299 research outputs found
Combustor design and analysis using the Rocket Combustor Interactive Design (ROCCID) methodology
The ROCket Combustor Interactive Design (ROCCID) Methodology is a newly developed, interactive computer code for the design and analysis of a liquid propellant rocket combustion chamber. The application of ROCCID to design a liquid rocket combustion chamber is illustrated. Designs for a 50,000 lbf thrust and 1250 psi chamber pressure combustor using liquid oxygen (LOX)RP-1 propellants are developed and evaluated. Tradeoffs between key design parameters affecting combustor performance and stability are examined. Predicted performance and combustion stability margin for these designs are provided as a function of the combustor operating mixture ratio and chamber pressure
Silage Corn Hybrid Response to Row Width and Plant Density in the Intermountain West
Corn (Zea mays L.) hectarage has increased rapidly in Utah and Idaho in recent years due to expansion of the dairy industry, but little is known about corn production practices that optimize yield and quality of silage corn in semi-arid irrigated cropping systems. The objective of this study was to determine the dry matter yield and quality effects of corn hybrids grown in different plant densities and row widths in the Intermountain West. Field experiments were conducted under irrigation in 2015 and 2016 at locations near North Logan, Utah and Jerome, Idaho. The experimental design was a randomized complete block in a split-split plot arrangement with four replications. The whole plot treatment was hybrid (DKC 49-29, DKC 56-54, and DKC 61-88), the sub-plot treatment was row width (76 and 51-cm), and the sub-sub plot treatment was plant density (61,776 to 123,552 plants ha-1 at intervals of 12,355 plants ha-1). The 51-cm row width resulted in forage dry matter yield increases of 4-7% over corn in 76-cm rows. Hybrids differed in response to row width, with no difference detected for the 99-RM hybrid but a significant yield increase for the 106- and 111-RM hybrids by planting in narrow rows. Yield increased quadratically as plant population increased from 61,776 to 123,552 plants ha-1 for all hybrids. The only forage nutritive value that was influenced by row spacing was crude protein (CP), where the 76-cm row spacing showed a 4.5% advantage over the 51-cm row width. Starch increased approximately 3% from the lowest to highest plant densities tested. Net returns showed possible positive increases when comparing row width adjustments. Silage corn yield and quality in the Intermountain West appears to be optimized in 51-cm rows at a plant population between 86,487 and 98,842 plants ha-1
Irrigated Alfalfa Variety Performance, 2011-2014; North Logan, Utah
Alfalfa is the most important crop in Utah, both in terms of acreage and revenue. Although often overlooked, one of the most critical decisions made in alfalfa production is determining which variety to plant. This fact sheet summarizes dry matter (DM) yields of alfalfa varieties during 4 years at the Utah Agricultural Experiment Station Greenville Farm in North Logan (Cache Co.)
Intersections of climate justice
This packet covers current information on climate justice issues in Minnesota including: Latinx immigration, public health, Black Lives Matter, native rights, LGBTQIA+ community, Somali livelihoods, and just transition.
We hope to help realize how we are connected to the climate crisis, identify action items for individuals, and build an understanding of how the crisis may affect our neighbors with different experiences. We believe that exchanging knowledge and raising awareness of local issues are essential to build a lasting and welcoming movement to secure healthy and happy livelihoods for all
Incorporation of doxorubicin in different polymer nanoparticles and their anticancer activity
Background: Nanoparticles are under investigation as carrier systems for anticancer drugs. The expression of efflux transporters such as the ATP-binding cassette (ABC) transporter ABCB1 is an important resistance mechanism in therapy-refractory cancer cells. Drug encapsulation into nanoparticles has been shown to bypass efflux-mediated drug resistance, but there are also conflicting results. To investigate whether easy-to-prepare nanoparticles made of well-tolerated polymers may circumvent transporter-mediated drug efflux, we prepared poly(lactic-co-glycolic acid) (PLGA), polylactic acid (PLA), and PEGylated PLGA (PLGA-PEG) nanoparticles loaded with the ABCB1 substrate doxorubicin by solvent displacement and emulsion diffusion approaches and assessed their anticancer efficiency in neuroblastoma cells, including ABCB1-expressing cell lines, in comparison to doxorubicin solution.
Results: The resulting nanoparticles covered a size range between 73 and 246 nm. PLGA-PEG nanoparticle preparation by solvent displacement led to the smallest nanoparticles. In PLGA nanoparticles, the drug load could be optimised using solvent displacement at pH 7 reaching 53 µg doxorubicin/mg nanoparticle. These PLGA nanoparticles displayed sustained doxorubicin release kinetics compared to the more burst-like kinetics of the other preparations. In neuroblastoma cells, doxorubicin-loaded PLGA-PEG nanoparticles (presumably due to their small size) and PLGA nanoparticles prepared by solvent displacement at pH 7 (presumably due to their high drug load and superior drug release kinetics) exerted the strongest anticancer effects. However, nanoparticle-encapsulated doxorubicin did not display increased efficacy in ABCB1-expressing cells relative to doxorubicin solution.
