Effect of seat cushions on human response to +Gz impact

Human response to vertical (+Gz) impact acceleration was evaluated as a function of various seat cushions, including current operational cushions used in such aircraft as the A-10, F-15, and F-111 and proposed alternative cushions comprised of rate-dependent, slow-recovery polyurethane foams. There were 133 tests conducted of volunteer subjects in seven different experimental conditions, using a vertical deceleration tower facility. The mean peak acceleration of the impact carriage for these tests was 9.85 G (S.D. = 0.07) and the mean carriage velocity change was 8.01 m X s-1 (S.D. = 0.05). Resultant seat loads and head and chest accelerations were significantly higher for the F-111 cushion than for the rate-dependent foam cushions, which included cushions comprised of Confor foam or Temper foam. Resultant head and chest accelerations were also significantly higher for the ACES II cushion than for the rate-dependent foam cushions. Therefore, from an impact protection standpoint, the operational cushions were inferior to the proposed alternative cushions. Operational use of rate-dependent foam cushions is recommended to improve the impact protection performance of escape systems. Flight tests conducted by the USAF Strategic Air Command have shown that these cushions enhance crewmember sitting comfort during long-duration missions.     

Acute and subacute dermal toxicity of Break-Free CLP: a weapons cleaning and maintenance compound

Break-Free CLP((R)) is a commercial cleaning, lubricating and preserving compound used in both the military and civilian sectors for maintenance of small- and large-caliber weapons. Like many commercial mixtures, there is very little information available on the toxicity of Break-Free CLP. Studies were conducted to characterize the biological effects of single or repeat dermal application of Break-Free CLP to the clipped backs of CD-1 mice. Break-Free CLP was applied neat, 50 microl three times of week for up to 2 weeks. Foci of epithelial ulceration were observed in skin sections from 22% of Break-Free CLP-treated animals in conjunction with markedly thickened epithelium suggesting that robust epithelial regeneration was occurring in these animals. Skin histopathology of Break-Free CLP-treated animals closely matched the histopathology from mice treated repeatedly with 2% croton oil in acetone (dermal irritation positive control). Serum alkaline phosphatase activity was significantly (P < 0.05) lower for mice treated with Break-Free CLP, 2% croton oil or 7,12-dimethylbenz[a]anthracene (DMBA) compared with negative and vehicle control mice. Skin nitric oxide (NO) levels were not significantly elevated for mice treated with Break-Free CLP but were significantly elevated for mice treated with dermal irritation positive control compound DMBA. The cumulative skin changes in Break-Free CLP-treated animals support conducting a subchronic dermal application study. The observed decreases in serum alkaline phosphatase activity suggest that future studies should include the liver and bone as possible target organs. Additionally, dermal penetration studies could provide key health risk assessment information for characterizing the potential health risks associated with chronic dermal exposure to Break-Free CLP.     

Dissociation of action and object naming: evidence from cortical stimulation mapping

This cortical stimulation mapping study investigates the neural representation of action and object naming. Data from 13 neurosurgical subjects undergoing awake cortical mapping is presented. Our findings indicate clear evidence of differential disruption of noun and verb naming in the context of this naming task. At the individual level, evidence was found for punctuate regions of perisylvian cortex subserving noun and verb function. Across subjects, however, the location of these sites varied. This finding may help explain discrepancies between lesion and functional imaging studies of noun and verb naming. In addition, an alternative coding of these data served to highlight the grammatical class vulnerability of the target response. The use of this coding scheme implicates a role for the supramarginal gyrus in verb-naming behavior. These data are discussed with respect to a functional-anatomical pathway underlying verb naming.     

Method for evaluating broth culture media: application to Haemophilus.

A method was devised to test the growth-promoting ability of a broth medium. The "dilute to extinction" method determines the inoculum required to develop heavy turbidity in a broth with overnight incubation. A statistical method using Poisson distribution was used to show that a single Haemophilus cell can develop heavy turbidity in an optimal broth. The dilute to extinction method was used to evaluate the shelf life of stored media, to titrate the growth factor requirements of Haemophilus, and to evaluate the use of purified hemin and nicotinamide adenine dinucleotide in a broth medium for the growth of Haemophilus. Of the media tested, the most suitable formulation was Mueller-Hinton broth supplemented with 10 microgram of hemin and 10 microgram of nicotinamide adenine dinucleotide per ml. The dilute to extinction method appears to be especially useful in the development of broth media for fastidious organisms. The method could also be used to assure the quality of other broth media which are required to support the growth of small inocula in the clinical or research laboratory.     

A doubly robust estimator for the attributable benefit of a treatment regime

The identification and study of treatment regimes (algorithms or policies for dictating treatments to patients) are a growing area of study in the statistical sciences. Many methods have been put forth to identify the ‘best’ or optimal treatment regime from observed data. Once the optimal treatment regime is identified, a secondary question of interest is to determine the public health impact of that health policy. Simply put, what is the benefit that can be attributed to using such a regime in practice? The attributable benefit of a treatment regime is a measure of the reduction in poor outcomes that would have been observed had the regime of interest been utilized. Methods for identifying the optimal treatment regime can use statistical modeling techniques which are susceptible to model misspecification in the identification of both the optimal treatment regime and its attributable benefit. Using notions from causal inference and building upon previous work, this paper identifies an estimator for attributable benefit that offers a second layer of protection in cases where an outcome regression model may be misspecified. The estimator is dubbed doubly robust in that it is unbiased for the true benefit if either a model for the outcome or a propensity model for treatment is correctly specified. Large sample properties are explored, and two sets of confidence intervals proposed. Simulation studies compare the proposed estimator with previous work, with a focus on model misspecification. The estimator is applied to real data to examine its utility in practice. Copyright © 2014 John Wiley & Sons, Ltd.     

