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Background: Globally, the incidence of allergic diseases is increasing along with cesarean delivery rates. Data regarding the association between cesarean delivery and allergic diseases are inconsistent. Here, we aimed to clarify the association between cesarean delivery and the development of asthma, atopic dermatitis, wheezing, and eczema. Methods: We used data from the Japan Environment and Children’s Study. The data included were those of 104,065 fetal records and their children. Information about the mode of delivery, asthma, atopic dermatitis, wheezing, and eczema was obtained from questionnaires and medical record transcripts. Multiple logistic regression analysis was used to assess the association between cesarean delivery and asthma, atopic dermatitis, wheezing, and eczema risk among infants at 1 year of age. Results: We included 74,639 subjects in this study, wherein 18.4% underwent cesarean deliveries. After adjusting for the perinatal, socioeconomic, and postnatal confounding factors, children born by cesarean delivery had no increased risk of developing asthma [95% confidence interval (CI) 0.84–1.08], atopic dermatitis (95% CI, 0.92–1.13), wheezing (95% CI, 0.94–1.04), or eczema (95% CI, 0.94–1.05). Conclusions: This nationwide cohort study found no association between cesarean delivery and asthma, atopic dermatitis, wheezing, and eczema among infants at 1 year of age. However, further studies are needed to evaluate whether cesarean delivery plays a role in the development of allergic diseases.

Methane hydrate has a unique structure that the host water framework forms two kinds of cages, which contain one methane molecule each. Therefore, it has been expected that there may exist three kinds of translational modes of a methane molecule and also the distortion of translational mode of host water molecules compared with normal ice. We need information of the host and guest molecular dynamics over the wide momentum and energy transfer region for studying such dynamics. In this study inelastic neutron measurements were carried under 40 K with MARI spectrometer at ISIS in UK, TAS at JRR-3 and CAT at KENS in Japan. For the methane molecular motion we could confirm its freelike rotation by complementary use of MARI and TAS spectra. After the subtraction of the scattering intensity of the rotation evaluated by the free rotation model from the experimental data, three kinds of translation modes were identified at first experimentally. On the experimental spectra there still remains the excess intensity which could not explain the single mode excitation. The libration mode of the water framework shows the different momentum and energy transfer dependence with those of normal ice. The feature of the libration mode is resemble to ice-IX, that could be considered as a proton ordering of the cage structure appeared in ice-II, VIII and IX.