Computer-based instruction in qualitative research practices

Abstract As a subject domain, qualitative research practice presents significant problems for instruction. It tends to be poorly codified and sometimes controversial. It is substantially skill-based and calls on a heterogeneous set of skills. And it is a means-domain rather than an end-domain for research students who invariably have widely varying disciplinary and experiential backgrounds when first coming to it. The experience of teaching the subject also suggests some important obstacles to learning good practices. For example, many of the underlying skills (like testing the self-interest of information sources) are skills developed in everyday life: yet new researchers often fail to transfer them to research work. This article describes an instructional system for qualitative research which is based on linking domain problems such as these to particular pedagogic mechanisms, and then linking these mechanisms in turn to various implementation decisions.     

The practical engineer. Making embedded systems year 2000 compliant

Most embedded systems are designed to work on their own, performing only one or two tasks independently of other systems. This paper details how fixing the Millennium bug in such systems will require not only a hardware change but also changes to the embedded software. In many cases, the companies that designed the devices no longer exist. In those whose doors are still open, management's concern with quarterly profit takes precedence over spending to fix a problem that has yet to occur. All the same, a few enlightened managers have realized that, while the costs of making these changes will be enormous, the price of not making them will be staggering     

Dermal uptake of solvents from the vapour phase: an experimental study in humans

An overview of computer models developed since the late seventies, which enable the simulation of the primary effects of spinal cord stimulation (SCS) on nerve fibres, is presented. These models consist of a 3-dimensional volume conductor model, representing anatomical structures and their electrical conductivities, and cable models representing the electrical behaviour of nerve fibres. The characteristics of these models and their relation to anatomy and physiology, as well as the calculation of stimulation-induced electrical fields and their effect on nerve fibre models, are reviewed. It is shown that most characteristics of SCS as predicted by computer modelling correspond well with empirical data. Accordingly, a theoretical framework describing the relations between relevant parameters in SCS is presented. Finally, it is shown how theory and computer modeling are applied to improve the efficacy of SCS by the optimization of its technique, primarily by the design of new epidural electrodes.     

Childhood conditions that predict survival to advanced ages among African-Americans

This paper investigates the social and economic circumstances of childhood that predict the probability of survival to age 85 among African-Americans. It uses a unique study design in which survivors are linked to their records in U.S. Censuses of 1900 and 1910. A control group of age and race-matched children is drawn from Public Use Samples for these censuses. It concludes that the factors most predictive of survival are farm background, having literate parents, and living in a two-parent household. Results support the interpretation that death risks are positively correlated over the life cycle.     

Techniques for rapid quantitative assessment of activity levels in small-group tutorials

OBJECTIVE: To describe a case of pemoline-induced liver failure resulting in liver transplantation. CASE SUMMARY: A 9-year-old white boy, diagnosed with attention deficit/hyperactivity disorder (ADHD) and treated with pemoline, developed signs and symptoms of liver failure. Pemoline therapy was discontinued, but the patient's liver function continued to decline. Ultimately, a liver transplantation was required. DISCUSSION: Pemoline, an agent used in ADHD treatment, has been associated with hepatotoxicity with the majority of cases occurring in pediatric patients. To our knowledge, this is the second reported case of pemoline-induced liver failure resulting in liver transplantation. The mechanism of action remains unclear, with several hypotheses being postulated including hypersensitivity reactions, dose-related phenomena, and autoimmune-mediated reactions. CONCLUSIONS: With increasing evidence linking pemoline to liver failure, this agent should not be considered first-line therapy for ADHD. Prior to initiating therapy, baseline liver function tests should be obtained and closely monitored, and parents and patients should be educated on the signs and symptoms of liver toxicity.     

A generic drug primer: regulatory aspects and scientific concepts

Organisms of Escherichia coli 1829 become alkali sensitized on transfer from pH 7.0 to pH 5.5 but they also secrete extracellular agents which induce alkali sensitivity when added (in neutralized filtrates) to organisms growing at pH 7.0. In contrast, filtrates from cultures grown at pH 7.0 have no effect. Filtrates were inactivated by protease but not by heat treatment in a boiling water-bath, suggesting that a very heat-stable protein is involved in alkali sensitivity induction. A heat-stable low molecular weight component (or components) may also be needed for induction, or the induction protein itself may be of low molecular weight. Strains with lesions in hns, fur or himA produced almost inactive filtrates and it therefore appears that H-NS, Fur and IHF are involved in synthesis of the induction components. As the presence of protease during incubation at pH 5.5 totally abolished alkali sensitization of strain 1829 while inhibition of sensitization induction occurred if the induction components were removed by filtration or dialysis during pH 5.5 incubation, it is proposed that the extracellular induction components (EICs) are essential for the original sensitization response. These results suggest that sensitization induction occurs by a different mechanism to that which is believed to occur for most bacterial inducible response systems; these are claimed to involve exclusively intracellular reactions and components whereas the present response involves functioning of extracellular components.     

