Sea surface temperature reconstruction for the middle Okinawa Trough during the last glacial-interglacial cycle using C-37 unsaturated alkenones

C-37 unsaturated alkenones were analyzed on a core retrieved from the middle Okinawa Trough. The calculated U-37(K') displays a trend generally parallel with those of the oxygen isotopic compositions of two planktonic foraminiferal species, Neogloboquadrina dutertrei and Globigerinoides sacculifer, suggesting that in this region, SST has varied in phase with global ice volume change since the last glacial -interglacial cycle. The U-37(K')-derived SST ranged from ca. 24.0 to 27.5 degrees C, with the highest value 27.5 degrees C occurring in marine isotope stage 5 and the lowest similar to 24.0 degrees C in marine isotope stage 2. This trend is consistent with the continental records from the East Asian monsoon domain and the marine records from the Equatorial Pacific. The deglacial increase of the U-37(K')-derived SST is similar to 2.4 degrees C from the Last Glacial Maximum to the Holocene. (c) 2007 Elsevier B.V. All rights reserved.

影响C4草本植物C／N比值变化的因素与土壤有机C积累的关系

文章对采自贵州从低海拔的东部到高海拔的西部且大致平行的石灰岩和砂岩两地带均生长的3种C4草本植物，即巴茅(Miscanthus floridulus)、白茅(Imperata cylindrica)和类芦(Neyraudia reynaudiana)，以及相对应的土壤表层样品，进行了营养元素和C同位素组成分析；研究营养元素含量随着海拔的不同而出现的变化趋势，以及这些元素之间的相互协变作用，尤其是Ca和N之间的相互协变作用对植物的N含量、C／N比值和δ^13C值的影响，以了解植物的C／N比值(指示植物残留物质量的一种标志)与土壤有机C积累的关系。研究结果表明，植物的N含量和δ^13C值具有随海拔的上升而显著增大趋势，而植物的C／N比值在砂岩地区虽有减小的趋势，在石灰岩地带则没有。对所研究的C4草本植物来说，在土壤pH值为5．8的中性条件下显示出Ca的最大吸收，因此，Ca与其他营养元素之间的协变模式在两种土壤类型中表现出相反的倾向，并存在土壤交换性Ca的边界浓度：当土壤可交换性Ca的含量为2．24mg／g，相应土壤的pH值在5．8以下时，随着土壤可交换性Ca浓度的增大，植物的N含量上升，而植物的C／N比值会显著降低；当Ca在边界浓度以上时，随着土壤可交换性Ca浓度的增大，植物的N含量下降，而植物的C／N比值有增加的趋势。由此可见，植物残留物的N含量和C／N比值受Ca元素含量的相互协变作用的影响。在砂岩地区，随着植物C／N比值的增高，土壤有机质的含量却随之下降，而在石灰岩地区则没有这种倾向。因此得出结论：植物的C／N比值的增大对土壤有机碳积累的影响主要取决于土壤的性质，尤其是取决于土壤可交换性Ca的含量。