A framework for image-based classification of mitotic cells in asynchronous populations

High content screening (HCS) has emerged an important tool for drug discovery because it combines rich readouts of cellular responses in a single experiment. Inclusion of cell cycle analysis into HCS is essential to identify clinically suitable anticancer drugs that disrupt the aberrant mitotic activity of cells. One challenge for integration of cell cycle analysis into HCS is that cells must be chemically synchronized to specific phases, adding experimental complexity to high content screens. To address this issue, we have developed a rules-based method that utilizes mitotic phosphoprotein monoclonal 2 (MPM-2) marker and works consistently in different experimental conditions and in asynchronous populations. Further, the performance of the rules-based method is comparable to established machine learning approaches for classifying cell cycle data, indicating the robustness of the features we use in the framework. As such, we suggest the use of MPM-2 analysis and its associated expressive features for integration into HCS approaches.     

A partnership approach for Electronic Data Capture in small-scale clinical trials

Amid researchers' growing need for study data management, the CTSA-funded Institute for Translational Health Sciences developed an approach to combine technical and scientific resources with small-scale clinical trials researchers in order to make Electronic Data Capture more efficient. In a 2-year qualitative evaluation we found that the importance of ease of use and training materials outweighed number of features and functionality. EDC systems we evaluated were Catalyst Web Tools, OpenClinica and REDCap. We also found that two other systems, Caisis and LabKey, did not meet the specific user needs of the study group.     

Pericardial fat is associated with carotid stiffness in the Multi-Ethnic Study of Atherosclerosis

Background and aims

Arterial stiffness is a prominent feature of vascular aging and a risk factor for cardiovascular disease (CVD). Fat around the heart and blood vessels (i.e. pericardial fat, Pfat) may contribute to arterial stiffness via a local paracrine effect of adipose tissue on the surrounding vasculature. Thus, we determined the association between Pfat and carotid stiffness in 5770 participants (mean age 62 years, 53% female, 25% African American, 24% Hispanic, and 13% Chinese) from the Multi-Ethnic Study of Atherosclerosis.

Methods and results

Pfat was measured by computed tomography, and ultrasonography of the common carotid artery was used to calculate the distensibility coefficient (DC) and Young's modulus (YM). Lower DC and higher YM values indicate stiffer arteries. Pfat quartile was highly associated with demographic, behavioral, anthropometric, hemodynamic, metabolic, and disease variables in both men and women. After adjusting for height, clinical site, CVD risk factors, and medications, a 1 standard deviation (41.91 cm³) increment in Pfat was associated with a 0.00007 ± 0.00002 1/mmHg lower DC (p = 0.0002) in men and a 48.1 ± 15.1 mmHg/mm higher YM in women (p = 0.002). Additional adjustment for C-reactive protein, coronary artery calcification, and carotid intima-media thickness had only modest effects. More importantly, adjusting for body mass index and waist circumference did not significantly change the overall results.

Conclusion

Higher Pfat is associated with higher carotid stiffness, independent of traditional CVD risk factors and obesity.     

Evaluation of a pilot emergency department linkage to care program for patients previously diagnosed with Hepatitis C

There is a significant number of Emergency Department (ED) patients with known chronic hepatitis C virus (HCV) infection who have not been treated with directly acting antivirals. We implemented a pilot ED-based linkage-to-care program to address this need and evaluated the impact of the program using the HCV Care Continuum metrics. Between March 2015 and May 2016, dedicated patient care navigators identified HCV RNA-positive patients in an urban ED and offered expedited appointments with the on-site viral hepatitis clinic. Patient demographics and care continuum outcomes were abstracted from the EMR and analysed to determine significant factors influencing linkage-to-care (LTC) and treatment initiation rates. The ED linkage-to-care program achieved a 43% linkage-to-care rate (165/384), 22% treatment rate (84/384) and 16% sustained virologic response rate (63/384). Significant associations were found between linkage-to-care and increasing age (OR = 1.03), Medicare insurance (OR = 2.21) and having a primary care physician (PCP) (OR = 4.03). For patients who were linked, the odds of initiating treatment were also positively significantly associated with increasing age (OR = 1.04) and having a PCP (OR = 2.77). For patients who initiated treatment, the odds of sustained virologic response were marginally associated with having a PCP (OR = 4.92).Our ED linkage-to-care program utilized care coordination to successfully link nearly half of approached HCV RNA-positive patients to care. This design can be feasibly replicated by other EDs given limited non-clinical training required for linkage-to-care staff. Adoption of similar programs in other EDs may improve the rates of LTC and treatment initiation for previously diagnosed HCV patients.