113 research outputs found
Combined Open and Endovascular Stent Grafting of Internal Carotid Artery Fibromuscular Dysplasia: Long Term Results
AbstractBackgroundSymptomatic fibromuscular dysplasia (FMD) of the internal carotid artery (ICA) can present as thrombo-embolic ischemic events, spontaneous or post-traumatic dissection, aneurysmal degeneration or intracranial haemorrhage and needs definitive surgical treatment.Patients and methodsSix patients and nine ICA with FMD were revascularised using a carotid approach with minimal exposure of the common, external and internal carotid arteries for covered stent repair. All patients were female, the age ranged from 30 to 65 years (mean 44).ResultsOne patient suffered from a perioperative transient neurological deficit. Duplex revealed a patent stent. The patient fully recovered after 5h, not showing any changes on repeat CT scans. One patient developed a recurrent laryngeal nerve palsy. The symptoms gradually resolved within 1 month. No perioperative strokes or deaths occurred. During a mean follow up of 48 months (range 13–63) no thromboembolic neurological events, graft occlusions or haemodynamically significant stenoses occurred.ConclusionICA FMD stent grafting is an alternative to open surgery or percutaneous endovascular intervention with excellent long-term results
Recommendations and requirements for soap and hand rub dispensers in healthcare facilities
Hand hygiene is one of the most important measures to prevent transmission of infectious agents and plays a major role in prevention of infection in any type of healthcare setting. While requirements for the efficacy of hand disinfectants are defined in European testing norms such as the EN 1500 for hygienic hand disinfection or EN 12791 for surgical hand preparation, no specific recommendations for hand rub dispensers and liquid soap dispensers have been given yet. Therefore, the intention of the present recommendation on soap and hand rub dispensers in healthcare facilities is to close this gap and to enhance future improvement of dispenser functionality and design. Regardless of manufacture and design of a hand rub or liquid soap dispensers the following requirements shall be met in healthcare facilities
A study of low-energy transfer orbits to the Moon: towards an operational optimization technique
In the Earth-Moon system, low-energy orbits are transfer trajectories from
the earth to a circumlunar orbit that require less propellant consumption when
compared to the traditional methods. In this work we use a Monte Carlo approach
to study a great number of such transfer orbits over a wide range of initial
conditions. We make statistical and operational considerations on the resulting
data, leading to the description of a reliable way of finding "optimal" mission
orbits with the tools of multi-objective optimization
Bacterial migration through punctured surgical gloves under real surgical conditions
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to confirm recent results from a previous study focussing on the development of a method to measure the bacterial translocation through puncture holes in surgical gloves under real surgical conditions.</p> <p>Methods</p> <p>An established method was applied to detect bacterial migration from the operating site through the punctured glove. Biogel™ double-gloving surgical gloves were used during visceral surgeries over a 6-month period. A modified Gaschen-bag method was used to retrieve organisms from the inner glove, and thus-obtained bacteria were compared with micro-organisms detected by an intra-operative swab.</p> <p>Results</p> <p>In 20 consecutive procedures, 194 gloves (98 outer gloves, 96 inner gloves) were examined. The rate of micro-perforations of the outer surgical glove was 10% with a median wearing time of 100 minutes (range: 20-175 minutes). Perforations occurred in 81% on the non-dominant hand, with the index finger most frequently (25%) punctured. In six cases, bacterial migration could be demonstrated microbiologically. In 5% (5/98) of outer gloves and in 1% (1/96) of the inner gloves, bacterial migration through micro-perforations was observed. For gloves with detected micro-perforations (n = 10 outer layers), the calculated migration was 50% (n = 5). The minimum wearing time was 62 minutes, with a calculated median wearing time of 71 minutes.</p> <p>Conclusions</p> <p>This study confirms previous results that bacterial migration through unnoticed micro-perforations in surgical gloves does occur under real practical surgical conditions. Undetected perforation of surgical gloves occurs frequently. Bacterial migration from the patient through micro-perforations on the hand of surgeons was confirmed, limiting the protective barrier function of gloves if worn over longer periods.</p
On the Experimental Analysis of Integral Sliding Modes for Yaw Rate and Sideslip Control of an Electric Vehicle with Multiple Motors
