Viable Mycobacterium avium ssp. paratuberculosis isolated from calf milk replacer

When advising farmers on how to control Johne's disease in an infected herd, one of the main recommendations is to avoid feeding waste milk to calves and instead feed calf milk replacer (CMR). This advice is based on the assumption that CMR is free of viable Mycobacterium avium ssp. paratuberculosis (MAP) cells, an assumption that has not previously been challenged. We tested commercial CMR products (n = 83) obtained from dairy farms around the United States by the peptide-mediated magnetic separation (PMS)-phage assay, PMS followed by liquid culture (PMS-culture), and direct IS900 quantitative PCR (qPCR). Conventional microbiological analyses for total mesophilic bacterial counts, coliforms, Salmonella, coagulase-negative staphylococci, streptococci, nonhemolytic Corynebacterium spp., and Bacillus spp. were also performed to assess the overall microbiological quality of the CMR. Twenty-six (31.3%) of the 83 CMR samples showed evidence of the presence of MAP. Seventeen (20.5%) tested positive for viable MAP by the PMS-phage assay, with plaque counts ranging from 6 to 1,212 pfu/50 mL of reconstituted CMR (average 248.5 pfu/50 mL). Twelve (14.5%) CMR samples tested positive for viable MAP by PMS-culture; isolates from all 12 of these samples were subsequently confirmed by whole-genome sequencing to be different cattle strains of MAP. Seven (8.4%) CMR samples tested positive for MAP DNA by IS900 qPCR. Four CMR samples tested positive by both PMS-based tests and 5 CMR samples tested positive by IS900 qPCR plus one or other of the PMS-based tests, but only one CMR sample tested positive by all 3 MAP detection tests applied. All conventional microbiology results were within current standards for whole milk powders. A significant association existed between higher total bacterial counts and presence of viable MAP indicated by either of the PMS-based assays. This represents the first published report of the isolation of viable MAP from CMR. Our findings raise concerns about the potential ability of MAP to survive manufacture of dried milk-based products.     

Failure of silver nanowire transparent electrodes under current flow

Silver nanowire transparent electrodes have received much attention as a replacement for indium tin oxide, particularly in organic solar cells. In this paper, we show that when silver nanowire electrodes conduct current at levels encountered in organic solar cells, the electrodes can fail in as little as 2 days. Electrode failure is caused by Joule heating which causes the nanowires to breakup and thus create an electrical discontinuity in the nanowire film. More heat is created, and thus failure occurs sooner, in more resistive electrodes and at higher current densities. Suggestions to improve the stability of silver nanowire electrodes are given.     

Time of Entry of Salmonella and Campylobacter into the Turkey Brooder House

The prevalence of Campylobacter (>90%) and Salmonella (33%) in turkeys at slaughter has been estimated. This report describes studies to estimate the time of entry of Campylobacter and Salmonella into the brooder house, which is the first stage of commercial turkey production. In trial 1, birds (∼100 per time point) were monitored by conventional culture at three intervals (0, 9, and 16 days of age). Campylobacter spp. were not detected in poults at the day of hatch; Salmonella was isolated from the ceca (3.9%) and yolk sac (0.1%). By day 9, Salmonella were frequently isolated from the ceca (55%) and small intestine (45%) while Campylobacter was not cultured. By day 16, the prevalence of Salmonella in the ceca (21%) and small intestine (5.1%) had declined; Campylobacter was infrequently isolated from either the ceca (2%) or small intestine (3%). In trial 2, poults (50 per time point at 5, 20, and 33 days of age) were monitored for Campylobacter and Salmonella by real-time polymerase chain reaction (PCR); Salmonella was also monitored by conventional culture. Whereas Campylobacter was not detected by real-time PCR in the ceca of 5-day-old birds, it was detected on days 20 (92%) and 33 (90%). In contrast, Salmonella was isolated from young birds at days 5 (98%), 20 (98%), and 33 (98%), after which time the turkeys were moved to the finisher house. At slaughter at 138 days, Salmonella prevalence in the ceca had declined (4.5%) in contrast to the prevalence of Campylobacter (92%). Antimicrobial sensitivity profiles of the Salmonella isolates indicated an increase of sulfonamide-resistant isolates throughout the brooder stage. Genotyping by pulsed-field gel electrophoresis analysis of Salmonella (45 isolates per sampling time) indicated fluctuating populations as the birds matured.     

Defecting From the Gutenberg Legacy: Employing Images to Test Knowledge Gaps

Education‐based knowledge gaps are well‐documented across countries, media platforms, and content. Without exception, knowledge is measured through words not images. Given the centrality of sight in the natural history of Homo sapiens, the extraordinary visual acuity of humans, and the proliferation of screen‐based visual media environments in contemporary life, an experiment was conducted to test the knowledge gap visually. Participants watched 8 audiovisual news stories. Simple recognition of story details and comprehension of that information were tested in verbal and visual modalities. Results offered the first confirmation of the knowledge gap in visual terms. Yet, gaps were significantly smaller employing visual than verbal measures, pointing to the need for continued efforts to develop visual measures for future memory studies.     

Impact of backwashing procedures on deep bed filtration productivity in drinking water treatment

Backwash procedures for deep bed filters were evaluated and compared by means of a new integrated approach based on productivity. For this, different backwash procedures were experimentally evaluated by using a pilot plant for direct filtration. A standard backwash mode as applied in practice served as a reference and effluent turbidity was used as the criterion for filter run termination. The backwash water volumes needed, duration of the filter-to-waste period, time out of operation, total volume discharged and filter run-time were determined and used to calculate average filtration velocity and average productivity.