224 research outputs found

    Lyotropic liquid crystallinity of amylose tris(alkylcarbamates): Cholesteric and smectic phase formation in different solvents

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    Oyamada K., Terao K., Suwa M., et al. Lyotropic liquid crystallinity of amylose tris(alkylcarbamates): Cholesteric and smectic phase formation in different solvents. Macromolecules, 46(11), 4589-4595, May 20, 2013. Copyright © 2013, American Chemical Society. https://doi.org/10.1021/ma400787c

    Solution properties of a cyclic chain having tunable chain stiffness: Cyclic amylose tris(n-butylcarbamate) in theta and good solvents

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    Terao K., Shigeuchi K., Oyamada K., et al. Solution properties of a cyclic chain having tunable chain stiffness: Cyclic amylose tris(n-butylcarbamate) in Θ and good solvents. Macromolecules, 46, 13, 5355. https://doi.org/10.1021/ma400774r

    Side-chain-dependent helical conformation of amylose alkylcarbamates: Amylose tris(ethylcarbamate) and amylose tris(n-hexylcarbamate)

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    Eight amylose tris(ethylcarbamate) (ATEC) samples ranging in the weight-average molar mass Mw from 1.0 - 104 to 1.1 - 106 g mol-1 and five amylose tris(n-hexylcarbamate) (ATHC) samples of which Mw varies from 4.9 - 104 to 2.2 - 106 g mol-1 have been prepared from enzymatically synthesized amylose samples having narrow dispersity indices and no branching. Small-angle angle X-ray scattering (SAXS), light scattering, viscometry, and infrared (IR) absorption measurements were carried out for their dilute solutions, that is, ATEC in tetrahydrofuran (THF), 2-methoxyethanol (2ME), methanol (MeOH), and ATHC in THF and 1-propanol (1PrOH) to determine M w, particle scattering functions, intrinsic viscosities, and IR spectra. SAXS and viscosity measurements were also made on ATEC in d- and l-ethyl lactates. The data were analyzed in terms of the wormlike cylinder model to estimate the helix pitch (or contour length) per residue h and the Kuhn segment length λ-1 (stiffness parameter, twice the persistence length). Both ATEC and ATHC have large λ-1 in THF, that is, 33 and 75 nm, respectively, and smaller λ-1 were obtained in alcohols, indicating that they have rigid helical conformation stabilized by intramolecular hydrogen bonds in THF. On the contrary, the helical structure estimated from the h value significantly depends on the alkyl side groups in a complex fashion, that is, h = 0.36 nm for ATEC, h = 0.29 nm for ATHC, and h = 0.26 nm for amylose tris(n-butylcarbamate) (ATBC). This is likely related to the bulkiness of side groups packed inside the amylosic helices. The solvent dependence of h, λ-1, and the fraction fhyd of intramolecular hydrogen bonds for ATEC can be explained by a current model as is the case with ATBC [ Terao, K.; Macromolecules 2010, 43, 1061 ], in which each contour point along the chain takes loose helical and rigid helical sequences independently. © 2012 American Chemical Society.Terao K., Maeda F., Oyamada K., et al. Side-chain-dependent helical conformation of amylose alkylcarbamates: Amylose tris(ethylcarbamate) and amylose tris(n-hexylcarbamate). Journal of Physical Chemistry B, 116(42), 12714-12720, October 5, 2012. Copyright © 2012, American Chemical Society. https://doi.org/10.1021/jp307998t

    Distinctions in Fine-Scale Spatial Genetic Structure Between Growth Stages of Picea jezoensis Carr.

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    Conifers in northern forests, such as fir and spruce, preferably regenerate on coarse woody debris, including fallen logs, stumps, and snags. In northern Japan, the sub-boreal conifer species Picea jezoensis is completely dependent on coarse woody debris for seedling establishment. To understand the fine-scale spatial genetic structure (FSGS) of this species, a 5-ha plot was established in central Hokkaido, and 531 individual trees were categorized into four life-stages (seedling, sapling, juvenile, and mature) on the basis of age and size. The FSGS of the established seedlings and later growth stages was investigated using 11 nuclear simple sequence repeat loci. A STRUCTURE analysis of seedlings and saplings established on fallen logs revealed that genetically related individuals were spatially localized between adjacent logs. We also found a significant FSGS in early life-stages based on a decline in the kinship coefficient calculated between individuals over shorter to longer spatial distances. Furthermore, the estimation of dispersal kernels indicated the frequent occurrence of short-distance seed dispersal. These results indicated that genetically related seedlings and saplings regenerated on the same or nearby fallen logs. In contrast to the results for the early stages, mature-stage trees showed no significant FSGS. We ran a simulation to examine the hypothesis that the FSGS could be eliminated by demographic thinning during life history processes. We calculated values for simulated offspring generated under three sets of conditions; i.e., by removing (i) inbred individuals, (ii) randomly chosen individuals, and (iii) all individuals on the specific fallen logs. However, the results for the FSGS were significant for all simulated data sets. This indicated that inbreeding depression, stochastic loss, or eradication of establishment sites by local disturbances alone could not explain the lack of FSGS among mature-stage trees. Therefore, it is possible that the colonization history of mature trees present on the study site might differ from that of the current offspring

    Secular changes in bone mineral density of adult Japanese women from 1995 to 2013

