修饰沙粒对Pb（II）的吸附性及其在痕量Pb（II）分离富集与测定中的应用

本文用不同浓度的氢氧化钠溶液修饰天然沙粒并通过扫描电镜、静态氮吸附和红外光谱法考察了修饰天然沙粒的表面结构、比表面积和功能基团,优化了修饰条件;以修饰天然沙粒为填料制备分离富集微柱,采用FAAS着重研究了修饰沙粒对Pb2+的动态吸附及其在痕量Pb2+分离富集和测定中的应用;结果表明：天然沙粒被修饰后其表面形貌、比表面积、表面孔体积和粒径分布发生变化,表面变得更粗糙,孔体积和比表面积增大,硅羟基红外吸收峰强度也明显增强;其比表面积为12．55m2/g,平均孔(坑)径为25．29nm,平均孔体积48．04mm3/g(D<8．3 nm);在室温下,溶液pH为5．5,上样流速为1．50mL·min-1时,修饰天然沙粒对Pb2+的动态吸附量可达到32．6 mg/g,吸附率为93．6%,选用0．5mol·L-1的盐酸溶液以3．0mL·min-1流速进行洗脱,洗脱率为97%;适用于痕量Pb2+的分离富集和测定,结果令人满意。     

桩基承载力计算程序GPILE

介绍了单桩和群桩承载力计算程序 GPILE。该程序利用 P-Y曲线、T-Z曲线和 Q-Z曲线将土体与桩之间的相互作用模拟为一系列非线性弹簧 ,然后通过迭代求解桩的变形和内力。在计算群桩时可以考虑群桩效应。另外 ,还可以在桩基上增加上部结构 ,从而考虑桩基和上部结构的共同作用     

A REGULAR VALUE OF COMPACT DEFORMATION

Sufficient conditions were given to assert that between any two Banach spaces over K, Fredholm mappings share at least one value in a specific open ball. The proof of the result is constructive and based upon continuation methods.     

Consumer perspectives on genetic testing, research and services for ethnoculturally diverse populations

A panel of individuals from diverse ethnocultural backgrounds and representing a variety of genetic disorders presented their consumer perspectives on genetic programs, testing and services. Their remarks emphasized how misunderstanding and miscommunication between health care professionals and many of the populations for whom they provide services can lead to unfilled genetic service needs. Panelists recommended that health care professionals become more aware and knowledgeable about the diversity of customs, beliefs and cultures of those receiving their services. Only by building a foundation of trust and mutual respect will genetic testing, research and services become more accessible to individuals from diverse populations, their families and their communities.     

Down syndrome and parity

OBJECTIVE: To investigate the effect of parity on Down syndrome (DS). METHODS: The study was conducted on data from Northeast Italy (NEI) (1981-1996) and Sicily (ISMAC) (1991-1996) Congenital Malformation Registries. In these areas, all DS births are recorded and confirmed by chromosomal analysis; the NEI Registry also registers pregnancy terminations (TOPs) after prenatal diagnosis of DS. In order to estimate the effect of parity independently of the mother's age and to reduce the truncation effect, different age classes and three classes of parity (1, 2-4, >4) were defined. RESULTS: The study sample consisted of 1,088 consecutive newborns and 169 consecutive fetuses affected by DS. In both NEI and ISMAC samples, we found a significantly increased risk of having a DS child for multiparas > or =35 years of age. In the NEI sample, the inclusion of TOP data did not seem to modify this finding. In the ISMAC sample, a significantly reduced risk for primiparas was found at all ages. CONCLUSIONS: Our data confirm a higher risk of having a DS child in women with parity >4. As this effect is evident only in women > or =35 years age, its practical impact is null because these women are usually offered prenatal diagnosis in any case. However, the mechanisms involved, if this association is true, are very intriguing and the observation should stimulate scientific studies allowing a better knowledge of the nondisjunction mechanism.     

Genetics in primary care: a USA faculty development initiative

The Genetics in Primary Care (GPC) project is a USA national faculty development initiative with the goal of enhancing the training of medical students and primary care residents by developing primary care faculty expertise in genetics. Educational strategies were developed for the project by an executive committee with input from an advisory committee, comprising individuals with primary care, medical education and genetics expertise. These committees identified the key issues in genetics education for primary care as (1) considering inherited disease in the differential diagnosis of common disorders; (2) using appropriate counseling strategies for genetic testing and diagnosis, and (3) understanding the implications of a genetic diagnosis for family members. The group emphasized the importance of a primary care perspective, which suggests that the clinical utility of genetic information is greatest when it has the potential to improve health outcomes. The group also noted that clinical practice already incorporates the use of family history information, providing a basis for discussing the application of genetic concepts in primary care. Genetics and primary care experts agreed that educational efforts will be most successful if they are integrated into existing primary care teaching programs, and use a case-based teaching format that incorporates both clinical and social dimensions of genetic disorders. Three core clinical skills were identified: (1) interpreting family history; (2) recognizing the variable clinical utility of genetic information, and (3) acquiring cultural competency. Three areas of potential controversy were identified as well: (1) the role of nondirective counseling versus shared decision-making in discussions of genetic testing; (2) the intrinsic value of genetic information when it does not influence health outcomes, and (3) indications for a genetics referral. The project provides an opportunity for ongoing discussion about these important issues.     

PopGen: population-based recruitment of patients and controls for the analysis of complex genotype-phenotype relationships

OBJECTIVE: Patient samples used for mapping complex human disease genes are unlikely to be representative of the phenotype spectrum of the respective population as a whole. On the other hand, most ongoing prospective studies are probably too small for evaluating polygenic disease markers. DESIGN: Precise estimates of population-specific genotypic risks can be obtained efficiently through the complete ascertainment of patients in a geographically confined area. The PopGen project uses the most northern part of Germany as a target region for such a pursuit. RESULTS: PopGen currently pursues recruitment, sampling and processing activities in close collaboration with a multitude of clinical partners, covering cardiovascular, neuropsychiatric and environmental diseases. CONCLUSION: PopGen has successfully established itself as a large-scale genetic epidemiological project of international recognition.     

一种扫描电镜准动态观察磨损表面形貌演变的方法

提出了一种扫描电镜准动态观察磨损表面形貌的方法－定位间断观察法，通过坐标定位和形貌特征定位，可简便，准确地确定跟踪观察位置。将试样表面的摩擦方向垂直于电子束的行扫描方向并使试样表面适度倾向二次电子探测器，可提高观察和拍摄效果，利用该方法观察了一种高铬铸铁中的（Ｆｅ，Ｃｒ）７Ｃ３碳化物与ＳｉＣ磨粒干滑动摩擦过程中的形貌演变。     

三维运动接触问题的广义Галин定理

本文给出了求解一类相当普遍的三维运动接触问题的分析解法,并且把仅仅对静态接触问题成立的 定理推广到动力学情形,作了严格证明。作为例子,对接触区为椭圆的情形给出了积分形式的解,并且作了数值计算,由这些结果可以看出运动压体速度的效应。     

从分子运动论看连续介质气体动力学和稀薄气体的新特性

首先，综述了根据分子运动论对连续介质极限气体行为的最近研究，它表明；经典的连续气体动力学是不完整的；用分子运动论分析在连续介质极限时一些重要情况得到氧化的正确行为是必不可免的。即，即作了特殊的情况，甚至在平均自由程变为零的极限下热传导方程不能描述静止气体温度场；文中给出了根据分子运动论导出的温度场的正确方程组和边界条件及其具体应用。