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Liquid culture of Mycobacterium avium subsp. paratuberculosis from clinical samples, such as feces, is the most sensitive antemortem test for the diagnosis of Johne's disease in ruminants. In Australia, New Zealand, the United States, and some other countries, the Bactec 460 system with modified Bactec 12B medium (Becton, Dickinson) has been the most commonly used liquid culture system, but it was discontinued in 2012. In this study, a new liquid culture medium, M7H9C, was developed. It consists of a Middlebrook 7H9 medium base with added Casitone, albumin, dextrose, catalase, egg yolk, mycobactin J, and a cocktail of antibiotics. We found that polyoxyethylene stearate (POES) was not essential for the cultivation of M. avium subsp. paratuberculosis in either the Bactec 12B or the M7H9C medium. The limit of detection determined using pure cultures of the C and S strains of M. avium subsp. paratuberculosis was 7 bacilli per 50 μl inoculum in the two media. The new medium was validated using 784 fecal and tissue samples from sheep and cattle, >25% of which contained viable M. avium subsp. paratuberculosis . Discrepant results for the clinical samples between the two media were mostly associated with samples that contained 900 PCR test had to be performed on every culture after the predetermined incubation period.

Public engagement in nanotechnology media products can lead to a greater interest in understanding of nanotechnology. A study was undertaken to determine middle school student engagement in Nanooze, a magazine featuring nanotechnology research that has been developed for a young adult audience. Teachers at 116 Detroit middle schools distributed two issues of the magazine to their students, and surveys were collected from 870 students after reading the magazines. Results suggest that the majority of students liked reading the magazine and learned something about nanotechnology. Engagement in nanotechnology led to understanding of nanotechnology. The Nanooze magazine was an effective medium for engaging middle school students in learning about nanotechnology.

The measurement of the effectiveness of cooking in the real world has received little attention in the scientific literature. In this study the core temperatures of 16 leg-of-lamb roasts were measured during baking in 14 electric or gas-fired domestic ovens in order to assess the adequacy of cooking relative to recommendations of food authorities to minimise foodborne illness due to microorganisms. The mass of the roasts was 1.80 ± 0.33 kg (mean ± s.d.). The intended extent of cooking indicated by volunteer cooks who were selected from a range of cultural backgrounds ranged from rare to well done, with most preferring greater than medium rare, but the actual degree of doneness achieved was slightly more than intended. One roast was unevenly cooked, with parts well done and other parts medium rare. Ovens reached peak temperature over a variable period ranging from 5 to 25 min. However, there was substantial variation between the oven set temperature and the actual maximum oven temperature recorded. Only five of 14 ovens provided an actual maximum temperature within 10 °C of the set temperature and some were as much as 50 °C below the set temperature. Peak temperatures at the core of the majority of roasts were attained after about 1.5–2.5 h. The maximum core temperatures recorded among roasts ranged from 59.6 °C to 98.3 °C; three roasts had maximum core temperatures less than 70 °C. The least well-cooked roast reached 59.6 °C at one probe site and 65.9 °C at the other. The variables observed in this study support recommendations for use of meat thermometers during baking of red meat and should stimulate further evaluation of domestic cooking practices.

Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition that few people understand the implications of the technology, the technology itself or even the definition of the word. This lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public, which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale.

Pathogenic mycobacteria are difficult to culture, requiring specialized media and a long incubation time, and have complex and exceedingly robust cell walls. Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease, a chronic wasting disease of ruminants, is a typical example. Culture of MAP from the feces and intestinal tissues is a commonly used test for confirmation of infection. Liquid medium offers greater sensitivity than solid medium for detection of MAP; however, support for the BD Bactec 460 system commonly used for this purpose has been discontinued. We previously developed a new liquid culture medium, M7H9C, to replace it, with confirmation of growth reliant on PCR. Here, we report an efficient DNA isolation and quantitative PCR methodology for the specific detection and confirmation of MAP growth in liquid culture media containing egg yolk. The analytical sensitivity was at least 10 4 -fold higher than a commonly used method involving ethanol precipitation of DNA and conventional PCR; this may be partly due to the addition of a bead-beating step to manually disrupt the cell wall of the mycobacteria. The limit of detection, determined using pure cultures of two different MAP strains, was 100 to 1,000 MAP organisms/ml. The diagnostic accuracy was confirmed using a panel of cattle fecal ( n = 54) and sheep fecal and tissue ( n = 90) culture samples. This technique is directly relevant for diagnostic laboratories that perform MAP cultures but may also be applicable to the detection of other species, including M. avium and M. tuberculosis .

The growing importance of nanotechnology in industry and society has not been accompanied by a widespread understanding of the subject among the general public. Simple questions to initially probe the smallest thing that people can see and can think of reveals a divide in the understanding of the general public. A survey of 1500 individuals ranging in age from 6 to 74 has revealed a lack of knowledge of nanotechnology and especially a lack of understanding of the context of nanotechnology in the world that is too small to see. Survey findings are corroborated by in-depth interviews with 400 adults in studies of nanoscience literacy commisioned by University of California, Berkeley and Cornell in 2002 and 2004, respectively. In general, with the exception of 14–28 year olds, over 60% of respondents say they have never heard of nano or nanotechnology. The results suggest that the general public, especially middle-school children, has no firm foundation to understand nanotechnology and likely will continue to be equally impressed by credible scientific information as well as pure fictional accounts of nanotechnology.