Thioredoxin peroxidase from Onchocerca volvulus: a major hydrogen peroxide detoxifying enzyme in filarial parasites

Random screening of an Onchocerca volvulus third-stage (L3) cDNA library identified a highly abundant cDNA encoding a newly discovered antioxidant enzyme, thioredoxin peroxidase (TPx), a member of the peroxidoxin superfamily. This TPx cDNA (Ov-tpx-2) encodes a polypeptide of 199 amino acid residues with a calculated molecular weight of 21,890 Da. The Ov-tpx-2 cDNA represents roughly 2.5% of the total cDNAs from the L3 cDNA library. The gene was expressed in Escherichia coli and the protein product was shown to have antioxidant activity. Antiserum raised against Ov-TPX-2 recognized a native protein from extracts of both the L3 and adult-stages with a molecular weight of 22 kD. The localization and stage-specificity of Ov-TPX-2 protein was analyzed by immunocytochemistry and immunoelectron microscopy using monospecific antibodies. Expression was detected in late first-stage larvae during development in the vector and increased in intensity during differentiation to the infective L3-stage. The antigen was also detected in post-infective larvae and adult worms. In larvae, Ov-TPX-2 protein was predominantly localized to the hypodermis and cuticle, with additional sites in the hypodermal chords and multivesicular bodies. In adult worms, the primary sites of expression were the uterine epithelium and intestine, with additional labeling of the body wall and cuticle. Developing embryos and microfilariae in utero were bathed in Ov-TPX-2 protein discharged from epithelial cells. These results suggest that Ov-TPX-2 may protect the parasites from being damaged by host-generated oxidative stress and that Ov-TPX-2 protein provides the H2O2-detoxifying activity predicted but not previously identified in filarial parasites. Its highly upregulated expression in infective larvae may aid in parasite establishment following transmission to the definitive host.     

Transurethral electrovaporization of the prostate vs. transurethral resection. Results of a multicentric, randomized clinical study on 150 patients

The present study was designed to evaluate tissue contrast characteristics obtained with the spin-lock (SL) technique by comparing the results with those generated with a magnetization transfer(MT)-weighted gradient echo [GRE, echo-time (TE)=40 ms] sequence. Twenty-eight patients with hepatic hemangiomas (n=14), or metastatic liver lesions (n=14) were imaged at 0.1 T by using identical imaging parameters. Gradient echo, single-slice off-resonance MT, and multiple-slice SL sequences were obtained. SL and MT-effects were measured from the focal liver lesions and from normal liver parenchyma. In addition, tissue contrast values for the liver lesions were determined. Statistically significant difference between the SL-effects of the hemangiomas and metastases, and also between the MT-effects of the lesions was observed (p < 0.02). Tissue contrast values for the lesions proved to be quite similar between the SL and MT techniques. Our results indicate that at 0.1 T multiple-slice SL imaging provides MT based tissue contrast characteristics in tissues rich in protein with good imaging efficiency and wide anatomical coverage, and with reduced motion and susceptibility artifacts.     

Multiple kainic acid seizures in the immature and adult brain: ictal manifestations and long-term effects on learning and memory

PURPOSE: While there is increasing evidence that the adverse effects of prolonged seizures are less pronounced in the immature than in the mature brain, there have been few investigations of the long-term effects of recurrent seizures during development. This study examined the effects of multiple administrations of the convulsant kainic acid (KA) on seizure characteristics and spatial learning as a function of brain development. METHODS: To determine the long-term effects of serial KA seizures during ontogeny, saline or convulsant doses of KA were given intraperitoneally 4 times, at 2-day intervals. Immature rats were given KA on P20, P22, P24 and P26; adult rats got KA on P60, P62, P64 and P66. Ictal characteristics and EEGs were recorded. To examine the effects of multiple KA seizures on the retention of spatial learning, water maze testing was performed before (immature group: from P16-19, adult group: from P56-P59) and after (immature: from P60-P63, adult: from P100-P103) KA injections. Finally, histology was performed to compare KA-induced damage at each age. RESULTS: In immature animals, serial KA administration resulted in seizures with a progressively longer onset latency and decreased severity. In contrast, KA serially administered to adult rats caused severe seizures after each of the 4 injections. In immature rats, epileptiform EEG changes were most prominent after the first KA injection, whereas in adults, prolonged paroxysmal EEG patterns were seen after all 4 KA injections. Before KA, both rat pups and adults acquired place learning in the water maze. One month after the final KA injection, there was no deficit in spatial learning retention in the immature group, whereas the adult group had profound impairment compared to age-matched, saline-injected controls. Histology revealed no lesions in immature rats treated multiple times with KA but profound cell loss in hippocampal fields CA4, CA3 and CA1 in rats treated serially with KA as adults. CONCLUSIONS: Previous studies have shown that a single KA injection causes prolonged status epilepticus (which persists for several hours), leading to severe histologic and behavioral sequelae in adult rats but not in pups. Our study extends those findings, demonstrating that immature rats are spared the cognitive and pathological sequelae of multiple injections of convulsant doses of KA as well.