bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Impairment of Simian Immunodeficiency Virus-Specific CD8+T Cells during the Chronic Phase of Infection
Authors: Vogel Thorsten U. , Allen Todd M. , Altman John D. , Watkins David I. 
Published: July 2002

ABSTRACTIn an attempt to determine why high frequencies of circulating virus-specific CD8+T cells are unable to control human immunodeficiency virus and simian immunodeficiency virus (SIV) replication, we assessed the functional nature of SIV-specific CD8+lymphocytes. After vaccination and early after infection, nearly all tetramer-staining CD8+cells produced gamma interferon in response to their specific stimulus. However, by 4 months postinfection with pathogenic SIVmac239, signs of functional impairment in the CD8+T-cell compartment were detected which might prevent these T cells from efficiently controlling the infection during the chronic phase.
Interferons Mediate Terminal Differentiation of Human Cortical Thymic Epithelial Cells
Authors: Vidalain Pierre-Olivier , Laine David , Zaffran Yona , Azocar Olga , Servet-Delprat Christine , Wild T. Fabian , Rabourdin-Combe Chantal , Valentin Hélène 
Published: July 2002

ABSTRACTIn the thymus, epithelial cells comprise a heterogeneous population required for the generation of functional T lymphocytes, suggesting that thymic epithelium disruption by viruses may compromise T-cell lymphopoiesis in this organ. In a previous report, we demonstrated that in vitro, measles virus induced differentiation of cortical thymic epithelial cells as characterized by (i) cell growth arrest, (ii) morphological and phenotypic changes, and (iii) apoptotis as a final step of this process. In the present report, we have analyzed the mechanisms involved. First, measles virus-induced differentiation of thymic epithelial cells is shown to be strictly dependent on beta interferon (IFN-β) secretion. In addition, transfection with double-stranded RNA, a common intermediate of replication for a broad spectrum of viruses, is reported to similarly mediate thymic epithelial cell differentiation through IFN-β induction. Finally, we demonstrated that recombinant IFN-α, IFN-β, or IFN-γ was sufficient to induce differentiation and apoptosis of uninfected thymic epithelial cells. These observations suggested that interferon secretion by either infected cells or activated leukocytes, such as plasmacytoid dendritic cells or lymphocytes, may induce thymic epithelium disruption in a pathological context. Thus, we have identified a new mechanism that may contribute to thymic atrophy and altered T-cell lymphopoiesis associated with many infections.
Persistence and Fitness of Multidrug-Resistant Human Immunodeficiency Virus Type 1 Acquired in Primary Infection
Authors: Brenner Bluma G. , Routy Jean-Pierre , Petrella Marco , Moisi Daniela , Oliveira Maureen , Detorio Mervi , Spira Bonnie , Essabag Vidal , Conway Brian , Lalonde Richard , Sekaly Rafick-Pierre , Wainberg Mark A. 
Published: July 2002

ABSTRACTThis study examines the persistence and fitness of multidrug-resistant (MDR) viruses acquired during primary human immunodeficiency virus infection (PHI). In four individuals, MDR infections persisted over the entire study period, ranging from 36 weeks to 5 years, in the absence of antiretroviral therapy. In stark contrast, identified source partners in two cases showed expected outgrowth of wild-type (WT) virus within 12 weeks of treatment interruption. In the first PHI case, triple-class MDR resulted in low plasma viremia (1.6 to 3 log copies/ml) over time compared with mean values obtained for an untreated PHI group harboring WT infections (4.1 to 4.3 log copies/ml). Increasing viremia in PHI patient 1 at week 52 was associated with the de novo emergence of a protease inhibitor-resistant variant through a recombination event involving the original MDR virus. MDR infections in two other untreated PHI patients yielded viremia levels typical of the untreated WT group. A fourth patient's MDR infection yielded low viremia (<50 to 500 copies/ml) for 5 years despite his having phenotypic resistance to all antiretroviral drugs in his treatment regimen. In two of these PHI cases, a rebound to higher levels of plasma viremia only occurred when the M184V mutation in reverse transcriptase could no longer be detected and, in a third case, nondetection of M184V was associated with an inability to isolate virus. To further evaluate the fitness of MDR variants acquired in PHI, MDR and corresponding WT viruses were isolated from index and source partners, respectively. Although MDR viral infectivity (50% tissue culture infective dose) was comparable to that observed for WT viruses, MDR infections in each case demonstrated 2-fold and 13- to 23-fold reductions in p24 antigen and reverse transcriptase enzymatic activity, respectively. In dual-infection competition assays, MDR viruses consistently demonstrated a marked replicative disadvantage compared with WT virus. These results indicate that MDR viruses that are generated following PHI can establish persistent infections as dominant quasispecies despite their impaired replicative competence.
B7 Costimulation Plays an Important Role in Protection from Herpes Simplex Virus Type 2-Mediated Pathology
Authors: Thebeau Lydia G. , Morrison Lynda A. 
Published: July 2002

