739 research outputs found
8: Action Research for Instructional Improvement: Using Data to Enhance Student Learning at Your Institution
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138872/1/tia200478.pd
16: Developing And Renewing Department Chair Leadership
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138885/1/tia200608.pd
Surgical Treatment of Induced PeriâImplantitis in the Micro Pig: Clinical and Histological Analysis
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141550/1/jper0984.pd
Notes and recommendations for the establishment of control programs for taeniasis and cysticercosis due to Taenia solium in Peru
Neurocysticercosis is a nervous system infection caused by the larvae (cysticercus) of the pork tapeworm (Taenia solium). Neurocysticercosis is the primary cause of acquired epilepsy worldwide and, therefore, a global public health problem. On the other hand, T. solium taeniasis/cysticercosis is one of very few infectious diseases considered to be potentially eradicable. Recently, a large-scale elimination program in Tumbes, Peru, demonstrated the feasibility of interrupting transmission. Based on these advances, a series of initial guidelines are proposed aimed at setting out the foundations for regional and national taeniasis/cysticercosis control programs, with simple and feasible local interventions as a starting point
Spatial Transferability of an AgentâBased Model to Simulate Taenia solium control interventions
Background
Models can be used to study and predict the impact of interventions aimed at controlling the spread of infectious agents, such as Taenia solium, a zoonotic parasite whose larval stage causes epilepsy and economic loss in many rural areas of the developing nations. To enhance the credibility of model estimates, calibration against observed data is necessary. However, this process may lead to a paradoxical dependence of model parameters on location-specific data, thus limiting the modelâs geographic transferability. Methods
In this study, we adopted a non-local model calibration approach to assess whether it can improve the spatial transferability of CystiAgent, our agent-based model of local-scale T. solium transmission. The calibration dataset for CystiAgent consisted of cross-sectional data on human taeniasis, pig cysticercosis and pig serology collected in eight villages in Northwest Peru. After calibration, the model was transferred to a second group of 21 destination villages in the same area without recalibrating its parameters. Model outputs were compared to pig serology data collected over a period of 2 years in the destination villages during a trial of T. solium control interventions, based on mass and spatially targeted human and pig treatments. Results
Considering the uncertainties associated with empirical data, the model produced simulated pre-intervention pig seroprevalences that were successfully validated against data collected in 81% of destination villages. Furthermore, the model outputs were able to reproduce validated pig seroincidence values in 76% of destination villages when compared to the data obtained after the interventions. The results demonstrate that the CystiAgent model, when calibrated using a non-local approach, can be successfully transferred without requiring additional calibration. Conclusions
This feature allows the model to simulate both baseline pre-intervention transmission conditions and the outcomes of control interventions across villages that form geographically homogeneous regions, providing a basis for developing large-scale models representing T. solium transmission at a regional level
Antibody Banding Patterns on the Enzyme-Linked Immunoelectrotransfer Blot (EITB) Assay Clearly Discriminate Viable Cysticercosis in Naturally Infected Pigs
Enzyme-linked immunoelectrotransfer blot (EITB) detects antibodies against seven Taenia solium larvae antigens in three protein families (GP50, T24/42, and 8-kDa) with different structures and functions. EITB banding patterns against these antigens in pigs provide information about the course of infection and may discriminate viable cysticercosis. We analyzed the banding patterns and infection outcomes (presence of viable cysts, degenerated cysts, and any cysts) of 512 rural pigs. Banding patterns were grouped into homogenous classes using latent class analysis, and relationships with infection outcomes were assessed. Four classes were identified: 1 (n = 308, EITB-negative or positive for the GP50 family), 2 (n = 127, positive for GP50 (GP50 family), GP42-39 and GP24 (T24/42 family), but negative for 8-kDa antigens), 3 (n = 22, positive for GP50 and T24/42 antigens (GP42-39 and GP24), as well as to 8-kDa bands GP13, GP14, and GP18, but negative for GP21), and 4 (n = 55, positive for GP50 and T24/42 antigens, as well as to 8-kDa antigens GP21 and GP18 in combination). Pigs in classes 3 and 4 were more likely to have viable cysts (72.6% and 96.4%, respectively) than pigs in classes 1 and 2 (0.7% and 27.6%, respectively; p \u3c 0.001). The number of infections with any cysts was higher in classes 3 and 4 (77.3% and 98.2%, respectively) and lower in classes 2 and 1 (34.7% and 4.9%, respectively; p \u3c 0.001). Pigs with viable cysts represented \u3e90% of pigs with any cysts in classes 3 and 4 (94.1% and 98.2%, respectively), while degenerated cysts were frequent among pigs with any cysts in classes 1, 3, and 2 (86.7%, 47.1%, and 43.2%, respectively; p \u3c 0.001). EITB banding patterns strongly correlate with cysticercosis infection status in rural pigs, with classes 3 and 4 being more predictive of viable infections
Tick Transmission of \u3ci\u3eBorrelia burgdorferi\u3c/i\u3e to the Murine Host is not Influenced by Environmentally Acquired Midgut Microbiota
Background
Ixodes scapularis is the predominant tick vector of Borrelia burgdorferi, the agent of Lyme disease, in the USA. Molecular interactions between the tick and B. burgdorferi orchestrate the migration of spirochetes from the midgut to the salivary glandsâcritical steps that precede transmission to the vertebrate host. Over the last decade, research efforts have invoked a potential role for the tick microbiome in modulating tick-pathogen interactions.
