Synthesis and conformational analysis of poly(phenylacetylene)s with serinol-tethered carbohydrate appendages.

We synthesized phenylacetylenes containing ß-lactoside, ß-cellobioside, or ß-maltoside, and polymerized them to produce the corresponding poly (phenylacetylene)s. In these poly (phenylacetylene)s, the pendent carbohydrates were tethered to the mainchains by serinol spacers. Because similar glycosyl serinol units are found in the natural glycosphingolipids in cell membranes, the densely packed carbohydrate clusters along the poly (phenylacetylene) mainchains act as molecular mimics of cell surface glycoclusters. We analyzed the conformation of the glycosylated poly (phenylacetylene)s using circular dichroism spectroscopy, and found that the spatial carbohydrate packing within the glycoclusters changed on the addition of salts.

Concerted cultivation developed in a standardized education system.

Annette Lareau coined the term "concerted cultivation" to describe the cultural logic of a distinctive middle-class parenting pattern. I explore whether concerted cultivation as practiced in Japan exhibits unique patterns in response to distinctive characteristics of the nation's education system (i.e., standardized compulsory education with high-stakes educational selection in secondary education). Using nationally representative longitudinal data on third-to sixth-grade children (N = 30187) through growth curve models, I show that college educated parents shift their focus of parenting practices (measured by four aspects) from providing diverse experiences to narrower academic preparation as the time for lower secondary education approaches. Using multivariate analyses with an additional wave of data in seventh grade, I further demonstrate that "unequal childhoods,"--the accumulated disparities in adult-led structured experiences--lead to unequal success in the transition to junior high school education, a critical period of preparation before the mass educational selection (i.e., high school admissions).

C6-Modifications on chitosan to develop chitosan-based glycopolymers and their lectin-affinities with sigmoidal binding profiles.

Chitosan-based glycopolymers having multiple ß-lactosides exclusively at their C6-positions were successfully synthesized from partially deacetylated chitin through perfect N-deacetylation/phthaloylation and C6-selective bromination/azidation to afford 6-azide-6-deoxy-N-phthaloyl-chitosan and the subsequent Cu(+)-catalyzed Huisgen cycloadditions using alkyne-terminated ß-lactoside and/or quaternary ammonium modules followed by dephthaloylations. Lectin-affinities of the resultant chitosan-based glycopolymers were assessed through fluorescence titration assays to show their unique sigmoidal binding profiles with amplified binding constants.

Emerging inequality in effort: A longitudinal investigation of parental involvement and early elementary school-aged children's learning time in Japan.

While studies on effort (e.g., Carbonaro, 2005; Kariya, 2000, 2013) have revealed relationships among students' effort (e.g., self-reported learning time), socioeconomic status, and school-related factors (e.g., tracking) through secondary education data, whether and how the effort gap emerges and widens in the early years of compulsory education have not been researched. This study investigates the beginning of inequality in effort by using four waves (from first- to fourth-grade students) of the Longitudinal Survey of Babies in the 21st Century, collected in Japan. The results indicate that college-educated parents tend to employ parenting practices that directly and indirectly shape children's learning time; inequality in effort exists, and it becomes exacerbated partly because of parenting differences in a society with a relatively equal elementary education system.

Overproduction of the membrane-bound [NiFe]-hydrogenase in Thermococcus kodakarensis and its effect on hydrogen production.

The hyperthermophilic archaeon Thermococcus kodakarensis can utilize sugars or pyruvate for growth. In the absence of elemental sulfur, the electrons via oxidation of these substrates are accepted by protons, generating molecular hydrogen (H2). The hydrogenase responsible for this reaction is a membrane-bound [NiFe]-hydrogenase (Mbh). In this study, we have examined several possibilities to increase the protein levels of Mbh in T. kodakarensis by genetic engineering. Highest levels of intracellular Mbh levels were achieved when the promoter of the entire mbh operon (TK2080-TK2093) was exchanged to a strong constitutive promoter from the glutamate dehydrogenase gene (TK1431) (strain MHG1). When MHG1 was cultivated under continuous culture conditions using pyruvate-based medium, a nearly 25% higher specific hydrogen production rate (SHPR) of 35.3 mmol H2 g-dcw(-1) h(-1) was observed at a dilution rate of 0.31 h(-1). We also combined mbh overexpression using an even stronger constitutive promoter from the cell surface glycoprotein gene (TK0895) with disruption of the genes encoding the cytosolic hydrogenase (Hyh) and an alanine aminotransferase (AlaAT), both of which are involved in hydrogen consumption (strain MAH1). At a dilution rate of 0.30 h(-1), the SHPR was 36.2 mmol H2 g-dcw(-1) h(-1), corresponding to a 28% increase compared to that of the host T. kodakarensis strain. Increasing the dilution rate to 0.83 h(-1) or 1.07 h(-1) resulted in a SHPR of 120 mmol H2 g-dcw(-1) h(-1), which is one of the highest production rates observed in microbial fermentation.

Distinct physiological roles of the three [NiFe]-hydrogenase orthologs in the hyperthermophilic archaeon Thermococcus kodakarensis.

Hydrogenases catalyze the reversible oxidation of molecular hydrogen (H2) and play a key role in the energy metabolism of microorganisms in anaerobic environments. The hyperthermophilic archaeon Thermococcus kodakarensis KOD1, which assimilates organic carbon coupled with the reduction of elemental sulfur (S°) or H2 generation, harbors three gene operons encoding [NiFe]-hydrogenase orthologs, namely, Hyh, Mbh, and Mbx. In order to elucidate their functions in vivo, a gene disruption mutant for each [NiFe]-hydrogenase ortholog was constructed. The Hyh-deficient mutant (PHY1) grew well under both H2S- and H2-evolving conditions. H2S generation in PHY1 was equivalent to that of the host strain, and H2 generation was higher in PHY1, suggesting that Hyh functions in the direction of H2 uptake in T. kodakarensis under these conditions. Analyses of culture metabolites suggested that significant amounts of NADPH produced by Hyh are used for alanine production through glutamate dehydrogenase and alanine aminotransferase. On the other hand, the Mbh-deficient mutant (MHD1) showed no growth under H2-evolving conditions. This fact, as well as the impaired H2 generation activity in MHD1, indicated that Mbh is mainly responsible for H2 evolution. The copresence of Hyh and Mbh raised the possibility of intraspecies H2 transfer (i.e., H2 evolved by Mbh is reoxidized by Hyh) in this archaeon. In contrast, the Mbx-deficient mutant (MXD1) showed a decreased growth rate only under H2S-evolving conditions and exhibited a lower H2S generation activity, indicating the involvement of Mbx in the S° reduction process. This study provides important genetic evidence for understanding the physiological roles of hydrogenase orthologs in the Thermococcales.