An enzyme-linked immunosorbent assay (ELISA) to determine Simian Varicella Virus antibody titers in infected rhesus monkeys (Macaca mulatta).

BACKGROUND: Simian varicella virus (SVV) is a primate herpesvirus that causes a natural varicella-like disease in Old World monkeys and may cause epizootics in facilities housing nonhuman primates. SVV infection of nonhuman primates is used as an experimental model to investigate varicella pathogenesis and to develop antiviral strategies. METHODS: An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect SVV antibodies in infected rhesus macaque monkeys. RESULTS: An ELISA determined SVV antibody titers following experimental infection. SVV IgG was detected by day 14 post-infection and remained elevated for at least 84 days. CONCLUSIONS: The SVV ELISA is a safe and rapid approach to confirm SVV seropositivity and to determine SVV antibody titers in naturally and experimentally SVV-infected monkeys. In addition to being a useful diagnostic assay to rapidly confirm acute disease or past SVV infection, the SVV ELISA is a valuable epidemiological tool to determine the incidence of SVV in non-human primate facilities.

Distinguishing experts from novices by the Mind's Hand and Mind's Eye.

Tetris is a complex task notable for the increasingly substantial demands it makes on perception, decision-making, and action as the game is played. To investigate these issues, we collected data on 39 features of Tetris play for each Tetris zoid (piece), for up to 16 levels of difficulty, as each of 240 players played an hour of Tetris under laboratory conditions. Using only early (level 1) data, we conducted a Principle Component Analysis which found intriguing differences among its three, statistically significant, principle components. Each of these components captures different combinations of perception, decision-making, and action which suggests differing higher level skills, tactics, and strategies. Each component is presented and discussed, and then used in a series of principle component regression analyses on subsets of these data (a) from different Tetris levels, as well as (b) from players of different levels of expertise. We validate these models with data collected at a locally held Tetris tournament. These components represent elements of expertise; namely, correlations among perceptual, decision-making, and motor features that represent processing stages and hierarchical control and which distinguish expert from novice Tetris players. These components provide evidence for an integrated complex of processes - the Mind's Hand and the Mind's Eye - that are the essence of expertise in the real-time, sequential-decision-making task of Tetris.

Meta-T: TetrisⓇ as an experimental paradigm for cognitive skills research.

Studies of human performance in complex tasks using video games are an attractive prospect, but many existing games lack a comprehensive way to modify the game and track performance beyond basic levels of analysis. Meta-T provides experimenters a tool to study behavior in a dynamic task environment with time-stressed decision-making and strong perceptual-motor elements, offering a host of experimental manipulations with a robust and detailed logging system for all user events, system events, and screen objects. Its experimenter-friendly interface provides control over detailed parameters of the task environment without need for programming expertise. Support for eye-tracking and computational cognitive modeling extend the paradigm's scope.

Attenuation of the adaptive immune response in rhesus macaques infected with simian varicella virus lacking open reading frame 61.

Varicella zoster virus (VZV) is a neurotropic alphaherpesvirus that causes chickenpox during primary infection and establishes latency in sensory ganglia. Infection of rhesus macaques (RM) with the homologous simian varicella virus (SVV) recapitulates hallmarks of VZV infection. We have shown that an antisense transcript of SVV open reading frame 61 (ORF61), a viral transactivator, was detected most frequently in latently infected RM sensory ganglia. In this study, we compared disease progression, viral replication, immune response, and the establishment of latency following intrabronchial infection with a recombinant SVV lacking ORF61 (SVVΔORF61) to those following infection with wild-type (WT) SVV. Varicella severity and viral latency within sensory ganglia were comparable in RMs infected with SVVΔORF61 and WT SVV. In contrast, viral loads, B and T cell responses, and plasma inflammatory cytokine levels were decreased in RMs infected with SVVΔORF61. To investigate the mechanisms underlying the reduced adaptive immune response, we compared acute SVV gene expression, frequency and proliferation of dendritic cell (DC) subsets, and the expression of innate antiviral genes in bronchoalveolar lavage (BAL) samples. The abundance of SVV transcripts in all kinetic classes was significantly decreased in RMs infected with SVVΔORF61. In addition, we detected a higher frequency and proliferation of plasmacytoid dendritic cells in BAL fluid at 3 days postinfection in RMs infected with SVVΔORF61, which was accompanied by a slight increase in type I interferon gene expression. Taken together, our data suggest that ORF61 plays an important role in orchestrating viral gene expression in vivo and interferes with the host antiviral interferon response.