ABSTRACTWe have used mice lacking both B7-1 and B7-2 costimulation molecules (B7KO) to investigate the effects of B7 costimulation on herpes simplex virus type 2 (HSV-2) pathogenesis. B7KO mice infected intravaginally with virulent HSV-2 showed more severe genital and neurologic disease and higher mortality rates than their wild-type counterparts. These results suggest that B7 costimulation molecules play an important role in the development of primary immune responses protective against HSV-2.
In Vivo Interference of Rous Sarcoma Virus Budding by
cis
Expression of a WW Domain
Authors: Patnaik Akash , Wills John W. 
Published: July 2002

ABSTRACT

For all enveloped viruses, the actual mechanism by which nascent virus particles separate or “pinch off” from the cell surface is largely unknown. In the case of retroviruses, the Gag protein drives the budding process, and the virus release step is directed by the late (L) assembly domain within Gag. A PPPPY motif within the L domain of Rous sarcoma virus (RSV) was previously characterized as being critical for the release of virions and shown to interact in vitro with the WW domain of Yes-associated protein (Yap). To determine whether WW domain-L domain interactions can occur in vivo, we attempted to interfere with the host cell machinery normally recruited to the site of budding by inserting this WW domain in different locations within Gag. At a C-terminal location, the WW
Yap
domain had no effect on budding, suggesting that the intervening I domains (which provide the major region of Gag-Gag interaction) prevent its access to the L domain. When positioned on the other side of the I domains closer to the L domain, the WW
Yap
domain resulted in a dramatic interference of particle release, and confocal microscopy revealed a block to budding on the plasma membrane. Budding was restored by attachment of the heterologous L domain of human immunodeficiency virus type 1 Gag, which does not bind WW
Yap
. These findings suggest that
cis
expression of WW domains can interfere with RSV particle release in vivo via specific, high-affinity interactions at the site of assembly on the plasma membrane, thus preventing host factor accessibility to the L domain and subsequent virus-cell separation. In addition, they suggest that L domain-specific host factors function after Gag proteins begin to interact.
School smoking policies and smoking prevalence among adolescents: multilevel analysis of cross-sectional data from Wales
Authors: Moore Laurence , Roberts Chris , Tudor-Smith Chris 
Published: July 2002

OBJECTIVETo examine the association between school smoking policies and smoking prevalence among pupils.DESIGNMultilevel analysis of cross-sectional data from surveys of schools and pupils.SETTING55 secondary schools in Wales.SUBJECTS55 teachers and 1375 pupils in year 11 (aged 15–16).MAIN OUTCOME MEASURESSelf-reported smoking behaviour.RESULTSThe prevalence of daily smoking in schools with a written policy on smoking for pupils, teachers, and other adults, with no pupils or teachers allowed to smoke anywhere on the school premises, was 9.5% (95% confidence interval (CI) 6.1% to 12.9%). In schools with no policy on pupils' or teachers' smoking, 30.1% (95% CI 23.6% to 36.6%) of pupils reported daily smoking. In schools with an intermediate level of smoking policy, 21.0% (95% CI 17.8% to 24.2%) smoked every day. School smoking policy was associated with school level variation in daily smoking (p = 0.002). In multilevel analysis, after adjusting for pupils' sex, parents' and best friends' smoking status, parental expectations, and alienation from school, there was less unexplained school level variation, but school smoking policy remained significant (p = 0.041). The association of smoking policy with weekly smoking was weaker than for daily smoking, and not significant after adjustment for pupil level variables. Both daily and weekly smoking prevalence were lower in schools where pupils' smoking restrictions were always enforced. Enforcement of teacher smoking restrictions was not significantly associated with pupils' smoking.CONCLUSIONSThis study demonstrates an association between policy strength, policy enforcement, and the prevalence of smoking among pupils, after having adjusted for pupil level characteristics. These findings suggest that the wider introduction of comprehensive school smoking policies may help reduce teenage smoking.
NEW INVARIANTS FOR GROUPS
Authors: CRUICKSHANK D. A. , PRIDE S. J. 
Published: July 2002

