THE HOME LITERACY ENVIRONMENT AND CHILD DEVELOPMENT: ACADEMIC ACHIEVEMENT AND SOCIAL SKILLS OF CHILDREN IN IMMIGRANT FAMILIES

The home literacy environment has been shown to be crucial to young children's academic achievement and social skills. This study examines the longitudinal effects of home-based literacy related activities on children's academic achievement test scores and social skills from kindergarten up to 5th grade. To conduct this study, data from the Early Childhood Longitudinal Study - Kindergarten Class of 1998-99 (ECLS-K), provided by the U.S. Department of Education, were utilized. Children with at least one immigrant parent were categorized according to their mother's country of origin: South America, Mexico, Caribbean/Central America, East Asia, Southeast Asia, other countries, and the U.S. (with a foreign-born father). Using a latent difference score model, parental involvement and reading activity at home were linked to children's academic achievement test scores and social skills at kindergarten, along with changes in scores between each time point. Results of analyses suggest that boys benefit more from parents' involvement at home than do girls. Both boys' and girls' independent reading appear to be strongly linked to developing strong reading and math skills. More parental involvement and their independent reading benefited boys' self-control and interpersonal skills, but it did not have that benefit for girls. In addition, there were substantial differences in the effects of parental involvement and children's reading activity on children depending on mother's country of origin. The reading and math score of children of East Asian and Southeast Asian mothers benefited from their independent reading activity, whereas the scores of children of Latin-origin mothers benefited from both parental involvement at home and reading activity. For children of Mexican and Caribbean/Central American descent, especially, parental involvement had a continuing significant effect on math and reading scores up to 5th grade. Similarly, compared to other immigrant groups, the social skills of Latin American-origin boys were influenced more by parental involvement at home, and those of Southeast Asian-origin boys were influenced more by reading time at home

Controlling Morphologies of Self-Assembled Structures of Block Copolymers by Molecular Designs and External Stimuli

Department of ChemistrySelf-assembly of amphiphilic block copolymers (BCPs) in solution has received attention from polymer chemists due to their potential applications such as drug delivery system and nanoreactors for two decades. Because sorts of morphologies formed by self-assembly were so diverse, predicting and designing the desired morphologies were considered as one of the goals. The morphologies were classically controlled by modifying a block ratio of BCPs. Herein, however, I demonstrated that morphologies of self-assembled structures of BCPs can be controlled by molecular designs and external stimuli with a fixed block ratio. In this dissertation, dendritic-linear poly(ethylene glycol)-block-polystyrene (PEG-b-PS) BCPs were synthesized and their self-assembled structures were observed. Morphologies of dendritic-linear PEG-b-PS were toroids while morphologies of linear-linear PEG-b-PS with same block ratios were polymersomes. That???s because the molecular area of BCPs was expanded by branched PEG chains. To stabilize those structures, photo-cross-linkable monomers were introduced to the hydrophobic blocks. Portions of indenylstyrene that can be dimerized under UV light were copolymerized with styrene monomers by atom transfer radical polymerization (ATRP). The BCPs could be self-assembled in various morphologies and they were cross-linked under an irradiation of UV light for few hours. The enhanced stability of morphologies was demonstrated by an extreme dilution into the organic solution and the self-assembled structures survived. Furthermore, BCPs with high molecular weights (> 200 kDa) were synthesized in order to access photonic bandgap properties of polymer cubosomes because structural periodicity of polymer cubosomes was proportion to their molecular weights. However, the polymerization of BCPs with high molecular weights through living radical polymerization has been challengeable. The problem was solved by the acceleration of propagation rates with an excess loading of CuBr catalysts but it simultaneously brought out broad distributions of molecular weights. Through a gradient column chromatography, high molecular weight BCPs with narrow distribution was achieved and blue light reflections were observed from their polymer cubosomes. Finally, to control morphologies of the branched-linear PEG-b-PS BCPs by external stimuli, three pyridine groups that can be utilized as stimuli-receptors were introduced into junctions of peripheral PEG chains. As a result, self-assemblies with and without external stimuli such as low pH and metal precursors produced significantly different morphologies. From the above experiments, I demonstrated that the morphologies can be controlled by designing molecular architectures and introducing external stimuli during self-assembly processes, and the morphologies can be stabilized efficiently by the photo-cross-linking system.ope

Gain-of-function oncogenic mutations in TP53 enhance defined factor-mediated cellular reprogramming

Cancer is a disorder with various genetic and epigenetic alterations. Genetic alterations such as mutations, i.e., substitutions, amplifications, and deletions of nucleotide sequences, are largely irreversible, whereas epigenetic alterations can be modified by pharmacological agents that target components of the epigenetic machinery. Recent studies have showed that introduction of defined factors such as those encoded by c-MYC, SOX2, OCT3/4, and KLF4 in normal somatic cells results in their dedifferentiation into induced pluripotent stem (iPS) cells. In addition, we have reported that these iPS factors induce the development of induced multipotent cancer (iPC) cells from gastrointestinal cancer cells by reducing tumor aggressiveness. The efficiency of iPS reprogramming increased when p53 was inhibited. The study of cancer cells suggests that the p53 pathways might be involved in the aggressive phenotypes of iPC cells in a long-term culture. However, the roles of gain-of-function oncogenic mutations in TP53, which is a key tumor suppressor gene, remain to be elucidated. We investigated reprogramming efficiency of iPS generation in human diploid fibroblasts that were co-transfected with TP53 mutants and defined factors. The results suggest that mutations in those TP53 regions that are involved in DNA contact might play a critical role in the efficiency of iPS generation. Taken together, our studies suggest 2 roles of TP53 mutations in reprogramming: (1) the structural mutations might contribute to, or collaborate with, other mutations to regulate the maintenance of genomic stability; (2) the DNA-contact mutations could affect the downstream target genes, which may be distinct from those involved in wild-type p53 function. These molecular manipulations of tumorigenicity and enhancement of cellular reprogramming efficiency by the p53 pathway will open an attractive and useful avenue for future medicine

A new dynamic property of human consciousness

As pointed out by William James, "the consciousness is a dynamic process, not a thing" , during which short term integration is succeeded by another differentiated neural state through the continual interplay between the environment, the body, and the brain itself. Thus, the dynamic structure underlying successive states of the brain is important for understanding human consciousness as a process. In order to investigate the dynamic property of human consciousness, we developed a new method to reconstruct a state space from electroencephalogram(EEG), in which a trajectory, reflecting states of consciousness, is constructed based on the global information integration of the brain. EEGs were obtained from 14 subjects received an intravenous bolus of propopol. Here we show that the degree of human consciousness is directly associated with the information integration capacity of gamma wave, which is significantly higher in the conscious state than in the unconscious state. And we found a new time evolutional property of human consciousness. The conscious state showed a lower dimensional dynamic process which changed to a random-like process after loss of consciousness. This characteristic dynamic property, appeared only in the gamma band, might be used as an indicator to distinguish the conscious and unconscious states and also considered as an important fact for the human consciousness model