Use of the web to provide learning support for a large metabolism and nutrition class

To support student learning in a large Metabolism and Nutrition class, we have introduced a web-based package, using a commercially available program, WebCT. The package was developed at a minimal cost and with limited resources. In addition to downloadable (PDF) versions of lecture Powerpoint presentations, tutorial outlines and a practical class exercise, web-based self-directed learning exercises were included to reinforce and extend lecture material in an active learning environment. The web-site also contained a variety of formative and summative assessment tasks that examined both factual recall and higher order thinking Detailed course information, timetables and a bulletin board were also readily accessible. Student usage of the site was generally high, but varied widely between individual students. Students who achieved a high overall score for the course completed on average three times as many formative assessment items and achieved a higher score for all tests than students who did poorly. Student feedback about the site was very positive with the majority of students reporting that the course material and assessment items that were available were useful to their learning. Administration of the course was also facilitated. (C) 2001 IUBMB. Published by Elsevier Science Ltd. All rights reserved.

The use of liquid phase adsorption isotherms for characterization of activated carbons

The characterization of three commercial activated carbons was carried out using the adsorption of various compounds in the aqueous phase. For this purpose the generalized adsorption isotherm was employed, and a modification of the Dubinin-Radushkevich pore filling model, incorporating repulsive contributions to the pore potential as well as bulk liquid phase nonideality, was used as the local isotherm. Eight different flavor compounds were used as adsorbates, and the isotherms were jointly fitted to yield a common pore size distribution for each carbon. The bulk liquid phase nonideality was incorporated through the UNIFAC activity coefficient model, and the repulsive contribution to the pore potential was incorporated through the Steele 10-4-3 potential model. The mean micropore network coordination number for each carbon was also determined from the fitted saturation capacity based on percolation theory. Good agreement between the model and the experimental data was observed. In addition, excellent agreement between the bimodal gamma pore size distribution and density functional theory-cum-regularization-based pore size distribution obtained by argon adsorption was also observed, supporting the validity of the model. The results show that liquid phase adsorption, using adsorptive molecules of different sizes, can be an effective means of characterizing the pore size distribution as well as connectivity. Alternately, if the carbon pore size distribution is independently known, the method can be used to measure critical molecular sizes. (C) 2001 Elsevier Science.

Coupling between replication and packaging of flavivirus RNA: Evidence derived from the use of DNA-based full-length cDNA clones of kunjin virus

In order to study whether flavivirus RNA packaging is dependent on RNA replication, we generated two DNA-based Kunjin virus constructs, pKUN1 and pKUN1dGDD, allowing continuous production of replicating (wild-type) and nonreplicating (with a deletion of the NS5 gene RNA-polymerase motif GDD) full-length Kunjin virus RNAs, respectively, via nuclear transcription by cellular RNA polymerase II. As expected, transfection of pKUN1 plasmid DNA into BHK cells resulted in the recovery of secreted infectious Kunjin virions. Transfection of pKUN1dGDD DNA into BHK cells, however, did not result in the recovery of any secreted virus particles containing encapsidated dGDD RNA, despite an apparent accumulation of this RNA in cells demonstrated by Northern blot analysis and its efficient translation demonstrated by detection of correctly processed labeled structural proteins (at least prM and E) both in cells and in the culture fluid using coimmunoprecipitation analysis with anti-E antibodies. In contrast, when dGDD RNA was produced even in much smaller amounts in PKUN1dGDD DNA-transfected repBHK cells (where it was replicated via complementation), it was packaged into secreted virus particles, Thus, packaging of defective Kunjin virus RNA could occur only when it was replicated. Our results with genome-length Kunjin virus RNA and the results with poliovirus replicon RNA (C, I. Nugent et al,, J, Virol, 73:427-435, 1999), both demonstrating the necessity for the RNA to be replicated before it can be packaged, strongly suggest the existence of a common mechanism for minimizing amplification and transmission of defective RNAs among the quasispecies in positive-strand RNA viruses, This mechanism may thus help alleviate the high-copy error rate of RNA-dependent RNA polymerases.

Assessing the Use of Flexible Assessment

A course which has a large student enrolment consequently puts a heavy load on instructors both in the presentation and the assessment areas. In the School of Economics at the University of Queensland, this is the case for the quantitative analysis subjects. Assessment for many years has been through mid-semester and end of semester exams, as well as Computer Managed Learning (CML) assignments. In 2000 it was decided to incorporate a system of flexible assessment where neither the CML nor the mid-semester exam was compulsory. The outcomes are assessed and the advantages and disadvantages discussed.

The use of perineal ultrasound to quantify levator activity and teach pelvic floor muscle exercises

Perineal ultrasound was used to detect and quantify levator activity by measuring the displacement of the internal urethral meatus against the inferoposterior margin of the symphysis pubis, Women who had previously been instructed in pelvic floor muscle exercises were more likely to contract the levator muscle when asked to do so than were those without previous instruction (P

Experimental infection of Australian brushtail possums, Trichosurus vulpecula (Phalangeridae : Marsupialia), with Ross River and Barmah Forest viruses by use of a natural mosquito vector system

Brushtail possums, Trichosurus vulpecula Kerr, were experimentally infected with Ross River (RR) or Barmah Forest (BF) virus by Aedes vigilax (Skuse) mosquitoes. Eight of 10 animals exposed to RR virus developed neutralizing antibody, and 3 possums developed high viremia for < 48 hr after infection, sufficient to infect recipient mosquitoes. Two of 10 animals exposed to BF virus developed neutralizing antibody. Both infected possums maintained detectable neutralizing antibody to BF for at least 45 days after infection (log neutralization index > 2.0 at 45 days). Eight possums did not develop neutralizing antibody to BF despite exposure to infected mosquitoes. These results suggest that T. vulpecula may potentially act as a reservoir species for RR in urban areas. However, T. vulpecula infected with BF do not develop viremia sufficient to infect mosquitoes and are unlikely to be important hosts for BF.

An equivalent waveguide approach to designing of reflect arrays with the use of variable-size microstrip patches

An equivalent unit cell waveguide approach (WGA) is described to study the behavior of a multilayer reflect array of variable-size patches/dipoles, The approach considers normal incidence of a plane wave on an infinite periodic array of identical radiating elements and introduces an equivalent unit cell waveguide to obtain the reflection coefficient. A field matching technique and method of moments (MoM) is used to determine fields in different layers of the equivalent waveguide. Good agreements for the phase of the reflection coefficient between the proposed model and those published in selected literatures are obtained. (C) 2002 Wiley Periodicals, Inc.