Johne's disease (JD) is a chronic enteric disease caused by Mycobacterium avium subsp. paratuberculosis that affects ruminants. Transmission occurs by the fecal-oral route. A commonly used antemortem diagnostic test for the detection of M. avium subsp. paratuberculosis in feces is liquid culture; however, a major constraint is the 2- to 3-month incubation period needed for this method. Rapid methods for the detection of M. avium subsp. paratuberculosis based on PCR have been reported, but comprehensive validation data are lacking. We describe here a new test, the high-throughput-Johnes (HT-J), to detect M. avium subsp. paratuberculosis in feces. Its diagnostic accuracy was compared with that of liquid radiometric (Bactec) fecal culture using samples from cattle (1,330 samples from 23 herds) and sheep (596 samples from 16 flocks). The multistage protocol involves the recovery of M. avium subsp. paratuberculosis cells from a fecal suspension, cell rupture by bead beating, extraction of DNA using magnetic beads, and IS 900 quantitative PCR. The limit of detection of the assay was 0.0005 pg, and the limit of quantification was 0.005 pg M. avium subsp. paratuberculosis genomic DNA. Only M. avium subsp. paratuberculosis was detected from a panel of 51 mycobacterial isolates, including 10 with IS 900 -like sequences. Of the 549 culture-negative fecal samples from unexposed herds and flocks, 99% were negative in the HT-J test, while 60% of the bovine- and 84% of the ovine-culture-positive samples were positive in the HT-J test. As similar total numbers of samples from M. avium subsp. paratuberculosis -exposed animals were positive in culture and HT-J tests in both species, and as the results of a McNemar's test were not significant, these methods probably have similar sensitivities, but the true diagnostic sensitivities of these tests are unknown. These validation data meet the consensus-based reporting standards for diagnostic test accuracy studies for paratuberculosis and the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines (S. A. Bustin et al., Clin. Chem. 55:611–622, 2009, doi:10.1373/clinchem.2008.112797). The HT-J assay has been approved for use in JD control programs in Australia and New Zealand.

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease in livestock and there is a debate about its role in humans in chronic inflammatory bowel disorders such as Crohn's disease, but the relationship remains unproven. Nevertheless livestock health authorities in many countries aim to lower the prevalence of this infection to reduce potential contamination of the human food supply. MAP may occur in bovine milk and data on thermal inactivation suggest pasteurisation is an effective process. Recently MAP has been identified in skeletal muscle of cattle and sheep but there are no data on its thermal inactivation in these substrates. In this study the inactivation of MAP was studied in a fluid homogenate of lamb skeletal muscle at temperatures previously identified as being relevant to cooking processes applied by domestic consumers. A PCR thermocycler was used to ensure accurate temperatures and rapid heat exchange, while radiometric culture was used to ensure sensitive detection of viable MAP for determination of D and z values. Among the two predominant strains of MAP, S and C, D(55) ranged from 56 to 89 min, D(60) was 8 to 11 min, D(65) was 26 to 35s while D(70) was 1.5 to 1.8s. Values for z were 4.21C degrees for the S strain and 4.51C degrees for the C strain. At temperatures of 65-70 degrees C, MAP appeared to be less heat tolerant in skeletal muscle fluid than in previous reports using milk as the medium. The total thermal exposure of MAP during baking of a sample of 16 leg-of-lamb roasts in domestic ovens was determined to result in more than 20 log reductions in most cases, that is the product was microbiologically safe. Based on the models used in this study, there is a low probability of survival of MAP provided that red meat is cooked to recommended standards.

What is the smallest thing you can think of? The answer may seem obvious to scientists, but for most the answer is a visible object.

Teaching nanotechnology in the high school and undergraduate environment is a challenge given the typical expense of instruments used to create micro- and nano-sized devices. To meet this challenge, a portable optical reduction stepper was designed, fabricated, and optimized for use in classrooms. This unique system was designed to provide a safe, hands-on experience for students to create microscale circuits using photolithography. Students are able to design, fabricate, and test a circuit with dimensions as small as 100 mm. The hands-on activity involves the use of a portable 5X optical reduction stepper that is able to transfer a pattern created on a simple acetate transparency to an aluminum coated slide. The etched aluminum features in the pattern can be tested by virtue of their ability to complete a circuit. The entire activity can be accomplished in 1–3 hours and all steps and reagents are designed to be carried out in a typical classroom laboratory environment. The teaching activity highlights important concepts in chemistry, optics, electricity, and engineering and used in a pilot study with students ages 12–14 years helped to convey key concepts in nanotechnology.

The Field Integrated Design and Operations (FIDO) Rover, a prototype vehicle designed to rehearse operations for the Mars Sample Return missions and associated Athena Rover, was put through a suite of field trials in the Silver Lake area of the Mojave Desert in April and October 1999. The trials also provided an opportunity to foster active involvement of students in rover missions using inquiry-based study An integrated team of more than two dozen high school students and their teachers from Los Angeles, Phoenix, Ithaca, and St. Louis (LAPIS) developed and implemented their own FIDO-based rover mission that employed long-distance traverses to explore terrains and make discoveries. LAPIS team members from each city were paired with local science mentors who are part of the Athena Science Team to ensure that the LAPIS activities furthered the overall mission objectives at Silver Lake and to provide expert advice.The students learned to work as a geographically distributed team, developed hypotheses to test, commanded the rover via the Internet to test their hypotheses, analyzed data, and generated their own Web site and archives. Post-LAPIS assessments demonstrated that the participants gained new communication and information technology skills, an enhanced ability to cut across traditional disciplines to solve problems, and a greater understanding of planetary exploration and discovery Further, for some of the students, LAPIS provided the right set of experiences needed to help them define specific career goals in science, mathematics, and engineering.