738 research outputs found
Saturn S-IB Stage assembly and test report, S-IB-1
Manufacture, assembly, and static tests of Saturn S-IB-1 stag
A high-input impedance differential millivolt meter for use with solid ceramic oxygen electrolyte cells
Design factors are given for a high-input impedance differential millivolt meter designed, built, and tested as an inexpensive solid-state electronic system for use in measuring the electromotive force from solid ceramic oxygen electrolyte cells. A schematic diagram is included
Celecoxib decreases prostaglandin E\u3csub\u3e2\u3c/sub\u3e concentrations in nipple aspirate fluid from high risk postmenopausal women and women with breast cancer
Background
Celecoxib inhibits PGE2 production in cancerous tissue. We previously reported that PGE2 levels in nipple aspirate fluid (NAF) and plasma were not decreased in women at increased breast cancer risk who received celecoxib 200 mg twice daily (bid). The endpoints of the current study were to determine if a short course of celecoxib 400 mg bid would decrease PGE2 levels in women 1) at increased breast cancer risk, and 2) with established breast cancer.
Methods
NAF and plasma samples were collected before, 2 weeks after taking celecoxib 400 mg bid, and two weeks after washout from 26 women who were at increased breast cancer risk. From 13 women with newly diagnosed breast cancer, NAF from the incident breast and plasma were collected before and on average 2 weeks after taking celecoxib. Additionally, in nine of the 13 women with breast cancer, NAF was collected from the contralateral breast.
Results
No consistent change in NAF or plasma PGE2 levels was noted in high risk premenopausal women. NAF PGE2 levels decreased after celecoxib administration in postmenopausal high risk women (p = 0.02), and in both the NAF (p = 0.02) and plasma (p = 0.03) of women with breast cancer.
Conclusion
Celecoxib 400 mg bid taken on average for 2 weeks significantly decreased NAF, but not plasma, PGE2 levels in postmenopausal high risk women, and decreased both NAF and plasma PGE2 levels in women with newly diagnosed breast cancer. PGE2 levels may predict celecoxib breast cancer prevention and treatment efficacy. Our observations are preliminary, and larger studies to confirm and extend these findings are warranted
Review of foundational concepts and emerging directions in metamaterial research: Design, phenomena, and applications
In the past two decades, artificial structures known as metamaterials have
been found to exhibit extraordinary material properties that enable the
unprecedented manipulation of electromagnetic waves, elastic waves, molecules,
and particles. Phenomena such as negative refraction, bandgaps, near perfect
wave absorption, wave focusing, negative Poissons ratio, negative thermal
conductivity, etc., all are possible with these materials. Metamaterials were
originally theorized and fabricated in electrodynamics, but research into their
applications has expanded into acoustics, thermodynamics, seismology, classical
mechanics, and mass transport. In this Research Update we summarize the
history, current state of progress, and emerging directions of metamaterials by
field, focusing the unifying principles at the foundation of each discipline.
We discuss the different designs and mechanisms behind metamaterials as well as
the governing equations and effective material parameters for each field. Also,
current and potential applications for metamaterials are discussed. Finally, we
provide an outlook on future progress in the emerging field of metamaterials.Comment: 22 pages, 3 figures, 1 tabl
Preliminary estimation of fat depth in the lamb short loin using a hyperspectral camera
© 2018 CSIRO. The objectives of the present study were to describe the approach used for classifying surface tissue, and for estimating fat depth in lamb short loins and validating the approach. Fat versus non-fat pixels were classified and then used to estimate the fat depth for each pixel in the hyperspectral image. Estimated reflectance, instead of image intensity or radiance, was used as the input feature for classification. The relationship between reflectance and the fat/non-fat classification label was learnt using support vector machines. Gaussian processes were used to learn regression for fat depth as a function of reflectance. Data to train and test the machine learning algorithms was collected by scanning 16 short loins. The near-infrared hyperspectral camera captured lines of data of the side of the short loin (i.e. with the subcutaneous fat facing the camera). Advanced single-lens reflex camera took photos of the same cuts from above, such that a ground truth of fat depth could be semi-automatically extracted and associated with the hyperspectral data. A subset of the data was used to train the machine learning model, and to test it. The results of classifying pixels as either fat or non-fat achieved a 96% accuracy. Fat depths of up to 12 mm were estimated, with an R 2 of 0.59, a mean absolute bias of 1.72 mm and root mean square error of 2.34 mm. The techniques developed and validated in the present study will be used to estimate fat coverage to predict total fat, and, subsequently, lean meat yield in the carcass
Lean meat yield estimation using a prototype 3D imaging approach.
