Properties of New Glass-Ionomer Restorative Systems Marketed for Stress-Bearing Areas.

OBJECTIVES: The purpose of this study was to evaluate the properties (fracture toughness, surface hardness) of newer conventional glass-ionomer restorative materials that are marketed for posterior stress-bearing areas compared with more traditional glass-ionomer restorative materials marketed for non-load-bearing areas and composite-resin restorative materials. METHODS AND MATERIALS: Notched-beam fracture toughness specimens were created in a mold with each tested material (Equia Forte, GC America, with and without a surface coating of Equia Forte Coat; Ketac Universal, 3M/ESPE; ChemFil Rock, Dentsply; Fuji IX GP Extra, GC; Ionostar Molar, VOCO; Filtek Z250, 3M/ESPE; Filtek Supreme Ultra, 3M/ESPE) and fractured using a universal testing machine after 24 hours of storage. Hardness values were determined on the surface of the fracture toughness specimens using a hardness tester. Data were analyzed with a one-way ANOVA and Tukey's post hoc test per property (alpha=0.05). RESULTS: The composite-resin restorative materials had significantly greater fracture toughness than the glass-ionomer materials. There was no significant difference in fracture toughness between the glass-ionomer materials. The use of a resin coating significantly increased the surface hardness of the newer glass ionomer marketed for stress-bearing areas. CONCLUSIONS: Fracture toughness was not improved with the newer glass-ionomer restorative materials marketed for stress-bearing areas compared to the conventional glass-ionomer materials, however a resin coating provided greater surface hardness.

Characterization of management and environmental factors associated with regional variations in potato zebra chip occurrence.

Potato zebra chip (ZC), caused by the bacterial pathogen 'Candidatus Liberibacter solanacearum', which is vectored by the potato psyllid (Bactericera cockerelli), has caused widespread damage to U.S. potato production ever since its first discovery in south Texas in 2000. To determine the influence of environmental factors and management practices on ZC occurrence, data on management and meteorological variables, field locations, and psyllid counts were collected over a 3-year period (2010 to 2012) from six locations across the central United States (south Texas to Nebraska). At these locations, ZC-symptomatic plants were counted in 26 fields from systematically established 20 m × 30 m plots around the field edges and field interiors. Mean numbers of symptomatic plants per plot were classified into two intensity classes (ZC ≤ 3 or ZC > 3) and subjected to discriminant function and logistic regression analyses to determine which factors best distinguish between the two ZC intensity classes. Of all the variables, location, planting date, and maximum temperature were found to be the most important in distinguishing between ZC intensity classes. These variables correctly classified 88.5% of the fields into either of the two ZC-intensity classes. Logistic regression analysis of the individual variables showed that location accounted for 90% of the variations, followed by planting date (86%) and maximum temperature (70%). There was a low but significant (r = -0.44983, P = 0.0211) negative correlation between counts of psyllids testing positive for pathogen and latitudinal locations, indicating a south-to-north declining trend in counts of psyllids testing positive for the pathogen. A similar declining trend also was observed in ZC occurrence (r = -0.499, P = 0.0094).

Comparisons of sperm storage tubule distribution and number in 4 strains of mature broiler breeders and in turkey hens before and after the onset of photostimulation.

The biological basis of sustained fertility in broiler and turkey hens is their capacity to store sperm in the oviductal sperm storage tubules (SST) located in the uterovaginal junction. The objectives of this study were to determine if the numbers of SST varied between 4 strains of broiler breeders and determine the number of SST in the turkey before (less than 9 d of photostimulation) and after (up to 22 d of photostimulation and laying) photostimulation. No statistical differences were observed in SST numbers in the 4 strains of broilers examined or in turkey hens before and after the onset of egg production. The mean numbers of SST for broilers and turkeys were 4,893 and 30,566, respectively. We conclude that any differences between the fertility of the 4 broiler breeder strains examined cannot be explained by differences in SST numbers. However, differences in the duration of fertility between broilers and turkeys are, in part, related to their respective numbers of number of SST. Furthermore, we conclude that turkey SST are morphologically differentiated and functional before the onset of photostimulation and while the oviduct is morphologically undeveloped.

Path-based network unfolding: A solution for the problem of mixed trophic and non-trophic processes in trophic dynamic analysis

