Interval timing accuracy and scalar timing in C57BL/6 mice.

In many species, interval timing behavior is accurate—appropriate estimated durations—and scalar—errors vary linearly with estimated durations. Whereas accuracy has been previously examined, scalar timing has not been clearly demonstrated in house mice (Mus musculus), raising concerns about mouse models of human disease. The authors estimated timing accuracy and precision in C57BL/6 mice, the most used background strain for genetic models of human disease, in a peak-interval procedure with multiple intervals. Both when timing 2 intervals (Experiment 1) or 3 intervals (Experiment 2), C57BL/6 mice demonstrated varying degrees of timing accuracy. An important finding was that, both at the individual and group levels, their precision varied linearly with the subjective estimated duration. Further evidence for scalar timing was obtained using an intraclass correlation statistic. This is the first report of consistent, reliable scalar timing in a sizable sample of house mice, thus validating the peak-interval procedure as a valuable technique, the intraclass correlation statistic as a powerful test of the scalar property, and the C57BL/6 strain as a suitable background for behavioral investigations of genetically engineered mice modeling disorders of interval timing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stormwater Quality and Local Government Innovation

This article investigates how local governments in Kansas approached planning for and implementing Phase II of the National Pollutant Discharge Elimination System (NPDES) storm water program, which required them to take measures to control nonpoint source pollution in order to improve surface water quality. We find that though these local governments undertook many new activities, there were few differences between those that acted early and those that waited until they were required to act, though the governments acting early had higher quality responses. Limitations on funds and personnel appear to have posed the most significant challenges to effective local innovation.     

Factors affecting calcium lactate and liquid expulsion defects in Cheddar cheese

This paper summarizes the results of 2 studies designed to investigate the influence of several manufacturing and curing treatments on the appearance of Cheddar cheese defects. Specifically, 2 defects, calcium lactate crystal formation and the expulsion of free liquid (weeping) were monitored in Cheddar cheese. Both studies were conducted at a commercial cheese manufacturing facility that produces Cheddar in 18.14-kg (40-lb) blocks. In the first study we monitored cheese calcium, both total and soluble during manufacture and early curing. In the second study we measured cheese pH from 3 d through 8 mo, as well as some factors that are influenced by cheese pH. Early cheese pH (3 d to 7 d) patterns were used to select vats of cheese for retail packaging. Mild Cheddar packaged at 30 d postmanufacture and sharp Cheddar packaged at 8 mo postmanufacture from the same vats were monitored for the incidence and severity of the defects. Our results indicated that factors measured in early stages of manufacture and curing (less than 7 d) such as cheese pH at mill, lactic acid concentration, nonprotein nitrogen, and calcium (total and soluble) in cheese did not correlate with the appearance of either calcium lactate or expulsion of free liquid in packaged cheeses. Factors including pH, lactic acid concentrations, and soluble calcium measured during curing (greater than 7 d) of cheese were found to be statistically significant in the development of defects and appeared to be associated with use of specific starter culture groups. In the study, 5 different starter culture groups, each consisting of a 4-strain blend of Lactococcus lactis ssp. cremoris and Lactococcus lactis ssp. lactis, were used to manufacture the cheeses. Cheese manufactured with one particular culture group showed no incidence of calcium lactate crystal formation or weeping during curing and shelf-life of cheeses in this study. This starter group also generated the least amount of pH change in cheese during the first month of curing. From these results we conclude that starter culture group, more than any other factor measured, played an important role in the development of calcium lactate and liquid expulsion defects in Cheddar cheese. Starter culture group appeared to strongly influence cheese pH, lactic acid, and soluble calcium concentrations during curing and storage.     