Simplifying the interaction between cognitive models and task environments with the JSON Network Interface.

Process models of cognition, written in architectures such as ACT-R and EPIC, should be able to interact with the same software with which human subjects interact. By eliminating the need to simulate the experiment, this approach would simplify the modeler's effort, while ensuring that all steps required of the human are also required by the model. In practice, the difficulties of allowing one software system to interact with another present a significant barrier to any modeler who is not also skilled at this type of programming. The barrier increases if the programming language used by the modeling software differs from that used by the experimental software. The JSON Network Interface simplifies this problem for ACT-R modelers, and potentially, modelers using other systems.

Insertion of foreign genes into the simian varicella virus genome by Tn7-mediated site-specific transposition.

A Tn7-transposition approach was utilized for site-specific insertion of foreign genes into the genome of simian varicella virus (SVV), the causative agent of simian varicella in nonhuman primates. The severe acute respiratory syndrome coronavirus (SARS-CoV-2) nucleocapsid (N) gene and receptor binding domain (RBD) of the spike gene were inserted into the ORF 14 region of the SVV genome cloned into a bacterial artificial chromosome and then transfected into Vero cells to generate the infectious recombinant SVV (rSVV). The rSVV replicated efficiently in infected Vero cells and expressed the N and RBD antigens as indicated by immunoblot and immunofluorescence assays. Tn7-mediated transposition provides a rapid and efficient method for constructing rSVVs which may be evaluated as live-attenuated vaccines.

Bacterial artificial chromosome derived simian varicella virus is pathogenic in vivo.

BACKGROUND: Varicella zoster virus (VZV) is a neurotropic alphaherpesvirus that infects humans and results in chickenpox and herpes zoster. A number of VZV genes remain functionally uncharacterized and since VZV is an obligate human pathogen, rigorous evaluation of VZV mutants in vivo remains challenging. Simian varicella virus (SVV) is homologous to VZV and SVV infection of rhesus macaques (RM) closely mimics VZV infection of humans. Recently the SVV genome was cloned as a bacterial artificial chromosome (BAC) and BAC-derived SVV displayed similar replication kinetics as wild-type (WT) SVV in vitro. METHODS: RMs were infected with BAC-derived SVV or WT SVV at 4x10(5) PFU intrabronchially (N=8, 4 per group, sex and age matched). We collected whole blood (PBMC) and bronchoalveolar lavage (BAL) at various days post-infection (dpi) and sensory ganglia during latent infection (>84 dpi) at necropsy and compared disease progression, viral replication, immune response and the establishment of latency. RESULTS: Viral replication kinetics and magnitude in bronchoalveolar lavage cells and whole blood as well as rash severity and duration were similar in RMs infected with SVV BAC or WT SVV. Moreover, SVV-specific B and T cell responses were comparable between BAC and WT-infected animals. Lastly, we measured viral DNA in sensory ganglia from both cohorts of infected RMs during latent infection. CONCLUSIONS: SVV BAC is as pathogenic and immunogenic as WT SVV in vivo. Thus, the SVV BAC genetic system combined with the rhesus macaque animal model can further our understanding of viral ORFs important for VZV pathogenesis and the development of second-generation vaccines.

Cross-subject workload classification with a hierarchical Bayes model.

Most of the current EEG-based workload classifiers are subject-specific; that is, a new classifier is built and trained for each human subject. In this paper we introduce a cross-subject workload classifier based on a hierarchical Bayes model. The cross-subject classifier is trained and tested with data from a group of subjects. In our work, it was trained and tested on EEG data collected from 8 subjects as they performed the Multi-Attribute Task Battery across three levels of difficulty. The accuracy of this cross-subject classifier is stable across the three levels of workload and comparable to a benchmark subject-specific neural network classifier.

