A comparison of two methods in acquiring stimulus-response curves with transcranial magnetic stimulation

Background
The stimulus–response (S–R) curve is a well accepted constituent in transcranial magnetic stimulation (TMS) studies. However, it has been suggested that parameters of the S–R curve differ when stimuli are provided in a “ramped” (measured steps from low to high intensity), or “random” fashion.

Hypothesis
We hypothesized that there would be no difference in the parameters of the S–R curve between either methodologies.

Methods
Using a randomised cross-over design, 10 healthy participants (29.6 ± 6.4 yrs, 3 f) completed “ramped” or “random” curves in biceps brachii (BB) and first dorsal interosseous (FDI) muscles of both limbs. Curves were compared using mixed-factor ANOVA and correlated between limbs and methodologies.

Results
No differences (P > 0.05) and high correlations (range 0.71–0.97; P < 0.001) were observed in BB and FDI data between curves.

Conclusions
This study demonstrated that either methodology provides similar parameters of the S–R curve in healthy participants.

Recovering private data : a comparison of three methods

We examine a recent proposal for data privatization by testing it agalnst three well-known attacks. We show that all three attacks successfully retrieve the original datta. We compare the strengths of the three attacks. Finally, we indicate how the data privatization method examined can be modified to assist it to withstand these attacks.

The use of mixed methods in health research

 In this chapter you will learn:
- what is meant by 'mixed methods'
- about the different types of 'mixed methods'
- what uses mixed methods have in health research
- about the advantages and diadvantages of mixed methods
- approaches to the critical appraisal of mixed methods studies
- what are the challenges in using mixed methods

The safety and effectiveness of different methods of ear wax removal: a systematic review and economic evaluation

Build-up of earwax is a common reason for attendance in primary care. Current practice for earwax removal generally involves the use of a softening agent, followed by irrigation of the ear if required. However, the safety and benefits of the different methods of removal are not known for certain.

Refraction in children: a comparison of two methods of accommodation control

Purpose: 

Visualization of HIV-1 interactions with penile and foreskin epithelia: clues for female-to-male HIV transmission

To gain insight into female-to-male HIV sexual transmission and how male circumcision protects against this mode of transmission, we visualized HIV-1 interactions with foreskin and penile tissues in ex vivo tissue culture and in vivo rhesus macaque models utilizing epifluorescent microscopy. 12 foreskin and 14 cadaveric penile specimens were cultured with R5-tropic photoactivatable (PA)-GFP HIV-1 for 4 or 24 hours. Tissue cryosections were immunofluorescently imaged for epithelial and immune cell markers. Images were analyzed for total virions, proportion of penetrators, depth of virion penetration, as well as immune cell counts and depths in the tissue. We visualized individual PA virions breaching penile epithelial surfaces in the explant and macaque model. Using kernel density estimated probabilities of localizing a virion or immune cell at certain tissue depths revealed that interactions between virions and cells were more likely to occur in the inner foreskin or glans penis (from local or cadaveric donors, respectively). Using statistical models to account for repeated measures and zero-inflated datasets, we found no difference in total virions visualized at 4 hours between inner and outer foreskins from local donors. At 24 hours, there were more virions in inner as compared to outer foreskin (0.0495 +/- 0.0154 and 0.0171 +/- 0.0038 virions/image, p = 0.001). In the cadaveric specimens, we observed more virions in inner foreskin (0.0507 +/- 0.0079 virions/image) than glans tissue (0.0167 +/- 0.0033 virions/image, p<0.001), but a greater proportion was seen penetrating uncircumcised glans tissue (0.0458 +/- 0.0188 vs. 0.0151 +/- 0.0100 virions/image, p = 0.099) and to significantly greater mean depths (29.162 +/- 3.908 vs. 12.466 +/- 2.985 μm). Our in vivo macaque model confirmed that virions can breach penile squamous epithelia in a living model. In summary, these results suggest that the inner foreskin and glans epithelia may be important sites for HIV transmission in uncircumcised men.

Evaluation of electrochemical methods for determination of the seebeck coefficient of redox electrolytes

Recent advances in thermoelectrochemical cells, which are being developed for harvesting low grade waste heat, have shown the promise of cobalt bipyridyl salts as the active redox couple. The Seebeck coefficient, Se, of a redox couple determines the open circuit voltage achievable, for a given temperature gradient, across the thermoelectrochemical cell. Thus, the accurate determination of this thermodynamic parameter is key to the development and study of new redox electrolytes. Further, techniques for accurate determination of Se using only one half of the redox couple reduces the synthetic requirements. Here, we compare three different experimental techniques for measuring Se of a cobalt tris(bipyridyl) redox couple in ionic liquid electrolytes. The use of temperature dependent cyclic voltammetry (CV) in isothermal and non-isothermal cells was investigated in depth, and the Se values compared to those from thermo-electromotive force measurements. Within experimental error, the Se values derived from CV methods were found to be in accordance with those obtained from electromotive force (emf) measurements. The applicability of cyclic voltammetry techniques for determining Se when employing only one part of the redox couple was demonstrated.

The use of mixed methods in drug discovery: integrating qualitative methods into clinical trials

Contemporary methods in clinical trials are pivoted around hypothesis confirmation, not generation. This is a problem for new drug discovery, since the pharmacokinetic or receptor profile of most novel agents do not link to pathophysiology, which is very poorly understood. Therefore, it is difficult to impute the therapeutic potential of a candidate agent. Most psychotropic agents were discovered serendipitously, either through careful clinical observation or by researchers finding unexpected associations in datasets. Methods that increase the ability to detect latent signals in data are needed. These include mixed methods that incorporate qualitative methods into randomized controlled trials.

This chapter proposes a methodology for the integration of mixed methods in clinical trials, fusing qualitative and quantitative methods, and presents an exemplar using this approach.

Mixed methods show potential for signal detection, hypothesis generation, and associations that may be otherwise undetected in traditional clinical trials.

Cost-effectiveness of recruitment methods in a population-based epidemiological study: the Melbourne Visual Impairment Project

The cost-effectiveness of five recruitment methods was evaluated to determine the best method of encouraging eligible persons to participate in the Melbourne Visual Impairment Project (a population-based epidemiological study). The evaluation was divided into two phases. Phase 1 included one of two types of initial contact, by direct personal contact or by telephone. Phase 2 involved recruiting residents after an attempt had been made by either the telephone or the doorstep approach, and included a second attempt by a field interviewer, subsequent attempts by senior field staff, and finally, financial incentives. The cost-effectiveness of each method was determined by dividing the approach's cost by the effectiveness ratio. We identified 269 eligible households with 356 eligible residents. An 89 per cent response rate was achieved at the examination centre, comprising 61 per cent from Phase 1 and 28 per cent from Phase 2. Although both recruitment methods in Phase 1 were equally cost-effective, there was a significant difference in the effectiveness of each method in actually recruiting residents. The doorstep method was more costly per attender but was far more effective at 76 per cent recruitment than the telephone method at 47 per cent (P < 0.001). We have demonstrated a practical two-stage approach (the doorstep method in Phase 1 and follow-up strategies in Phase 2) to population-based recruitment involving the middle to elderly age group that should be relevant to many epidemiological studies.