湖泊沉积物碳氧同位素和介形虫Li/Ca比值与古环境重建

了解过去是认识现在和预测未来的基础。晚全新世是PAGES研究的目标时段之一。寻找和解译最近2000年连续、高分辨率自然记录是古气候研究的热点与难点。本项研究有针对性地选择程海、草海和青海湖开展湖泊沉积物环境记录的精细研究，结合14C、210Pb和137Cs定年，系统探讨了碳酸盐碳氧同位素、纤维素碳氧同位素、有机质碳同位素以及介形虫壳体Li/Ca比值指标的古环境指示意义。 通过研究，本论文取得了如下成果和新的认识： 1. 建立了一套有效的四阶段湖泊沉积物有机质纤维素提取方法（5%NaOH碱洗、5%HCl酸洗、亚氯酸钠和冰醋酸混合溶液漂白以及17.5%NaOH碱洗），红外光谱鉴定提取物为纯的α-纤维素，表明该实验方法是可行的，为今后广泛开展湖泊沉积物纤维素稳定同位素研究打下了坚实基础。 2. 多指标综合辨识了程海和草海沉积物碳酸盐主要是自生碳酸盐。程海和草海沉积物有机质C/N比值结合有机质碳同位素结果表明两湖的有机质分别源于水生植物藻类和大型水草。程海和草海沉积物碳酸盐含量主要反映了湖区温度的变化。 3. 程海、草海沉积物碳酸盐与青海湖沉积物介形虫壳体氧同位素组成均反映了湖区降水/蒸发比。降水/蒸发比大的湿润期，碳酸盐δ18O值小；降水/蒸发比小的干旱期，碳酸盐δ18O值大。程海沉积物碳酸盐碳同位素组成影响因素复杂，除了受大气与湖水之间的CO2交换影响外，还受水生植物光合/吸收作用的影响；草海沉积物碳酸盐碳同位素组成更大的变化范围，反映了湖区水生植物光合/吸收作用的影响，其异常的正值可能指示了湖区细菌参与有机质碳同位素分馏过程。 4. 利用草海沉积物有机质纤维素氧同位素定量恢复了湖水氧同位素组成变化。在此基础上，结合碳酸盐氧同位素组成初步恢复了草海地区过去500年来温度变化历史：草海地区在过去500年明显存在四个冷期，包括1550－1610年，1670－1730年，1770－1870年和1890－1920年冷期，其中前三个发生在传统意义上的现代小冰期时段。与其它记录研究结果的一致性表明纤维素氧同位素结合碳酸盐氧同位素是恢复古温度变化的最有效途径之一，同时也为现代小冰期在中国西南地区的存在提供了湖泊沉积学方面的证据。 5. 不同类型水生植物湖泊，湖泊沉积物有机质δ13C值对湖泊初级生产力变化的响应过程不同。大型水草为主的湖泊（草海），其沉积物有机质δ13C值随湖泊生产力的增大呈现增加的变化趋势；藻类为主的湖泊（程海），其沉积物有机质δ13C随湖泊生产力的增大呈现减小的变化趋势，藻类易降解是导致δ13C值随湖泊生产力的增大呈现减小变化趋势的主要原因。 6. 程海沉积物碳酸盐和有机质碳同位素组成的正相关变化以及草海沉积物碳酸盐和有机质碳同位素组成的负相关变化.表明湖泊生产力变化并不是导致碳酸盐和有机质碳同位素正相关变化的主要原因，湖泊水生植物类型以及湖泊大小均起着重要作用。湖泊沉积物碳酸盐与有机质之间的碳同位素分馏（△δ13C）是一种有效的湖泊生产力指示剂，即使是在有微生物参与有机质碳同位素分馏过程的草海，△δ13C值也反映了湖泊生产力的变化过程。 7. 青海湖沉积物单一种属介形虫壳体胖真星介（Eucypris inflata）Li/Ca比值与气象记录以及邻近地区都兰和祁连山树轮宽度指数恢复的古温度变化序列的对比研究揭示，介形虫壳体Li/Ca比值与温度呈明显的负相关变化（Li/Ca比值高，温度低；Li/Ca比值低，温度高），表明介形虫壳体Li/Ca比值是一种有效的古温度代用指标。 8. 青海湖沉积物单一种属介形虫壳体胖真星介（Eucypris inflata）Li/Ca比值、氧同位素与反映太阳活动的大气14C含量和冰芯10Be含量的一致性变化表明青海湖地区温度和降雨量的同步变化主要受太阳活动控制。

Preparation of supported PtRu/C electrocatalyst for direct methanol fuel cells

In this work, high-surface supported PtRu/C were prepared with Ru(NO)(NO3)(3) and [Pt(H2NCH2CH2NH2)(2)]Cl-2 as the precursors and hydrogen as a reducing agent. XRD and TEM analyses showed that the PtRu/C catalysts with different loadings possessed small and homogeneous metal particles. Even at high metal loading (40 wt.% Pt, 20 wt.% Ru) the mean metal particle size is less than 4 nm. Meanwhile, the calculated Pt crystalline lattice parameter and Pt (220) peak position indicated that the geometric structure of Pt was modified by Ru atoms. Among the prepared catalysts, the lattice parameter of 40-20 wt.% PtRu/C contract most. Cyclic voltammetry (CV), chronoamperometry (CA), CO stripping and single direct methanol fuel cell tests jointly suggested that the 40-20 wt.% PtRu/C catalyst has the highest electrochemical activity for methanol oxidation. (c) 2004 Elsevier Ltd. All rights reserved.