Use of ferrocenyl surfactants of varying chain lengths to study electron transfer reactions in native montmorillonite clay

A series of ferrocenyl surfactants was tested as model compounds to study electron transfer reactions involving structural Fe(III) in clay minerals. The surfactants contain trimethylammonium headgroups, ferrocene tail groups, and intervening hydrocarbon chain lengths of one, six, or 11 carbons. Two factors considered to be decisive for electron transfer were addressed: (1) physical access of the surfactant ferrocene to the reactive sites through hexagonal holes in the clay lattice by X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) and (2) thermodynamic favorability of the overall oxidation/reduction reaction based on experimentally determined oxidation/reduction potentials. In suspensions of clay with the longer chain surfactants, (ferrocenylhexyl)trimethylammonim (FHTMA+) and (ferrocenylundecyl)trimethylammonium (FUTMA+), where electron transfer may be expected to be favored by both factors, physical accessibility, and thermodynamic favorability, ferroecene oxidation was observed by diffuse reflectance infrared spectroscopy (DRIFT), ultraviolet-visible spectroscopy (UV-vis), and visual color changes. In contrast, the shorter chain length surfactant, (ferrocenylmethyl)trimethylammonium (FMTMA+), did not participate in electron transfer with the clay, as substantiated by UV-vis and no visible color changes. Rigid conformation and/or higher oxidation/reduction potential than clay Fe can accountforthe lack of reaction. The utility and limitations of using these surfactants as model compounds is discussed.     

Interdisciplinary quality improvement from the perspective of a clinical pathway team

The U.S. health care sector is following the path of the revitalized U.S. economy with the creation of focused health care factories that provide coordinated care primarily for high-cost chronic diseases, disabilities, and surgical procedures, and with increased response to the demands of hard-working, well-educated Americans for convenience and support. Everything-for-everybody vertically integrated systems and managed care organizations will be sorely tested by these efficient, consumer-friendly innovations. This managerial revolution will create substantial opportunities for important health care administration research.     

Batch Comparisons of Sr and Ba Retention and Capacities on AnaLig® Sr-01 and Eichrom Sr Resins

The isolation of strontium from aqueous media may be required for environmental monitoring or nuclear forensics sample analyses.^[1–4] The prevalent method is to use a strontium selective extraction chromatographic resin. Two such products are Eichrom Technologies Sr resin and IBC Advanced Technologies AnaLig® Sr-01 resin. Eichrom Technologies Sr resin utilizes a crown ether (4,4′(5′)-di-t-butylcyclohexano-18-crown-6) diluted in 1-octanol and coated onto Amberchrom^TM CG71 resin, and IBC Advanced Technologies AnaLig® Sr-01 resin features a proprietary extractant covalently tethered to a silica support. The use of each resin is reported in the literature; Eichrom Sr Resin specifications, including the resin’s weight distribution ratio and capacity factor for analytes, have been reported but no such data have been published for IBC Analig® Sr-01 resin. In this work, batch studies were completed to determine the capacity and weight distribution ratio of both AnaLig® Sr-01 and Eichrom Sr resins for strontium and barium. This work shows that both resins retained Sr from aqueous samples, but Eichrom Sr resin provided superior Sr/Ba separation compared with Analig® Sr-01 resin.     

Pocket 4 of the HLA-DR(alpha,beta 1*0401) molecule is a major determinant of T cells recognition of peptide

To investigate the functional roles of individual HLA-DR residues in T cell recognition, transfectants expressing wild-type or mutant DR(alpha,beta 1*0401) molecules with single amino acid substitutions at 14 polymorphic positions of the DR beta 1*0401 chain or 19 positions of the DR alpha chain were used as antigen-presenting cells for five T cell clones specific for the influenza hemagglutinin peptide, HA307-19. Of the six polymorphic positions in the DR beta floor that were examined, mutations at only two positions eliminated T cell recognition: positions 13 (four clones) and 28 (one clone). In contrast, individual mutations at DR beta positions 70, 71, 78, and 86 on the alpha helix eliminated recognition by each of the clones, and mutations at positions 74 and 67 eliminated recognition by four and two clones, respectively. Most of the DR alpha mutations had minimal or no effect on most of the clones, although one clone was very sensitive to changes in the DR alpha chain, with loss of recognition in response to 10 mutants. Mutants that abrogated recognition by all of the clones were assessed for peptide binding, and only the beta 86 mutation drastically decreased peptide binding. Single amino acid substitutions at polymorphic positions in the central part of the DR beta alpha helix disrupted T cell recognition much more frequently than substitutions in the floor, suggesting that DR beta residues on the alpha helix make relatively greater contributions than those in the floor to the ability of the DR(alpha,beta 1*0401) molecule to present HA307-19. The data indicate that DR beta residues 13, 70, 71, 74, and 78, which are located in pocket 4 of the peptide binding site in the crystal structure of the DR1 molecule, exert a major and disproportionate influence on the outcome of T cell recognition, compared with other polymorphic residues.     

