A higher-than-predicted measurement of iron opacity at solar interior temperatures.

Nearly a century ago it was recognized that radiation absorption by stellar matter controls the internal temperature profiles within stars. Laboratory opacity measurements, however, have never been performed at stellar interior conditions, introducing uncertainties in stellar models. A particular problem arose when refined photosphere spectral analysis led to reductions of 30-50 per cent in the inferred amounts of carbon, nitrogen and oxygen in the Sun. Standard solar models using the revised element abundances disagree with helioseismic observations that determine the internal solar structure using acoustic oscillations. This could be resolved if the true mean opacity for the solar interior matter were roughly 15 per cent higher than predicted, because increased opacity compensates for the decreased element abundances. Iron accounts for a quarter of the total opacity at the solar radiation/convection zone boundary. Here we report measurements of wavelength-resolved iron opacity at electron temperatures of 1.9-2.3 million kelvin and electron densities of (0.7-4.0) × 10(22) per cubic centimetre, conditions very similar to those in the solar region that affects the discrepancy the most: the radiation/convection zone boundary. The measured wavelength-dependent opacity is 30-400 per cent higher than predicted. This represents roughly half the change in the mean opacity needed to resolve the solar discrepancy, even though iron is only one of many elements that contribute to opacity.

The effects of progressing and nonprogressing Mycobacterium avium ssp. paratuberculosis infection on milk production in dairy cows.

Longitudinal data from 3 commercial dairy herds in the northeast United States, collected from 2004 to 2011, were analyzed to determine the effect of Mycobacterium avium ssp. paratuberculosis (MAP) infection status and progression path on milk production. Disease status, as indicated by MAP test results, was determined through quarterly ELISA serum testing, biannual fecal culture, and culture of tissues and feces at slaughter. Milk production data were collected from the Dairy Herd Information Association. Animals with positive MAP test results were categorized, based on test results over the full course of the study, as high path (at least one high-positive culture) or low path (at least one positive culture or ELISA). The cumulative numbers of positive ELISA and culture results were recorded. The effects of both MAP infection path, status, and number of positive tests on milk production were analyzed using a mixed linear model with an autocorrelation random effect structure. Low- and high-path animals produced more milk before their first positive test than always-negative animals, especially high-path animals. Although mean production decreased after a first positive test, low-path animals were shown to recover some productivity. High-path animals continued to exhibit a decrease in milk production, especially after their first high-positive fecal culture. These results show that not all animals that test positive for MAP will have long-term production losses. Milk production decreased significantly with each additional positive test. Ultimately, production loss appeared to be a function of MAP infection progression.

Self-assembled hierarchical nanostructures composed of novel chalcopyrite nanosheets for photovoltaic properties.

Self-assembled nanostructures of CulnGaSe2 (CIGS) comprising of nanosheets with sheet thickness of 20 nm have been developed via one-step electrochemically alloying technique. These self-assembled nanoplates exhibit highly intersecting behavior and transform from CuSe to CIGS as the reduction potential was varied. The morphological analysis indicated that the process resulted in a progression of crystallites to a series of heavy dense intersecting nanoplates. Further analyses revealed that the nanostructures keep their integrity on heat treatment. The structure confirms the inclusion of Indium and Gallium at higher reduction potentials and its transition from pseudoamorphous to polycrystalline structure. A strong correlation between reduction potential, and the composition was established. The spectroscopic and optical spectra clearly prove that the direct band gap for the as-grown and annealed thin films, and appropriate for solar cell applications. These self-assembled dense interweaved nanoplates structure have not been observed previously in CIGS semiconductor system and have potential implications forenergy applications.

Effects of surface potential on growth of ZnO nanorod arrays investigated by electric force microscopy.

The electric and Kelvin force probe microscopy were used to investigate the surface potentials on the ZnO seed layer, which shows a remarkable dependence on the annealing temperature. The optimum temperature for the growth of nanorod arrays normal to the surface was found to be at 600 degrees C, which is in the range of right surface potentials and energy measured between 500 degrees C and 700 degrees C. We demonstrated from both electric and Kelvin force probe microscopy studies that surface potential controls the growth of ZnO nanorods, illustrating the fact that this is a promising technique to visualize the control of ZnO nanorod arrays by studying their surface potentials. This study will provide important understanding of growth of other nanostructures.