Increased cellular immune responses and CD4+ T-cell proliferation correlate with reduced plasma viral load in SIV challenged recombinant simian varicella virus - simian immunodeficiency virus (rSVV-SIV) vaccinated rhesus macaques.

BACKGROUND: An effective AIDS vaccine remains one of the highest priorities in HIV-research. Our recent study showed that vaccination of rhesus macaques with recombinant simian varicella virus (rSVV) vector - simian immunodeficiency virus (SIV) envelope and gag genes, induced neutralizing antibodies and cellular immune responses to SIV and also significantly reduced plasma viral loads following intravenous pathogenic challenge with SIVMAC251/CX1. FINDINGS: The purpose of this study was to define cellular immunological correlates of protection in rSVV-SIV vaccinated and SIV challenged animals. Immunofluorescent staining and multifunctional assessment of SIV-specific T-cell responses were evaluated in both Experimental and Control vaccinated animal groups. Significant increases in the proliferating CD4+ T-cell population and polyfunctional T-cell responses were observed in all Experimental-vaccinated animals compared with the Control-vaccinated animals. CONCLUSIONS: Increased CD4+ T-cell proliferation was significantly and inversely correlated with plasma viral load. Increased SIV-specific polyfunctional cytokine responses and increased proliferation of CD4+ T-cell may be crucial to control plasma viral loads in vaccinated and SIVMAC251/CX1 challenged macaques.

The simian varicella virus ORF A is expressed in infected cells but is non-essential for replication in cell culture.

The simian varicella virus (SVV) genome encodes ORF A, a truncated homolog of SVV ORF 4. The SVV ORF A was expressed as a 1.0-kb transcript in SVV-infected Vero cells. The ORF A promoter was active in infected Vero cells and was stimulated by the SVV immediate-early gene ORF 62 product (IE62), a viral transactivator of SVV genes. The SVV ORF A did not transactivate SVV IE, early, or late gene promoters in transfected Vero cells and was unable to augment IE62-mediated transactivation of SVV promoters. A SVV mutant lacking ORF A replicated as efficiently as wild-type SVV in infected Vero cells, indicating that ORF A expression is not essential for in vitro replication.

A new estimate of the impact of OSHA inspections on manufacturing injury rates, 1998-2005.

BACKGROUND: A prior study indicated that the effect of OSHA inspections on lost workday injuries had declined from 1979 through 1998. This study provides an updated estimate for 1998-2005. METHODS: Injury data from the Pennsylvania workers' compensation program were linked with employment data from unemployment compensation records to calculate lost-time rates for single-establishment manufacturing firms with more than 10 employees. These rates were linked to OSHA inspection findings. The RAND Human Subjects Protection Committee determined that this study was exempt from review. RESULTS: Inspections with penalties reduced injuries by an average of 19-24% annually in the 2 years following the inspection. These effects were not found for workplaces with fewer than 20 or more than 250 employees or for inspections without penalties. CONCLUSIONS: These findings should be generalizable to the 29 states where federal OSHA directly enforces standards. They suggest that the impact of inspections has increased from the 1990s.

Comparative Analysis of the Simian Varicella Virus and Varicella Zoster Virus Genomes.

Varicella zoster virus (VZV) and simian varicella virus (SVV) cause varicella (chickenpox) in children and nonhuman primates, respectively. After resolution of acute disease, the viruses establish latent infection in neural ganglia, after which they may reactivate to cause a secondary disease, such as herpes zoster. SVV infection of nonhuman primates provides a model to investigate VZV pathogenesis and antiviral strategies. The VZV and SVV genomes are similar in size and structure and share 70-75% DNA homology. SVV and VZV DNAs are co-linear in gene arrangement with the exception of the left end of the viral genomes. Viral gene expression is regulated into immediate early, early, and late transcription during in vitro and in vivo infection. During viral latency, VZV and SVV gene expression is limited to transcription of a viral latency-associated transcript (VLT). VZV and SVV are closely related alphaherpesviruses that likely arose from an ancestral varicella virus that evolved through cospeciation into species-specific viruses.

