Broadband inelastic light scattering of a relaxor ferroelectric 0.71Pb(Ni1/3Nb2/3)O3-0.29PbTiO3

Brillouin and Raman scatterings of a 0.71Pb(Ni1/3Nb2/3)O3-0.29PbTiO3 single crystal have been measured to investigate broadband inelastic spectra. The two different central peaks related to fast and slow relaxation processes have been observed separately. These two processes are attributed to the thermally activated switching of polarization in polar nanoregions. By the analysis of modified superparaelectric model, the activation energies of fast and slow relaxation processes are determined to be 3.66×103 and 4.31×102 K, respectively. The fast process with the lower activation energy probably originated from 180° switching, whereas the slow one with the higher energy from non-180° switching

The effects of resistive exercise with low intensity-high frequency on essential mild hypertension in men

高血圧症は心筋梗塞, 脳卒中, 動脈硬化の独立した危険因子になっている。日本人30歳以上の成人男子の約48%が軽症を含めた高血圧症とされている。高血圧関連疾患や死亡の予防として軽症高血圧症時の血圧コントロールは重要な関心点である。薬物による高血圧治療は著しい効果をあげているが, 好ましくない副作用の発現も見逃せない。薬物療法に対して運動療法が近年広く処方されるようになってきた。これまでに多くの研究が有酸素運動の降圧効果を報告しているが, レジスタンス運動による降圧効果については異なる知見が出されている。そこで本研究においては, 有酸素運動の様式に似た低強度-高頻度レジスタンス運動を用いて中年軽症高血圧男子に対する降圧効果を検索した。方法。42歳-56歳 (平均48.3) の男子10名が被検者として参加し, 内5名がレジスタンス運動群 (RE) に他の5名がウオーキング群 (AE) に区分された。RE群は10種目のウエイト運動を最大筋力の40-50%強度, 20-25レペテイションで2-3セット, 週3回の形で12週間行った。一方のAE群は同様に予測最大心拍数の60-75%強度の30分速歩を週3回, 12週間行った。結果。安静時血圧においてRE群はAE群より程度は低いものの有意な (P値2.3ml/kg/min=6.9%) と身体組成の改善 (体脂肪1.5kg=8.8%減) が見られ, その改善率はAE群に比べて小さいがいずれも有意であった (AE群 : 6ml/kg/min=17%, 3.1kg=18.9%)。また, 体重もしくは体脂肪の減少量と降圧値との間には有意差が得られなかったが相関傾向が見られた。しかし, AE群と異なり, RE群では血清総コレステロール, 高比重リポ蛋白コレステロール, 低比重リポ蛋白コレステロール, トリグリセライド (中性脂肪) の血清脂質・リポ蛋白濃度の有意な改善は見られなかった。結語。これまで血圧や身体組成もしくは有酸素性体力の改善, 向上に対するレジスタンス運動の効果については意見の一致をみていない。考えられる要因の一つに運動の処方の違いが挙げられる。血圧や身体組成の改善に対しては低強度・高頻度による運動量負荷 (Volume loading) の処方が好ましく, 高強度による過重負荷 (Over-weight loading) は至適処方とは言えないであろう。今回の研究においてレジスタンス運動による血清脂質の有意な改善が見られなかったのは総運動量が十分な刺激とならなかったものと考えられる。本研究は低強度高頻度のレジスタンス運動の習慣化が軽症高血圧患者の健康改善に効果的であることを示唆するものである。Five sedentary middle-aged men with mild hypertension were studied to determine the effects of a low-to moderate-intensity resistive exercise program (RE group) on resting systolic and diastolic blood pressures. Another group of five mild hypertensive men was also examined to determine the effects of a moderate aerobic exercise program (AE group) on the resting blood pressures. Besides blood pressures, effects of respective training programs were studied on aerobic capacity, muscle strengths, and serum lipid and lipoprotein concentrations. Resistive exercise consisted of 10 stations of weight training machines for 12 weeks. Workloads were set at 40-50% maximum and the subjects performed 10 repetitions for each station with 2-3 sets, 3 times per week. The subjects in the aerobic exercise group performed 30-min brisk waking or jogging with intensities of 60-75% their predicted maximum heart rates. The following changes occurred in the resistive exercise group : (1) resting systolic blood pressure dropped significantly (from 150 to 143mm Hg) after training and diastolic blood pressure dropped significantly (from 91 to 88mm Hg) after training ; (2) VO_ significantly increased 2.3 ml/kg/min or 6.9% (from 33.3 to 35.6 ml/kg/min) after training ; (3) increases of muscle strengths were profound, 17.9% and 23% in lower and upper body strengths, respectively ; (4) body weight and body fat decreased 2.6% (P) as well as body composition. Serum lipid lipoproteins included total cholesterol (TC), high-density cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). Significant (P<0.01) increase was noted for HDL-C while significant decreases were seen in TC, LDL-C, and TG

Suppressor Analysis of the MotB(D33E) Mutation To Probe Bacterial Flagellar Motor Dynamics Coupled with Proton Translocation ▿ †

MotA and MotB form the stator of the proton-driven bacterial flagellar motor, which conducts protons and couples proton flow with motor rotation. Asp-33 of Salmonella enterica serovar Typhimurium MotB, which is a putative proton-binding site, is critical for torque generation. However, the mechanism of energy coupling remains unknown. Here, we carried out genetic and motility analysis of a slowly motile motB(D33E) mutant and its pseudorevertants. We first confirmed that the poor motility of the motB(D33E) mutant is due to neither protein instability, mislocalization, nor impaired interaction with MotA. We isolated 17 pseudorevertants and identified the suppressor mutations in the transmembrane helices TM2 and TM3 of MotA and in TM and the periplasmic domain of MotB. The stall torque produced by the motB(D33E) mutant motor was about half of the wild-type level, while those for the pseudorevertants were recovered nearly to the wild-type levels. However, the high-speed rotations of the motors under low-load conditions were still significantly impaired, suggesting that the rate of proton translocation is still severely limited at high speed. These results suggest that the second-site mutations recover a torque generation step involving stator-rotor interactions coupled with protonation/deprotonation of Glu-33 but not maximum proton conductivity