261 research outputs found
Matrix-assisted laser desorption/ionization mass spectrometry for the analysis of collected bioaerosols
The goal of this dissertation was to demonstrate collection, detection and identification of microorganisms from bioaerosols using offline matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of proteins. MALDI-MS intact bacteria techniques were adapted for use with an orthogonal MALDI quadrupole-time-of-flight mass spectrometer. Results indicate the instrument is capable of analyzing intact whole-cells. The first phase was to evaluate three bioaerosol samplers, an Andersen N6 single-stage impactor (AI), a cyclone impactor, and a vacuum filter system. The samplers collected test bioaerosols using a constructed bioaerosol exposure chamber (BEC). The BEC allowed all three samplers to operate in parallel. Each sampler demonstrated the ability to successfully collect and detect the test bioaerosol by offline MALDI-MS. Using the TOF-MS spectra from impacted bacteria, the Expert Protein Analysis System\u27s (ExPASy) sequence retrieval system (SRS) was used to search the SWISS-PROT database. A total of 19 unique proteins were identified for E. coli,8 for B. Thuringiensis, and 6 for B. subtilis. Subsequently, cytochrome c and E. coli samples were proteolyzed in situ using trypsin and CNBr. The digestions were done using removable mini-wells. The mini-wells were placed on top of collected spots on the MALDI target and served as a mini chemical reactor for digestion. Using the TOF-MS spectra of the digested samples, peptide mass mapping was done using the MASCOT search engine. A progressive reductive iterative search mapping (PRISM) technique was used in order to assist in optimizing protein matches from E. coli. In this approach, four of seven iterations produced protein matches. To determine the suitability of MS/MS techniques for use with in situ digests, selected fragments from the cytochrome c and E. coli digests was done. MS/MS was successful for cytochrome c, but was unable to produce spectra for E. coli
POLYMER SEAL USE IN CENTRIFUGAL COMPRESSORS – TWO USERS’ EXPERIENCES OVER 15 YEARS
LectureFor over 20 years now, the efficiency and reliability of centrifugal compressors has been enhanced by the application of engineered thermoplastic materials to the eye, shaft, and balance piston labyrinth seals. Traditionally these seals have been manufactured from metallic materials (such as aluminum) and have required relatively large clearances for reliability reasons. By upgrading to carefully selected engineered thermoplastics the clearances can be reduced without sacrificing reliability. Polymer seals maintain their clearances even after typical start up rubs, whereas metallic seals open up during these rubs and are then open for the remainder of that run cycle (3, 4, 5 years or more). Polymer seal upgrades result in increased compressor efficiencies with the added benefit of easier installation.
Of course whenever an upgrade of this type is first pursued the question of reliability and long term sustained success needs to be considered. Replacing a metallic component with a plastic one, in a service where running 24/7 for several years is imperative, needs to be carefully considered. Now that the seals have been successfully applied for over 20 years now, and individual seals have run for 9 years and more, we can evaluate the applicability of these materials to this type of application
Maximizing An Ethylene Plant's Turbomachinery Reliability.
LecturePg. 85-90The ethylene plant in DuPont's major petrochemical complex
in Orange, Texas was designed and built in the late 1960s,
using the latest proven technology of that period. From plant
startup in 1967 to 1981, there were eighteen ethylene plant shutdowns
caused by problems associated with the large compressors
and turbines. After two very long outages which occurred
in 1980 and 1981, an extensive turbomachinery upgrading program
was undertaken to improve utility.
This presentation sets forth reasons for the reliability problems
experienced through 1981 and illustrates the program undertaken
to increase equipment utility. This program has allowed
the ethylene plant to run from 1981 to 1989 with only one
turbomachinery related shutdown
Cost Effective Re-Engineering Of A Propylene Compressor String.