Recombinant Simian Varicella Virus-Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection against Repeated Mucosal SIV Challenges in Rhesus Macaques.

HIV vaccine mediated efficacy, using an expanded live attenuated recombinant varicella virus-vectored SIV rSVV-SIVgag/env vaccine prime with adjuvanted SIV-Env and SIV-Gag protein boosts, was evaluated in a female rhesus macaques (RM) model against repeated intravaginal SIV challenges. Vaccination induced anti-SIV IgG responses and neutralizing antibodies were found in all vaccinated RMs. Three of the eight vaccinated RM remained uninfected (vaccinated and protected, VP) after 13 repeated challenges with the pathogenic SIVmac251-CX-1. The remaining five vaccinated and infected (VI) macaques had significantly reduced plasma viral loads compared with the infected controls (IC). A significant increase in systemic central memory CD4+ T cells and mucosal CD8+ effector memory T-cell responses was detected in vaccinated RMs compared to controls. Variability in lymph node SIV-Gag and Env specific CD4+ and CD8+ T cell cytokine responses were detected in the VI RMs while all three VP RMs had more durable cytokine responses following vaccination and prior to challenge. VI RMs demonstrated predominately SIV-specific monofunctional cytokine responses while the VP RMs generated polyfunctional cytokine responses. This study demonstrates that varicella virus-vectored SIV vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus specific neutralizing antibodies, binding antibodies, and polyfunctional T-cell responses.

Simian varicella virus open reading frame 63/70 expression is required for efficient virus replication in culture.

Simian varicella virus (SVV) open reading frame (ORF) 63, duplicated in the virus genome as ORF 70, is homologous to varicella zoster virus ORF 63/70. Transfection of bacterial artificial chromosome clones containing the wild-type SVV genome and mutants with stop codons in ORF 70, in both ORFs 63 and 70 and the repaired virus DNA sequences into Vero cells produced a cytopathic effect (CPE). The onset of CPE was much slower with the double-mutant transfectants (10 days vs. 3 days) and plaques were smaller. While SVV ORF 63 is not required for replication in culture, its expression leads to robust virus replication.

Simian varicella virus: molecular virology.

Simian varicella virus (SVV) is a primate herpesvirus that is closely related to varicella-zoster virus (VZV), the causative agent of varicella (chickenpox) and herpes zoster (shingles). Epizootics of simian varicella occur sporadically in facilities housing Old World monkeys. This review summarizes the molecular properties of SVV. The SVV and VZV genomes are similar in size, structure, and gene arrangement. The 124.5 kilobase pair (kbp) SVV genome includes a 104.7 kbp long component covalently linked to a short component, which includes a 4.9 kbp unique short segment flanked by 7.5 kbp inverted repeat sequences. SVV DNA encodes 69 distinct open reading frames, three of which are duplicated within the viral inverted repeats. The viral genome is coordinately expressed, and immediate early (IE), early, and late genes have been characterized. Genetic approaches have been developed to create SVV mutants, which will be used to study the role of SVV genes in viral pathogenesis, latency, and reactivation. In addition, SVV expressing foreign genes are being investigated as potential recombinant varicella vaccines.

Cloning the simian varicella virus genome in E. coli as an infectious bacterial artificial chromosome.

Simian varicella virus (SVV) is closely related to human varicella-zoster virus and causes varicella and zoster-like disease in nonhuman primates. In this study, a mini-F replicon was inserted into a SVV cosmid, and infectious SVV was generated by co-transfection of Vero cells with overlapping SVV cosmids. The entire SVV genome, cloned as a bacterial artificial chromosome (BAC), was stably propagated upon serial passage in E. coli. Transfection of pSVV-BAC DNA into Vero cells yielded infectious SVV (rSVV-BAC). The mini-F vector sequences flanked by loxP sites were removed by co-infection of Vero cells with rSVV-BAC and adenovirus expressing Cre-recombinase. Recombinant SVV generated using the SVV-BAC genetic system has similar molecular and in vitro replication properties as wild-type SVV. To demonstrate the utility of this approach, a SVV ORF 10 deletion mutant was created using two-step Red-mediated recombination. The results indicate that SVV ORF 10, which encodes a homolog of the HSV-1 virion VP-16 transactivator protein, is not essential for in vitro replication but is required for optimal replication in cell culture.