The purpose of this paper is to describe a quantitative method of trophic dynamic analysis derived from a systems ecology theoretical foundation. This method was devised to provide a solution for the problem of how to deal with mixed trophic and non-trophic processes in cyclic ecosystem networks, a problem that has vexed trophic ecology since Lindeman first presented a formal concept of trophic dynamics in 1942. The author's initial attempt to solve this problem was presented in Whipple & Patten (1993, J. theor. Biol. 163, 393-411). The path-based network unfolding method described in this paper provides a quantitative method for conducting trophic dynamic analysis of cyclic ecosystems containing non-living storages and non-trophic flows to produce a true energy-transformation trophic macrochain. This method solves the "trophic-level inflation" problem described in Whipple & Patten (193, J. theor. Biol. 163, 393-411). The results of the analysis of an oyster reef ecosystem model demonstrate that the dual trophic macrochain produced by path-based network unfolding may be used to compare the relative contribution of grazing and detrital sub-webs to the trophic dynamics of ecosystems. It was found that the standing stock and flow contribution of the detrital sub-web was quantitatively dominant in the oyster reef ecosystem model. This method might be used to compare the contribution of grazing and detrital sub-webs for models of different ecosystem types. Because a true energy transformation trophic chain is produced, the progressive efficiency concept of the Lindeman-Hutchinson paradigm may be applied in comparative trophic analyses of ecosystems. In comparing the oyster reef model results of three quantitative trophic analysis methods, the path-based network unfolding method was found to produce a trophic macrochain with progressive efficiencies intermediate between those produced by the original Higashi et al. method and the Burns et al. unfolding analysis of a modified version of the oyster reef model.Copyright 1998 Academic Press Limited

University of Southern California Repeatable Episodic Memory Test.

The University of Southern California Repeatable Episodic Memory Test (USC-REMT) was developed to provide a brief assay of memory in clinical drug trials where the same subject is tested multiple times over days or weeks. Therefore, it had to be minimally affected by repeated testing. The test also provides a measure of subjective organization, a cognitive strategy that might be sensitive to frontal lobe dysfunction and HIV-related memory deficits. The USC-REMT has seven different lists, each composed of 15 semantically unrelated, high-frequency nouns. The words are presented in a different order on three study-test trials. After each study trial the subject recalls the words in any order. The test takes about 10 min to administer and score. The recall protocol can be scored for (a) global mnemonic efficiency, (b) primary and secondary memory, (c) subjective organization, (d) recall consistency and (e) recall as a function of serial position. We report initial data showing that the test is sensitive to memory decrements. Thirty-six HIV-1 seropositive men, at various stages of illness, recalled significantly fewer words and exhibited less subjective organization than 14 matched controls. The test had no significant practice effects over the first three administrations when separated by several days. The seven alternate lists are essentially equivalent. The USC-REMT appears to complement currently published verbal memory tasks.

P3 in young boys as a predictor of adolescent substance use.

Event-related potentials were recorded during a visual, continuous performance task from 36 boys before use of alcohol or other drugs began. The boys were sons of 13 recovering alcoholics who themselves had a family history of alcoholism, 11 nonalcoholics with a family history of alcoholism, and 12 nonalcoholics with no family history of alcoholism. Four years after electrophysiological assessment, a behavioral questionnaire was administered (mean age = 16.1 years). A Substance Use score was derived from reported use of alcohol and other drugs, and from highly correlated delinquent behavior scores. P3s of lowest amplitude were associated with the highest adolescent Substance Use. The combination of reduced amplitude and prolonged latency of both target and nontarget P3 significantly predicted adolescent Substance Use scores after correction for subjects' age. Although this is the first electrophysiological predictor of adolescent substance use we are aware of, the effect was small, indicating the utility of P3 as a vulnerability marker for substance abuse disorders is likely to depend on its joint use with other measures.

Event-related potentials in alcoholic fathers and their sons.

ERPs were recorded during a simple color discrimination and a more difficult visual continuous performance task (CPT) from three father-son (n = 15) pair groups: recovering alcoholics with a family history of alcoholism and their sons (A+), nonalcoholics with a family history of alcoholism and their sons (NA+), and nonalcoholics with no family history of alcoholism and their sons (NA-). The sons, aged 8 to 12, had not begun drinking or using other drugs. Groups were matched on age, education and socioeconomic status. There were two principal findings. Compared to nonalcoholic groups, both A+ sons and fathers exhibited increased latency and decreased amplitude of P3 for the difficult task, but not for the easy task. This result helps to explain previous inconsistencies in the literature, and strengthens the suggestion that one indication of a vulnerability to develop alcoholism is an abnormal P3, when elicited by an appropriate task. Additionally, A+ fathers had more negative amplitudes for a late slow wave in both tasks, suggesting electrophysiological consequences of long-term alcohol abuse.

Personality characteristics of alcoholic fathers and their sons.

Recovering alcoholic fathers with a positive family history of alcoholism and their 10-15 year-old sons were assessed on a variety of personality measures and compared to a matched group of nonalcoholic fathers with a negative family history of alcoholism, and their sons. Assessment instruments for the sons included the Personality Inventory for Children, High School Personality Questionnaire, Junior Eysenck Personality Inventory and the Tridimensional Personality Questionnaire. Comparable questionnaires were administered to the fathers: the MMPI, 16 Personality Factor Questionnaire, Eysenck Personality Inventory and the Tridimensional Personality Questionnaire. No psychopathology or extreme personality variants were observed in either fathers' or sons' groups. However, MANOVAS and linear discriminant functions revealed significant differences on several personality measures between fathers' and sons' groups. Compared to sons of nonalcoholics, sons of alcoholics were relatively more compulsive, insecure and fearful while being more subdued and detached. The recovering alcoholics were more impulsive and regimented than the nonalcoholics. An index resulting from the combination of the best personality discriminators was significantly correlated in father-son pairs. In addition, this index was significantly correlated with key neurocognitive variables from our previous study which assessed the same father-son pairs. This atypical CNS profile, encompassing altered electrophysiology, neuropsychological performance and personality traits, may be useful in identifying those at increased risk for developing alcoholism.