The aim of this paper is to begin the development of a theory of higher-dimensional Alexander ideals for groups. The classical Alexander ideals of a finitely generate group take the form of an ascending chain of ideals in a commutative ring. For a group of type FPn, we define a group invariant in every dimension up to n, also in the form of a chain of ideals, the ideals in dimension 1 being precisely the chain of Alexander ideals. We show how these invariants can be calculated for certain groups, such as R. Thompson's group, (relatively) aspherical groups and graphs of groups, and we demonstrate that the higher-dimension invariants can distinguish groups which the classical Alexander ideals cannot.We also define Alexander-type ideals for modules as well as a number of secondary group invariants in the form of polynomials and 'ranks', which are connected with work of Swan, Hattori and Stallings, K. S. Brown and Lustig. Finally, we explain how this theory can be extended to monoids.
CMB ANISOTROPY AND POLARIZATION MEASUREMENTS WITH RATAN-600
Authors: NASELSKY P. , NOVIKOV I. , PARIJSKIJ YU. , TCIBULEV P. 
Published: July 2002

Some aspects of the Cosmological Gene project and the possibilities of the measurements of the Cosmic Microwave Background (CMB) anisotropy and polarization using the radio-telescope RATAN-600 (Special Astrophysical Observatory) are discussed. We study different strategies of the measurements and present main parameters of the antenna beam for these strategies at the frequency diapason ν=1–30 GHz. We simulate Cosmological Gene observations using a standard Cold Dark Matter cosmological model. We quantify the distortions of the primordial CMB-signal in the RATAN-600 scans by the atmosphere emission, foreground and noise in RATAN-600 scans. We emphasize that RATAN-600 is the unique instrument which allows the investigation of anisotropy and polarization of the CMB and investigate foreground and noise up to the multipole numbers l ∝ 105.
ADAPTIVE SCHEMES FOR REDUCING POWER CONSUMPTION OF MOBILE DATA HANDSETS
Authors: CHEN RONG-JAYE , LIN TING-YU , LIN YI-BING 
Published: July 2002

This paper describes a threshold-based wake-up mechanism to reduce the battery power consumption of a mobile data handset. The threshold approach switches the system into the sleep mode when the memory queue for arriving packets is empty, and switches on the system when the number of packets in the memory queue is above a threshold value. We propose several adaptive schemes capable of dynamically selecting the threshold value for the threshold approach. An adaptive algorithm adjusts the threshold value based on a pre-defined packet-dropping probability, for which the switch-on rate is kept reasonably small to maintain the actual packet-dropping probability as close as the pre-defined value. Two strategies are used in the adaptive algorithm to adjust the threshold value: binary-division and fixed-amount. Two calculation strategies are considered to measure the packet-dropping probability: window-averaging and leaky-bucket integration (LBI). Our study indicates that the binary-division strategy outperforms the fixed-amount strategy in adjusting the threshold value. Furthermore, with proper setting, the LBI strategy outperforms the window-averaging strategy.
On contention resolution protocols and associated probabilistic phenomena
Authors: MacKenzie P. D. , Plaxton C. G. , Rajaraman R. 
Published: July 2002