Lean Meat Yield (LMY, %) of carcass is an important industry trait, which currently is not routinely measured in Australian beef abattoirs. Objective on-line technology to determine LMY is key for wider adoption. This paper presents a proof-of-concept approach for estimating the LMY of beef carcasses from the 3D information provided by RGB-D cameras. Moreover, a specifically designed on-line data acquisition system for abattoir applications is presented, consisting of three cameras moving on a scanning rig to generate 3D carcass side reconstructions. The hindquarter is then segmented consistently across all the 3D models to extract curvature information and LMY estimated via non-linear regression based on Gaussian Process models. Sides from 119 carcasses at two different commercial abattoirs were used to evaluate this approach. Results from this preliminary study (RMSEÂ =Â 3.91%, R2Â =Â 0.69) using curvature, P8 fat and HSCW indicate that 3D imaging of beef carcasses is a viable and relatively accurate technology to estimate LMY
Molecular Basis for the Substrate Specificity of Quorum Signal Synthases
In several Proteobacteria, LuxI-type enzymes catalyze the biosynthesis of acyl–homoserine lactones (AHL) signals using S-adenosyl– L-methionine and either cellular acyl carrier protein (ACP)-coupled fatty acids or CoA–aryl/acyl moieties as progenitors. Little is known about the molecular mechanism of signal biosynthesis, the basis for substrate specificity, or the rationale for donor specificity for any LuxI member. Here, we present several cocrystal structures of BjaI, a CoAdependent LuxI homolog that represent views of enzyme complexes that exist along the reaction coordinate of signal synthesis. Complementary biophysical, structure–function, and kinetic analysis define the features that facilitate the unusual acyl conjugation with S-adenosylmethionine (SAM). We also identify the determinant that establishes specificity for the acyl donor and identify residues that are critical for acyl/aryl specificity. These results highlight howa prevalent scaffold has evolved to catalyze quorum signal synthesis and provide a framework for the design of small-molecule antagonists of quorum signaling
Effects of maternal bisphenol A diglycidyl ether exposure during gestation and lactation on behavior and brain development of the offspring
Bisphenol A diglycidyl ether (BADGE) is an epoxy resin used for the inner coating of canned food and beverages. BADGE can easily migrate from the containers and become a contaminant. In this study, we examined the effects of BADGE exposure to the dams on the behavioral, structural, and developmental abnormalities in the offspring. Female pregnant mice were fed with a diet containing BADGE (0.15 or 1.5 mg/kg/day) during gestation and lactation periods. In an open field test, the time spent in the corner area significantly increases in male mice of high-dose BADGE group at 5 weeks old. The histological analysis using offspring brain at postnatal day 1 delivered from BADGE (1.5 mg/kg/day)-treated dams demonstrates that positive signals of Forkhead box P2- and COUP-TF interacting protein 2 are restricted in each cortical layer, but not in the control brain. In addition, the maternal BADGE exposure reduces nestin-positive fibers of the radial glia and T-box transcription factor 2-positive intermediate progenitors in the inner subventricular zone. Furthermore, a direct BADGE exposure promotes neurite outgrowth and neuronal connection in the primary cultured cortical neurons. These data suggest that maternal BADGE exposure can accelerate neuronal differentiation in fetuses and induce anxiety-like behavior in juvenile mice
Heart Failure Symptom Biology in Response to Ventricular Assist Device Implantation.
BACKGROUND: We have a limited understanding of the biological underpinnings of symptoms in heart failure (HF), particularly in response to left ventricular assist device (LVAD) implantation.
OBJECTIVE: The aim of this study was to quantify the degree to which symptoms and biomarkers change in parallel from before implantation through the first 6 months after LVAD implantation in advanced HF.
METHODS: This was a prospective cohort study of 101 patients receiving an LVAD for the management of advanced HF. Data on symptoms (dyspnea, early and subtle symptoms [HF Somatic Perception Scale], pain severity [Brief Pain Inventory], wake disturbance [Epworth Sleepiness Scale], depression [Patient Health Questionnaire], and anxiety [Brief Symptom Inventory]) and peripheral biomarkers of myocardial stretch, systemic inflammation, and hypervolumetric mechanical stress were measured before implantation with a commercially available LVAD and again at 30, 90, and 180 days after LVAD implantation. Latent growth curve and parallel process modeling were used to describe changes in symptoms and biomarkers and the degree to which they change in parallel in response to LVAD implantation.
RESULTS: In response to LVAD implantation, changes in myocardial stretch were closely associated with changes in early and subtle physical symptoms as well as depression, and changes in hypervolumetric stress were closely associated with changes in pain severity and wake disturbances. Changes in systemic inflammation were not closely associated with changes in physical or affective symptoms in response to LVAD implantation.
CONCLUSIONS: These findings provide new insights into the many ways in which symptoms and biomarkers provide concordant or discordant information about LVAD response
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Influence of time and ageing conditions on the properties of ferrihydrite
Natural conversion of ferrihydrite (Fh), a widespread Fe(iii)-oxyhydroxide mineral at the Earth's surface, to thermodynamically more stable iron oxides such as goethite (Gt) and hematite (Hm) is a slow process that spans months to years. Here we examined the effects of synthesis and storage conditions on the hydration, the ratio of tetrahedral to octahedral iron sites, and the transformation of naturally aged 2-line Fh at room temperature and mildly acidic pH over an ageing period of 5 years. Fh samples synthesized and aged in either aerobic or anaerobic conditions were characterized over time by XRD, SEM, thermogravimetric analysis - mass spectroscopy (TGA-MS), and X-ray absorption spectroscopies (XANES and XMCD). The findings show that the ratio of tetrahedral to octahedral Fe(iii) sites in Fh is correlated to its extent of hydration, with fresher Fh samples exhibiting a higher ratio and more bound water. Fresh Fh aged in aerobic conditions has similar bound inorganic carbon, is more hydrated, and has less tetrahedral Fe(iii) than that aged in anaerobic conditions. Hence, for relatively fresh Fh there is a link between Fh properties and storage conditions. However, the long-term ageing characteristics, such as the transformation rate and relative phase fraction of Gt and Hm products, are not noticeably impacted by storage conditions. TGA-MS measurements coupled with O K-edge XANES spectra confirm that Fh tends to lose its hydration as it ages, as expected. Corresponding Fe L2,3-edge XMCD spectra reveal that this dehydration is coupled to a steady decrease in the ratio of tetrahedral to octahedral Fe(iii) sites. In addition to the obvious constraints these findings place on making comparisons across Fh samples of different age and environmental settings, they also highlight that Fh structure, and consequently magnetism, are linked to its bound water content
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