21 research outputs found
Impact of Glass Cockpit Experience on Manual Flight Skills
Modern aircraft employ a wide variety of advanced flight instrument systems that have been designed to reduce pilot workload and promote safe, efficient flight operations. Research to date on advanced flight instrumentation has primarily focused on mode confusion or pilot misinterpretation of system information. A few studies have also identified pilot concern with a reduction in manual flight skills as a result of regular operation in automated modes. This paper addresses that concern in an attempt to identify factors useful to flight curriculum development. Study participants included 110 experienced airline, corporate, and military pilots who were surveyed before and after a training session in a transport category flight training device with round dial instrumentation. An experienced instructor rated participant flight skills during the simulator activity. Study findings suggest that pilots who are more likely to use automated modes of modern glass cockpit aircraft have a less effective crosscheck and reduced manual flight skills. Issues related to advanced flight deck operations and training are discussed
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Risk Factor Analyses for Immune Reconstitution Inflammatory Syndrome in a Randomized Study of Early vs. Deferred ART during an Opportunistic Infection
Background: Immune reconstitution inflammatory syndrome (IRIS) is reported widely in patients initiating antiretroviral therapy (ART). However, few studies are prospective, and no study has evaluated the impact of the timing of ART when allocated randomly during an acute opportunistic infection (OI). Methodology/Principal Findings: A5164 randomized 282 subjects with AIDS-related OIs (tuberculosis excluded), to early or deferred ART. IRIS was identified prospectively using pre-defined criteria. We evaluated associations between IRIS and baseline variables in subjects with follow-up on ART using Wilcoxon and Fisher's exact tests, logistic regression, and Cox models with time-varying covariates. Twenty of 262 (7.6%) subjects developed IRIS after a median of 33 days on ART. Subjects with fungal infections (other than pneumocystis) developed IRIS somewhat more frequently (OR = 2.7; 95% CI: 1.02, 7.2; p-value = 0.06 (using Fisher's exact test)). In Cox models, lower baseline and higher on-treatment CD4+ T-cell counts and percentage were associated with IRIS. Additionally, higher baseline and lower on-treatment HIV RNA levels were associated with IRIS. Corticosteroids during OI management and the timing of ART were not associated with the development of IRIS. Implications: In patients with advanced immunosuppression and non-tuberculous OIs, the presence of a fungal infection, lower CD4+ T-cell counts and higher HIV RNA levels at baseline, and higher CD4+ T-cell counts and lower HIV RNA levels on treatment are associated with IRIS. Early initiation of ART does not increase the incidence of IRIS, and concern about IRIS should not prompt deferral of ART
Cross-species global and subset gene expression profiling identifies genes involved in prostate cancer response to selenium
BACKGROUND: Gene expression technologies have the ability to generate vast amounts of data, yet there often resides only limited resources for subsequent validation studies. This necessitates the ability to perform sorting and prioritization of the output data. Previously described methodologies have used functional pathways or transcriptional regulatory grouping to sort genes for further study. In this paper we demonstrate a comparative genomics based method to leverage data from animal models to prioritize genes for validation. This approach allows one to develop a disease-based focus for the prioritization of gene data, a process that is essential for systems that lack significant functional pathway data yet have defined animal models. This method is made possible through the use of highly controlled spotted cDNA slide production and the use of comparative bioinformatics databases without the use of cross-species slide hybridizations. RESULTS: Using gene expression profiling we have demonstrated a similar whole transcriptome gene expression patterns in prostate cancer cells from human and rat prostate cancer cell lines both at baseline expression levels and after treatment with physiologic concentrations of the proposed chemopreventive agent Selenium. Using both the human PC3 and rat PAII prostate cancer cell lines have gone on to identify a subset of one hundred and fifty-four genes that demonstrate a similar level of differential expression to Selenium treatment in both species. Further analysis and data mining for two genes, the Insulin like Growth Factor Binding protein 3, and Retinoic X Receptor alpha, demonstrates an association with prostate cancer, functional pathway links, and protein-protein interactions that make these genes prime candidates for explaining the mechanism of Selenium's chemopreventive effect in prostate cancer. These genes are subsequently validated by western blots showing Selenium based induction and using tissue microarrays to demonstrate a significant association between downregulated protein expression and tumorigenesis, a process that is the reverse of what is seen in the presence of Selenium. CONCLUSIONS: Thus the outlined process demonstrates similar baseline and selenium induced gene expression profiles between rat and human prostate cancers, and provides a method for identifying testable functional pathways for the action of Selenium's chemopreventive properties in prostate cancer
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ARHGEF9 disease: Phenotype clarification and genotype-phenotype correlation.