Consider an on-line scheduling problem in which a set of abstract processes are competing for the use of a number of resources. Further assume that it is either prohibitively expensive or impossible for any two of the processes to directly communicate with one another. If several processes simultaneously attempt to allocate a particular resource (as may be expected to occur, since the processes cannot easily coordinate their allocations), then none succeed. In such a framework, it is a challenge to design efficient contention resolution protocols.
Two recently-proposed approaches to the problem of PRAM emulation give rise to scheduling problems of the above kind. In one approach, the resources (in this case, the shared memory cells) are duplicated and distributed randomly. We analyze a simple and efficient deterministic algorithm for accessing some subset of the duplicated resources. In the other approach, we analyze how quickly we can access the given (nonduplicated) resource using a simple randomized strategy. We obtain precise bounds on the performance of both strategies. We anticipate that our results with find other applications.
Theta Oscillations and Human Navigation: A Magnetoencephalography Study
Authors: Araújo Dráulio B. de , Baffa Oswaldo , Wakai Ronald T. 
Published: July 2002

Abstract
Magnetoencephalography (MEG) was used to study alpha and theta activity while subjects navigated through a computer-generated virtual reality town. The subjects were first allowed to explore the environment freely. They then had to navigate from a starting point to a destination, knowing that an obstruction would appear at one of several possible locations along the main route and force them to take a detour. Spatiotemporal analysis of the theta and alpha bands were performed (1) prior to the start of navigation, (2) from the start of navigation until the obstruction was encountered, (3) during the time subjects were contemplating a detour and were not navigating, and (4) from the resumption of navigation until the destination was reached. In all subjects, theta power was strongest during the two periods of navigation. The peak frequency of the oscillations was approximately 3.7 Hz. Control studies consisted of a motor task similar to that required for navigation, passive viewing of a tour through the same virtual reality town, and a mental concentration task. No consistent increases in theta power were seen in the MEG during any of the control tasks. The results suggest an association between theta rhythm and the performance of navigational tasks in humans.
The von Restorff Effect in Visual Object Recognition Memory in Humans and Monkeys: The Role of Frontal/Perirhinal Interaction
Authors: Parker Amanda , Wilding Edward , Akerman Colin 
Published: July 2002

Abstract
This study reports the development of a new, modified delayed matching to sample (DMS) visual recognition memory task that controls the relative novelty of test stimuli and can be used in human and nonhuman primates. We report findings from normal humans and unoperated monkeys, as well as three groups of operated monkeys. In the study phase of this modified paradigm, subjects studied lists of two-dimensional visual object stimuli. In the test phase each studied object was presented again, now paired with a new stimulus (a foil), and the subject had to choose the studied item. In some lists one study item (the novel or isolate item) and its associated foil differed from the others (the homogenous items) along one stimulus dimension (color). The critical experimental measure was the comparison of the visual object recognition error rates for isolate and homogenous test items.
This task was initially administered to human subjects and unoperated monkeys. Error rates for both groups were reliably lower for isolate than for homogenous stimuli in the same list position (the von Restorff effect). The task was then administered to three groups of monkeys who had selective brain lesions. Monkeys with bilateral lesions of the amygdala and fornix, two structures that have been proposed to play a role in novelty and memory encoding, were similar to normal monkeys in their performance on this task. Two further groups— with disconnection lesions of the perirhinal cortex and either the prefrontal cortex or the magnocellular mediodorsal thalamus—showed no evidence of a von Restorff effect. These findings are not consistent with previous proposals that the hippocampus and amygdala constitute a general novelty processing network. Instead, the results support an interaction between the perirhinal and frontal cortices in the processing of certain kinds of novel information that support visual object recognition memory.
Occlusion Culling in Large Virtual Environments
Authors: Bormann Karsten 
Published: July 2002