Conclusion: Doxorubicin-loaded nanoparticles made by different methods from different materials displayed substantial discrepancies in their anticancer activity at the cellular level. Optimised preparation methods resulted in PLGA nanoparticles characterised by increased drug load, controlled drug release, and high anticancer efficacy. The design of drug-loaded nanoparticles with optimised anticancer activity at the cellular level is an important step in the development of improved nanoparticle preparations for anticancer therapy. Further research is required to understand under which circumstances nanoparticles can be used to overcome efflux-mediated resistance in cancer cells
The pharmacological rationale for combining muscarinic receptor antagonists and beta-adrenoceptor agonists in the treatment of airway and bladder disease
Muscarinic receptor antagonists and beta-adrenoceptor agonists are used in the treatment of obstructive airway disease and overactive bladder syndrome. Here we review the pharmacological rationale for their combination. Muscarinic receptors and beta-adrenoceptors are physiological antagonists for smooth muscle tone in airways and bladder. Muscarinic agonism may attenuate beta-adrenoceptor-mediated relaxation more than other contractile stimuli. Chronic treatment with one drug class may regulate expression of the target receptor but also that of the opposing receptor. Prejunctional beta(2)-adrenoceptors can enhance neuronal acetylcholine release. Moreover, at least in the airways, muscarinic receptors and beta-adrenoceptors are expressed in different locations, indicating that only a combined modulation of both systems may cause dilatation along the entire bronchial tree. While all of these factors contribute to a rationale for a combination of muscarinic receptor antagonists and beta-adrenoceptor agonists, the full value of such combination as compared to monotherapy can only be determined in clinical studies
Water permeation through stratum corneum lipid bilayers from atomistic simulations
Stratum corneum, the outermost layer of skin, consists of keratin filled
rigid non-viable corneocyte cells surrounded by multilayers of lipids. The
lipid layer is responsible for the barrier properties of the skin. We calculate
the excess chemical potential and diffusivity of water as a function of depth
in lipid bilayers with compositions representative of the stratum corneum using
atomistic molecular dynamics simulations. The maximum in the excess free energy
of water inside the lipid bilayers is found to be twice that of water in
phospholipid bilayers at the same temperature. Permeability, which decreases
exponentially with the free energy barrier, is reduced by several orders of
magnitude as compared to with phospholipid bilayers. The average time it takes
for a water molecule to cross the bilayer is calculated by solving the
Smoluchowski equation in presence of the free energy barrier. For a bilayer
composed of a 2:2:1 molar ratio of ceramide NS 24:0, cholesterol and free fatty
acid 24:0 at 300K, we estimate the permeability P=3.7e-9 cm/s and the average
crossing time \tau_{av}=0.69 ms. The permeability is about 30 times smaller
than existing experimental results on mammalian skin sections.Comment: latex, 8 pages, 6 figure
Repeatability of Multiparametric Prostate MRI Radiomics Features
In this study we assessed the repeatability of the values of radiomics
features for small prostate tumors using test-retest Multiparametric Magnetic
Resonance Imaging (mpMRI) images. The premise of radiomics is that quantitative
image features can serve as biomarkers characterizing disease. For such
biomarkers to be useful, repeatability is a basic requirement, meaning its
value must remain stable between two scans, if the conditions remain stable. We
investigated repeatability of radiomics features under various preprocessing
and extraction configurations including various image normalization schemes,
different image pre-filtering, 2D vs 3D texture computation, and different bin
widths for image discretization. Image registration as means to re-identify
regions of interest across time points was evaluated against human-expert
segmented regions in both time points. Even though we found many radiomics
features and preprocessing combinations with a high repeatability (Intraclass
Correlation Coefficient (ICC) > 0.85), our results indicate that overall the
repeatability is highly sensitive to the processing parameters (under certain
configurations, it can be below 0.0). Image normalization, using a variety of
approaches considered, did not result in consistent improvements in
repeatability. There was also no consistent improvement of repeatability
through the use of pre-filtering options, or by using image registration
between timepoints to improve consistency of the region of interest
localization. Based on these results we urge caution when interpreting
radiomics features and advise paying close attention to the processing
configuration details of reported results. Furthermore, we advocate reporting
all processing details in radiomics studies and strongly recommend making the
implementation available
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