442 research outputs found
The effects of corticosteroids and nonsteroidal anti-inflammatory drugs, including aspirin, on coagulation
The immune and coagulation systems have numerous interactions, as evidenced by the increased risk of venous thromboembolism in inflammatory bowel disease. In general, proinflammatory states are prothrombotic, while a reduction in inflammation reduces thrombotic risk. Corticosteroids, such as hydrocortisone and prednisone, tend to reduce inflammation and thus thrombosis, while being prothrombotic in non-inflammatory states, e.g. Cushing’s syndrome. The nonsteroidal anti-inflammatory drugs also have a dual effect, through interaction with different cyclo-oxygenase enzyme isoforms, on platelets and the vascular endothelium.Keywords: coagulation, corticosteroids, nonsteroidal anti-inflammatory drugs, NSAID
Oral to nasal endotracheal tube exchange using both video and flexible laryngoscopes
This case describes the use of a video laryngoscope and flexible intubation scope to facilitate the exchange of an oral endotracheal tube for a nasal endotracheal tube in a patient with a potentially difficult airway
Sensitivity to Rate of Change in Gains Applied by Redirected Walking
Redirected walking allows for natural locomotion in virtual environments that are larger than a user’s physical environment. The mapping between real and virtual motion is modified by scaling some aspect of motion. As a user traverses the virtual environment these modifications (or gains) must be dynamically adjusted to prevent collision with physical obstacles. A significant body of work has established perceptual thresholds on rates of absolute gain, but the effect of changing gain is little understood.
We present the results of a user study on the effects of rate of gain change. A psychophysical experiment was conducted with 21 participants. Each participant completed a series of two-alternative forced choice tasks in which they determined whether their virtual motion differed from their physical motion while experiencing one of three different methods of gain change: sudden gain change, slow gain change and constant gain. Gain thresholds were determined by 3 interleaved 2-up 1-down staircases, one per condition. Our results indicate that slow gain change is significantly harder to detect than sudden gain change
Abundance of Soil-Borne Entomopathogenic Fungi in Organic and Conventional Fields in the Midwestern USA with an Emphasis on the Effect of Herbicides and Fungicides on Fungal Persistence
Entomopathogenic fungi (EPF) are widespread in agricultural fields and help suppress crop pests. These natural enemies may be hindered by certain agronomic practices associated with conventional agriculture including the use of pesticides. We tested whether the abundance of EPF differed between organic and conventional fields, and whether specific cropping practices and soil properties were correlated with their abundance. In one year of the survey, soil from organic fields and accompanying margins had significantly more EPF than conventional fields and accompanying margins. Regression analysis revealed that the percentage of silt and the application of organic fertilizer were positively correlated with EPF abundance; but nitrogen concentration, tillage, conventional fields, and margins of conventional fields were negatively correlated with EPF abundance. A greenhouse experiment in which fungicides and herbicides were applied to the soil surface showed no significant effect on EPF. Though organic fields were perceived to be more suitable environments for EPF, abiotic factors and cropping practices such as tillage may have greater impacts on the abundance of EPF. Also, fungicides and herbicides may not be as toxic to soil-borne EPF as originally thought
Mechanical Seals
Discussion GroupMechanical seals are the most common method of sealing industrial centrifugal pumps
and other rotary equipment. Although the basic concepts of a seal is simple,
successfully using seals requires an understanding of the selection and operational
requirements which can be unique for a specific application. In this discussion group,
we will cover many of these considerations along with other application experiences
from end users and seal OEMs. The discussion group will actively solicit topics from the
attendees so the discussions will address real-world problems and challenges faced by
the group.
Typical topics covered in this discussion group include:
Changes in upcoming API 682 4th edition
Air testing of seals in pumps prior to installation
Challenges with low temperatures sealing
Effective leakage containment of single seals
Strengths and weaknesses in Plan 53A, 53B, and 53C piping plans
Considerations when sealing abrasive slurries
How to apply dual pressurized gas seals
Mechanical seals for multiphase applications
Advances in seal face materials
Process for handling problem pump and seal applications
Definition of mean time between failure and industry best practices
How and when to use split seal
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