ObjectiveWe aimed to generate a review and description of the phenotypic and genotypic spectra of ARHGEF9 mutations.MethodsPatients with mutations or chromosomal disruptions affecting ARHGEF9 were identified through our clinics and review of the literature. Detailed medical history and examination findings were obtained via a standardized questionnaire, or if this was not possible by reviewing the published phenotypic features.ResultsA total of 18 patients (including 5 females) were identified. Six had de novo, 5 had maternally inherited mutations, and 7 had chromosomal disruptions. All females had strongly skewed X-inactivation in favor of the abnormal X-chromosome. Symptoms presented in early childhood with delayed motor development alone or in combination with seizures. Intellectual disability was severe in most and moderate in patients with milder mutations. Males with severe intellectual disability had severe, often intractable, epilepsy and exhibited a particular facial dysmorphism. Patients with mutations in exon 9 affecting the protein's PH domain did not develop epilepsy.ConclusionsARHGEF9 encodes a crucial neuronal synaptic protein; loss of function of which results in severe intellectual disability, epilepsy, and a particular facial dysmorphism. Loss of only the protein's PH domain function is associated with the absence of epilepsy
Micro-CT Based Experimental Liver Imaging Using a Nanoparticulate Contrast Agent: A Longitudinal Study in Mice
BACKGROUND: Micro-CT imaging of liver disease in mice relies on high soft tissue contrast to detect small lesions like liver metastases. Purpose of this study was to characterize the localization and time course of contrast enhancement of a nanoparticular alkaline earth metal-based contrast agent (VISCOVER ExiTron nano) developed for small animal liver CT imaging. METHODOLOGY: ExiTron nano 6000 and ExiTron nano 12000, formulated for liver/spleen imaging and angiography, respectively, were intravenously injected in C57BL/6J-mice. The distribution and time course of contrast enhancement were analysed by repeated micro-CT up to 6 months. Finally, mice developing liver metastases after intrasplenic injection of colon carcinoma cells underwent longitudinal micro-CT imaging after a single injection of ExiTron nano. PRINCIPAL FINDINGS: After a single injection of ExiTron nano the contrast of liver and spleen peaked after 4-8 hours, lasted up to several months and was tolerated well by all mice. In addition, strong contrast enhancement of abdominal and mediastinal lymph nodes and the adrenal glands was observed. Within the first two hours after injection, particularly ExiTron nano 12000 provided pronounced contrast for imaging of vascular structures. ExiTron nano facilitated detection of liver metastases and provided sufficient contrast for longitudinal observation of tumor development over weeks. CONCLUSIONS: The nanoparticulate contrast agents ExiTron nano 6000 and 12000 provide strong contrast of the liver, spleen, lymph nodes and adrenal glands up to weeks, hereby allowing longitudinal monitoring of pathological processes of these organs in small animals, with ExiTron nano 12000 being particularly optimized for angiography due to its very high initial vessel contrast
PET/CT Imaging of c-Myc Transgenic Mice Identifies the Genotoxic N-Nitroso-Diethylamine as Carcinogen in a Short-Term Cancer Bioassay
Background: More than 100,000 chemicals are in use but have not been tested for their safety. To overcome limitations in the cancer bioassay several alternative testing strategies are explored. The inability to monitor non-invasively onset and progression of disease limits, however, the value of current testing strategies. Here, we report the application of in vivo imaging to a c-Myc transgenic mouse model of liver cancer for the development of a short-term cancer bioassay. Methodology/Principal Findings: mCT and 18 F-FDG mPET were used to detect and quantify tumor lesions after treatment with the genotoxic carcinogen NDEA, the tumor promoting agent BHT or the hepatotoxin paracetamol. Tumor growth was investigated between the ages of 4 to 8.5 months and contrast-enhanced mCT imaging detected liver lesions as well as metastatic spread with high sensitivity and accuracy as confirmed by histopathology. Significant differences in the onset of tumor growth, tumor load and glucose metabolism were observed when the NDEA treatment group was compared with any of the other treatment groups. NDEA treatment of c-Myc transgenic mice significantly accelerated tumor growth and caused metastatic spread of HCC in to lung but this treatment also induced primary lung cancer growth. In contrast, BHT and paracetamol did not promote hepatocarcinogenesis. Conclusions/Significance: The present study evidences the accuracy of in vivo imaging in defining tumor growth, tumor load, lesion number and metastatic spread. Consequently, the application of in vivo imaging techniques to transgeni
Evolution of the MRO business: findings from research at the floor level
Presently the airline business is evolving in response to a number of economic factors.