Tertiary syphilis of the face.

We report a case of noduloulcerative tertiary syphilis that had gone misdiagnosed as discoid lupus erythematosus for many years. This case is noteworthy for (1) a Jarisch-Herxheimer-like reaction, (2) a dramatic response to penicillin therapy despite the presence of long-standing disease, and (3) posttreatment granulomas of possible hypersensitivity origin.

An atypical neurocognitive profile in alcoholic fathers and their sons.

Prepubescent boys and their recovering alcoholic fathers exhibited an Atypical Neurocognitive Profile consisting of (1) a reduction in amplitude of the late positive complex (LPC) of the event-related potential (ERP) during a complex visual discrimination task, and (2) reduced visuoperceptual performance evidenced by significantly lower scores on the Object Assembly, Block Design and Picture Completion subtests of the WISC-R and the Embedded Figures Test. Low LPC amplitudes were significantly correlated with poorer visuoperceptual performance. This Atypical Neurocognitive Profile may represent a marker for alcoholism.

Effects of spontaneous cortical slow potentials on semantic information processing.

Adult subjects were tested on a choice reaction time (RT) task for decisions of word pairs as synonyms or unrelated. For each trial the word stimuli were presented contingent upon computer-detection of a predetermined negative or positive EEG baseline shift, recorded from either parietal or frontal midline electrodes. With parietal slow potential (SP) shifts, RTs were significantly faster and less variable under negative than positive polarity conditions. No appreciable RT differences were found between negative and positive SP shifts from frontal electrodes or for control subjects. The parietal negative SP shifts are considered to reflect enhanced semantic processing. The present findings in combination with previous results (Born et al., 1982, Electroencephalogr. Clin. Neurophysiol., 54: 668-676) demonstrate a double dissociation between the functional properties of negative SP shifts from parietal and frontal cortical areas, with respective involvements in semantic processing and response selection and execution.

Spontaneous cortical slow-potential shifts and choice reaction time performance.

EEGs from Fz, Cz and Pz locations (reference--right mastoid) were obtained from 36 adults. For experimental trials the Fz slow potentials (SP) were determined for a pretask interval of: a 3 sec baseline, followed by a 2.5 sec SP shift, in either negative (3.5 microV) or positive (1.5 microV) direction, and maintenance at this level for another 2.5 sec. When this criterion was met the stimuli for a choice RT task were presented (potential-related event, PRE), which required a button-press response with the right or left hand for differing stimulus configurations. During subsequent control sessions subjects were tested without pretask criterion SP shifts, with yoked pretask intervals from the experimental sessions. For the experimental conditions the mean RTs were significantly faster and less variable with the negative than with the positive SP shift condition. For the control conditions mean RTs were somewhat faster for the positive than for the negative criterion, which might be attributed to the more variable pretask intervals during the latter polarity condition. For confirmation of the cortical localization of this effect, the experimental session was replicated with corresponding negative and positive SP shift criteria from Pz. No significant differences among means and standard deviations of RTs were found. SP shifts from criterion electrodes (Fz or Pz) were significantly greater in mean amplitude than the concomitant SP shifts from the other electrodes. The present findings demonstrate the feasibility of the PRE methodology for investigations of human brain functions.

Loneliness and alcoholism: a study of three groups of male alcoholics.

Three groups of alcoholics at different stages of recovery were tested for loneliness with the Sisenwein Loneliness Scale. The groups consisted of alcoholics going through detoxification (acute), alcoholics in outpatient treatment who had had at least two drinking episodes in the previous 6 months (chronic), and alcoholics having at least 1 year of sobriety (recovering). It was hypothesized that the acute group would exhibit more loneliness than the chronic group, who would in turn demonstrate more loneliness than the recovering group. Results showed that acute group to demonstrate significantly (p less than .01) more loneliness on the Sisenwein (mean = 134.4) than the recovering group (mean = 54.6). The chronic group (mean = 91.0) was not significantly different than the others at the p less than .01 level, but the mean score did fall in the expected direction.

Anorexia nervosa. Commitment to a multifaceted treatment program.

Anorexia nervosa, a complicated and serious illness, warrants the comprehensive use of several treatment modalities: behavior therapy, individual psychotherapy and family therapy. Singular use of and of these three have resulted in high mortality rates. The importance of legal commitment in dealing with this illness is also discussed.