Gry fabularne jako technika autonomizująca studenta

Publikacja (…) jest zbiorem tekstów poświęconych zagadnieniu autonomii w dydaktyce języków obcych. Teksty te – w obecnej postaci artykułów – stanowią zapis referatów wygłoszonych na konferencji poświęconej temu właśnie, niezwykle istotnemu dla nowoczesnej dydaktyki zagadnieniu. Konferencje tego typu nigdy dotąd w Polsce się nie odbywały. Jest to więc novum na naszym terenie i wielki tytuł do chwały dla uczelni, która podjęła się organizacji takiego wydarzenia i publikacji artykułów opracowanych na podstawie wygłoszonych tam referatów. Dlatego publikację uważam za niezwykle ważną i potrzebną. (z recenzji wydawniczej Prof. dr hab. Hanny Komorowskiej)

Sieć grodowa na Kujawach oraz jej funkcje od połowy X do końca XIII wieku

Wydział Historyczny: Instytut Historii

Variaciones temporales en las determinaciones de Ca, Mg y K intercambiables

p.317-323

Edta como extractante universal : I- cationes mayores (Ca, Mg y K)

p.133-137

Los diferentes tipos de láser y sus aplicaciones en podología

Los diferentes tipos de láseres, sobre todo el láser de diodo, irrumpen en la terapéutica podológica para proporcionar una alternativa más de tratamiento en muchas patologías que son el día a día de las consultas. El buen manejo y el conocimiento de sus características son requisitos imprescindibles para no tener efectos secundarios indeseados y poder llevar a cabo tratamientos poco dolorosos, minimizando el tiempo total, y muchas veces proporcionando una solución a diversas patologías.

Carbachol triggers RyR-dependent Ca(2+) release via activation of IP(3) receptors in isolated rat gastric myocytes.

Possible interactions between different intracellular Ca(2+) release channels were studied in isolated rat gastric myocytes using agonist-evoked Ca(2+) signals. Spontaneous, local Ca(2+) transients were observed in fluo-4-loaded cells with linescan confocal imaging. These were blocked by ryanodine (100 microM) but not by the inositol 1,4,5-trisphosphate receptor (IP(3)R) blocker, 2-aminoethoxydiphenyl borate (100 microM), identifying them as Ca(2+) sparks. Caffeine (10 mM) and carbachol (10 microM) initiated Ca(2+) release at sites which co-localized with each other and with any Ca(2+) spark sites. In fura-2-loaded cells extracellular 2-aminoethoxydiphenyl borate and intracellular heparin (5 mg ml(-1)) both inhibited the global cytoplasmic [Ca(2+)] transient evoked by carbachol, confirming that it was IP(3)R-dependent. 2-Aminoethoxydiphenyl borate and heparin also increased the response to caffeine. This probably reflected an increased Ca(2+) store content since 2-aminoethoxydiphenyl borate more than doubled the amplitude of transients evoked by ionomycin. Ryanodine completely abolished carbachol and caffeine responses but only reduced ionomycin transients by 30 %, suggesting that blockade of carbachol transients by ryanodine was not simply due to store depletion. Double labelling of IP(3)Rs and RyRs demonstrated extensive overlap in their distribution. These results suggest that carbachol stimulates Ca(2+) release through co-operation between IP(3)Rs and RyRs, and implicate IP(3)Rs in the regulation of Ca(2+) store content.

