Karyotypic differences between cells from placenta and other fetal tissues

Six cases are reported with discrepancies between the karyotypes of placental cells and cells from other fetal tissue. The respective findings were: (a) 48,+7,+18 resp. 47,+18. (b) 46, i(18q) resp. 46, del18(p11). (c) 46, XX resp. 46, XX/47, XXX. (d) 46, X, Yq+ and 46, XY resp. 46, XY. (e) 46/47,+12 resp. 46. (f) 46/47,+5 resp. 46. These differences were found in both early and term pregnancies. Care should be taken in deducing the fetal karyotype from the chromosomal pattern of placental cells.     

Early prenatal diagnosis of short rib-polydactyly (SRP) syndrome type I (Majewski) by ultrasound in a case at risk

Short rib-polydactyly (SRP) syndrome Type I was diagnosed accurately in an at-risk fetus at 16 weeks of gestation by real-time sonography. The most important findings were a narrow thorax, significant shortening of the long bones, particularly the tibiae, and–by directed search–the polydactyly.     

Prenatal diagnosis of del(11)(p13p15)

Prenatal diagnosis of del(11)(p13p15) was made on cultured amniotic fluid cells and confirmed on fetal skin fibroblasts after termination of pregnancy. Both irides appeared behind schedule in development by 2–3 weeks in reference to the gestational age of the fetus. It is suggested that the aniridia of the aniridia-Wilms tumour association is due to developmental arrest. Confirmation of this complex is difficult at mid-gestation without critical pathological study of the eyes.     

A collaborative study of the segregation of inherited chromosome structural rearrangements in 1356 prenatal diagnoses

A collaborative study involving 71 European prenatal diagnosis centres has collected 1356 observations on the karyotype of fetal cells in diagnoses performed in couples in which a parent had a balanced structural rearrangement. The segregations of the inherited chromosome structural rearrangement were analysed in relation to the types of rearrangement, to the sex of the carrier parent, the methods of ascertainment of the anomaly in the family, the chromosomes involved and the potential imbalance of the anomaly. Wide differences in the incidence of unbalanced fetuses were observed in relation to these criteria, and these results can be used in counselling parents with balanced rearrange- ments. Distortions in segregation of normal versus balanced karyotypes were observed in some types of anomalies.     

基于SVM的通风系统故障诊断惩罚系数与核函数系数优化研究

使用支持向量机（SVM）方法对矿井通风系统进行故障诊断,存在惩罚系数（c）和核函数系数（g）,通过人工方法选取效率低、难以达到较高准确率并且出现过拟合的问题。为了提高矿井通风故障诊断的效率、准确率,同时避免过拟合现象,提出了一种改进遗传算法（GA）,在故障诊断过程中对支持向量机的c,g参数进行优化。经过多组试验分析,研究结果表明:用遗传算法优化的SVM矿井通风故障诊断系统相比于未优化系统的故障诊断准确率有所提升,参数未优化前故障诊断的准确率为60%,优化后的准确率为97.894 7%,并且优化参数经过大数据样本验证,未出现过拟合现象,证明了本文提出方法的有效性。