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    Introduction: Secular changes in hip fracture incidence have been reported in the last few decades in Japan, but whether long-term bone mineral density (BMD) is also changing is unclear. This study aimed to determine whether BMD of Japanese women has changed over time. Methods: Subjects were 10,649 adult women who underwent BMD measurement in a health check-up population in Niigata, Japan, between 1995 and 2013. BMD of the distal, non-dominant forearm was measured by dual-energy X-ray absorptiometry. Demographic information and BMI were also obtained. Secular trends were determined by linear regression analysis. Results: BMD of subjects in their 40's decreased significantly in the age-adjusted model (P for trend=0.0162), but not in the age- and BMI-adjusted model (P for trend=0.2171). BMD of subjects in their 50's decreased marginally in the age-adjusted model (P for trend=0.0535), but not in the age- and BMI-adjusted model (P for trend=0.6601). BMDs of subjects in their 30's and 60's did not significantly change, while BMIs of subjects in their 40's-60's decreased significantly. Conclusions: A secular decrease in BMD, partly attributed to decreases in BMI, was observed in middle-aged Japanese women from 1995 to 2013. Measures to help maintain suitable BMI will be necessary to prevent a decrease in BMD among women

    cis interaction of CD153 with TCR/CD3 is crucial for the pathogenic activation of senescence-associated T cells

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    老化T細胞が自己免疫病や慢性炎症疾患を引き起こすメカニズムを解明 --老化関連疾患克服への新しいアプローチ--. 京都大学プレスリリース. 2022-09-22.With age, senescence-associated (SA) CD4+ T cells that are refractory to T cell receptor (TCR) stimulation are increased along with spontaneous germinal center (Spt-GC) development prone to autoantibody production. We demonstrate that CD153 and its receptor CD30 are expressed in SA-T and Spt-GC B cells, respectively, and deficiency of either CD153 or CD30 results in the compromised increase of both cell types. CD153 engagement on SA-T cells upon TCR stimulation causes association of CD153 with the TCR/CD3 complex and restores TCR signaling, whereas CD30 engagement on GC B cells induces their expansion. Administration of an anti-CD153 antibody blocking the interaction with CD30 suppresses the increase in both SA-T and Spt-GC B cells with age and ameliorates lupus in lupus-prone mice. These results suggest that the molecular interaction of CD153 and CD30 plays a central role in the reciprocal activation of SA-T and Spt-GC B cells, leading to immunosenescent phenotypes and autoimmunity

    Analysis of Immunity against Measles, Mumps, Rubella, and Varicella Zoster in Adult Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Experience

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    Vaccine-preventable disease (VPD) infections are more severe in immunocompromised hosts. Vaccination against measles, mumps, rubella, and varicella zoster (VZV) (MMRV) is therefore recommended for hematopoietic stem cell transplantation (HCT) recipients. However, studies on adult HCT recipients with VPD infections are limited. At our institution, we have systematically conducted serological MMRV tests as a part of check-up examinations during long-term follow-up (LTFU) after HCT since 2015. This retrospective study aimed to evaluate changes in the serostatus between before and 2 years after allogeneic HCT. Among 161 patients, the pre-transplant seropositivity was 82.7% for measles, 86.8% for mumps, 84.2% for rubella, and 94.3% for VZV. Among 56 patients who underwent LTFU including serological MMRV tests at 2 years after HCT, the percentages maintaining seroprotective antibody levels for measles, mumps, rubella and VZV were 71.5% (40/56), 51.8% (29/56), 48.2% (27/56), and 60.7% (34/56), respectively. Vaccination was recommended for 22 patients, and 12 were vaccinated. Among the 12 vaccinated patients, rates of seroconversion were examined in 2-6 patients for each of the four viruses. They were 100% (3/3) for measles, 33.3% (1/3) for mumps, 50% (3/6) for rubella, and 0% (0/2) for VZV. Further studies are warranted to clarify the effect of vaccination in adult HCT recipients

    Factors associated with motivation and hesitation to work among health professionals during a public crisis: a cross sectional study of hospital workers in Japan during the pandemic (H1N1) 2009

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    <p>Abstract</p> <p>Background</p> <p>The professionalism of hospital workers in Japan was challenged by the pandemic (H1N1) 2009. To maintain hospital function under critical situations such as a pandemic, it is important to understand the factors that increase and decrease the willingness to work. Previous hospital-based studies have examined this question using hypothetical events, but so far it has not been examined in an actual pandemic. Here, we surveyed the factors that influenced the motivation and hesitation of hospital workers to work in Japan soon after the pandemic (H1N1) 2009.</p> <p>Methods</p> <p>Self-administered anonymous questionnaires about demographic character and stress factors were distributed to all 3635 employees at three core hospitals in Kobe city, Japan and were collected from June to July, 2009, about one month after the pandemic (H1N1) in Japan.</p> <p>Results</p> <p>Of a total of 3635 questionnaires distributed, 1693 (46.7%) valid questionnaires were received. 28.4% (N = 481) of workers had strong motivation and 14.7% (N = 249) had strong hesitation to work. Demographic characters and stress-related questions were categorised into four types according to the odds ratios (OR) of motivation and hesitation to work: some factors increased motivation and lowered hesitation; others increased motivation only; others increased hesitation only and others increased both motivation and hesitation. The strong feeling of being supported by the national and local governments (Multivariate OR: motivation; 3.5; CI 2.2-5.4, hesitation; 0.2; CI 0.1-0.6) and being protected by hospital (Multivariate OR: motivation; 2.8; CI 2.2-3.7, hesitation; 0.5; CI 0.3-0.7) were related to higher motivation and lower hesitation. Here, protection included taking precautions to prevent illness among workers and their families, providing for the care of those who do become ill, reducing malpractice threats, and financial support for families of workers who die on duty. But 94.1% of the respondents answered protection by the national and local government was weak and 79.7% answered protection by the hospital was weak.</p> <p>Conclusions</p> <p>Some factors have conflicting effects because they increase both motivation and hesitation. Giving workers the feeling that they are being protected by the national and local government and hospital is especially valuable because it increases their motivation and lowers their hesitation to work.</p
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