An investigation of fluid transport in porous solids using nuclear magnetic resonance

A commercially available NMR spectrometer has been used to investigate fluid transport within porous solids. Two water-wet porous solids were investigated. The first was a sample of Fontainebleau sandstone, and the second was an idealised porous solid made from a random packing of glass beads. The samples were saturated with two immiscible phases, i.e. an oil and water phase. Pulsed field gradient (PFG) NMR measurements of one- and two-dimensional displacement probability distributions are reported, for steady-state flow and diffusion, within two phase saturated porous solids. Measurements were made with the porous solids prepare in different steady-state saturations. NMR relaxation measurements are also reported. Using the NMR data it was possible to evaluate the physical importance of parameters such as wettability and phase saturation on transport phenomena in two phase saturated porous solids. Various computer simulations were developed to model the experimental data

An investigation of fluid transport in porous solids using nuclear magnetic resonance

A commercially available NMR spectrometer has been used to investigate fluid transport within porous solids. Two water-wet porous solids were investigated. The first was a sample of Fontainebleau sandstone, and the second was an idealised porous solid made from a random packing of glass beads. The samples were saturated with two immiscible phases, i.e. an oil and water phase. Pulsed field gradient (PFG) NMR measurements of one- and two-dimensional displacement probability distributions are reported, for steady-state flow and diffusion, within two phase saturated porous solids. Measurements were made with the porous solids prepare in different steady-state saturations. NMR relaxation measurements are also reported. Using the NMR data it was possible to evaluate the physical importance of parameters such as wettability and phase saturation on transport phenomena in two phase saturated porous solids. Various computer simulations were developed to model the experimental data

Patient Willingness to Have Tests to Guide Antibiotic Use for Respiratory Tract Infections: From the WWAMI Region Practice and Research Network (WPRN).

INTRODUCTION: The majority of consultations for acute respiratory tract infections (RTIs) lead to prescriptions for antibiotics, which have limited clinical benefit. We explored patients' willingness to have blood tests as part of the diagnostic work-up for RTIs, and patient knowledge about antibiotics. METHODS: Patients at 6 family medicine clinics were surveyed. Regression modeling was used to determine independent predictors of willingness to have venous and point-of-care (POC) blood tests, and knowledge of the value of antibiotics for RTIs. RESULTS: Data were collected from 737 respondents (response rate 83.8%), of whom 65.7% were women, 60.1% were white, and 25.1% were current smokers; patients' mean age was 46.9 years. Sex (female), race (white), and a preference to avoid antibiotics were independent predictors of greater level of antibiotic knowledge. A total of 63.1% were willing to have a venous draw and 79% a POC blood test, to help guide antibiotic decision-making. Non-American Indian/Alaskan Native race, current smoking, and greater knowledge of antibiotics were independent predictors of willingness to have a POC test. CONCLUSION: A large majority of patients seemed willing to have POC tests to facilitate antibiotic prescribing decisions for RTIs. Poor knowledge about antibiotics suggests better education regarding antibiotic use might influence patient attitudes towards use of antibiotics for RTIs

Microbial Cycling of C and N in Northern Hardwood Forests Receiving Chronic Atmospheric NO 3 − Deposition

Sugar maple ( Acer saccharum Marsh.)-dominated northern hardwood forests in the upper Lakes States region appear to be particularly sensitive to chronic atmospheric NO 3 − deposition. Experimental NO 3 − deposition (3 g NO 3 − N m −2 y −1 ) has significantly reduced soil respiration and increased the export of DOC/DON and NO 3 − across the region. Here, we evaluate the possibility that diminished microbial activity in mineral soil was responsible for these ecosystem-level responses to NO 3 − deposition. To test this alternative, we measured microbial biomass, respiration, and N transformations in the mineral soil of four northern hardwood stands that have received 9 years of experimental NO 3 − deposition. Microbial biomass, microbial respiration, and daily rates of gross and net N transformations were not changed by NO 3 − deposition. We also observed no effect of NO 3 − deposition on annual rates of net N mineralization. However, NO 3 − deposition significantly increased (27%) annual net nitrification, a response that resulted from rapid microbial NO 3 − assimilation, the subsequent turnover of NH 4 + , and increased substrate availability for this process. Nonetheless, greater rates of net nitrification were insufficient to produce the 10-fold observed increase in NO 3 − export, suggesting that much of the exported NO 3 − resulted directly from the NO 3 − deposition treatment. Results suggest that declines in soil respiration and increases in DOC/DON export cannot be attributed to NO 3 − -induced physiological changes in mineral soil microbial activity. Given the lack of response we have observed in mineral soil, our results point to the potential importance of microbial communities in forest floor, including both saprotrophs and mycorrhizae, in mediating ecosystem-level responses to chronic NO 3 − deposition in Lake States northern hardwood forests.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41375/1/10021_2005_Article_85.pd

