畅想无线网络的应用

2005年7月,美国国家自然科学基金会NSF资助了一个项目。这个项目的目标是:整合大学、公司和政府中无线移动和传感器网络研究者的研究成果,创新网络结构,并且整理这些成果成为一个连贯的议程。这个计划极大地促进了无线网络的研究发展。这些研究者汇聚在一起,被称为NSF无线移动计划编制组WMPG。不久前,工作组发表了该项目的报告。从本期起,本刊将选择报告中的重点内容进行连续登载。     

Size and shape based chromosome separation in the inertial focusing device

In this paper, we use a spiral channel inertial focusing device for isolation and purification of chromosomes, which are highly asymmetric. The method developed is proposed as a sample preparation process for transchromosomic research. The proposed microfluidics-based chromosome separation approach enables rapid, label-free isolation of bioactive chromosomes and is compatible with chromosome buffer. As part of this work, particle force analysis during the separation process is performed utilizing mathematic models to estimate the expected behavior of chromosomes in the channel and the model validated with experiments employing fluorescent beads. The chromosome sample is further divided into subtypes utilizing fluorescent activated cell sorting , including small condensed chromosomes, single chromosomes, and groups of two chromosomes (four sister chromatids). The separation of chromosome subtypes is realized based on their shape differences in the spiral channel device under high flow rate conditions. When chromosomes become aligned in the shear flow, the balance between the inertial focusing force and the Dean flow drag force is determined by the chromosome projection area and aspect ratio, or shape difference, leading to different focusing locations in the channel. The achieved results indicate a new separation regime in inertial microfluidics that can be used for the separation of non-spherical particles based on particle aspect ratios, which could potentially be applied in fields such as bacteria subtype separation and chromosome karyotyping.     

Linking university and industry: An organizational experience in Mexico

This paper describes the experience gained in the Center for Technological Innovation since its creation three years ago within the National Autonomous University of Mexico. By offering the services of locating clients, drafting and negotiating contracts, providing specialized information services, and project follow-up, the Center pursues the establishment of effective ties between University projects and industrial production. In so doing, its staff informally assumes the critical “dgate-keeper” and “entrepreneur” roles, not easily accepted in other areas of the University.The main difficulties encountered so far have been in developing interdisciplinary projects, providing due academic recognition for technological activities and extending knowledge about innovation throughout the University. On the other hand, a great advantage is the interest shown by the academic community; likewise is UNAM's stability and autonomy, structural characteristics which have stimulated the development of technically sound teams over several decades. To date, the Center has provided support services for 125 projects and has participated in establishing 44 contracts between the University and industry.     

The incompatibility of science and religion sustained: A reply to our critics

This article replies to a number of criticisms levelled at us by Tom Settle, Hugh Lacey, Michael Poole, Brian Woolnough, John Wren-Lewis, and Harold Turner in a series of comments on our paper entitled ‘Is religious education compatible with science education?’ By offering counter-arguments and by clarifying certain misunderstandings, we show that these criticisms fail to affect our position.     

Students' preconceptions of the nature of gases

A total of 1098 students, from second graders to university chemistry students, drew representations of highly magnified views of air at 1.0 atmosphere of pressure and at 0.5 atmosphere of pressure. The drawings were classified and the authors inferred from them a relatively limited number of preconceptions of the nature of gases. Several major trends occurred in the frequencies of these inferred preconceptions held at different grade levels. The majority of the drawings that were not in fairly close agreement with atomic theory seemed to reflect one or more of the following misconceptions: (a) air is a continuous (nonparticulate) substance, (b) gas behavior is similar to liquid behavior, and (c) there is relatively little space between gas particles. The number of drawings that gave evidence of particulate views ranged from 8% for Grades 2–4 to 85% for university chemistry students. However, 33% of the university students' drawings showed highly packed particles, and only 37% showed particles in an approximately correct geometrical distribution. The authors suggest a technique for promoting conceptual change among students who possess alternative views of the nature of gases.     

If star scientists do not patent: The effect of productivity, basicness and impact on the decision to patent in the academic world

We run an Event History Analysis on a sample of Italian researchers in the field of Materials Science, aiming at understanding how the characteristics of the research trajectories followed by scientists in academia affect their opportunities to do development of industrial applications. Results of our estimates suggest that all measures of academic performances have a dual effect, although different in magnitude. Scientists that are moving along applied research trajectories find it easier to produce industrial applications than their colleagues engaged in the quest for very fundamental understanding. We interpret our results by suggesting that, for the former, more academic research results in more exploitable results, hence in more chances to patent; for the latter, more academic research makes it just more unlikely that they will find the time to produce industrial applications. Similar results apply for the low versus high research impact.     

Unusually difficult clinical presentation of an infant suffering from congenital cytomegalovirus (CMV) infection combined with alpha 1-antitrypsin (A1AT) deficiency

Congenital Cytomegalovirus (CMV) infection and alpha 1-antitrypsin (A1AT) deficiency are separately well described entities, but their simultaneous occurrence can pose a special challenge to a clinician, especially dealing with optimal diagnostic as well as therapeutic approach. Congenital CMV infection is the most common vertically transmitted infection in developed countries. In 85–95% of newborns it runs asymptomatic, while in others it is presented with jaundice, petechias, hepatosplenomegaly and central nervous system damage. A1AT deficiency is on the other hand, the most common genetic liver disease in children, and the clinical spectrum varies from the accidentally detected increased levels of transaminases through to the severe infant cholestasis that can progress to cirrhosis. The following case report describes a two-month old male with severe clinical presentation of congenital CMV infection probably exacerbated due to A1AT deficiency comorbidity. The clinical manifestations and unusually difficult clinical signs this infant presented lead to assumption that the additional liver damage exists. Extensive laboratory analyses were performed, including PCR for CMV DNA, A1AT serum concentration, A1AT genotyping, followed and confirmed with phenotyping. Patient was treated parenteral with ganciclovir, what continued with oral valganciclovir and supportive therapy. Intensive and thorough supportive treatment of the infant resulted in satisfactory progress and excellent outcome. Patient was followed-up till the age of 18 months. The presented case provides excellent example about successful overcoming obstacles in differential diagnosis of A1AT in neonates and infants. Medical charts analysis was the methodology used in making this report.     

Metabolic optimisation of the basketball free throw

The free throw (FT) is a fundamental basketball skill used frequently during a match. Most of actual play occurs at about 85% of maximum heart rate (HR). Metabolic intensity, through fatigue, may influence a technically skilled move as the FT is. Twenty-eight under 17 basketball players were studied while shooting FTs on a regular indoor basketball court. We investigated FT accuracy in young male basketball players shooting at three different HRs: at rest, at 50% and at 80% of maximum experimentally obtained HR value. We found no significant FT percentage difference between rest and 50% of the maximum HR (FT percentage about 80%; P > 0.05). Differently, at 80% of the maximum HR the FT percentage decreased significantly by more than 20% (P < 0.001) down to about 60%. No preliminary warm-up is needed before entering game for the FT accuracy. Furthermore, we speculate that time-consuming, cooling-off routines usually performed by shooters before each FT may be functional to improve its accuracy.