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Sato Harumi,Murakami Rumi,Zhang Jianming,Ozaki Yukihiro,Mori Katsuhito,Takahashi Isao,Terauchi Hikaru,Noda Isao The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.4
Temperature-dependent, wide-angle, x-ray diffraction (WAXD) patterns and infrared (IR) spectra were measured for biodegradable poly(3-hydroxybutyrate) (PHB) and its copolymers, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(HB-co-HHx) (HHx=2.5, 3.4, 10.5, and 12 mol%), in order to explore their crystal and lamellar structure and their pattern of C-H...O=C hydrogen bonding. The WAXD patterns showed that the P(HB-co-HHx) copolymers have the same orthorhombic system as PHB. It was found from the temperature-dependent WAXD measurements of PHB and P(HB-co-HHx) that the a lattice parameter is more enlarged than the b lattice parameter during heating and that only the a lattice parameter shows reversibility during both heating and cooling processes. These observations suggest that an interaction occurs along the a axis in PHB and P(HB-co-HHx). This interaction seems to be due to an intermolecular C-H...O=C hydrogen bonding between the C=O group in one helical structure and the $CH_3$ group in the other helical structure. The x-ray crystallographic data of PHB showed that the distance between the O atom of the C=O group in one helical structure and the H atom of one of the three C-H bonds of the $CH_3$ group in the other helix structure is $2.63{\AA}$, which is significantly shorter than the sum of the van der Waals separation ($2.72{\AA}$). This result and the appearance of the $CH_3$ asymmetric stretching band at $3009 cm^{-1}$ suggest that there is a C-H...O=C hydrogen bond between the C=O group and the $CH_3$ group in PHB and P(HB-co-HHx). The temperature-dependent WAXD and IR measurements revealed that the crystallinity of P(HB-co-HHx) (HHx =10.5 and 12 mol%) decreases gradually from a fairly low temperature, while that of PHB and P(HB-co-HHx) (HHx = 2.5 and 3.5 mol%) remains almost unchanged until just below their melting temperatures. It was also shown from our studies that the weakening of the C-H...O = C interaction starts from just above room temperature and proceeds gradually increasing temperature. It seems that the C-H...O=C hydrogen bonding stabilizes the chain holding in the lamellar structure and affects the thermal behaviour of PHB and its copolymers.
Analysis of bone in adenine-induced chronic kidney disease model rats
Hikaru Saito,Naohisa Miyakoshi,Yuji Kasukawa,Koji Nozaka,Hiroyuki Tsuchie,Chiaki Sato,Kazunobu Abe,Ryo Shoji,Yoichi Shimada 대한골다공증학회 2021 Osteoporosis and Sarcopenia Vol.7 No.4
Objectives: The purpose of this study is to investigate the stage of chronic kidney disease (CKD) in adenine-induced CKD model rats by serum analyses, and to examine bone mineral density (BMD), bone strength, and microstructure of trabecular and cortical bone in these rats. Methods: Eight-week-old, male Wistar rats (n ¼ 42) were divided into 2 groups: those fed a 0.75% adenine diet for 4 weeks until 12 weeks of age to generate CKD model rats (CKD group); and sham rats. The CKD and sham groups were sacrificed at 12, 16, and 20 weeks of age (n ¼ 7 in each group and at 12, 16, and 20 weeks), and various parameters were evaluated, including body weight, renal wet weight, muscle wet weight, renal histology, biochemical tests, BMD, biomechanical testing, and micro-computed tomography (CT). The parameters were compared between the 2 groups at the various time points. Results: In the CKD model rats, at 20 weeks of age, serum creatinine, phosphorus, and intact-PTH levels were elevated, and serum calcium levels were normal, indicating that the CKD was stage IV and associated with secondary hyperparathyroidism. Decreased BMDs of the whole body and the femur were observed as bone changes, and micro-CT analysis showed deterioration of bone microstructure of the cortical bone that resulted in decreased bone strength in the cortical and trabecular bone. Conclusions: These CKD model rats showed stage IV CKD and appear appropriate for evaluating the effects of several treatments for CKD-related osteoporosis and mineral bone disorder.
Daijiro Ogumi,Shota Abe,Hikaru Sato,Fumihiko Suzuki,Hiroyoshi Kawaai,Shinya Yamazaki 대한치과마취과학회 2023 Journal of Dental Anesthesia and Pain Medicine Vol.23 No.4
Background: We assessed the relationship between patient age and remifentanil dosing rate in patients managed under general anesthesia with spontaneous breathing using low-dose remifentanil in sevoflurane. Methods: The participants were patients with an American Society of Anesthesiologists Physical Status of 1 or 2 maintained under general anesthesia with low-dose remifentanil in 1.5-2.0% sevoflurane. The infusion rate of remifentanil was adjusted so that the spontaneous respiratory rate was half the rate prior to the induction of anesthesia, and γH (µg/kg/min) was defined as the infusion rate of remifentanil under stable conditions where the respiratory rate was half the rate prior to the induction of anesthesia for ≥ 15 minutes. The relationship between γH and patient age was analyzed statistically by Spearman's correlation analysis. Results: During dental treatment under general anesthesia using low-dose remifentanil in sevoflurane, a significant correlation was detected between γH and patient age. The regression line of y = − 0.00079 x + 0.066 (y-axis; γH, x-axis; patient's age) was provided. The values of γH provide 0.064 µg/kg/min at 2 years and 0.0186 µg/kg/min at 60 years. Therefore, as age increases, the dosing rate exhibits a declining trend. Furthermore, in the dosing rate of remifentanil when the patient's respiratory rate was reduced by half from the preanesthetic respiratory rate, the dosing rate provided was around 0.88 mL/h in all ages if the remifentanil was diluted as 0.1 mg/mL. EtCO2 showed 51.0 ± 5.7 mmHg, and SpO2 was controlled within the normal range by this method. In addition, all dental treatments were performed without major problems, such as awakening and body movement during general anesthesia, and the post-anesthetic recovery process was stable. Conclusion: General anesthesia with spontaneous breathing provides various advantages, and the present method is appropriate for minimally invasive procedures.
Ultrasonic Investigation of the Eu-based Intermetallic System EuZn₂Ge₂
Shinya Kudo,Kazuki Saito,Takuto Sato,Mitsuteru Nakamura,Masahito Yoshizawa,Kazuhei Wakiya,Yoshiki Nakanishi,Hikaru Hirabayashi,Shinji Michimura,Masashi Kosaka 한국물리학회 2023 새물리 Vol.73 No.12
In this study, an elastic property of EuZn₂Ge₂ with the tetragonal ThCr₂Si₂-type structure has been investigated by ultrasonic measurements. Elastic constants C<SUB>33</SUB> and C<SUB>44</SUB> were measured as a function of temperature and magnetic _eld applied along the [001] direction. A previous study reported that EuZn₂Ge₂ exhibited three magnetic phase transitions at T<SUB>N1</SUB> = 14.9 K, T<SUB>N2</SUB> = 8.4 K, and T<SUB>t</SUB> = 5 K. We found that an elastic anomaly appeared in the temperature dependence of both of C<SUB>33</SUB> and C<SUB>44</SUB> at T<SUB>N2</SUB>. On the other hand, the corresponding anomaly was hardly visible at T<SUB>N1</SUB> and T<SUB>t</SUB>. These results suggest that a magneto-elastic coupling at T<SUB>N2</SUB> may be relatively large compared with those at T<SUB>N1</SUB> and T<SUB>t</SUB>.