A modified Weibull model for growth and survival of Listeria innocua and Salmonella Typhimurium in chicken breasts during refrigerated and frozen storage.

The potential of food-borne pathogens to survive and grow during refrigerated and frozen storage has raised serious concerns over the safety of stored poultry products. In this study, the effect of refrigeration and freezing temperatures (-20, -12, 0, 4, and 8°C) on growth and survival of Listeria innocua and Salmonella enterica serovar Typhimurium in raw chicken breasts for storage times of 3, 7, 10, 14, and 21 d were investigated. A modified Weibull model was also developed to analyze the microbial behavior of both microorganisms in raw chicken breasts under different refrigerated storage conditions over time. The results showed that the bacterial loads of L. innocua at 4 and 8°C and Salmonella Typhimurium at 8°C were significantly different (P < 0.05) from those at other refrigerated and frozen storage temperatures over storage times. The loads of both bacteria at frozen storage temperatures did not change significantly over time. At a storage time of 7 d, the increase in bacterial loads of L. innocua at 4 and 8°C was 2.1 log cfu/g and 3.7 log cfu/g, respectively, and that of Salmonella Typhimurium at 8°C was 1.2 log cfu/g. The root mean square errors, median relative error, mean absolute relative error, and the plot of predicted versus observed bacterial loads showed a good performance of the model. The results from this study provided useful information regarding the behavior of Listeria and Salmonella in raw chicken breast meat during refrigerated and frozen storage, which would be helpful in giving insight over the safety of poultry products storage.

The effects of focused attention training on the duration of novice drivers' glances inside the vehicle.

Several studies have documented that the failure of drivers to attend to the forward roadway for a period lasting longer than 2-3 s is a major cause of highway crashes. Moreover, several studies have demonstrated that novice drivers are more likely to glance away from the roadway than the experienced drivers for extended periods when attempting to do a task inside the vehicle. The present study examines the efficacy of a PC-based training programme (FOrward Concentration and Attention Learning, FOCAL) designed to teach novice drivers not to glance away forthese extended periods of time. A FOCAL-trained group was compared with a placebo-trained group in an on-road test, and the FOCAL-trained group made significantly fewer glances away from the roadway that were more than 2 s than the placebo-trained group. Other measures indicated an advantage for the FOCAL-trained group as well. Statement of relevance: Distracted driving is increasingly a problem, as cell phones, navigation systems, and other in-vehicle devices are introduced into the cabin of the automobile. A training programme is described that has beentested on the open road and can reduce the behaviours that lead to crashes caused by the distracted driving.

Synthesis and magnetic characterizations of La(1-x)Sr(x)MnO3 nanoparticles for biomedical applications.

The La(1-x)Sr(x)MnO3 (LSMO) nanoparticles have been synthesized by citric gel process followed by ball milling method. These nanoparticles demonstrated high crystalline quality. Nanoparticle size was further decreased by ball milling technique as observed by the field-emission scanning electron microscopic studies. The ball milled and silica coated LSMO nanoparticles show magnetic transition at about 370 K with a superparamagnetic properties. The ferromagnetic resonance (FMR) spectra analysis of LSMO nanoparticles shows large FMR linewidth due to the surface strain of the nanoparticles. Both magnetization and FMR studies demonstrate that the LSMO nanoparticles are highly anisotropic. The toxicity of the nanoparticles was studied for safe biomedical applications. Measurement of intracellular reactive oxygen species (ROS) and MTT assay results show that LSMO nanoparticles are relatively nontoxic and the toxicity is further reduced by SiO2 coating. These results are very important for applications in the field of biotechnology.

Biofilm in milking equipment on a dairy farm as a potential source of bulk tank milk contamination with Listeria monocytogenes.

