广西凭祥英安岩的化学风化作用研究

利用薄片观察、X射线粉晶衍射分析和化学分析方法研究了广西凭祥英安岩风化剖面的形成作用。风化作用初期,母岩中微量黄铁矿的氧化分解导致方解石与绿泥石的迅速分解;风化中期形成了大量的高岭石、伊利石、蒙脱石和蛭石;风化作用高级阶段以高岭石、石英和氧化铁矿物的富集为特征,但仍然存在少量蒙脱石、伊利石和蛭石。风化剖面的部分层段显示出与剖面其他部分明显不同的地球化学特征,即Na的富集和K的亏损。在Al2O3-(CaO+Na2O)-K2O三角图上,风化中期这些层段明显偏离了正常的风化趋势。矿物学和微形貌的研究表明,造成偏离的原因是古地下水引起的正长石的钠长石化作用。

喀斯特河流溶解态稀土元素组成变化及其控制因素

以化学萃取一反萃取分离法为手段，结合等离子质谱分析仪测量了喀斯特地区乌江、沅江两大水系的枯水期河流的溶解态稀土元素含量。该两河流的化学组成代表了流经碳酸盐岩地层的河水的化学组成。与世界其它地区低pH的河水不同，喀斯特地区河水溶解态稀土元素含量较低，页岩标准化配分模式并不平坦，轻、重稀土元素分异因河流的不同而不同，乌江水系上游轻稀土元素(LREE)相对重稀土元素(HREE)富集，中下游HREE相对于LREE富集，沅江水系河水HREE相对于LREE富集，页岩标准化配分模式具明显的Ce、Eu负异常。乌江、沅江及其支流有高的溶解盐，含有较高的溶质浓度，河水水化学(高碱度、高离子含量、高pH值)和水／粒相互作用控制了喀斯特河水中溶解态稀土元素的含量和轻、重稀土元素的分异。

Characteristic infrared spectroscopic patterns in the protein bands of human breast cancer tissue

Infrared (IR) spectra of normal, hyperplasia, fibroadenoma and carcinoma tissues of human breast obtained from 96 patients have been determined and analyzed statistically. Several spectral differences were detected in the frequency regions of N-H stretching, amide I, II and III bands: (1) the bands in the region 3000-3600cm-1 shifted to lower frequencies for the carcinomatous tissue; (2) the A(3300)/A(3075) absorbance ratio was significantly higher for the fibroadenoma than for the other types of tissues; (3) the frequency of the a-helix amide I band decreased for the malignant tissue, while the corresponding beta -sheet amide I band frequency increased; (4) the A(1657)/A(1635) and A(1553)/A(1540) absorbance ratios were the highest for fibroadenoma and carcinoma tissues; (5) the A(1680)/A(1657) absorbance ratio decreased significantly in the order of normal > hyperplasia > fibroadenoma > carcinoma; (6) the A(1651)/A(1545) absorbance ratio increased slightly for the fibroadenoma and the carcinoma tissues; (7) the bands at 1204 and 1278 cm(-1), assigned to the vibrational modes of the collagen, did not appear in the original spectra as resolved peaks and were distinctly stronger in the deconvoluted spectra of the carcinoma tissue and (8) the A(1657)/A(1204) and A(1657)/A(1278) absorbance ratios, both yielding information on the relative content of collagen, increased in the order of normal < hyperplasia < carcinoma < fibroadenoma. The said differences imply that the information is useful for the diagnosis of breast cancer and malignant breast abnormalities, and may serve as a basis for further studies on conformational changes in tissue proteins during carcinogenesis. (C) 2001 Elsevier Science B.V. All rights reserved.