Understanding the yeast host cell response to recombinant membrane protein production

Membrane proteins are drug targets for a wide range of diseases. Having access to appropriate samples for further research underpins the pharmaceutical industry's strategy for developing new drugs. This is typically achieved by synthesizing a protein of interest in host cells that can be cultured on a large scale, allowing the isolation of the pure protein in quantities much higher than those found in the protein's native source. Yeast is a popular host as it is a eukaryote with similar synthetic machinery to that of the native human source cells of many proteins of interest, while also being quick, easy and cheap to grow and process. Even in these cells, the production of human membrane proteins can be plagued by low functional yields; we wish to understand why. We have identified molecular mechanisms and culture parameters underpinning high yields and have consolidated our findings to engineer improved yeast host strains. By relieving the bottlenecks to recombinant membrane protein production in yeast, we aim to contribute to the drug discovery pipeline, while providing insight into translational processes

The Impact of Real-Time Whole-Genome Sequencing in Controlling Healthcare-Associated SARS-CoV-2 Outbreaks.

Nosocomial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have severely affected bed capacity and patient flow. We utilized whole-genome sequencing (WGS) to identify outbreaks and focus infection control resources and intervention during the United Kingdom's second pandemic wave in late 2020. Phylogenetic analysis of WGS and epidemiological data pinpointed an initial transmission event to an admission ward, with immediate prior community infection linkage documented. High incidence of asymptomatic staff infection with genetically identical viral sequences was also observed, which may have contributed to the propagation of the outbreak. WGS allowed timely nosocomial transmission intervention measures, including admissions ward point-of-care testing and introduction of portable HEPA14 filters. Conversely, WGS excluded nosocomial transmission in 2 instances with temporospatial linkage, conserving time and resources. In summary, WGS significantly enhanced understanding of SARS-CoV-2 clusters in a hospital setting, both identifying high-risk areas and conversely validating existing control measures in other units, maintaining clinical service overall

Retrospective screening of routine respiratory samples revealed undetected community transmission and missed intervention opportunities for SARS-CoV-2 in the United Kingdom.

In the early phases of the SARS coronavirus type 2 (SARS-CoV-2) pandemic, testing focused on individuals fitting a strict case definition involving a limited set of symptoms together with an identified epidemiological risk, such as contact with an infected individual or travel to a high-risk area. To assess whether this impaired our ability to detect and control early introductions of the virus into the UK, we PCR-tested archival specimens collected on admission to a large UK teaching hospital who retrospectively were identified as having a clinical presentation compatible with COVID-19. In addition, we screened available archival specimens submitted for respiratory virus diagnosis, and dating back to early January 2020, for the presence of SARS-CoV-2 RNA. Our data provides evidence for widespread community circulation of SARS-CoV-2 in early February 2020 and into March that was undetected at the time due to restrictive case definitions informing testing policy. Genome sequence data showed that many of these early cases were infected with a distinct lineage of the virus. Sequences obtained from the first officially recorded case in Nottinghamshire - a traveller returning from Daegu, South Korea - also clustered with these early UK sequences suggesting acquisition of the virus occurred in the UK and not Daegu. Analysis of a larger sample of sequences obtained in the Nottinghamshire area revealed multiple viral introductions, mainly in late February and through March. These data highlight the importance of timely and extensive community testing to prevent future widespread transmission of the virus.Whole genome sequencing of SARS-CoV-2 was funded by COG-UK; COG-UK is supported by funding from the Medical Research Council (MRC) part of UK Research and Innovation (UKRI), the National Institute of Health Research (NIHR) and Genome Research Limited, operating as the Wellcome Sanger Institute

Modeling and characterization of the SPIDER half-wave plate

Spider is a balloon-borne array of six telescopes that will observe the Cosmic Microwave Background. The 2624 antenna-coupled bolometers in the instrument will make a polarization map of the CMB with approximately one-half degree resolution at 145 GHz. Polarization modulation is achieved via a cryogenic sapphire half-wave plate (HWP) skyward of the primary optic. We have measured millimeter-wave transmission spectra of the sapphire at room and cryogenic temperatures. The spectra are consistent with our physical optics model, and the data gives excellent measurements of the indices of A-cut sapphire. We have also taken preliminary spectra of the integrated HWP, optical system, and detectors in the prototype Spider receiver. We calculate the variation in response of the HWP between observing the CMB and foreground spectra, and estimate that it should not limit the Spider constraints on inflation

A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument

We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the Cosmic Microwave Background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when the motors are depowered. A custom-built optical encoder system monitors the bearing angle to an absolute accuracy of +/- 0.1 degrees. The system performed well in Spider during its successful 16 day flight.Comment: 11 pages, 7 figures, Published in Review of Scientific Instruments. v2 includes reviewer changes and longer literature revie