The objective of this study was to assess the presence of a Listeria monocytogenes-containing biofilm in milking equipment as a potential source of bulk tank milk contamination on a dairy farm where milk contamination had been previously documented. Samples were collected from milking equipment and milking parlor premises on 4 occasions and analyzed for the presence of L. monocytogenes. Pulsed-field gel electrophoresis (PFGE) typing was conducted on L. monocytogenes isolates from the milking equipment, parlor and storage room floors, bulk tank milk, and in-line milk filters. Pieces from milk meters and rubber liners were obtained to visually assess the presence of a biofilm using scanning electron microscopy. A total of 6 (15%), 4 (25%), and 1 (6%) samples were culture-positive for L. monocytogenes in the first, second, and third sample collection, respectively. Two samples were L. monocytogenes hly PCR-positive but were culture-negative in the fourth sample collection. Combined AscI and ApaI restriction analysis yielded 6 PFGE types for 15 L. monocytogenes isolates obtained from milking equipment, parlor, bulk tank milk, and milk filters. A predominant and persistent PFGE type (PFGE type T) was observed among these L. monocytogenes isolates (9/15 isolates). Scanning electron microscopy of samples from the bottom cover of 2 milk meters showed the presence of individual and clusters of bacteria, mainly associated with surface scratches. The presence of a bacterial biofilm was observed on the bottom covers of the 2 milk meters. Prevention of the establishment of biofilms in milking equipment is a crucial step in fulfilling the requirement of safe, high-quality milk.

Effect of Johne's disease status on reproduction and culling in dairy cattle.

Among the costs attributed to Mycobacterium avium ssp. paratuberculosis (MAP) infection in dairy cattle, the effects on reproduction and culling are the least documented. To estimate the cost of MAP infections and Johne's disease in a dairy herd, the rates of calving and culling were calculated for cows in each stage of MAP infection relative to uninfected cows. Data from 6 commercial dairy herds, consisting of 2,818 cows with 2,754 calvings and 1,483 cullings, were used for analysis. Every cow in each study herd was tested regularly for MAP, and herds were followed for between 4 and 7 yr. An ordinal categorical variable for Johne's disease status [test-negative, low-positive (low-shedding or ELISA-positive only), or high-shedding] was defined as a time-dependent variable for all cows with at least 1 positive test result or 2 negative test results. A Cox regression model, stratified on herd and controlling for the time-dependent infection variable, was used to analyze time to culling. Nonshedding animals were significantly less likely to be culled in comparison with animals in the low-shedding or ELISA-positive category, and high-shedding animals had nonsignificantly higher culling rates than low-shedding or ELISA-positive animals. Time to calving was analyzed using a proportional rates model, an analog to the Andersen-Gill regression model suitable for recurrent event data, stratifying on herd and weighted to adjust for the dependent censoring caused by the culling effects described above. High-shedding animals had lower calving rates in comparison with low-shedding or ELISA-positive animals, which tended to have higher calving rates than test-negative animals.

Magnetic characterization of radio frequency heat affected micron size Fe3O4 powders: a bio-application perspective.

Micron size Fe3O4 powders were chemically prepared and processed by radio frequency (13.56 MHz) oxygen plasma irradiation technique at different elevated temperatures using low radio frequency (RF) power level. Low magnetic field RF superconducting quantum interference device (SQUID) magnetization studies were performed up to a maximum magnetic field of 100 Oe, which was well below the magnetic field tolerance factor of human beings and at different temperatures (down to 5 K). Heat-treated powders in RF oxygen plasma showed significant changes in blocking temperature, magnetization and susceptibility, which are important parameters for bio-applications. It is observed that blocking temperature is decreased under identical RF heat treatment in oxygen plasma and noted to be dependent on average particle size. Microscopic rise in electron temperature during RF heating may likely to enhance the electron-hopping rate between Fe(+2) and Fe(+3) in the octahedral site of Fe3O4 molecular crystal structure, which in turn exhibit changes in blocking temperature including low field magnetization and susceptibility. These properties of Fe3O4 fine powder are likely to play important role in generating and processing biocompatible Ferro-fluid down to nanoscopic size for biomaterials applications.

