Short-term memory scan in normal individuals and individuals with aphasia

Ten matched pairs of normal adults and adults with aphasia participated in a short-term memory, visual recognition paradigm wherein each determined whether or not a probe digit appeared in a subset of digits previously presented. Reaction times, measured in milliseconds from onset of probe digits until completion of visual-motor responses, were analyzed as a function of increasing subset size (two, four, and six digits) and the positive versus the negative response condition. Reaction times were significantly slower for the subjects with aphasia. Both groups of subjects demonstrated linear increases in reaction time across levels of subset size. For both groups, increases in reaction time were similar in the positive vs the negative-response conditions. Resulting parallel slopes suggested that both groups of subjects used a serial exhaustive scan of short-time memory. Results from this study did not support results obtained by others in previous studies which may have been confounded by group differences in visual retention spans.     

Gas chromatography of the fat-soluble vitamins: A review

The application of gas liquid chromatography (GLC) as an analytical tool for the determination of the fat-soluble vitamins A, D, E and K has yet to be utilized to its full potential. A review of the published work of many researchers in this field is presented. GLC methods to measure the vitamin A isomers have not been developed to any appreciable practical extent. Liquid liquid chromatography might well be the technique of choice. In the field of vitamin D there are indications that a practical GLC analysis is feasible for pharmaceutical preparations. The GLC applications for vitamin E are diverse, well defined and generally widely accepted in research laboratory situations and for regulatory and quality control usage. Vitamins K₁ and K₂ have been measured with limited success in a few research laboratories, but the GLC methods have not developed on a practical basis. However GLC is used for measuring vitamin K₃ (menadione and menadione sodium bisulfite) on a fairly routine basis in quality control laboratories.     

Disease induced dynamics in host–parasitoid systems: chaos and coexistence

All animals and plants are, to some extent, susceptible to disease caused by varying combinations of parasites, viruses and bacteria. In this paper, we present a mathematical model of interactions between a host, two parasitoids and a pathogen which shows that the presence of an infection can preserve and promote diversity in such multi-species systems. Initially, we use a system of ordinary differential equations to investigate interactions between two species of parasitoids, a host and a host infection. We show that the presence of all four species is necessary for the system as a whole to persist, and that in particular, the presence of the pathogen is necessary for the coexistence of the two parasitoid species. The inclusion of infection induces a wide range of dynamics, including chaos, and these dynamics are robust for a wide range of parameter values. We then extend the model to include spatial effects by introducing random motility (diffusion) of all three species and examine the subsequent spatio-temporal dynamics, including travelling waves and other more complicated heterogeneous behaviour. The computational simulation results of the model suggest that infection in the hosts can blunt the effects of competition between parasitoids, allowing the weaker competitor to survive. Regardless of the nature of the stability of the coexistent steady state of the system, there is an initial period of transient dynamics, the length of which can be extended by an appropriate choice of initial conditions. The existence of these transient dynamics suggests that systems subject to regular restoration to a starting state, such as agro-ecosystems, may be kept in a continual state of dynamic transience, and this has implications for the use of natural enemies to control insect pests, the preservation of biodiversity in farmland habitats and the more general dynamics of disease processes.     

BPA,BPAF and TMBPF Alter Adipogenesis and Fat Accumulation in Human Mesenchymal Stem Cells,with Implications for Obesity

Bisphenol A (BPA) is an endocrine-disrupting chemical used in the production of plastics, and is linked to developmental, reproductive, and metabolic disorders including obesity. Manufacturers have begun using ‘BPA-free’ alternatives instead of BPA in many consumer products. However, these alternatives have had much less testing and oversight, yet they are already being mass-produced and used across industries from plastics to food-contact coatings. Here, we used human female adipose-derived stem cells (hASCs), a type of adult mesenchymal stem cell, to compare the effects of BPA and BPA alternatives on adipogenesis or fat cell development in vitro. We focused on two commonly used BPA replacements, bisphenol AF (BPAF) and tetramethyl bisphenol F (TMBPF; monomer of the new valPure V70 food-contact coating). Human ASCs were differentiated into adipocytes using chemically defined media in the presence of control differentiation media with and without 17β-estradiol (E2; 10 μM), or with increasing doses of BPA (0, 0.1 and 1 μM), BPAF (0, 0.1, 1 and 10 nM), or TMBPF (0, 0.01 and 0.1 μM). After differentiation, the cells were stained and imaged to visualize and quantify the accumulation of lipid vacuoles and number of developing fat cells. Treated cells were also examined for cell viability and apoptosis (programmed cell death) using the respective cellular assays. Similar to E2, BPA at 0.1 μM and BPAF at 0.1 nM, significantly increased adipogenesis and lipid production by 20% compared to control differentiated cells (based on total lipid vacuole number to cell number ratios), whereas higher levels of BPA and BPAF significantly decreased adipogenesis (p < 0.005). All tested doses of TMBPF significantly reduced adipogenesis and lipid production by 30–40%, likely at least partially through toxic effects on stem cells, as viable cell numbers decreased and apoptosis levels increased throughout differentiation. These findings indicate that low, environmentally-relevant doses of BPA, BPAF, and TMBPF have significant effects on fat cell development and lipid accumulation, with TMBPF having non-estrogenic, anti-adipogenic effects. These and other recent results may provide a potential cellular mechanism between exposure to bisphenols and human obesity, and underscore the likely impact of these chemicals on fat development in vivo.     

