近50年丝绸之路经济带中国境内冰川变化

冰川是丝绸之路经济带中国境内重要的水资源,对该区农业建设和经济发展至关重要。基于修订后的中国第一次冰川编目数据和最新发布的第二次冰川编目数据,对丝绸之路经济带中国境内冰川变化进行分析。结果表明：（1）丝绸之路经济带中国境内现有冰川22523条,面积25516.80 km²,冰储量约2592.85 km³,分别占我国冰川相应总量的46.37%、49.22%和57.39%,其中新疆维吾尔自治区冰川储量最为丰富,共计2366.25 km³。（2）丝绸之路经济带中国境内冰川以面积<0.5 km²的冰川数量最多,共计15519条,占冰川总数量的68.90%;面积则以介于1~5 km²冰川为主,共计6833.71 km²,占冰川总面积的26.78%;各山系的冰川退缩海拔高度不同,面积减少速度在各个高度带均有差异。（3）近50年间丝绸之路经济带中国境内冰川面积共减少4527.43 km²,变化百分比为-20.88%,有3114条冰川消失,冰川冰储量损失约419.35 km³。（4）丝绸之路经济带中国境内冰川变化整体呈现自西向东加快趋势,减少速率整体上有自西南向东北加快趋势;冰川朝北消失数量大于朝南消失数量,东北方向面积减少最多,东南方向面积减少最快。（5）近50年间丝绸之路经济带中国境内有暖湿化趋势,冬季气温升高速率大于夏季且降水增加幅度小于夏季的气候组合模式,不利于冰川的积累从而导致冰川退缩;冰川发育规模对冰川退缩也有一定影响,但各山系冰川变化驱动力具有空间差异。     

城市草坪温室气体排放特征及影响因素

草坪作为城市绿地的重要组成部分，其温室气体的吸收或排放不容忽视.然而当前对亚热带城市草坪温室气体通量的研究相对匮乏.采用静态箱-气相色谱法，对杭州市城区典型城市草坪的多种温室气体（CO₂、CH₄、N₂O和CO）地气交换通量进行了连续观测研究.结果表明，城市草坪的温室气体月平均通量变化明显，而其日变化特征并不明显.城市草地和土壤（无植被生长的裸土）是大气N₂O的源，平均通量分别为（0.66±0.17）μg·（m²·min）^-1和（0.58±0.20）μg·（m²·min）^-1；是CH₄和CO的汇，其中CH₄平均通量分别为（-0.21±0.078）μg·（m²·min）^-1和（-0.26±0.10）μg·（m²·min）^-1，CO分别为（-6.36±1.28）μg·（m²·min）^-1和（-6.55±1.69）μg·（m²·min）^-1.城市草地和土壤CO₂平均通量分别为（5.28±0.75） mg·（m²·min）^-1和（4.83±0.91） mg·（m²·min）^-1.基于相关性分析研究发现，草地和土壤的CO₂和N₂O通量均与降水量呈显著的负相关，而CH₄和CO通量与降水量呈显著的正相关；除草地CH₄通量与土壤温度无显著相关、草地N₂O通量与土壤温度呈显著负相关外，其余各温室气体通量与土壤温度均呈显著正相关.另外，城市草坪的草地和土壤CO₂（R²为0.371和0.314）和N₂O （R²为0.371和0.284）通量季节变化受降水量的影响要大于其它温室气体，而土壤温度对CO通量的影响（R²为0.290和0.234）要显著于其它温室气体.     

Prenatal diagnosis of spinal muscular atrophy in Russia

Ninety-two families with spinal muscular atrophy (SMA) applied for genetic counselling and further prenatal diagnosis. To minimize expenses, only one tightly linked informative marker was determined in the course of preliminary examination, and non-radioactive allele detection was preferably used. Four prenatal diagnoses of SMA type I, four of SMA type II, and one of SMA type III were made. This trial programme shows the considerable requirements, importance, and potential effectiveness of prenatal prediction of SMA in Russia.     

Verification of carrier status for Becker muscular dystrophy from analysis of a blighted ovum

The polymerase chain reaction (PCR) was used on material from a blighted ovum to confirm indirectly the carrier status of a woman with a family history of Becker muscular dystrophy. Conventional testing including creatine kinase levels, muscle biopsy, and EMG had been inconclusive, and on the basis of one elevated creatine kinase level, the woman had been designated a possible carrier. Ultrasound examination at 10 weeks of pregnancy indicated a blighted ovum, from which DNA was subsequently extracted and subjected to PCR testing for determination of sex and genotypic status with respect to the known familial deletion of the dystrophin gene. The blighted ovum was found to have a Y chromosome and also to be deleted for at least exon 6 of the dystrophin gene, indirectly indicating that the mother most likely carried the family mutation for Becker muscular dystrophy.     

Prenatal diagnosis of Freeman–Sheldon syndrome (whistling face)

The diagnosis of Freeman–Sheldon syndrome was made by ultrasonographic evaluation of a 20-week fetus with a positive family history. The ultrasonographic features were abnormalities of the extremities and mouth.     

Extraction of DNA from amniotic fluid cells for the early prenatal diagnosis of genetic disease

Ten-ml samples of amniotic fluid were taken from pregnancies being terminated at 8–14 weeks' gestation. DNA was extracted from the amniotic cells by sequential centrifugation and analysed using the polymerase chain reaction (PCR). Fifteen samples were analysed for evidence of maternal contamination using Mfd5 oligo-nucleotide primers for repeat polymorphisms. Ten amniotic fluid samples were tested for the Delta-F₅₀₈ deletion characteristic of cystic fibrosis to demonstrate a diagnostic application for the technique. In each case, DNA extracted from fetal tissue from the same pregnancy was included in the controls. In 14 of the 15 cases tested with the Mfd5 primers, both the amniotic fluid DNA and the fetal DNA showed no evidence of contaminating DNA. In one case, neither the amniotic fluid cells nor the fetal cells yielded results. In nine of the ten cases tested with the Delta-F₅₀₈ primers, the amniotic fluid cell DNA provided accurate information about the genetic status of the fetus; in the tenth, the fetal DNA failed to amplify. The results indicate that adequate DNA can be extracted from amniotic fluid from 8 weeks' gestation onward and these samples are suitable for prenatal diagnosis using PCR.