Imitative behavior underlaid by perception and action links during children's development in complex locomotor skills has been the object of relatively few studies. In order to explore children's motor coordination modes, 130 children divided into five age groups from 3.5 to 7.5 years were instructed to imitate jumping tasks in spontaneous motor situation and in various imitative contexts by an adult providing verbal orders and gestural demonstrations. Their conformity to the model, stability and variability scores were coded from a video analysis when they performed jumps with obstacles. To evaluate their postural-motor control level, the durations of the preparatory phase and jumping flights were also timed. Results showed that all age groups generated the demonstrator's goal but not necessarily the same coordination modes of jumping. In imitation with temporal proximity, the model helped the youngest age groups to adopt his coordination modes and stabilized only the oldest age groups' performances starting from 5.5 years old, without effect on learning imitation. Differences between the youngest and oldest children in the jump duration suggested that the reproduction of a complex motor activity such as jumping with a one foot take-off would require resolution and adjustment of main postural stability.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jelekin.2009.05.005 | DOI Listing |
J Am Chem Soc
December 2024
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Compared with chiral β-amino phosphorus compounds, which can be easily derived from natural optically pure α-amino acids, obtaining chiral β-amino phosphorus derivatives remains a challenge. These derivatives, which cannot be derived from chiral natural amino acids, possess unique biological activities or potential catalytic activities. Herein, highly enantioselective hydrogenation for the preparation of chiral β-amino phosphorus derivatives from -β-enamido phosphorus compounds is reported by using a green and low-cost earth-abundant metal nickel catalyst (13 examples of 99% ee).
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Department of Chemistry and Chemical Engineering, Taiyuan Institute of Technology, Taiyuan 030008, China.
Cisplatin-based platinum compounds are important clinical chemotherapeutic agents that participate in most tumor chemotherapy regimens. Through density-functional theory calculations, the formation and stability of the inorganic oxide carrier, the mechanisms of the hydrolysis reaction of the activated platinum compound, and its binding mechanism with DNA bases can be studied. The higher the oxidation state of Pt (II to IV), the more electrons transfer from the magnesia-gold composite material to the platinum compound.
View Article and Find Full Text PDFInorg Chem
December 2024
Institute of Inorganic Chemistry (IAC), Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131 Karlsruhe, Germany.
Crown-ether coordination compounds of europium(II/III) and the crown ether (CHO) (24-crown-8, 24c8) are prepared, aiming at novel compounds, structures, and coordination modes as well as potential luminescence properties. By reacting EuCl, EuI, or EuCl with 24c8 or its derivatives in ionic liquids, the novel compounds [BuMeN][Eu(II)(NTf)] (), [BMIm][EuI] (), [EuCl(dibenzo-18c6)] (), [EuI(dibenzo-24c8)] (), [(Eu(III)Cl)(CHO)](24c8) (), and [Eu(III)Cl(24c8)]I () are obtained (BMIm: 1-butyl-3-methylimidazolium; EMIm: 1-ethyl-3-methylimidazolium). Based on different reaction conditions, different coordinative modes including the absence of the crown ether in the product (, ), splitting of the crown ether (), and coordination of 24c8 via six of eight oxygen atoms () and, finally, via all oxygen atoms () are observed.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
Changping Laboratory, No. 28 Life Science Park Rd., Beijing 102206, China.
Accurate modeling of host-guest systems is challenging in modern computational chemistry. It requires intermolecular interaction patterns to be correctly described and, more importantly, the dynamic behaviors of macrocyclic hosts to be accurately modeled. Pillar[]arenes as a crucial family of macrocycles play a critical role in host-guest chemistry and biomedical applications.
View Article and Find Full Text PDFAdv Mater
December 2024
Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
Cisplatin is widely used in clinical cancer treatment; however, its application is often hindered by severe side effects, particularly inherent or acquired resistance of target cells. To address these challenges, an effective strategy is to modify the metal core of the complex and introduce alternative coordination modes or valence states, leading to the development of a series of metal complexes, such as platinum (IV) prodrugs and cyclometalated complexes. Recent advances in nanotechnology have facilitated the development of multifunctional nanomaterials that can selectively deliver drugs to tumor cells, thereby overcoming the pharmacological limitations of metal-based drugs.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!