Extreme ultraviolet emission lines of Ca XV in solar and laboratory spectra

New R-matrix calculations of electron impact excitation rates in Ca XV are used to derive theoretical electron density diagnostic emission line intensity ratios involving 2s(2)2p(2)- 2s2p(3) transitions, specifically R-1 = I(208.70 Angstrom)/I(200.98 Angstrom), R-2 = I(181.91 Angstrom)/I(200.98 Angstrom), and R-3 = I(215.38 Angstrom)/I(200.98 Angstrom), for a range of electron temperatures (T-e = 10(6.4)-10(6.8) K) and densities (Ne = 10(9)-10(13) cm(-3)) appropriate to solar coronal plasmas. Electron densities deduced from the observed values of R-1, R-2, and R-3 for several solar flares, measured from spectra obtained with the Naval Research Laboratory's S082A spectrograph on board Skylab, are found to be consistent. In addition, the derived electron densities are in excellent agreement with those determined from line ratios in Ca XVI, which is formed at a similar electron temperature to Ca XV. These results provide some experimental verification for the accuracy of the line ratio calculations, and hence the atomic data on which they are based. A set of eight theoretical Ca XV line ratios involving 2s(2)2p(2)-2s2p(3) transitions in the wavelength range similar to140-216 Angstrom are also found to be in good agreement with those measured from spectra of the TEXT tokamak plasma, for which the electron temperature and density have been independently determined. This provides additional support for the accuracy of the theoretical line ratios and atomic data.

Preproendothelin-1 expression in human mesangial cells: evidence for a p38 mitogen-activated protein kinase/protein kinases- C-dependent mechanism

Endothelin-1 (ET-1) has been implicated in the pathogenesis of renal inflammation. This study investigated the mechanisms underlying the synergistic upregulation of preproET-1 gene expression in human mesangial cells after co-stimulation with thrombin and tumor necrosis factor alpha (TNFalpha). Whereas thrombin induced a moderate upregulation of preproET-1 mRNA, co-stimulation with TNFalpha resulted in a strong and protracted upregulation of this mRNA species. Thrombin+TNFalpha-induced upregulation of preproET-1 expression was found to require p38 mitogen-activated protein kinase and protein kinases C, whereas activation of extracellular signal-regulated kinase, c-Jun-N-terminal kinase, or intracellular Ca(2+) release were not required. Actinomycin D chase experiments suggested that enhanced stability of preproET-1 mRNA did not account for the increase in transcript levels. PreproET-1 promoter analysis demonstrated that the 5'-flanking region of preproET-1 encompassed positive regulatory elements engaged by thrombin. Negative modulation of thrombin-induced activation exerted by the distal 5' portion of preproET-1 promoter (-4.4 kbp to 204 bp) was overcome by co-stimulation with TNFalpha, providing a possible mechanism underlying the synergistic upregulation of preproET-1 expression by these two agonists. In conclusion, human mesangial cell expression of preproET-1 may be increased potently in the presence of two common proinflammatory mediators, thereby providing a potential mechanism for ET-1 production in inflammatory renal disease.

Ca(2+)-activated Cl(-) current in sheep lymphatic smooth muscle.

Freshly dispersed sheep mesenteric lymphatic smooth muscle cells were studied at 37 degrees C using the perforated patch-clamp technique with Cs(+)- and K(+)-filled pipettes. Depolarizing steps evoked currents that consisted of L-type Ca(2+) [I(Ca(L))] current and a slowly developing current. The slow current reversed at 1 +/- 1.5 mV with symmetrical Cl(-) concentrations compared with 23.2 +/- 1.2 mV (n = 5) and -34.3 +/- 3.5 mV (n = 4) when external Cl(-) was substituted with either glutamate (86 mM) or I(-) (125 mM). Nifedipine (1 microM) blocked and BAY K 8644 enhanced I(Ca(L)), the slow-developing sustained current, and the tail current. The Cl(-) channel blocker anthracene-9-carboxylic acid (9-AC) reduced only the slowly developing inward and tail currents. Application of caffeine (10 mM) to voltage-clamped cells evoked currents that reversed close to the Cl(-) equilibrium potential and were sensitive to 9-AC. Small spontaneous transient depolarizations and larger action potentials were observed in current clamp, and these were blocked by 9-AC. Evoked action potentials were triphasic and had a prominent plateau phase that was selectively blocked by 9-AC. Similarly, fluid output was reduced by 9-AC in doubly cannulated segments of spontaneously pumping sheep lymphatics, suggesting that the Ca(2+)-activated Cl(-) current plays an important role in the electrical activity underlying spontaneous activity in this tissue. PMID: 11029279 [PubMed - indexed for MEDLINE]