Constructing Expertise: Surmounting Performance Plateaus by Tasks, by Tools, and by Techniques.

Acquiring expertise in a task is often thought of as an automatic process that follows inevitably with practice according to the log-log law (aka: power law) of learning. However, as Ericsson, Chase, and Faloon (1980) showed, this is not true for digit-span experts and, as we show, it is certainly not true for Tetris players at any level of expertise. Although some people may simply "twitch" faster than others, the limit to Tetris expertise is not raw keypress time but the techniques acquired by players that allow them to use the tools provided by the hardware and software to compensate for the game's relentlessly increasing drop speed. Unfortunately, these increases in drop speed between Tetris levels make performance plateaus very short and quickly followed by game death. Hence, a player's success at discovering, exploring, and practicing new techniques for the tasks of board preparation, board maintenance, optimal placement discovery, zoid rotation, lateral movement of zoids, and other tasks important to expertise in Tetris is limited. In this paper, we analyze data collected from 492 Tetris players to reveal the challenges they confronted while constructing expertise via the discovery of new techniques for gameplay at increasingly difficult levels of Tetris.

Editors' Introduction to Tasks, Tools, and Techniques.

Tasks, tools, and techniques that we perform, use, and acquire, define the elements of expertise which we value as the hallmarks of goal-driven behavior. Somehow, the creation of tools enables us to define new tasks, or is it that the envisioning of new tasks drives us to invent new tools? Or maybe it is that new tools engender new techniques which then result in new tasks? This jumble of issues will be explored and discussed in this diverse collection of papers. Individually, few of the papers are related to each other by topic or by techniques of analysis. Collectively, all focus on tasks performed using tools and discuss the techniques of tool use which enable differences in performance and expertise across individuals, societies, and (even) species.

The Pennsylvania certified safety committee program: an evaluation of participation and effects on work injury rates.

BACKGROUND: Since 1994, Pennsylvania, like several other states, has provided a 5% discount on workers' compensation insurance premiums for firms with a certified joint labor management safety committee. This study explored the factors affecting program participation and evaluated the effect of this program on work injuries. METHODS: Using Pennsylvania unemployment insurance data (1996-2006), workers' compensation data (1998-2005), and the safety committee audit data (1999-2007), we conducted propensity score matching and regression analysis on the program's impact on injury rates. RESULTS: Larger firms, firms with higher injury rates, firms in high risk industries, and firms without labor unions were more likely to join the safety committee program and less likely to drop out of the program. The injury rates of participants did not decline more than the rates for non-participants; however, rates at participant firms with good compliance dropped more than the rates at participant firms with poor compliance. CONCLUSIONS: Firm size and prior injury rates are key predictors of program participation. Firms that complied with the requirement to train their safety committee members did experience reductions in injuries, but non-compliance with that and other requirements was so widespread that no overall impact of the program could be detected.

Visual scan adaptation during repeated visual search.

There is no consensus as to how to characterize eye fixations during visual search. On the one hand, J. M. Wolfe, G. A. Alvarez, and T. S. Horowitz (2000) have described them as a haphazard sequence of fixations. On the other hand is research that shows systematic repetition of visual patterns when freely viewing a scene (T. Foulsham & G. Underwood, 2008; D. Noton & L. W. Stark, 1971a). Two experiments are reported that demonstrate the repetition and adaptation of visual scans during visual search, supporting an adaptive scanning hypothesis. When trials were repeated in a simple search task, visual scan similarity and search efficiency increased. These increments in similarity and efficiency demonstrate the systematic and adaptive nature of visual scans to the characteristics of the visual environment during search.