Continued Corrosion After Removal of Corrosive Drywall

Copper coupons in sealed glass jars were exposed to corrosive drywall (CDW) and a moisture source while experiencing temperature variation from room temperature to about 120 °F (49 °C). After several weeks of exposure, the CDW source was removed and coupons were replaced into sealed glass jars with a moisture source for extended periods of time under similar temperature cycling. These coupons continued to corrode at a faster rate than coupons that had only been exposed to moisture in the absence of CDW. Analytical scanning electron microscopy (SEM) was used to augment weight change measurements. The results demonstrate that once corrosion is initiated by exposure to CDW, simple removal/replacement of the drywall will not mitigate the corrosion process.     

Bright fluorescent dsDNA probes: novel polycationic asymmetric monomethine cyanine dyes based on thiazolopyridine‐quinolinium chromophore

Seven tri‐ and tetracationic monomeric and homodimeric monomethine cyanine dyes based on thiazolo[4,5‐b]pyridinium and quinolinium end groups were synthesised and characterised. The dyes were tested as fluorescent DNA intercalating probes to apply in DNA gel electrophoresis. The DNA samples stained with all dyes from the series demonstrated bright fluorescent signals. DNA fragments were successfully visualised under orange and green filters as well as under standard UV transillumination. Two of the studied dyes revealed higher sensitivity to DNA when compared with the commercial dimeric cyanine dye TOTO‐1. Their sensitivity reached that of the commercial dimeric cyanine dye YOYO‐1, but the emission was shifted to longer wavelengths. These qualities make the dyes suitable to apply in a wide range of medical and scientific analytical methods.     

Impact of Mechanical Shear on the Survival of Listeria monocytogenes on Surfaces

Abstract: The impact of mechanical surface shear on microbial viability is rarely a subject for exploration in food processing. The objective of this research was to investigate the impact of mechanical shear on the survival of Listeria monocytogenes on surfaces. Mechanical shear created by slicing a model food was explored to investigate the viability of L. monocytogenes. Cell injury/death was readily demonstrated in fluorescence images by confocal microscopy in which the live and dead cells were fluorescently stained green and red, respectively, with a viability dye kit. Images showed that a large percentage of dead cells appeared after slicing, and they were readily transferred from the slicer blade onto the surfaces of sliced agar, indicating that surface shear may cause the lethal effect on L. monocytogenes. Surface transfer results also showed that viable cell counts on agar slices (in a slicing series) followed a consistently decreasing pattern. The cell counts initially at 5 to 6.5 log CFU/slice (slices 1 to 6), decreased to 3 to 4 log CFU/slice (slices 8 to 30), then to 2 to 3 log CFU/slice (slices 31 to 40), and counts would be expected to further decrease if slicing continued. The overall cell recovery (survival) ratio was about 2% to 3% compared to the initial 8.4 log CFU/blade on a 10 cm² edge area. The impact of shear on microbial viability during slicing may contribute 99% of viable cell count reduction. This study provides clear evidence that surface shear can kill foodborne pathogens and reduce cross-contamination. The lethal effects of surface shear may further enhance food safety.     

Hands‐On CFD Educational Interface for Engineering Courses and Laboratories

This study describes the development, implementation, and evaluation of an effective curriculum for students to learn computational fluid dynamics (CFD) in introductory and intermediate undergraduate and introductory graduate level courses/laboratories. The curriculum is designed for use at different universities with different courses/laboratories, learning objectives, applications, conditions, and exercise notes. The common objective is to teach students from novice to expert users who are well prepared for engineering practice. The study describes a CFD Educational Interface for hands‐on student experience, which mirrors actual engineering practice. The Educational Interface teaches CFD methodology and procedures through a step‐by‐step interactive implementation automating the CFD process. A hierarchical system of predefined active options facilitates use at introductory and intermediate levels, encouraging self‐learning, and eases transition to using industrial CFD codes. An independent evaluation documents successful learning outcomes and confirms the effectiveness of the interface for students in introductory and intermediate fluid mechanics courses.     

Characterization of biodegradable core–clad borosilicate glass fibers with round and rectangular cross-section

Here, we report on core–clad bioactive borosilicate fibers, that we have prepared both with round and rectangular cross-section profile. The exposed approach, which relies on the stacking and drawing of glass slabs, demonstrates our ability to develop bioactive-based glass fibers with tailored cross-section profiles. Tens-of-meters-long fibers were successfully drawn, although suffering from elevated losses in the case of the rectangular ones. The response of the fibers in simulated body fluid was studied for both geometries. We found that a round cladding can act as protective layer, tempering effects of the corrosion. We also noticed that rectangular fibers are more prone to degradation, the enhanced corrosion beginning from their sharp corners as they accumulated residual tensile stress during drawing. To the best of our knowledge, this is the first report on the effect of residual tensile stresses from surface tension deformations applied to the corrosion of rectangular fibers. As geometry plays a critical role on the biodegradation behavior of the fiberglass, we believe the enclosed results could lead to the design of fiber devices with tailored cross-section profile in order to tune their rate of degradation on solely based geometrical effects.     

The future of manufacturing: Utopia or dystopia?

Digital manufacturing technologies (DMTs) have the potential to transform industry productivity, but their introduction into the workplace is often a complex process, requiring not only technical expertise but also an awareness of ethical and societal challenges surrounding human–system integration. Concerns about the introduction of new technology have been prevalent throughout history, and exploring public perceptions of these technologies can provide insight to help address such cultural anxieties. However, evaluating user perceptions of futuristic technology is difficult, requiring novel approaches to provide context and understanding. To explore users' perceptions of future DMTs, we applied the ContraVision technique in a questionnaire-based study. Participants viewed films, representing fictionalized utopic and dystopic visions of what the future of these DMTs might involve, and a questionnaire probed the perceptions of the technologies afterward. Findings showed that irrespective of the way technology was portrayed, participants had concerns about the ethical and responsible implementation of these tools. Participant responses were analyzed to identify key challenges for policy surrounding DMT implementation in the future of manufacturing.