhesion and moderate friction coefficient.

Drug resistance in tuberculosis-a reinfection model.

Paula Rodrigues — 2006-12-28T14:14:19-00:00

Theor Popul Biol (26 October 2006)

There is increasing recognition that reinfection is an important component of TB transmission. Moreover, it has been shown that partial immunity has significant epidemiological consequences, particularly in what concerns disease prevalence and effectiveness of control measures. We address the problem of drug resistance as a competition between two types of strains of Mycobacterium tuberculosis: those that are sensitive to anti-tuberculosis drugs and those that are resistant. Our objective is to characterise the role of reinfection in the transmission of drug-resistant tuberculosis. The long-term behaviour of our model reflects how reinfection modifies the conditions for coexistence of sensitive and resistant strains. This sets the scene for discussing how strain prevalence is affected by different control strategies. It is shown that intervention effectiveness is highly sensitive to the baseline epidemiological setting.

Evaluating treatment protocols to prevent antibiotic resistance.

S Bonhoeffer — 2008-08-14T14:50:40-00:00

Proceedings of the National Academy of Sciences of the United States of America, Vol. 94, No. 22. (28 October 1997), pp. 12106-12111.

The spread of bacteria resistant to antimicrobial agents calls for population-wide treatment strategies to delay or reverse the trend toward antibiotic resistance. Here we propose new criteria for the evaluation of the population-wide effects of treatment protocols for directly transmitted bacterial infections and discuss different usage patterns for single and multiple antibiotic therapy. A mathematical model suggests that the long-term benefit of single drug treatment from introduction of the antibiotic until a high frequency of resistance precludes its use is almost independent of the pattern of antibiotic use. When more than one antibiotic is employed, sequential use of different antibiotics in the population ("cycling") is always inferior to treatment strategies where, at any given time, equal fractions of the population receive different antibiotics. However, treatment of all patients with a combination of antibiotics is in most cases the optimal treatment strategy.

A "Silent" Polymorphism in the MDR1 Gene Changes Substrate Specificity.

Chava Kimchi-Sarfaty — 2007-01-18T12:01:38-00:00

Science (21 December 2006)

Synonymous Single Nucleotide Polymorphisms (SNPs) do not change the coding sequences, and, therefore, are not expected to change the function of the protein in which they occur. Here, we report that a synonymous SNP in the Multidrug Resistance 1 (MDR1) gene, part of a haplotype previously linked to altered function of the MDR1 gene product, P-glycoprotein (P-gp), nonetheless results in P-gp with altered drug and inhibitor interactions. Similar mRNA levels and protein, but altered conformations were found for wild-type and polymorphic P-gp. We hypothesize that the presence of a rare codon, marked by the synonymous polymorphism, affects the timing of co-translational folding and insertion of P-gp into the membrane, thereby altering the structure of substrate and inhibitor interaction sites.

Rhetorical Refusals: Defying Audiences' Expectations

John Schilb — 2007-05-29T17:38:14-00:00

(03 December 2007)