A longitudinal study on the impact of Johne's disease status on milk production in individual cows.

Longitudinal data from 3 commercial dairy herds in the northeast United States were collected from 2004 to 2007. Johne's disease status, as indicated by Mycobacterium avium ssp. paratuberculosis infection levels, was determined through quarterly ELISA serum testing, biannual fecal culture, and culture of tissues at slaughter. Milk production data were collected from the Dairy Herd Improvement Association. The effect of Johne's disease status on milk production was analyzed using a mixed linear model with an autocorrelation random effect structure. Infected animals produced more milk than uninfected cows before they began shedding M. avium ssp. paratuberculosis. Cows infected with M. avium ssp. paratuberculosis had monthly decreases of 0.05 to 1 kg in daily milk production relative to uninfected animals, with greater decreases in progressive disease categories. Animals with fecal culture results of >30 cfu/g produced approximately 4 kg less milk per day compared with uninfected cows. These results will be valuable in calculating the economic effect of Johne's disease.

Dynamics of endemic infectious diseases of animal and human importance on three dairy herds in the northeastern United States.

Endemic infectious diseases in dairy cattle are of significant concern to the industry as well as for public health because of their potential impact on animal and human health, milk and meat production, food safety, and economics. We sought to provide insight into the dynamics of important endemic infectious diseases in 3 northeastern US dairy herds. Fecal samples from individual cows and various environmental samples from these farms were tested for the presence of major zoonotic pathogens (i.e., Salmonella, Campylobacter, and Listeria) as well as commensal bacteria Escherichia coli and enterococci. Additionally, the presence of Mycobacterium avium ssp. paratuberculosis was tested in fecal and serum samples from individual cows. Test results and health and reproductive records were maintained in a database, and fecal, plasma, DNA, and tissue samples were kept in a biobank. All bacteria of interest were detected on these farms and their presence was variable both within and between farms. The prevalence of Listeria spp. and L. monocytogenes in individual fecal samples within farm A ranged from 0 to 68.2% and 0 to 25.5%, respectively, over a period of 3 yr. Within farm B, continuous fecal shedding of Salmonella spp. was observed with a prevalence ranging from 8 to 88%; Salmonella Cerro was the predominant serotype. Farm C appeared less contaminated with Salmonella and Listeria, although in the summer of 2005, 50 and 19.2% of fecal samples were positive for Listeria and L. monocytogenes, respectively. The high prevalence of E. coli (89 to 100%), Enterococcus (75 to 100%), and Campylobacter (0 to 81%) in feces suggested they were ubiquitous throughout the farm environment. Fecal culture and ELISA results indicated a low prevalence of Mycobacterium avium ssp. paratuberculosis infection in these farms (0 to 13.6% and 0 to 4.9% for culture-positive and ELISA-positive, respectively), although the occasional presence of high shedders was observed. Results have major implications for food safety and epidemiology by providing a better understanding of infectious disease dynamics on dairy farms. Comprehensive understanding of these infections may lead to better farm management practices and pathogen reduction programs to control and reduce the on-farm contamination of these pathogens and to prevent their further entry into the food-chain.

Toxoplasma gondii tissue cyst formation and density of tissue cysts in shoulders of pigs 7 and 14 days after feeding infected mice tissues.