Results
Using multiple strategies to perturb the microbiome composition of B. burgdorferi-infected nymphal ticks, we observe that changes in the microbiome composition do not significantly influence B. burgdorferi migration from the midgut, invasion of salivary glands, or transmission to the murine host. We also show that within 24 and 48 h of the onset of tick feeding, B. burgdorferi spirochetes are within the peritrophic matrix and epithelial cells of the midgut in preparation for exit from the midgut.
Conclusions
This study highlights two aspects of tick-spirochete interactions: (1) environmental bacteria associated with the tick do not influence spirochete transmission to the mammalian host and (2) the spirochete may utilize an intracellular exit route during migration from the midgut to the salivary glands, a strategy that may allow the spirochete to distance itself from microbiota in the midgut lumen effectively. This may explain in part, the inability of environment-acquired midgut microbiota to significantly influence spirochete transmission. Unraveling a molecular understanding of this exit strategy will be critical to gain new insights into the biology of the spirochete and the tick
Concordance Between Two Monoclonal Antibody-Based Antigen Detection Enzyme-Linked Immunosorbent Assays for Measuring Cysticercal Antigen Levels in Sera from Pigs Experimentally Infected with Taenia Solium and Taenia Hydatigena
Background: Antigen detection in Taenia solium cysticercosis confirms viable infection in the intermediate host (either pig or human). The reference B158/B60 monoclonal antibody (mAb)-based Ag-enzyme-linked immunosorbent assay (ELISA) has acceptable levels of sensitivity and specificity in human neurocysticercosis with multiple brain cysts, although its sensitivity is lower in cases with single brain cysts, whereas in porcine cysticercosis the assay specificity is affected by its frequent cross-reaction with Taenia hydatigena, another common cestode found in pigs. Our group has produced 21 anti-T. solium mAbs reacting against antigens of the whole cyst, vesicular fluid, and secretory/excretory products, identifying TsW8/TsW5 as the most promising pair of mAbs for an Ag-ELISA. Methods We report the use of the TsW8/TsW5 Ag-ELISA to measure cysticercus antigen levels [expressed as optical density (OD) values] in two panels of sera collected from day 0 (baseline) to day 90 postinfection (PI) from pigs experimentally infected with T. solium (nâ=â26) and T. hydatigena (nâ=â12). At baseline and on days 28 and 90 PI, we used BlandâAltman (BA) analysis and Linâs concordance correlation coefficients (CCC) to determine the concordance between the TsW8/TsW5 and the B158/B60 Ag-ELISA. Results The TsW8/TsW5 Ag-ELISA was able to efficiently measure circulating antigen levels in T. solium-infected pigs, similar to that obtained with the B158/B60 Ag-ELISA. Almost all paired log-OD differences between assays were within the limits of agreement (LoA) in the BA analysis at baseline and on days 28 and 90 PI (92.3%, 100%, and 100%, respectively), and a high concordance of log-ODs between assays was also found (Linâs CCC: 0.69, 0.92, and 0.96, respectively, all Pâ\u3câ0.001). In pigs infected with T. hydatigena, almost all paired log-OD differences were within the LoA in the BA analysis, whereas the concordance of log-ODs between assays was low at baseline (Linâs CCC: 0.24) but increased on days 28 and 90 PI (Linsâ CCC: 0.88 and 0.98, Pâ\u3câ0.001). Conclusions/significance The TsW8/TsW5 Ag-ELISA recognizes antigens in pigs with T. solium cysticercosis and is highly concordant with the B158/B60 Ag-ELISA. However, its diagnostic use is hampered by cross-reactions with T. hydatigena, as in other mAb-based Ag-ELISAs. Graphical Abstrac
Reevaluating electron-phonon coupling strengths: Indium as a test case for ab initio and many-body-theory methods
Using indium as a test case, we investigate the accuracy of the
electron-phonon coupling calculated with state-of-the-art ab initio and
many-body theory methods. The ab initio calculations -- where electrons are
treated in the local-density approximation, and phonons and the electron-phonon
interaction are treated within linear response -- predict an electron-phonon
spectral function alpha^2 F(omega) which translates into a relative tunneling
conductance that agrees with experiment to within one part in 1000. The
many-body theory calculations -- where alpha^2 F(omega) is extracted from
tunneling data by means of the McMillan-Rowell tunneling inversion method --
provide spectral functions that depend strongly on details of the inversion
process. For the the most important moment of alpha^2 F(omega), the
mass-renormalization parameter lambda, we report 0.9 +/- 0.1, in contrast to
the value 0.805 quoted for nearly three decades in the literature. The ab
initio calculations also provide the transport electron-phonon spectral
function alpha_{tr}^2 F(omega), from which we calculate the resistivity as a
function of temperature in good agreement with experiment.Comment: 16 pages, 5 figure
Structural Transitions and Global Minima of Sodium Chloride Clusters
In recent experiments on sodium chloride clusters structural transitions
between nanocrystals with different cuboidal shapes were detected. Here we
determine reaction pathways between the low energy isomers of one of these
clusters, (NaCl)35Cl-. The key process in these structural transitions is a
highly cooperative rearrangement in which two parts of the nanocrystal slip
past one another on a {110} plane in a direction. In this way the
nanocrystals can plastically deform, in contrast to the brittle behaviour of
bulk sodium chloride crystals at the same temperatures; the nanocrystals have
mechanical properties which are a unique feature of their finite size. We also
report and compare the global potential energy minima for (NaCl)NCl- using two
empirical potentials, and comment on the effect of polarization.Comment: extended version, 13 pages, 8 figures, revte
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