Instability, changes, and internal structure of children's attitudes toward mathematics in primary school: A four-wave investigation.

The longitudinal person-oriented study aimed to explore profiles, stability, gender differences, and compositional relations of math attitudes by tracking Chinese third graders (Ntotal = 1013, Mage(T1) = 8.92 ± 0.46, Ngirls = 404) in four waves with 1-year intervals. Five profiles and unstable transitional probabilities were identified among the four waves. The relations between enjoyment to confidence and value shifted from reciprocity to enjoyment dominance, but value negatively predicted later enjoyment and confidence. Additionally, boys' advantages were significant in late elementary school (fifth, sixth grades) and girls benefited from initial positive attitudes. These findings suggest that Chinese students' math attitudes in middle childhood are unstable, shaped by internal and external environmental dynamics, and need to be further explored in cross-cultural research.

The influence of semantic alignment on the performance of addition and division operation: age-related differences.

Semantic alignment refers to the cognitive tendency that people always seek for the matching of semantic relations between mathematical cognition and objects in specific situations. In developing individuals, language ability and mathematical ability are in the development stage, and the development of semantic consistency is more helpful to reveal the relationship between the two. From the perspective of semantic alignment, this study aims to explore the age-related difference in the effects of semantic relationship on arithmetic operations. Sixty-two children and 62 adults were recruited to perform an arithmetical verification task. The results showed that: (1) Compared with children, adults had shorter response times and higher accuracy in mathematical operations. (2) Both adults and children showed longer response times in division condition than that in addition condition. (3) Children are more affected by semantic alignment than adults in addition. (4) For addition operation, participants performed better under semantic consistent condition than under semantic inconsistent condition, but the opposite result was found for division operation. It indicated that semantic consistently promoted the addition operation and semantic inconsistently promoted the division operation. This suggests that teachers should pay attention to integrating mathematical conceptual knowledge and language context in future educational practice.

Determination of d-limonene in mice plasma and tissues by a new GC-MS/MS method: Comparison of the pharmacokinetics and tissue distribution by oral and inhalation administration in mice.

The aim of the present study was to develop a method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) to determine and quantify the d-limonene in mouse plasma and tissue samples. This new method was validated for the quantification of d-limonene with the linearity ranges 1.0-1000.0 ng/mL (r2 > 0.9952) for plasma samples and 5.0-5000.0 ng/g (r2 > 0.9940) for tissue samples. The intra- and inter-day assay of precisions in plasma and tissues were <13.4% and the accuracies were within 91.1-105.8%. In the oral/inhalation administration pharmacokinetics and tissue distribution studies, the main pharmacokinetic parameters were the peak concentration = (97.150 ± 34.450)/(4336.415 ± 1142.418) ng/mL, the area under the curve = (162.828± 27.447)/(2085.721 ± 547.787) h ng/mL and the half-life = (3.196 ± 0.825)/(0.989 ± 0.095) h. The tissue distribution of d-limonene in mice after oral/inhalation administration demonstrated a decreasing tendency in different tissues (liver > kidney > heart > lung > spleen).