Among the meat sources of Toxoplasma gondii, pork is considered important in the epidemiology of toxoplasmosis in the USA. How soon after infection T. gondii forms tissue cysts in pork is unknown. In the present study, eight serologically negative ˜3 months old pigs were fed mouse tissues infected with VEG (Type III) strain of T. gondii and euthanized 7 (4 pigs) and 14 days (4 pigs) post-inoculation (p.i.). Meat from the right shoulder of each pig was bioassayed in mice for T. gondii tissue cysts by peptic digestion. From each pig, the shoulder muscle was cut at random spots into 5 g, 10 g and 50 g portions. Extreme care was taken to use different scalpels and forceps to minimize cross contamination among 17 samples (6 replicates of each 5 g and 10 g portions and 5 replicates of 50 g). From the four pigs euthanized at 7 days p.i., a composite of ˜200 g of leftover meat from each shoulder was bioassayed in cats and their feces were tested for oocyst excretion. All eight pigs developed T. gondii antibodies (modified agglutination test, MAT, 1: 80 or higher) and viable T. gondii was isolated from shoulder meat of each pig. All four cats fed pork from excreted T. gondii oocysts. The density of T. gondii, based on mouse infectivity, varied within 5-50 g samples each pig, and between pigs within the same group, day 7 versus day 14 p.i. There were no significant differences in mouse bioassay results obtained with day 7 versus day 14 infected pigs. Overall, the rate of isolation of T. gondii increased with sample size of meat bioassayed. Results demonstrate that tissue cysts are formed early in infection and they are unevenly distributed.

Surface plasmon resonance in CdSe semiconductor coated with gold nanoparticles.

We have grown CdSe semiconductor films on glass substrates and the films were coated with Au nanoparticles of 10 nm in size by the pulsed-laser deposition technique. The films demonstrate a large enhancement of Raman intensity and photoluminescence of CdSe semiconductor via excitation of surface plasmon resonances in proximate gold metal nanoparticles deposited on the surface of CdSe film. These observations suggest a variety of approaches for improving the performance of devices such as photodetectors, photovoltaics, and related devices, including biosensors.

Exploring the Magnetoelectric Coupling at the Composite Interfaces of FE/FM/FE Heterostructures.

Multiferroic materials have attracted considerable attention as possible candidates for a wide variety of future microelectronic and memory devices, although robust magnetoelectric (ME) coupling between electric and magnetic orders at room temperature still remains difficult to achieve. In order to obtain robust ME coupling at room temperature, we studied the Pb(Fe0.5Nb0.5)O3/Ni0.65Zn0.35Fe2O4/Pb(Fe0.5Nb0.5)O3 (PFN/NZFO/PFN) trilayer structure as a representative FE/FM/FE system. We report the ferroelectric, magnetic and ME properties of PFN/NZFO/PFN trilayer nanoscale heterostructure having dimensions 70/20/70 nm, at room temperature. The presence of only (00l) reflection of PFN and NZFO in the X-ray diffraction (XRD) patterns and electron diffraction patterns in Transmission Electron Microscopy (TEM) confirm the epitaxial growth of multilayer heterostructure. The distribution of the ferroelectric loop area in a wide area has been studied, suggesting that spatial variability of ferroelectric switching behavior is low, and film growth is of high quality. The ferroelectric and magnetic phase transitions of these heterostructures have been found at ~575 K and ~650 K, respectively which are well above room temperature. These nanostructures exhibit low loss tangent, large saturation polarization (Ps ~ 38 µC/cm2) and magnetization (Ms ~ 48 emu/cm3) with strong ME coupling at room temperature revealing them as potential candidates for nanoscale multifunctional and spintronics device applications.

Isolation of viable Toxoplasma gondii, molecular characterization, and seroprevalence in elk (Cervus canadensis) in Pennsylvania, USA.

Toxoplasmosis is a worldwide zoonosis. The ingestion of uncooked/undercooked meat and consumption of water contaminated with Toxoplasma gondii oocysts excreted by felids are the main modes of transmission of this parasite. T. gondii has been reported in multiple cervid species; however, little is known of the parasite in North American elk (Cervus canadensis). In the present study, antibodies to T. gondii were detected in serum of wild elk from Pennsylvania collected during 2013-2016 by the modified agglutination test (MAT, cut-off 1:25); 221 of 317 (69.7%) had MAT titers of 1:25 in 19, 1:50 in 28, 1:100 in 34, and 1:200 or higher in 140. Thus most (44.1%) elk had relatively high titers. Seroprevalence was slightly higher in males (76.9%) than females (67.5%, not statistically significant, Chi-square tests, P<0.0001) and was higher in adults (76.5%) than yearlings (46.4%, Odds ratio 3.82; 95% CL 1.72-8.47; P=0.001) or calves (21.7%, Odds ratio 12.58; 95% CL 4.51-35.10; P<0.0001). Annual seroprevalence was relatively stable throughout the period tested and ranged from 66.6% to 72.2%. Of the 101 elk harvested in 2016, hearts were bioassayed from 20 elk and tongues were bioassayed from 56; all tongue samples were negative. Viable T. gondii was isolated from hearts of two female elk, one of these was a seronegative adult and the other was a calf with no serum available for testing. Both T. gondii isolates were cultivated in cell culture and DNA derived from tachyzoites was characterized using the PCR-RFLP markers including SAG1, SAG2 (5'- 3'SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. One isolate belongs to ToxoDB PCR-RFLP genotype #2 and the other is genotype #5. Both genotypes are frequently identified in animals in North America.