While some of these factors are external, including the cost of fuel and new security
measures, airlines have begun to recognize that survival may depend on their ability to
control the internal factors. New or growing competitive airlines have built their
enterprises on lower labor costs, higher efficiency, greater effectiveness, and the ability to
adjust to customers needs. One component of these successful models is the out sourcing
of work tasks that can be priced at a fixed and per unit basis. Establishing outside aircraft
maintenance arrangements with large Maintenance, Repair, and Overhaul (MRO)
companies is a major trend in today’s airline environment. This trend appears to be
gaining momentum and has the potential to play a significant role in the turnaround
sought by the airlines. Purdue University’s Aviation Technology Department has
completed extensive research into the MRO business, both in the U.S. and overseas,
including China. Much of this research has been concentrated on floor level operations,
revealing many important factors for consideration as this business continues to expand.
The MRO business is a complex business that must answer to a number of different
stakeholders, including airline customer requirements, repair station regulations, EPA,
and OSHA. Given the nature of the business, it is no surprise that interpretations of repair
requirements and FAA policy differ from one station to another. Nonetheless, compliance
with required and accepted maintenance procedures is of fundamental importance and of
primary concern for maintaining safe and efficient airline travel. This paper will focus on
the changes and support of oversight and the need for standardization as the MRO
business expands in the United States and around the world
Sampling Dissolved Gases in Groundwater at in Situ Pressure: A Simple Method for Reducing Uncertainty in Hydrogeological Studies of Coal Seam Gas Exploration
The ability to accurately and precisely measure dissolved gas concentrations in groundwater is crucial for environmental monitoring purposes. Unfortunately, the collection of dissolved gas samples in groundwater is challenging because of the loss of dissolved gas in the groundwater as a result of inadequate sampling methodologies and the need to avoid exposure of the samples to the atmosphere. In environments where water can contain large amounts of methane and carbon dioxide (e.g., coal basins), there is a high probability of separation between the water and gas phases during sample collection, making it impossible to accurately measure the gas concentrations in a groundwater sample. In this paper, we describe the design and development of a novel downhole sampler that is used to collect dissolved gas samples in groundwater at in situ pressure. The sampler was used to collect samples from 26 bores in a proposed coal seam gas field in regional New South Wales, Australia. Comparison of CH4 concentration data showed that the gas concentrations were higher using our methodology than when using alternate methodologies, especially when CH4 concentrations were >10000 μg L–1. Not surprisingly, results from the new methodology suggest that isotopic fractionation occurs when samples are collected using alternate methodologies
Complex Data Integration for Training in Technologically-Advanced Aircraft
Flight data collection systems have been used for many years to help monitor and trend flight parameters to better understand aircraft performance and maintenance. However, this information is rarely used to understand and enhance cognitive/behavioral factors impacting flight and maintenance training. This conceptual paper outlines a strategic research model in the collegiate aviation setting, designed to manage the successful integration of data from technologically-advanced aircraft (TAA) into flight, maintenance, and dispatch training and operations. A critical review of the key issues and approach framework should be discussed in the research community. The model will address issues of organizational change management, training and curriculum modification research to accompany data utilization in conjunction with TAA aircraft integration, safety and human factors issues, and perceptual/attitudinal factors. The model presents a framework for assessing and guiding the potentially revolutionary change inherent when advanced aircraft and their data are integrated into training, maintenance, and operations
Multi-tracer and hydrogeophysical investigation of the hydraulic connectivity between coal seam gas formations, shallow groundwater and stream network in a faulted sedimentary basin
Characterization of geological fault networks in sedimentary basins targeted for coal seam gas development typically use deep-penetrating seismic data. Such methods can reveal the presence of numerous fault zones at depths greater than 100 m but not necessarily show if these extend to the surface or provide a significant degree of hydraulic connectivity between deep and shallower geological formations. Our combined multi-tracer and hydrogeophysical study used transient electromagnetic surveys to image the subsurface in a sedimentary coal seam gas basin (Gloucester Basin, NSW, Australia) and indicated that deep faults (greater than 200 m) from seismic analysis may extend to within metres of the ground surface. Analysis of environmental tracers in surface water and groundwater samples near fault traces showed the presence of hotspots of deeper groundwater from the coal seams discharging into the stream network via the alluvial aquifer. The isotopic composition of methane was extremely variable in groundwater (δC-CH from –81.6 to –29.2‰ V-PDB) and surface water (δ C-CH from –56.0 to –19.9‰ V-PDB), suggesting several sources of methane being recycled in the connected alluvial aquifer and stream network. A He hotspot (1.67 × 10 cm STP g) in the alluvial aquifer close to a fault line showed high methane (463 µg L) with a thermogenic signature (δ C-CH of −62.4‰ and δH-CH of −174.7‰). The Gloucester Basin, which has experienced multiple episodes of complex restructuring, displays high dilation tendency of fractures close to fault damage zones with fracture orientations parallel to the orientation of maximum horizontal stress. As a result, there is increased permeability for wells close to the fault damage zone and with increasing depth. These findings resulted in a robust hydrogeological conceptual model of a faulted basin, which can be used in a monitoring and modelling framework for improved evaluation of risk associated with unconventional gas developments