Prenatal diagnosis of cystic fibrosis using linked DNA probes

This paper presents data collected in Europe on 107 prenatal diagnoses of cystic fibrosis (CF) using linked DNA markers. To date, 38 children have been born without CF, as predicted, demonstrating the present rapid move from research to clinical genetic service.     

First-trimester prenatal diagnosis of Sanfilippo C disease

At 10 weeks' gestation, chorionic villus biopsy was obtained from a woman at risk for Sanfilippo type C disease. Acetyl-CoA: α-glucosaminide N-acetyltransferase activity was markedly deficient. The pregnancy was terminated at 12 weeks' gestation and follow-up study on fetal fibroblasts confirmed the diagnosis.     

Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour.

A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and Chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagymophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi-disc transparency(0.48 m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 degrees C. Here, the nanoflagellates (spumella) colonized first, followed by microcilliate(Tetrahymena) and sessile form(Vorticella). Station B, located on the seaward side, was characterized by relatively less-stressed environmental conditions with transparency 1.85 m and dissolved oxygen value of 6.04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 degrees C were recorded at "B". At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate(Lagynophrya) and suctorid(Heliophyra). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.     

High-performance permanent magnets

 High-performance permanent magnets (pms) are based on compounds with outstanding intrinsic magnetic properties as well as on optimized microstructures and alloy compositions. The most powerful pm materials at present are RE–TM intermetallic alloys which derive their exceptional magnetic properties from the favourable combination of rare earth metals (RE=Nd, Pr, Sm) with transition metals (TM=Fe, Co), in particular magnets based on (Nd,Pr)₂Fe₁₄B and Sm₂(Co,Cu,Fe,Zr)₁₇. Their development during the last 20 years has involved a dramatic improvement in their performance by a factor of >15 compared with conventional ferrite pms therefore contributing positively to the ever-increasing demand for pms in many (including new) application fields, to the extent that RE–TM pms now account for nearly half of the worldwide market. This review article first gives a brief introduction to the basics of ferromagnetism to confer an insight into the variety of (permanent) magnets, their manufacture and application fields. We then examine the rather complex relationship between the microstructure and the magnetic properties for the two highest-performance and most promising pm materials mentioned. By using numerical micromagnetic simulations on the basis of the Finite Element technique the correlation can be quantitatively predicted, thus providing a powerful tool for the further development of optimized high-performance pms.     

Determination and discussion hydraulic retention time in membrane bioreactor system

Based on the microorganism kinetic model, the formula for computing hydraulic retention time in a membrane bioreactor system (MBR) is derived. With considering HRT as an evaluation index a combinational approach was used to discuss factors which have an effect on MBR. As a result, the influencing factors were listed in order from strength to weakness as: maximum specific removal rate K, saturation constant Ks, maintenance coefficient m, maximum specific growth rate ,ua and observed yield coefficient Yobs. Moreover, the formula was simplified, whose parameters were experimentally determined in petrochemical wastewater treatment. The simplified formula is θ= 1.1( 1/β -1)(Kｓ S)/KXo , for oetroehemical wastewater treatment K and Ko eaualed 0.185 and 154.2, resoectively.     

CLIMATE CHANGE AND NATURAL HAZARDS IN NORTHERN CANADA: INTEGRATING INDIGENOUS PERSPECTIVES WITH GOVERNMENT POLICY

A study of the relationship between natural hazards and climate change in the international context provides the background for a discussion of the expected changes. In the context of this global discussion, this paper reviews the current perspectives of those natural hazards that are likely to be influenced by climate change, using northern Canada as a regional case study. The northern implications of the United Nations Framework Convention on Climate Change are examined, including the status of climate change action by the northern territorial governments, the evolving role of indigenous people, and the responsibility for climate change impacts. The difficulties surrounding natural hazards research in remote locations, and the approaches of indigenous people to natural hazards are then presented. The paper concludes with a suggested policy approach for climate change and natural hazards in northern Canada, underscoring the need for more comprehensive adaptive strategies to complement the current tendency to focus on the mitigation of greenhouse gases produced in this region.