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251.
The prenatal diagnosis of skeletal dysplasias is often initiated by the finding of a shortened extremity during a routine sonographic examination. Second-trimester diagnosis of these anomalies allows the couple to consider the option of terminating a pregnancy when a lethal anomaly is detected. A 21-year-old Bedouin woman underwent routine ultrasonographic screening at 20 weeks' gestation. Severe micromelia, a narrow thorax with shortened ribs, and postaxial polydactyly were detected. The patient delivered a male dwarf at 20 weeks' gestation following prostaglandin induction of labour for a diagnosis of short-rib polydactyly syndrome type III. The prenatal ultrasonographic diagnosis of short-rib polydactyly syndrome type III was made at 20 weeks' gestation, allowing termination of the pregnancy. A proper sonographic approach to skeletal dysplasias allows both early detection and differentiation between lethal and non-lethal anomalies. 相似文献
252.
This report describes the early prenatal diagnosis of the Pena Shokeir phenotype in an at-risk patient at 14 weeks' gestation. The diagnosis was based on an abnormal fetal movement profile, in association with an abnormal position of the fetal limbs. Pena Shokeir phenotype describes an inherited condition characterized by arthrogryposis and dysmorphic features as a result of fetal akinesia. It is a lethal abnormality and early diagnosis allows safer surgical methods of termination. 相似文献
253.
The advantages of a routine screening or indication-based ultrasound investigation during pregnancy are still under debate. This is the first study where both methods are compared in two different time periods. More malformations were diagnosed before the 24th week of gestation by means of screening-based than indication-based investigation (18 per cent vs. 5 per cent, P<0·005), and before 28 weeks in 26 per cent compared with 15 per cent respectively (P<0·01). Twenty-six per cent of all malformations were detected by means of screening-based investigations as opposed to 15 per cent by means of indication-based scans. Primary fetal malformations were also diagnosed much earlier (25 weeks vs. 30 weeks). Except for the fetal head, the detection rate of malformations was higher in nearly all other body regions of the fetus in the screening-based investigation. The most important advantage of a screening-based ultrasound investigation during pregnancy is to detect the malformations early enough in pregnancy for possible intrauterine treatment or to offer safe termination of pregnancy for the woman, at least for those anomalies that are lethal or significantly handicapping. 相似文献
254.
利用频率为40 kHz的超声(US)活化过硫酸盐(PS)氧化降解甲基橙.系统研究了超声(US)声强、过硫酸盐(PS)浓度对US/PS组合工艺降解甲基橙的影响.采用单独超声(US)或单独过硫酸盐(PS)时,甲基橙的降解率随US声强和PS浓度的增加而增大.在PS浓度为0.5~3 mmol·L-1和US声强为0.22~0.54 W·cm-2条件下,60 min时甲基橙的最大降解率分别为52.22%和16.7%.采用US/PS高级氧化工艺时,甲基橙的降解率也随PS浓度和US声强的增加而增大,60 min时甲基橙的最大降解率高达87.38%,比单独US和PS提高70.68%和35.16%.同种条件下,TOC的降解率小于甲基橙的降解率.甲醇和叔丁醇(自由基抑制剂)的加入降低甲基橙的降解率,且甲醇对甲基橙降解的抑制程度更明显.US/PS高级氧化工艺对甲基橙的降解主要依靠硫酸根自由基. 相似文献
255.
M. M. van Zalen-Sprock J. M. G. van Vugt Md Phd V. H. M. Karsdorp R. Maas H. P. van Geijn 《黑龙江环境通报》1991,11(8):655-660
Over a 65½ year period, in 288 pregnancies a variety of fetal malformations were detected by ultrasound. Two hundred and ten fetuses (73 per cent) were karyotyped. Gestational age at detection ranged from 11 to 38 weeks. The incidence of an abnormal karyotype in the total series was 14 per cent and 14.7 per cent in the 210 pregnancies in which a karyotype was performed. Single structural anomalies were found in 149 cytogenetically investigated fetuses, of which 25 had a chromosomal abnormality (17 per cent). Multiple structural malformations were present in 61 fetuses, of which 16 had an abnormal karyotype (26 per cent). Trisomy 18 was the most frequent finding. The most constant ultrasound finding in cases of an abnormal karyotype was polyhydramnios and severe IUGR in combination with structural defects. There is a need for extensive detailed ultrasound examination in high-risk pregnancies. 相似文献
256.
超声对SBR工艺中剩余污泥的减量化研究 总被引:3,自引:0,他引:3
实验采用超声处理已稳定运行的SBR系统产生的剩余污泥,通过改变声能密度和作用时间对污泥进行处理,并回流至反应器,研究在不影响出水水质的前提下实现污泥减量化的条件。实验表明:在不同的声能密度和作用时间下系统出水仍可达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级排放标准,且系统污泥量稳定。在声能密度1W/mL、作用时间15min,系统运行时间为6h时,可将进水COD487mg/L降至57mg/L,MLSS维持在约3000mg/L,污泥SVI为79。 相似文献
257.
超声波辅助离子液体-盐酸溶液预处理稻秆的研究 总被引:1,自引:0,他引:1
为研究超声波对离子液体-盐酸溶液预处理木质纤维素的影响,采用氯化-1-丁基-3-甲基咪唑和氯化-1-烯丙基-3-甲基咪唑的盐酸溶液在超声辅助下对稻秆于30~70℃进行预处理,探讨了温度、酸度和处理时间对酶解产糖量的影响,并在最佳条件下通过酶解糖化、成分分析、表面形貌、结晶度及化学结构的变化对有无超声辅助下预处理的效果进行考察.结果表明,温度、酸度及处理时间对酶解产糖量具有显著影响,在超声波辅助下,产糖量、纤维转化率及脱木质素率分别提高20.13%~28.96%、31.69%~35.23%和18.06%~19.33%.扫描电镜、X-射线衍射及傅里叶变换红外光谱分析表明,超声波辅助离子液体-盐酸溶液预处理能够促进对稻秆表面形貌和化学结构的破坏,并降低纤维素的结晶度. 相似文献
258.
259.
The tibial hemimelia syndrome is a rare autosomal dominant condition associated with limb deficiencies. We recently diagnosed this condition in a pregnancy at 16·5 weeks' gestation by ultrasound and a positive family history. To our knowledge, this represents the first case to be detected prenatally. 相似文献
260.
Horst Steiner MD Dietmar Spitzer Peter H. Weiss-Wichert Anton H. Graf Alf Staudach 《黑龙江环境通报》1995,15(4):373-377
A lethal form of bone dysplasia, platylospondylic lethal chondrodysplasia, was diagnosed prenatally using three-dimensional ultrasound. The various types of three-dimensional imaging mode provided diagnostic details not available by conventional two-dimensional ultrasound. The diagnosis was made after referral in the 23rd week of gestation, allowing termination of pregnancy due to the poor prognosis. Prenatal sonograms were compared with postnatal radiographs. 相似文献