Life events and psychological distress: A prospective study of young adolescents.

Seventh and 8th graders were administered measures of negative and positive life experiences and psychological distress on 2 occasions approximately 5 mo apart to examine the etiologic role of negative life events in the maladjustment of early adolescents. 233 7th–8th graders were administered the Junior High Life Experiences Survey, the State-Trait Anxiety Inventory, and a child development inventory at Time 1. 79 of the 233 Ss completed the 3 measures at Time 2. Cross-sectional regression analyses revealed a significant positive relationship between negative events and distress but generally failed to support the stress-buffering effects of positive events. However, in the prospective analyses, negative events were not predictive of psychological distress and were, in fact, themselves partly determined by previous distress. Results are compared with previous studies of adult life events and suggest the importance of ongoing stressful processes as engendering both maladjustment and stressful events in the lives of early adolescents. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors affecting solubility of calcium lactate in aqueous solutions

Calcium lactate (CaL2) crystal formation on the surface of cheese continues to be a widespread problem for the cheese industry despite decades of research. To prevent those crystals from forming, it is necessary to keep the concentration of CaL2 below saturation level. The limited data available on the solubility of CaL2 at conditions appropriate for the storage of cheese are often conflicting. In this work, the solubility of L(+)-CaL2 in water was evaluated at 4, 10, and 24 degrees C, and the effects of salt and pH at those temperatures were investigated. The effects of additional calcium and lactate ions on solubility also were studied. The results suggested that temperature and the concentration of lactate ions are the main factors influencing the solubility of CaL2, with the other parameters having limited effect.     

Isolation, characterization, and influence of native, nonstarter lactic acid bacteria on Cheddar cheese quality

To determine whether adventitious nonstarter lactic acid bacteria (NSLAB) might affect cheese flavor and quality, we studied a population of NSLAB present in 30 premium quality Cheddar cheeses (3-mo ripened) produced at a commercial facility in the United States. DNA fingerprinting analysis with a sensitive strategy for arbitrary priming polymerase chain reaction showed that 75 isolates corresponded to at least 18 distinct nonstarter organisms. According to ribotype database comparisons of representatives from the 18 groups, 9 matched Lactobacillus (closest to paracasei species), 8 matched Streptococcus thermophilus, and 1 matched to a Lactococcus species. This finding indicated that among the 75 NSLAB isolates, Lactobacillus made up 64%, S. thermophilus 32%, and Lactococcus 4%. Isolates representing 11 NSLAB groups were characterized for protease, peptidase, and diacetyl production. Based on this phenotypic analysis, two Lactobacillus isolates were evaluated as adjuncts in Cheddar cheese. All of the NSLAB identified from the adjunct cheese at 3 mo by DNA fingerprinting consisted of the adjunct lactobacilli, showing that the adjunct strains predominated throughout the early stages of ripening. The impact of adjunct lactobacilli was evident after 6 mo when free amino acids significantly increased and sensory scores improved in adjunct cheese as compared with a control cheese. The largest impact was found in adjunct cheese containing a blend of both lactobacilli strains. These results show that certain adventitious NSLAB positively contribute to flavor development.