30 research outputs found
Experiments with the REMUS AUV
This thesis centers around actual field operations and post-mission analysis of data acquired using a REMUS AUV operated by the Naval Postgraduate School Center for Autonomous Underwater Vehicle Research. It was one of many platforms that were utilized for data collection during AOSN II, (Autonomous Oceanographic Sampling Network II), an ONR sponsored exercise for dynamic oceanographic data taking and model based analysis using adaptive sampling. The vehicle's ability to collect oceanographic data consisting of conductivity, temperature, and salinity during this experiment is assessed and problem areas investigated. Of particular interest are the temperature and salinity profiles measured fromlong transect runs of 18 Km. length into the southern parts of Monterey Bay. Experimentation with the REMUS as a mine detection asset was also performed. The design and development of the mine hunting experiment is discussed as well as its results and their analysis. Of particular interest in this portion of the work is the issue relating to repeatability and precision of contact localization, obtained from vehicle position and sidescan sonar measurements.http://archive.org/details/experimentswithr109451533Lieutenant, United States NavyApproved for public release; distribution is unlimited
Are a âcan doâ Attitude and a can of Red Bull Enough? Workload and Fatigue in High-stakes, High-demand Carrier Sortie Operations
AbstractThe purpose of this investigation was to examine the role of fatigue and crew endurance in human performance of Carrier Sortie requirements; this mission capability involves high-stakes, high-demand, high-tempo operations in a challenging maritime environment. The researchers engaged with a panel of Nimitz crewmembers for a discussion of workload, notional schedules, and endurance risk factors. Workload was examined with models that consider the human capacity for sustaining. The investigation found that more attention is paid to physical fatigue, compared to cognitive or mental fatigue. Crewmembers emphasized that crew has a âcan doâ attitude to combat fatigue; the crew stated that âpride and adrenaline overpower fatigueâŠplus coffee and Red Bull.â They indicated that this results in good initiative, but at times bad judgment while trying to accomplish the work. The current research posits that fatigue is likely to reduce the ability of crewmembers to tolerate sustained performance and associated increased physiological and cognitive costs. However, the authors also recognize the limits of fatigue science with regard to predicting human capacity in intense operational and combat conditions. There is much anecdotal information to suggest that sailors are managing fatigue despite the predictions of various fatigue models. As a result, we cannot yet predict with certainty when the accumulated workload and fatigue of the individual sailor will be untenable, or identify critical thresholds of degraded cognitive capacity and decision making. Rather than rely solely on fatigue prediction software, it is recommended that potential mitigations are considered that might provide the crew more tools to manage endurance as a fatigue abatement strategy. The development of a crew endurance program to mitigate the risks posed by fatigue and reduced alertness during carrier sortie operations would identify risks relating to fatigue and alertness, and generate solutions to mitigate these risks by controlling exposure to endurance risk factors during normal operations so that the crew will be better prepared to respond to any operational demand
Nanofibrous Biocomposite Prosthetic Vascular Graft
The present invention provides a bioactive, small-diameter (typically less than 6 mm in internal diameter) vascular graft prosthesis, and is a textile conduit preferably manufactured using a novel electrospinning perfusion methodology. One preferred embodiment is a nanofibrous biocomposite textile conduit which comprises a prepared liquid admixture of polyester (Dacron), a biodurable implantable synthetic polymer, and Type IV collagen, an extracellular matrix protein. This prepared admixture and blending of diverse fibrous matter is utilized in a novel electrospinning perfusion process to form a small-diameter (less than 6 mm) fabricated textile conduit, a discrete article of manufacture, which then serves as an antecedent tangible workpiece for a subsequently-made prosthetic vascular graft construct
Electrospinning Process for Making a Textile Suitable for use as a Medical Article
The present invention is a bioactive, nanofibrous material construct which is manufactured using a unique electrospinning perfusion methodology. One embodiment provides a nanofibrous biocomposite material formed as a discrete textile fabric from a prepared liquid admixture of (i) a non-biodegradable durable synthetic polymer; (ii) a biologically active agent; and (iii) a liquid organic carrier. These biologically-active agents are chemical compounds which retain their recognized biological activity both before and after becoming non-permanently bound to the formed textile material; and will become subsequently released in-situ as discrete freely mobile agents from the fabric upon uptake of water from the ambient environment
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
Rapid, Portable, Multiplexed Detection of Bacterial Pathogens Directly from Clinical Sample Matrices
Enteric and diarrheal diseases are a major cause of childhood illness and death in countries with developing economies. Each year, more than half of a million children under the age of five die from these diseases. We have developed a portable, microfluidic platform capable of simultaneous, multiplexed detection of several of the bacterial pathogens that cause these diseases. This platform can perform fast, sensitive immunoassays directly from relevant, complex clinical matrices such as stool without extensive sample cleanup or preparation. Using only 1 ”L of sample per assay, we demonstrate simultaneous multiplexed detection of four bacterial pathogens implicated in diarrheal and enteric diseases in less than 20 min
Development of an infection-resistant, bioactive wound dressing surface
Trauma, whether caused by an accident or in an intentional manner, results in significant morbidity and mortality. The goal of this study was to develop a novel biomaterial surface in vitro and ex vivo that provides both localized infection resistance nd hemostatic properties. Our hypothesis is that a combination of specific surface characteristics can be successfully incorporated into a single biomaterial. Functional groups were created with woven Dacron (Cntrl) material via exposure to ethylenediamine (C-EDA). The antibiotic ciprofloxacin (Cipro) was then applied to the C-EDA material using pad/autoclave technique (C-EDA-AB) followed by surface immobilization of the coagulation cascade enzyme thrombin (C-EDA-AB-Thrombin). Antimicrobial activity by the C-EDA-AB surface persisted for 5 days compared with Cntrl and dipped controls, which lasted \u3c1 h. C-EDA-AB-Thrombin surfaces had 2.6- and 105-fold greater surface thrombin activity compared with nonspecifically bound thrombin and Cipro-dyed surfaces, respectively. Surface thrombus formation ex vivo was evident after 1 min of exposure, with thrombus organization evident by 2.5 min. In contrast, C-EDA-AB and Cntrl segments showed only blood protein adsorption on the fibers. Thus, this study demonstrated that Cipro and thrombin can be simultaneously incorporated onto a biomaterial surface while maintaining their respective biological activities. © 2005 Wiley Periodicals, Inc