异丙酚对大鼠海马CAl区神经元兴奋性突触传递的影响

目的研究异丙酚对大鼠海马CA1区神经元兴奋性突触后电流(EPSC)和自发性兴奋性突触后电流(sEPSC)的影响。方法 Wistar大鼠断头后分离海马脑组织,制成400μm厚度的海马脑片,脑片随机分为5组(n=10)。脂肪乳剂Ⅰ组、异丙酚Ⅰ组、SR95531+异丙酚组:记录EPSC 10 min (基础值)后分别加入10％脂肪乳剂90μl、1％异丙酚90μl(相当于100μmol／L)、10μmol／L SR95531+100 μmol／L异丙酚,继续记录EPSC 40 min,分析EPSC幅值的变化。脂肪乳剂Ⅱ组、异丙酚Ⅱ组:细胞破膜后稳定10-15 min,分别加入10％脂肪乳剂90μl和1％异丙酚90μl,记录sEPSC 40 min,分析sEPSC频率、幅值和半衰期的变化。膜钳制电压均为-70 mV。结果与基础值比较,给药后脂肪乳剂Ⅰ组和 SR95531+异丙酚组EPSC幅值差异无统计学意义,异丙酚Ⅰ组EPSC幅值降低;给药后异丙酚Ⅰ组 EPSC幅值比脂肪乳剂Ⅰ组降低(P<0．05)。与脂肪乳剂Ⅱ组比较,异丙酚Ⅱ组sEPSC的频率、幅值降低、半衰期缩短(P<0．05)。结论异丙酚主要通过增强大鼠海马CA...

咪唑安定拮抗戊四氮对大鼠海马CAl区动作电位和突触传递的影响

观褰戊四氮对大鼠海马CAl区动作电位(action potential，AP)、兴奋性突触后电流(excitatory poBtsynapfic cu膈I吐，皿sc)的影响以厦眯唑安定的拮抗作用。方法断头法分离Wistar大鼠海马半脑，切片机切出 400脚厚度的海马脑片，奎细胞电流钳记录CAl区锥体神经元动作电位发放情况，全细胞电压钳记录电刺激 Sch踮如r侧支／联合鲆维诱发的CAl区锥体神经元EPSC的变化。结果戊四氮健动作电位发放频率增加．脚值降低；咪唑安定拮抗戊四氪的作用，使动作电值发放减少甚至消失，EPSC值上升互加八咪唑安定前的2．5倍左右。结论眯唑安定可以部分恢复大鼠海马cAl区戌四氮谤发的动作电位发放和E巧c的改变，从而产生抗癫痫作用。

Vegetation and climate variations at Taibai, Qinling Mountains in central China for the last 3 500 cal BP

IEECAS SKLLQG

Especiação iônica da solução percolada de um solo tratado com lama de cal.

2005

Crescimento de Eucalyptus benthamii submetido à aplicação de lama de cal e cinza de madeira.

2015

Tephra-linked peat humification records from Irish ombrotrophic bogs question nature of solar forcing at 850 cal. yr BC.

This paper investigates evidence for palaeoclimatic changes during the period ca. 1500-500 cal. yr BC through peat humification studies on seven Irish ombrotrophic bogs. The sites are well-correlated by the identification of three mid-first millennium BC tephras, which enable the humification records at specific points in time to be directly compared. Phases of temporarily increased wetness are suggested at ca. 1300-1250 cal. yr BC, ca. 1150-1050 cal. yr BC, ca. 940 cal. yr BC and ca. 740 cal. yr BC. The last of these is confirmed to be synchronous at five sites, suggesting external forcing on a regional scale. The timing of this wet-shift is constrained by two closely dated tephras and is demonstrated to be distinct from the widely reported changes to cooler/wetter conditions associated with a solar minimum at 850-760 cal. yr BC, at which time the Irish sites appear instead to experience drier conditions. The results suggest the possibility of either non-uniform responses to solar forcing in northwest Europe at this time, or the existence of unrelated climate events in the early first millennium BC. The findings caution against the correlation of loosely dated palaeoclimate data if the effects of forcing mechanisms are to be understood.

Marine04 marine radiocarbon age calibration, 0-26 cal kyr BP

New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration data sets extend an additional 2000 yr, from 0–26 cal kyr BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision, and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically-dated tree-ring samples, converted with a box diffusion model to marine mixed-layer ages, cover the period from 0–10.5 cal kyr BP. Beyond 10.5 cal kyr BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific 14C reservoir age information to provide a single global marine mixed-layer calibration from 10.5–26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the 14C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring data sets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al. (this issue).

ShCal04 Southern Hemisphere Calibration, 0–11.0 Cal Kyr BP

Recent measurements on dendrochronologically-dated wood from the Southern Hemisphere have shown that there are differences between the structural form of the radiocarbon calibration curves from each hemisphere. Thus, it is desirable, when possible, to use calibration data obtained from secure dendrochronologically-dated wood from the corresponding hemisphere. In this paper, we outline the recent work and point the reader to the internationally recommended data set that should be used for future calibration of Southern Hemisphere 14C dates.

IntCal04 terrestrial radiocarbon age calibration, 0-26 cal kyr BP

A new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace IntCal98, which extended from 0-24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0-26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than IntCal98. Dendrochronologically-dated tree-ring samples cover the period from 0-12.4 cal kyr BP. Beyond the end of the tree rings, data from marine records (corals and foraminifera) are converted to the atmospheric equivalent with a site-specific marine reservoir correction to provide terrestrial calibration from 12.4-26.0 cal kyr BP. A substantial enhancement relative to IntCal98 is the introduction of a coherent statistical approach based on a random walk model, which takes into account the uncertainty in both the calendar age and the (super 14) C age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The tree-ring data sets, sources of uncertainty, and regional offsets are discussed here. The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed in brief, but details are presented in Hughen et al. (this issue a). We do not make a recommendation for calibration beyond 26 cal kyr BP at this time; however, potential calibration data sets are compared in another paper (van der Plicht et al., this issue).