Abstract Working memory dysfunction is a prominent impairment in patients with schizophrenia. Our aim was to determine cerebral dysfunctions by means of functional magnetic resonance imaging (fMRI) ...in a large sample of first-episode schizophrenia patients during a working memory task. 75 first-episode schizophrenia patients and 81 control subjects, recruited within a multi-center study, performed 2- and 0-back tasks while brain activation was measured with fMRI. In order to guarantee comparability between data quality from different scanners, we developed and adopted a standardized, fully automated quality assurance of scanner hard- and software as well as a measure for in vivo data quality. After these quality-control measures had been implemented, 48 patients and 57 controls were included in the final analysis. During attention-related processes, even when the performance between patients and controls was comparable, there was a recognizable emergence of cerebral dysfunctions with hypoactivations in the ventrolateral prefrontal cortex (VLPFC), in the superior temporal cortex and in the thalamus. During working memory performance, parietal hypoactivations, especially in the precuneus, were prominent and were accompanied by poorer performance in patients. A hyperfrontality emerged in the ventrolateral prefrontal cortex. Hence, results point to a dysfunctional ventrolateral prefrontal–parietal network during working memory in patients, suggesting impairments in basic functions such as retrieval, storage and maintenance. The brain activation pattern of this large and significant sample of first-episode schizophrenia patients indicates an imbalanced system failing to adjust the amount of brain activity required in the cerebral network involved in attention and working memory.
Proofs as epistemic tools are central to mathematical practice, as they establish and provide explanations for the validity of mathematical statements. Considering the challenge that proof ...construction poses to learners of all ages, prior research has investigated its cognitive determinants, but the impact of affective-motivational experiences on proof construction has been insufficiently investigated. Emotions related to knowledge acquisition (i.e., epistemic emotions) are assumed to play a key role in epistemic processes. In this study we investigated how the performance of 80 mathematics undergraduate students in a geometric proof construction task relates to the epistemic emotions experienced during proof construction. Controlling for geometry knowledge, we included control and value appraisals as antecedents in our investigation of epistemic emotions, and attention and motivation as mediators of their effects on proof construction performance. The results indicate that positive as well as negative emotions are influenced by students’ appraisals, also indicating an interaction of both appraisal dimensions. Primarily enjoyment and curiosity mediate the effects of these appraisals on attention and motivation. These two markers of the proof construction process, in turn, mediate the effects of enjoyment and boredom on proof construction performance. In this study we investigated systematically the role of epistemic emotions in geometric proof construction and we offer insights that complement the existing research on the cognitive determinants of proof performance. Moreover, this study extended research on epistemic emotions into the area of proof construction, an epistemic process central to mathematics.
The study aimed to develop and test an
model to investigate the staining potential of mouth rinses on human enamel, considering alternating intake of black tea and tooth brushing, thus mimicking the ...situation in the oral cavity more realistically.
Eight mouth rinses with six different active ingredients (benzydamine hydrochloride BNZ, polyhexamethylene biguanide hydrochloride PHMB, chlorhexidine digluconate CHX, hexetidine gluconate HEX, octenidine dihydrochloride OCT and octenidine dihydrochloride + 2-phenoxyethanol OCTP) and concentrations were tested. Sets of six halved human molar crowns were initially pretreated by soaking in artificial saliva (30 min). Afterward, the cyclic treatment was started by soaking in artificial saliva (2 min), staining with black tea (1 min), brushing with toothpaste (5 s), and soaking in the mouth rinse (30 s). Samples were rinsed with distilled water after each treatment step. The cyclic treatment was repeated 30 times, mimicking the consumer behavior after 15 days. Photographic images were taken after 0, 10, 20, and 30 cycles. Color measurements were conducted after each staining and brushing step using a VITA-Easyshade spectrophotometer to determine the difference in lightness ∆L and the total color difference ∆E.
Analysis of variance and post-hoc Tukey test (α = 0.05) were applied.
The new testing model with included brushing sequences allowed to assess the staining behavior on human teeth and provided a clear differentiation between the different investigated products. In detail, up to cycle 10, ΔE values increased for all mouth rinses with each additional cycle number. However, while ΔE values continued to increase for 0.15% BNZ, 0.1% PHMB, and 0.2% CHX between treatment cycle 10 and 30, ΔE values only slightly increased after treatment with 0.08% OCTP, 0.1% OCTP, 0.1% OCT, and 0.1% HEX. After 20 and 30 cycles, significantly less staining was found for 0.08% OCTP, 0.1% OCT, 0.1% HEX as compared to 0.2% CHX, 0.15% BNZ, and 0.1% PHMB (
< 0.05). ΔE-values were significantly lower after treatment with 0.1% OCTP as compared to 0.2% CHX1 and 0.2% CHX2 (p < 0.05).
The proposed new methodology was found to be appropriate for assessing the staining progression of mouth rinses over a simulated application period of 15 days. The model allows differentiation of products with different active ingredients and concentrations.
