185 research outputs found
Propensity score matching in estimating the effect of managerial education on academic planning behavior. Study design: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>In many academic settings teaching a particular topic is applied to every student enrolled in the same academic year, it is a difficult task for researchers to design a randomized control group study. This research aimed to estimate the effect of teaching management and planning on increasing academic planning behavior (APB), using propensity score matching (PSM).</p> <p>Methods</p> <p>In a cross-sectional survey utilizing a self-reported structured questionnaire on a systematic random sample of 421 students in Hanoi Medical University, one of the eight medical schools in Vietnam, this evaluation study adopted regression procedures to assess model fit, then PSM to create a matched control group in order to allow for evaluating the effect of management education.</p> <p>Results</p> <p>The study showed both direct and indirect effects of the education on behavior. After PSM to adjust for the possible confounders to balance statistically two groups - with and without management education, there is statistically a significant difference in APB between these two groups, making a net difference of 18.60% (p < .05). The estimated 18.6 percentage point increase can be translated into the practice of APB by 670 students in the population. This number of academic planners can be attributed to a high recall of important management and planning education.</p> <p>Conclusions</p> <p>The study provided theoretical as well as practical implications to guide the design of the education and evaluation of teaching.</p
Eddy-Current Probe Design
This paper describes theoretical and experimental work directed toward finding the optimum probe dimensions and operating frequency for eddy current detection of half-penny surface cracks in nonmagnetic conducting materials. The study applies to probes which excite an approximately uniform spatial field over the length of the crack at the surface of the material. In practical terms, this means that the probe is not smaller than the crack length in any of its critical dimensions
Reconstructing the three-dimensional GABAergic microcircuit of the striatum
A system's wiring constrains its dynamics, yet modelling of neural structures often overlooks the specific networks formed by their neurons. We developed an approach for constructing anatomically realistic networks and reconstructed the GABAergic microcircuit formed by the medium spiny neurons (MSNs) and fast-spiking interneurons (FSIs) of the adult rat striatum. We grew dendrite and axon models for these neurons and extracted probabilities for the presence of these neurites as a function of distance from the soma. From these, we found the probabilities of intersection between the neurites of two neurons given their inter-somatic distance, and used these to construct three-dimensional striatal networks. The MSN dendrite models predicted that half of all dendritic spines are within 100 mu m of the soma. The constructed networks predict distributions of gap junctions between FSI dendrites, synaptic contacts between MSNs, and synaptic inputs from FSIs to MSNs that are consistent with current estimates. The models predict that to achieve this, FSIs should be at most 1% of the striatal population. They also show that the striatum is sparsely connected: FSI-MSN and MSN-MSN contacts respectively form 7% and 1.7% of all possible connections. The models predict two striking network properties: the dominant GABAergic input to a MSN arises from neurons with somas at the edge of its dendritic field; and FSIs are interconnected on two different spatial scales: locally by gap junctions and distally by synapses. We show that both properties influence striatal dynamics: the most potent inhibition of a MSN arises from a region of striatum at the edge of its dendritic field; and the combination of local gap junction and distal synaptic networks between FSIs sets a robust input-output regime for the MSN population. Our models thus intimately link striatal micro-anatomy to its dynamics, providing a biologically grounded platform for further study
Renal artery stenosis-when to screen, what to stent?
Renal artery stensosis (RAS) continues to be a problem for clinicians, with no clear consensus on how to investigate and assess the clinical significance of stenotic lesions and manage the findings. RAS caused by fibromuscular dysplasia is probably commoner than previously appreciated, should be actively looked for in younger hypertensive patients and can be managed successfully with angioplasty. Atheromatous RAS is associated with increased incidence of cardiovascular events and increased cardiovascular mortality, and is likely to be seen with increasing frequency. Evidence from large clinical trials has led clinicians away from recommending interventional revascularisation towards aggressive medical management. There is now interest in looking more closely at patient selection for intervention, with focus on intervening only in patients with the highest-risk presentations such as flash pulmonary oedema, rapidly declining renal function and severe resistant hypertension. The potential benefits in terms of improving hard cardiovascular outcomes may outweigh the risks of intervention in this group, and further research is needed
Can user testing of a clinical trial patient information sheet make it fit-for-purpose? - a randomized controlled trial
Background:
The participant information sheet (PIS) provided to potential trial participants is a critical part of the process of valid consent. However, there is long-standing concern that these lengthy and complex documents are not fit-for-purpose. This has been supported recently through the application of a performance-based approach to testing and improving readability called user testing. This method is now widely used to improve patient medicine leaflets - determining whether people can find and understand key facts. This study applied for the first time a controlled design to determine whether a PIS developed through user testing had improved readability over the original, using a sheet from a UK trial in acute myeloid leukemia (AML16).
Methods:
In the first phase the performance of the original PIS was tested on people in the target group for the trial. There were three rounds of testing including 50 people in total - with the information revised according to its performance after each of the first 2 rounds. In the second phase, the revised PIS was compared with the original in a parallel groups randomised controlled trial (RCT) A total of 123 participants were recruited and randomly allocated to read one version of the PIS to find and show understanding of 21 key facts.
Results:
The first, developmental phase produced a revised PIS significantly altered in its wording and layout. In the second, trial phase 66% of participants who read the revised PIS were able to show understanding of all aspects of the trial, compared with 15% of those reading the original version (Odds Ratio 11.2; Chi-square = 31.5 p < .001). When asked to state a preference, 87.1% participants chose the revised PIS (Sign test p < .001).
Conclusions:
The original PIS for the AML16 trial may not have enabled valid consent. Combining performance-based user testing with expertise in writing for patients and information design led to a significantly improved and preferred information sheet. User testing is an efficient method for indicating strengths and weaknesses in trial information, and Research Ethics Committees and Institutional Review Boards should consider requesting such testing, to ensure that PIS are fit-for-purpose
Suboptimal Activation of Antigen-Specific CD4+ Effector Cells Enables Persistence of M. tuberculosis In Vivo
Adaptive immunity to Mycobacterium tuberculosis controls
progressive bacterial growth and disease but does not eradicate infection. Among
CD4+ T cells in the lungs of M.
tuberculosis-infected mice, we observed that few produced IFN-γ
without ex vivo restimulation. Therefore, we hypothesized that one mechanism
whereby M. tuberculosis avoids elimination is by limiting
activation of CD4+ effector T cells at the site of infection in
the lungs. To test this hypothesis, we adoptively transferred Th1-polarized
CD4+ effector T cells specific for M.
tuberculosis Ag85B peptide 25 (P25TCRTh1 cells), which trafficked
to the lungs of infected mice and exhibited antigen-dependent IFN-γ
production. During the early phase of infection, ∼10% of P25TCRTh1
cells produced IFN-γ in vivo; this declined to <1% as infection
progressed to chronic phase. Bacterial downregulation of fbpB
(encoding Ag85B) contributed to the decrease in effector T cell activation in
the lungs, as a strain of M. tuberculosis engineered to express
fbpB in the chronic phase stimulated P25TCRTh1 effector
cells at higher frequencies in vivo, and this resulted in CD4+ T
cell-dependent reduction of lung bacterial burdens and prolonged survival of
mice. Administration of synthetic peptide 25 alone also increased activation of
endogenous antigen-specific effector cells and reduced the bacterial burden in
the lungs without apparent host toxicity. These results indicate that
CD4+ effector T cells are activated at suboptimal
frequencies in tuberculosis, and that increasing effector T cell activation in
the lungs by providing one or more epitope peptides may be a successful strategy
for TB therapy
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