Convergent behavioral and neuropsychological evidence for a distinction between identification and production forms of repetition priming.

Four experiments examined a distinction between kinds of repetition priming which involve either the identification of the form or meaning of a stimulus or the production of a response on the basis of a cue. Patients with Alzheimer's disease had intact priming on picture-naming and category-exemplar identification tasks and impaired priming on word-stem completion and category-exemplar production tasks. Division of study-phase attention in healthy participants reduced priming on word-stem completion and category-exemplar production tasks but not on picture-naming and category-exemplar identification tasks. The parallel dissociations in normal and abnormal memory cannot be explained by implicit-explicit or perceptual-conceptual distinctions but are explained by an identification-production distinction. There may be separable cognitive and neural bases for implicit modulation of identification and production forms of knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of growth on the thermal resistance and survival of Salmonella Tennessee and Oranienburg in peanut butter, measured by a new thin-layer thermal death time device

In published data the thermal destruction of Salmonella species in peanut butter deviates from pseudo-first-order kinetics. The reasons for such deviation are unknown. This study examined both the method used to measure the thermal destruction rate and the method of growth of the microorganisms to explain variations in destruction kinetics. Growth on a solid matrix results in a different physiological state that may provide greater resistance to adverse environments. In this study, Salmonella Tennessee and Oranienburg were grown for 24 h at 37°C under aerobic conditions in broth and agar media to represent planktonic and sessile cell growth, respectively. Peanut butter was held at 25°C and tested for Salmonella levels immediately after inoculation and at various time intervals up to 2 weeks. Thermal resistance was measured at 85°C by use of a newly developed thin-layer metal sample holder. Although thermal heat transfer through the metal device resulted in longer tau values than those obtained with plastic bags (32.5 ± 0.9 versus 12.4 ± 1.9 s), the bags have a relative variability of about 15 % compared with about 3 % in the plates, allowing improved uniformity of sample treatment. The two serovars tested in the thin-layer device showed similar overall thermal resistance levels in peanut butter regardless of growth in sessile or planktonic states. However, thermal destruction curves from sessile cultures exhibited greater linearity than those obtained from planktonic cells (P = 0.0198 and 0.0047 for Salmonella Oranienburg and Salmonella Tennessee, respectively). In addition, both Salmonella serovars showed significantly higher survival in peanut butter at 25°C when originally grown on solid media (P = 0.001) with a <1-log loss over 2 weeks as opposed to a 1- to 2-log loss when grown in liquid culture. Consequently, the use of cells grown on solid media may more accurately assess the survival of Salmonella at different temperatures in a low-water-activity environment such as peanut butter.     

Thermal death time measurement using thin flexible sleeves: a new experimental approach for determining microbial destruction kinetics in fluids of arbitrary viscosity

The thermal death time kinetics of Salmonella Enteritidis (SE) was measured in buffer, egg yolk, and albumen using thin layer plastic sleeves. The sleeves allowed for the loading and sampling of liquids of high or unusual viscosity, as in the case of yolk and albumen, and accepted relatively large volumes (2 to 3 ml) of fluid. The sleeves maintained the volume of the fluid in a thin layer and could be easily handled for heat exposure. The thin layer maintained one-dimensional heat transfer and minimized temperature gradients, thus preventing parts of the fluid from experiencing different heating rates. A representative strain of SE associated with an egg-based salmonellosis outbreak was used in this study. The D- and z-values of the chosen strain, H7037, were measured in buffer, yolk, and albumen. In buffer, SE had the following mean (±standard deviation) D-values: D(55°C) = 3.51 ± 0.30 min, D(57°C) = 1.75 ± 0.13 min, and D(60°C) = 0.25 ± 0.06 min. In yolk, D(58°C) = 0.90 ± 0.05, D(60°C) = 0.26 ± 0.03, and D(62°C) = 0.20 ± 0.02. In albumen, D(55°C) = 1.26 ± 0.31, D(56°C) = 0.68 ± 0.10, and D(57°C) = 0.44 ± 0.04. The z-values for SE calculated from these D-values were 4.29 ± 0.39°C in buffer, 6.12 ± 0.26°C in yolk, and 4.63 ± 1.14°C in albumen. The sleeves allowed one consistent approach to determining thermal death time kinetics regardless of viscosity.     

