蔬菜含锗（Ge）量的初探

研究发现，在普通蔬菜中亦不乏锗的存在。本文报导了１８个蔬菜品种可食部分的含锗量平均值为１．０３±０．４９ｍｇ／ｋｇ（以干物质计）。其含量因品种而异，也受土壤的影响。蔬菜含锗量相当于人参含锗量的４０％；蔬菜对土壤锗的富集系数在０．０５４０～１．１２之间；蔬菜中锗与其它１２种元素间无显著相关性。     

First and early second-trimester diagnosis of fetal urinary tract anomalies using transvaginal sonography

Urinary tract anomalies are common. Prenatal diagnosis is important and enables either special obstetric management or termination of pregnancy and probably in the future, intrauterine intervention. Transvaginal sonography (TVS) allows visualization of the normal and anomalous fetal urinary tract at an early stage. One thousand nine hundred and forty women were examined via TVS at an early stage of pregnancy between 10 and 16 weeks from the last menstrual period (LMP) and 35 anomalies (1·8 per cent) were clearly identified: 29 cases of low urinary tract obstruction, 2 cases of multicystic dysplastic kidney, 2 cases of polycystic kidney (infantile type), 1 case of double collecting system, and 1 case of horseshoe kidney. Potter syndrome could be ruled out in three patients who had delivered fetuses suffering from this anomaly in previous pregnancies. The concise and early identification of anomalies makes TVS an important aid in the hands of the obstetrician, ultrasonographer, and neonatologist.     

克螨特和霸螨灵及其混剂对土壤微生物的影响及安全评价

通过模拟试验研究了杀螨剂克螨特、霸螨灵及其混剂速霸螨(霸螨灵:克螨特=1:3)对土壤呼吸作用的影响.结果表明,克螨特、霸螨灵及其混剂对土壤的呼吸作用均有一定的影响,表现为各浓度处理对土壤呼吸作用均具有抑制作用,且浓度越高抑制越明显.统计分析表明霸螨灵、克螨特及其混剂各浓度处理对土壤微生物的活动没有明显的影响.采用危害系数法来评价克螨特、霸螨灵及其混剂速霸螨的危害程度,各处理浓度的霸螨灵、霸螨灵及其混剂速霸螨的危害系数均不超过20,亦表明霸螨灵、霸螨灵及其混剂速霸螨对土壤微生物均属于低毒级或无实际危害级的农药.     

Design of policy mechanism to promote cleaner production in China

ＩｎｔｒｏｄｕｃｔｉｏｎＣｌｅａｎｅｒｐｒｏｄｕｃｔｉｏｎ (ＣＰ)ｈｏｌｄｓｇｒｅａｔｐｒｏｍｉｓｅａｓａｎｅｆｆｅｃｔｉｖｅｓｔｒａｔｅｇｙｉｎｔｈｅｆａｃｅｏｆｄｏｕｂｌｅｃｈａｌｌｅｎｇｅｓｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｐｒｏｔｅｃｔｉｏｎａｎｄｅｃｏｎｏｍｉｃｄｅｖｅｌｏｐｍｅｎｔ.Ｉｎ 1993,ａｄｅｍｏｎｓｔｒａｔｉｏｎｐｒｏｊｅｃｔ (Ｂ 4ｐｒｏｊｅｃｔ) ,ｄｅｓｉｇｎｅｄａｎｄｅｘｅｃｕｔｅｄｂｙｔｈｅＳｔａｔｅＥｎｖｉｒｏｎｍｅｎｔａｌＰｒｏｔｅｃｔｉｏｎＡｄｍｉｎｉｓｔｒａｔｉｏｎ (…     

Zelluläre Wirkungen der ultravioletten Komponente des Sonnenlichts

The discussion on the possible increase of solar UV on earth due to the destruction of the stratospheric ozone has led to a renewed interest in the action of ultraviolet radiation on biological systems. The paper deals with changes at the cellular level stressing particularly molecular alterations in deoxyribonucleic acid, the carrier of genetic information. The most important repair processes by which lesions are removed or bypassed are described. It is also discussed whether the effectivity of a complex spectrum can be predicted on the basis of measurements with monochromatic radiation. Furthermore, possible consequences on human health are outlined which may be derived from cellular studies.     

Prenatal diagnosis of the fragile X using thymidine induction

Eleven pregnancies in ten patients at risk for the fragile X were monitored by amniocentesis or chorion villus biopsy and induction of the fragile site using thymidine, methotrexate and FUdR. Three female fetuses and one male fetus were found to have the fragile X. The results obtained using thymidine induction were superior to those using methotrexate induction and probably better than those obtained using FUdR induction.     

Hydrogen storage and distribution systems

Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels. Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can be thermally reduced to the metals in a solar furnace.