The aim of this
study was to test the influence of the amount of toothpaste on enamel cleaning efficacy.
The hydrated silica-based test toothpaste (radioactive dentin abrasion: 60.19 ± 1.35) ...contained all ingredients of a regular fluoride toothpaste. The cleaning efficacy of four different toothpaste amounts (1.00 g, 0.50 g both "full length of brush", 0.25 g "pea-size", and 0.125 g "grain of rice-size") diluted in 1.00 mL water were each tested for different brushing times (10, 30, 60, 120, 180, and 300 seconds) using a standardized staining model on human molars with a brushing machine. Photographic documentation and colorimetric measurements were conducted, respectively, initially, after staining and after each brushing step. Colorimetric measurements were used to calculate the stain removal (in %).
Results were analyzed by one-way analysis of variance with post hoc Tukey test and Levene's test for analysis of homogeneity of variance. The level of significance
was set at ≤ 0.05.
The cleaning efficacy decreased significantly when using smaller toothpaste amounts. Stain removal after 120 seconds brushing time was: 77.4 ± 5.0% (1.00 g toothpaste), 75.7 ± 3.4% (0.50 g toothpaste), 54.1 ± 6.7% (0.25 g toothpaste), and 48.2 ± 7.1% (0.125 g toothpaste), respectively.
In this
study the cleaning efficacy of a medium-abrasive, hydrated silica-based toothpaste was analyzed. Note that 1.00 g toothpaste showed for all brushing times a significantly higher cleaning efficacy than 0.25 g toothpaste and 0.125 g toothpaste.
Some amphibians occur in agricultural landscapes during certain periods of their life cycle and consequently might be exposed to plant protection products (PPPs). While the sensitivity of aquatic ...life-stages is considered to be covered by the standard assessment for aquatic organisms (especially fish), the situation is less clear for terrestrial amphibian life-stages. In this paper, considerations are presented on how a risk assessment for PPPs and terrestrial life-stages of amphibians could be conducted. It discusses available information concerning the toxicity of PPPs to terrestrial amphibians, and their potential exposure to PPPs in consideration of aspects of amphibian biology. The emphasis is on avoiding additional vertebrate testing as much as possible by using exposure-driven approaches and by making use of existing vertebrate toxicity data, where appropriate. Options for toxicity testing and risk assessment are presented in a flowchart as a tiered approach, progressing from a non-testing approach, to simple worst-case laboratory testing, to extended laboratory testing, to semi-field enclosure tests and ultimately to full-scale field testing and monitoring. Suggestions are made for triggers to progress to higher tiers. Also, mitigation options to reduce the potential for exposure of terrestrial life-stages of amphibians to PPPs, if a risk were identified, are discussed. Finally, remaining uncertainties and research needs are considered by proposing a way forward (road map) for generating additional information to inform terrestrial amphibian risk assessment.
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•Exposure and toxicity data for pesticides and terrestrial amphibians were considered in a risk assessment context•Dermal exposure of terrestrial amphibians appears more important than dietary exposure•Therefore, a screening risk assessment approach is presented for dermal toxicity to terrestrial amphibians•The exposure-driven approach uses existing vertebrate data and would significantly reduce amphibian (vertebrate) testing•The approach can be used to identify pesticide applications of low concern and those that need further consideration
The modulation of the intestinal expression of detoxifying proteins by relevant transcription factors, intracellular receptors and cytokines in ulcerative colitis (UC) is poorly understood. Here, we ...compared the intestinal expression of drug transporters, metabolizing enzymes and putative regulatory genes between inflamed and noninflamed tissue and studied their modulation by disease activity.
Sigmoidal biopsies of 18 UC patients and 18 healthy volunteers matched for age, gender and ABCB1 3435C>T genotype were investigated for mRNA expression levels of 43 systematically selected candidate genes by low-density array real-time PCR. Additionally, the ABCB1 gene product P-glycoprotein was visualized by immunohistochemistry and quantified by western blotting. Disease phenotype was categorized by clinical, endoscopic and histopathological examination. Disease activity was quantified by clinical activity index.
In inflamed sigmoidal tissue from UC patients, 11 genes (NAT1, NR2B1, CEBPB, IFG, IL8, IL10, S100A12, SPP1, DEFA5, DEFA6 and HAMP) were overexpressed. By contrast, only the major human efflux transporter ABCB1 showed significantly lower expression levels, that were inversely correlated with those of certain antimicrobial peptides (DEFA5/6) and cytokines (IL1beta and IL8). Cell culture experiments revealed a time-dependent decrease of ABCB1 expression upon IL8 exposure. Disease activity profoundly modified ABCB1 expression, indicated by an inverse correlation of clinical activity index values with ABCB1 mRNA expression (r = -0.603; p = 0.017) and markedly reduced protein expression in UC patients with moderate and severe symptomology (p = 0.011).
Cytokine-mediated downregulation of the major human efflux transporter ABCB1 in inflamed intestine of UC patients is presumably dependent on disease activity, with a possible contribution from IL8.