In this paper, occlusion testing in very large virtual environments is discussed from two perspectives: a theoretical one, discussing occlusion culling in relation to detail elision (level of detail), and a practical one, relating to an adaptive occlusion-culling algorithm developed in this paper. The theoretical perspective formally demonstrates the efficiency of detail elision in the face of real-world-like environments. It further shows the utility of using detail elision not only to lower the triangle count of individual objects but also to lower the load on the scene graph traversal algorithm. Finally, the results indicate that, even in open environments, one needs occlusion culling and that approaches based on choosing only a few good (convex) occluders are insufficient in this case. Practically, the theoretical perspective is reflected in the development of an occlusion-culling algorithm based on a marriage of the frustum-slicing approach to view frustum culling and hierarchical occlusion maps (HOMs). The resulting algorithm is much simpler than the original HOM algorithm, requires little pre-processing, and integrates detail elision with the occlusion-culling algorithm in a natural way. The approach is well suited for use with large, complex models with a long mean free line of sight (“the great outdoors”), models for which it is not feasible to construct, or search, a database of occluders to be rendered in each frame. The algorithm is tested for such large models, and results show that frame rates tend to converge as the geometrical complexity of the model increases.
Opium and Sexuality in late Qing Fiction
Authors: McMahon Keith 
Published: July 2002

AbstractThis article examines opium smoking in two gendered contexts of the late Qing, as an activity among socializing men and in situations between men and women. The method is to use fiction to ask how male and female smokers differed and in general to show how opium came to symbolize an uncanny and ominous disruption of the social fabric. In terms of gender, the obscene enjoyment of the female smoker was exponentially more threatening in the prohibitionist's eyes than that of the male. As the sign of an unprecedented type of pleasure, opium addiction threatened to denaturalize the boundaries of cultural as well as gender identity.
JUDAH'S COVENANT WITH DEATH (ISAIAH XXVIII 14-22)
Authors: Blenkinsopp Joseph 
Published: July 2002

AbstractThe prophetic diatribe in Isa. xxviii 7-22 is directed against the Judean political and religious leadership anxiously seeking an alliance with Egypt of the twenty-fifth (Nubian) dynasty shortly before the Assyrian punitive campaign of 701 B.C. The opponents are accused of entering into a covenant with Death and Sheol. It is suggested that the covenant is represented as made with the Canaanite deity Mot (mōtu), rather than with Molech, in the expectation that Mot would take up their cause against his adversary Hadad, personification of the ô ô p of xxviii 15, 18, thus enabling them to survive the anticipated Assyrian attack. Isa. xxviii 7-8 suggests the possibility that the ceremony by which the pact was sealed, reminiscent of the Ugaritic texts KTU I.114, is represented as a parody of the tradition about covenant making at Sinai represented by Exod. xxiv 9 11.
IMMANENT DUALISM AS AN ALTERNATIVE TO DUALISM AND MONISM: THE WORLD VIEW OF MAX WEBER
Authors: Steiner-Aeschliman Sherrie 
Published: July 2002

AbstractExploration of the roots of accumulating environmental degradation has reached to the very foundations of Western civilization. The dominant critiques of these foundations primarily focus on two cosmologies: monism and dualism. The purpose of this paper is to examine these foundations from a Weberian perspective and to offer a little known alternative: immanent dualism. This alternative cosmology suggests that religion could help reorganize late industrial capitalism.
X- ray photoelectron spectroscopic study of layer charge magnitude in micas and illite-smectite clays
Authors: Johns W. D. , Gier S. 
Published: July 2002

AbstractX-ray photoelectron spectroscopy (XPS) was used to determine the surface-charge magnitude and distribution for some micas and high-illite I-S clays. Based on predictable layer by layer atomic ratios for margarite, muscovite and sericite it was possible to establish an escape depth of ∼15 Å for photoelectrons. After the replacement of surface ions by Ba2+, interlayer ion (Ca, K, Na)/Ba ratios are a measure of the relative layer charges on external surfaces and the first internal interlayer. These ratios can be used to assign charge magnitudes and ascertain layer charge asymmetry when it occurs. The O/Ba ratios determined by XPS serve the same purpose. Diagenetic I-S from the Vienna Basin gives an XPS-determined symmetrical layer charge of 0.41; in a similar clay from the Gulf Coast sequence, the outer surface is smectitic, with an external charge of 0.21, in contrast to an opposing silica layer with a charge of 0.31.