LecturePg. 123-128The discussed rerate method will provide users of turbomachinery with a new, cost/leadtime saving approach to plant upgrades. Although rerates of existing turbomachinery are common, this approach is unique in that the rerate was not performed by the original equipment manufacturer (OEM), yet it involved the utilization of existing aerodynamic hardware instead of the more common situation where all internals are replaced. This involves extensive engineering and design with limited data and increased cooperation between the rerate engineer and the end user. However, the resulting savings have proven to be worth the effort as evidenced by the project discussed. The following key areas of the project are covered in detail. • Project definition and quotation phase • Aerodynamic modelling • Design drafting • Manufacturing and assembly process • Operating performance from startup to present The methods used and the lessons learned in each of the above areas are discussed with the intent to provide turbomachinery users with a detailed example to follow in pursuing the savings that are available through this rerate process
Extreme Events Reveal an Alimentary Limit on Sustained Maximal Human Energy Expenditure
Acknowledgments: We thank the RASUA runners for their participation and the 100 Mile Club ® for developing and supporting RAUSA. Jenny Paltan assisted with isotope analyses. Funding: Hunter College, Loyola Medical School, Grand Valley State University, and Purdue University. J.R.S. was supported by the strategic priority research program of the Chinese Academy of Sciences (grant XDB13030100), the 1000 Talents organization, and a Wolfson merit award from the UK Royal society. Author contributions: All authors contributed to study design and writing the manuscript. H.P. designed DLW analyses for the RAUSA subjects. C.T. collected DLW and other RAUSA data in the field. L.D. collected RMR measures for RAUSA subjects. B.C. organized RAUSA data collection. H.P. and J.R.S. analyzed data on expenditure and weight change, and developed the alimentary constraint model. Competing interests: Authors declare no competing interests. Data and materials availability: All data is available in the main text or the supplementary materials.Peer reviewedPublisher PD
Postnatal prevention of childhood obesity in offspring prenatally exposed to gestational diabetes mellitus : where are we now?
Children exposed to gestational diabetes mellitus (GDM) in utero are at high risk of developing many health problems such as obesity. There is an urgent need to find new strategies to prevent obesity development among high-risk populations such as those children. Accordingly, the aim of this review was to summarize current knowledge on the postnatal prevention of childhood obesity in offspring born from mothers with GDM. Specifically, this review addresses the impact of breastfeeding, complementary feeding practices as well as dietary intake and physical activity during childhood on obesity risk of children exposed to GDM in utero. Furthermore, breast milk composition of diabetic mothers and its potential impact on growth is discussed. According to the available literature, breastfeeding may reduce obesity risk in children exposed to GDM in utero but a longer duration seems necessary to achieve its protective effect against obesity. Detailed analysis of breast milk composition of mothers with GDM will be necessary to fully understand the relationship between breastfeeding and obesity in this specific population. This review highlights the need for more studies addressing the impact of complementary feeding practices and lifestyle habits during childhood on obesity risk of children exposed to GDM in utero
Thermoplastic Labyrinth Seals In Centrifugal Compressors -15 Years Of Experiences
Case Studypg. 553-60
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Paramedic Pain Management Practice with Introduction of a Non-opiate Treatment Protocol
INTRODUCTION: There is concern about the initiation of opiates in healthcare settings due to the risk of future misuse. Although opiate medications have historically been at the core of prehospital pain management, several states are introducing non-opiate alternatives to prehospital care. Prior studies suggest that non-opiate analgesics are non-inferior to opiates for many acute complaints, yet there is little literature describing practice patterns of pain management in prehospital care. Our goal was to describe the practice patterns and attitudes of paramedics toward pain management after the introduction of non-opiates to a statewide protocol.
METHODS: This study was two-armed. The first arm employed a pre/post retrospective chart review model examining medication administrations reported to the Massachusetts Ambulance Trip Information System between January 1, 2017-December 31, 2018. We abstracted instances of opiate and non-opiate utilizations along with patients\u27 clinical course. The second arm consisted of a survey administered to paramedics one year after implementation of non-opiates in the state protocol, which used binary questions and Likert scales to describe beliefs pertaining to prehospital analgesia.
RESULTS: Pain medications were administered in 1.6% of emergency medical services incidents in 2017 and 1.7% of incidents in 2018. The rate of opiate analgesic use was reduced by 9.4% in 2018 compared to 2017 (90.6% vs 100.0%). The absolute reduction in opiate use in 2018 was 3.6%. Women were less likely (odds ratio [OR] = 0.78, 95% confidence interval [CI], 0.69-0.89) and trauma patients were more likely to receive opiates (OR = 2.36, CI, 1.96-2.84). Mean transport times were longer in opiate administration incidents (36.97 vs 29.35 minutes, t = 17.34, p \u3c 0.0001). We surveyed 100 paramedics (mean age 41.98, 84% male). Compositely, 85% of paramedics planned to use non-opiates and 35% reported having done so. Participants planning to use non-opiates were younger and less experienced. Participants indicated that concern about adverse effects, efficacy, and time to effect impacted their practice patterns.
CONCLUSION: The introduction of non-opiate pain medication to state protocols led to reduced opiate administration. Men and trauma patients were more likely to receive opiates. Paramedics reported enthusiasm for non-opiate medications. Beliefs about non-opioid analgesics pertaining to adverse effects, onset time, and efficacy may influence their utilization
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