Identification and characterization of a novel structural protein of porcine reproductive and respiratory syndrome virus, the replicase nonstructural protein 2

Porcine reproductive and respiratory syndrome virus (PRRSV) is a rapidly mutating pathogen eliciting respiratory and reproductive disease of high economic consequence. The PRRSV non-structural protein 2 (nsp2) is a large multifunctional protein encoded by the most genetically diverse region of the genome - the selective pressure potentiating mutation within this region is unknown. Here we report the identification of a unique function of nsp2 as a structural component of the PRRSV virion; the first PRRSV structural protein identified which is not expressed from a sub-genomic RNA or regulated via the discontinuous transcription pathway. Through the use of a set of custom á-nsp2 antibodies nsp2 was identified on the surface of the PRRSV virion by immunoelectron microscopy. Further, a class of nsp2 isoforms was defined to be packaged within or upon the PRRSV virion. Nsp2 packaging was found to be conserved across a panel of highly divergent stains of PRRSV including the genotype 1 and genotype 2 prototype strains as well as contemporary and highly-pathogenic isolates. Next the hydrophobic domain of nsp2 was characterized as a putative multi-pass transmembrane domain predicted to facilitate nsp2 packaging through association with the viral envelope. Within an in vitro cell-free translation system nsp2 was found to strongly associate with canine microsomal membranes. Through high-speed ultracentrifugation, protease protection assay, and immunoprecipitation nsp2 was defined as an integral membrane protein and additionally identified to display an unexpected N-terminal cytoplasmic / C-terminal luminal topological orientation. Finally, membrane isolation demonstrated two sub-dominant nsp2 isoforms of approximately 117 and 106 kDa in size and of unknown composition or function were enriched within membranes. Together, these results define previously unknown attributes of nsp2. Identification of nsp2 as a structural protein implicates it in previously unpredicted functions related to attachment, entry, or early replication events and further provides rationale for the high mutation rate and robust adaptive immune response targeting the nsp2 protein. Characterization of the nsp2 transmembrane domain demonstrates its role as an integral membrane protein and additionally raises new questions related to the unexpected topological orientation or enrichment of select isoforms within the membrane fraction

Particle Size Distributions of Debris Upstream and Downstream of the Containment Sump Strainer in a Light Water Reactor

During a LOCA in a LWR, a containment-sump strainer filters debris, generated from fibrous thermal insulation, from the water collected in the containment sump. The buildup of debris on the strainer and the bypass of debris through the strainer lead to upstream and downstream effects, respectively. The objective of this research was to create a methodology for obtaining PSDs for this debris upstream and downstream of a sump strainer in multiple size ranges. Fibrous debris was injected into an experimental facility which simulated the conditions in a LWR containment sump. Samples were taken downstream of the strainer during the experiment. Using a NanoSight LM10 and two optical microscope systems, size measurements of particles were made. The fractional number of particles between 55-188 nm increased from 0.591 to 0.734 upstream to downstream; the number of all other particle sizes decreased. This trend is consistent with Hutten’s [8] statements about the MPPS. For AMIS-1, from upstream to downstream, the fraction of particles smaller than 55 μm increased from 0.77 to 0.89; almost all of the larger particles sizes decreased in number. This demonstrates larger particles being more efficiently filtered. For AMIS-2, from upstream to downstream, the fraction of particles smaller than 340 μm increased from 0.536 to 0.668; all of the larger particle sizes decreased in number. This again demonstrates higher filtration efficiency for larger particles. Different PDFs provided the best fit for the PSDs in each of the size ranges measured. For the nanometer range, the Johnson’s SB function provided the best fit. For the 10-500 μm range, the upstream and downstream results were fit best with the log-logistic and lognormal functions, respectively. For the 100-2500 μm size range, the Weibull distribution was found to fit best. Changes in the PDFs fit to the upstream and downstream PSDs were similar to what was found when comparing the upstream and downstream PSD histograms. Size distributions for spherical (tin powder) and angular (SiC F600) particles were easily obtained using the Coulter Counter, however, it didn’t provide reliable results for fibrous debris

Tribo-corrosion mechanisms of stainless steel in soft drinks

Tribo-corrosion mechanisms of 316L Stainless Steel in slurries containing common household soft drinks have been studied through investigating the micro-abrasion-corrosion performance using a ball and disk apparatus which has been modified to measure the in-situ corrosion current during the abrasion process. The objective of this study was to evaluate the effect of pH and solution viscosity on the micro-abrasion-corrosion performance of the material. 316L Stainless Steel was selected because it is commonly used as a dental replacement material. This is an important area of work as the use of steel retainers as well as other stainless steel dental replacements is still widespread and the effectiveness of these devices will be determined by their tribological and tribo-corrosion performance. Additionally, an attempt has been made to investigate the importance of the pH and viscosity variables on the tribo-corrosive synergism, wastage and mechanism maps

Vaccination with NS1-Truncated H3N2 Swine Influenza Virus Primes T Cells and Confers Cross-Protection against an H1N1 Heterosubtypic Challenge in Pigs

The diversity of contemporary swine influenza virus (SIV) strains impedes effective immunization of swine herds. Mucosally delivered, attenuated virus vaccines are one approach with potential to provide broad cross-protection. Reverse genetics-derived H3N2 SIV virus with truncated NS1 (NS1Δ126 TX98) is attenuated and immunogenic when delivered intranasally in young pigs. We analyzed T-cell priming and cross-protective efficacy in weanling piglets after intranasal inoculation with NS1Δ126 TX98 versus wild type TX98. In vivo replication of the truncation mutant was minimal compared to the wild type virus. T-cell responses were greater in magnitude in pigs infected with the wild type virus in in vitro restimulation assays. According to the expression of activation marker CD25, peripheral T cell recall responses in NS1Δ126 TX98 infected pigs were minimal. However, intracellular IFN-γ data indicate that the attenuated virus induced virus-specific CD4+CD8–, CD4+CD8+, CD4–CD8+, and γδ T cells within 28 days. The IFN-γ response appeared to contract, as responses were reduced at later time points prior to challenge. CD4+CD8+ cells isolated 5 days after heterosubtypic H1N1 challenge (day 70 overall) showed an elevated CD25 response to virus restimulation. Pigs previously infected with wild type TX98 were protected from replication of the H1N1 challenge virus. Vaccination with NS1Δ126 TX98 was associated with significantly lower levels of Th1-associated cytokines in infected lungs but provided partial cross-protection against the H1N1 challenge. These results demonstrate that NS1Δ SIV vaccines can elicit cell-mediated cross-protection against antigenically divergent strains

Investigating variation in replicability

Although replication is a central tenet of science, direct replications are rare in psychology. This research tested variation in the replicability of 13 classic and contemporary effects across 36 independent samples totaling 6,344 participants. In the aggregate, 10 effects replicated consistently. One effect – imagined contact reducing prejudice – showed weak support for replicability. And two effects – flag priming influencing conservatism and currency priming influencing system justification – did not replicate. We compared whether the conditions such as lab versus online or US versus international sample predicted effect magnitudes. By and large they did not. The results of this small sample of effects suggest that replicability is more dependent on the effect itself than on the sample and setting used to investigate the effect

Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo

We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p