With the advent of electric vehicles with multiple motors, the steady-state and transient cornering responses can be designed and implemented through the continuous torque control of the individual wheels, i.e., torque-vectoring or direct yaw moment control. The literature includes several papers on sliding mode control theory for torque-vectoring, but the experimental investigation is so far limited. More importantly, to the knowledge of the authors, the experimental comparison of direct yaw moment control based on sliding modes and typical controllers used for stability control in production vehicles is missing. This paper aims to reduce this gap by presenting and analyzing an integral sliding mode controller for concurrent yaw rate and sideslip control. A new driving mode, the Enhanced Sport mode, is proposed, inducing sustained high values of sideslip angle, which can be limited to a specified threshold. The system is experimentally assessed on a four-wheel-drive electric vehicle. The performance of the integral sliding mode controller is compared with that of a linear quadratic regulator during step steer tests. The results show that the integral sliding mode controller significantly enhances the tracking performance and yaw damping compared to the more conventional linear quadratic regulator based on an augmented singletrack vehicle model formulation. © 2018, The Korean Society of Automotive Engineers and Springer-Verlag GmbH Germany, part of Springer Natur
On Optimal Two-Impulse Earth-Moon Transfers in a Four-Body Model
In this paper two-impulse Earth-Moon transfers are treated in the restricted four-body problem with the Sun, the Earth, and the Moon as primaries. The problem is formulated with mathematical means and solved through direct transcription and multiple shooting strategy. Thousands of solutions are found, which make it possible to frame known cases as special points of a more general picture. Families of solutions are defined and characterized, and their features are discussed. The methodology described in this paper is useful to perform trade-off analyses, where many solutions have to be produced and assessed
Estimated Benefits of IBWC Rio Grande Flood-Control Projects in the United States
The International Boundary and Water Commission (IBWC) is responsible for
maintaining a series of flood-control projects beginning in New Mexico and extending along the
Rio Grande’s international border dividing the United States and Mexico. A review by the
USIBWC indicate that, over time, the flood-control capability of the levees has been
compromised, possibly to the point where the level of protection is below original-design
capacities. Prior to investing federal monies in the rehabilitation of major flood-system
infrastructure, the U.S. Office of Management and Budget requires an economic analysis of
expected benefits, or losses avoided with implemented protection measures. Recent flood events
along the international border, resulting in significant economic damages and loss of human life,
emphasized the need for a timely assessment of impacts of potential flood-control failure. Given
a short project time line mandated by IBWC and the large geographic extent of the river- and
floodway-levee system, innovative methods were developed to conduct a rapid and preliminary
economic assessment of the flood-control infrastructure. Estimates for four major project areas
relating only to the U.S.-side of the border only (stretching from Caballo Reservoir in New
Mexico to the Rio Grande’s mouth, near Brownsville, TX.) comprise the study’s focus.
Millions populate the cities and towns along these economic reaches of the Rio Grande
where extensive housing, commerce, industry, tourism, and irrigated agricultural production
exist. Areas susceptible to flooding, along with land-use, were identified and quantified through
high-resolution map imagery. Estimates of representative residential, commercial, and industrial
property values and agricultural production values were developed from property assessment
records, economic development councils, crop enterprise budgets and cropping patterns, census
data, previous U.S. Army Corps of Engineers’ flooding studies, etc. Gross economic values of
flood-control benefits for a sample of each of the land-use types were determined and
extrapolated to similar land-use areas in the flood zone. This analytical method provides a rapidassessment of potential flood-control benefits for a single event for each of the four IBWCdesignated
flood-control project areas. An aggregate estimate arrived at by summing the
potential benefits across all four project areas assumes avoidance of, or protection against, a
simultaneous breach in all areas.
Baseline economic benefits for agriculture and developed property along the Rio Grande
Canalization project are estimated at 139.1 million, while those for the Presidio Valley
Flood Control project amount to 167.2 million in flood-control benefits.
Combined, the four project areas provide 183.0 million in other costs
(i.e., emergency, roads, utilities, and vehicles) are added to the baseline estimate, the total floodcontrol
protection benefits provided by the four project areas increases to $506.0 million
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