Growth of aligned ZnO nanorods.

Growth of high-density and aligned ZnO nanorods on ZnO film substrate has been demonstrated using vapor-transport of thermally evaporated Zn metal powders followed by condensation. Morphological studies show that the nanorods grow preferentially from a hexagonal ZnO base with a uniform hexagonal structure following three-dimensional island-like growth mechanism. Structural and spectroscopic properties clearly indicate that the nanorods are relatively good and defect-free in quality. These nanorods have potential for technological implications.

Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications.

We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5-10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.

Novel ZnO:Al contacts to CdZnTe for X- and gamma-ray detectors.

CdZnTe (CZT) has made a significant impact as a material for room-temperature nuclear-radiation detectors due to its potential impact in applications related to nonproliferation, homeland security, medical imaging, and gamma-ray telescopes. In all such applications, common metals, such as gold, platinum and indium, have been used as electrodes for fabricating the detectors. Because of the large mismatch in the thermal-expansion coefficient between the metal contacts and CZT, the contacts can undergo stress and mechanical degradation, which is the main cause for device instability over the long term. Here, we report for the first time on our use of Al-doped ZnO as the preferred electrode for such detectors. The material was selected because of its better contact properties compared to those of the metals commonly used today. Comparisons were conducted for the detector properties using different contacts, and improvements in the performances of ZnO:Al-coated detectors are described in this paper. These studies show that Al:ZnO contacts to CZT radiation detectors offer the potential of becoming a transformative replacement for the common metallic contacts due to the dramatic improvements in the performance of detectors and improved long-term stability.

Predictive model for the survival, death, and growth of Salmonella typhimurium in broiler hatchery.

Contamination and penetration of salmonellae into hatching eggs may comprise an important link in the transmission of these bacteria to growing birds, processed carcasses, and eventually to the consumer. In this study, a predictive model for Salmonella typhimurium as a function of initial cell number and storage or incubation time at a nearly constant temperature and humidity was developed and evaluated to compute the bacterial load after 1 d (holding), 10 d (candling), 17 d (incubation), and 21 d (chick processing). Experiments were conducted for S. typhimurium with both high initial bacterial load (HIBL) and low initial bacterial load (LIBL) of 6.0 and 3.5 log cfu/egg, respectively. Eggs with HIBL experienced 2.0 log reduction in the bacterial load after holding at 4 degrees C for 24 h and 3.0 log increase in the bacterial load during incubation and hatch at approximately 37 degrees C between 17 d and 21 d. Experimental data showed that bacterial load of S. typhimurium from holding to chick processing changed from 3.7 to 6.6 log cfu/egg and from 3.7 to 2.7 log cfu/egg in HIBL and LIBL eggs, respectively. The developed model was able to predict bacterial load of S. typhimurium from 3.6 to 6.6 log cfu/egg in HIBL eggs and from 3.4 to 2.7 log cfu/egg in LIBL eggs from holding to chick processing. Root mean square errors and plot of predicted compared with observed bacterial load of S. typhimurium in contaminated eggs yielded a good fit and prediction. The predicted and experimental results indicated that incubated broiler eggs have an increase in internal bacterial loads between incubation and hatch. This model can be used as a tool to predict bacterial load of S. typhimurium in contaminated eggs as well as help predict the behavior of S. typhimurium during hatch.