Preserved priming across study-test picture transformations in patients with Alzheimer's disease

Picture-naming priming was examined across different study-test transformations to explore the nature of memory representations of objects supporting implicit memory processes in patients with Alzheimer's disease (AD). Although severely impaired in explicit memory for pictures and words, AD patients demonstrated normal priming across perceptual transformations in picture orientation (Experiment 1) and picture size (Experiment 2) and across symbolic transformations from words to pictures (Experiment 3). In addition, the priming across alterations in picture size was invariant. This demonstrates that AD patients have preserved implicit memory for high-level, abstract representations of objects.     

A Longitudinal Study of Implicit and Explicit Memory in Old Persons.

Decline in explicit memory with advancing age is a common finding, but it is unclear whether implicit memory (repetition priming) declines or remains stable. Meta-analyses of studies that examined differences between extreme groups (young-old), typically at a single point in time and on a single test, suggest that a mild reduction in priming occurs with advancing age. The authors examined explicit memory and priming, on multiple tests over 4 annual data-collection waves, in a large group of older persons without dementia at baseline. Explicit memory declined significantly, but priming remained stable. Findings indicate that explicit memory and priming are dissociable on the basis of age-related change and that mildly reduced priming is not an inevitable consequence of growing older. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

CLASS: A standardized in-class program for acting-out children: II. Field test evaluations.

Two experiments evaluated the effects of a packaged teacher-consultant-mediated intervention program (CLASS) for modifying acting-out behavior in the regular classroom. Consultants were instructed (a) as part of an 8-wk course by 2 briefly trained college instructors, or (b) in a 2–4 day workshop by the program's developers. 27 experimental and 27 control Ss (from kindergarten through 2nd grade) from 3 school districts were involved. Results indicate that the experimentals, in contrast to the controls, significantly increased their proportion of appropriate behavior postintervention in the next academic year (Exp II) and required fewer remedial services and special class placements up to 3 yrs later. The program's external generalizability and cost-effective service-delivery strategy are discussed. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A system for inducing hyperthermia in sheep

A system that produces hyperthermia in pregnant sheep in a consistent and reproducible manner was designed. The experimental approach was through control of ambient temperature and relative humidity in a closed chamber; the sheep was unable to lose its metabolic heat in an environment of 42 degrees C and 75% relative humidity. This system resulted in a steady and progressive temperature rise of 2.5 degrees C in the maternal abdominal aorta in 120 +/- 17 min.     

Long term human studies on the lipid effects of oral calcium

Ingestion of 2 g of supplemental dietary calcium carbonate daily over a period of one year by eight hyperlipemic men and two hyperlipemic women caused a significant 25% decrease in serum cholesterol, after these subjects had shown stable levels for the previous year, and when compared to a group without therapy. Body weights for both groups remained stable throughout the period of observation. The experimental group also showed a reversal in the cholesterol-phospholipid ratio from a preexperimental ratio of 1.04 to a ratio of 0.92. In addition there was a 113 mg per 100 ml decrease in serum triglycerides and a 48 mg per 100 ml decrease in serum phospholipids, but these were not statistically significant due to the large between individual variations and the limited sample size. Calcium carbonate should be considered as a potential agent for usage in long term studies designed to produce hypolipemia, since it appears to be effective and without significant side effects.     

From white spots to stem cells: the role of the Kit receptor in mammalian development

The Kit tyrosine kinase membrane receptor is essential for melanogenesis, gametogenesis and hematopoiesis during embryonic development and postnatal life. This review summarizes the genetic evidence implicating Kit and its ligand, Steel factor, in the control of stem cell proliferation, migration and survival, with emphasis on mutations in the human and mouse genes.