422 research outputs found
Determination of Soluble Phosphorus Content in Black Walnut Husk Compost via Formation of Molybdenum Blue
Author Institution: Chemistry Department, University of Rio GrandeWalnut fruit husk compost is a by-product of the commercial processing of walnuts. These outer husks collect into generous size piles and are normally left to decompose. Black walnut (Juglans nigra) husk compost was analyzed for phosphorus content to determine its potential as a phosphorus fertilizer or soil additive. Twenty-two samples of walnut husk compost of varying decomposition times were collected and dried. Soluble phosphate was extracted with distilled water and reacted with ammonium molybdate and stannous chloride to form the brightly blue-colored heteropoly-molybdenum blue which was analyzed
spectrophotometrically at 650 nm. Soluble phosphorus (as mass percent of dried samples) decreased by nearly 50 percent in the first year from 0.1708 ± 0.0199 percent in three-week-old compost (n = 7) to 0.0967 ± 0.0099 percent in 52-week-old compost (n = 8). In conclusion, the water soluble phosphorus found in walnut husk compost is within a suitable range for plant usage, but as a fertilizer it would be very mild. Due to the known allelopathic effects of this species, this level of phosphorus might make such
compost an acceptable candidate for herbicidal applications with concurrent fertilizing benefits
Inheritance of resistance to white mold disease in Phaseolus coccineus
A white-seeded selection of Phaseolus coccineus (P.I. 175829) from Turkey was found to be highly resistant to Whetzelinia screcotiorum. Intraspecilic crosses and backcrosses made with susceptible Phaseolus vulgaris germplasm indicate that a single completely dominant gene governs this high level of resistance. The symbol Ws is proposed for this gene. The inoculation procedure used to evaluate bean germplasm simulated natural disease occurrence in commercial bean fields. Plants at the susceptible blossom stage were sprayed with a suspension of ascospores obtained from aseptically produced apothecia. Immediately after inoculation, plants were placed in a mist chamber at 21-25°C for one week before final evaluatio
Macrophages enhance Vegfa-driven angiogenesis in an embryonic zebrafish tumour xenograft model
Tumour angiogenesis has long been a focus of anti-cancer therapy; however, anti-angiogenic cancer treatment strategies have had limited clinical success. Tumour-associated myeloid cells are believed to play a role in the resistance of cancer towards anti-angiogenesis therapy, but the mechanisms by which they do this are unclear. An embryonic zebrafish xenograft model has been developed to investigate the mechanisms of tumour angiogenesis and as an assay to screen anti-angiogenic compounds. In this study, we used cell ablation techniques to remove either macrophages or neutrophils and assessed their contribution towards zebrafish xenograft angiogenesis by quantitating levels of graft vascularisation. The ablation of macrophages, but not neutrophils, caused a strong reduction in tumour xenograft vascularisation and time-lapse imaging demonstrated that tumour xenograft macrophages directly associated with the migrating tip of developing tumour blood vessels. Finally, we found that, although macrophages are required for vascularisation in xenografts that either secrete VEGFA or overexpress zebrafish vegfaa, they are not required for the vascularisation of grafts with low levels of VEGFA, suggesting that zebrafish macrophages can enhance Vegfa-driven tumour angiogenesis. The importance of macrophages to this angiogenic response suggests that this model could be used to further investigate the interplay between myeloid cells and tumour vascularisation
Using virtual environment technology for preadapting astronauts to the novel sensory conditions of microgravity
A unique training device is being developed at the Johnson Space Center Neurosciences Laboratory to help reduce or eliminate Space Motion Sickness (SMS) and spatial orientation disturbances that occur during spaceflight. The Device for Orientation and Motion Environments Preflight Adaptation Trainer (DOME PAT) uses virtual reality technology to simulate some sensory rearrangements experienced by astronauts in microgravity. By exposing a crew member to this novel environment preflight, it is expected that he/she will become partially adapted, and thereby suffer fewer symptoms inflight. The DOME PAT is a 3.7 m spherical dome, within which a 170 by 100 deg field of view computer-generated visual database is projected. The visual database currently in use depicts the interior of a Shuttle spacelab. The trainee uses a six degree-of-freedom, isometric force hand controller to navigate through the virtual environment. Alternatively, the trainee can be 'moved' about within the virtual environment by the instructor, or can look about within the environment by wearing a restraint that controls scene motion in response to head movements. The computer system is comprised of four personal computers that provide the real time control and user interface, and two Silicon Graphics computers that generate the graphical images. The image generator computers use custom algorithms to compensate for spherical image distortion, while maintaining a video update rate of 30 Hz. The DOME PAT is the first such system known to employ virtual reality technology to reduce the untoward effects of the sensory rearrangement associated with exposure to microgravity, and it does so in a very cost-effective manner
Vertical distribution of sub-micron aerosol chemical composition from North-Western Europe and the North-East Atlantic
A synthesis of UK based airborne in-situ measurements of aerosol properties representing air masses from North-West Europe and the North-East Atlantic is presented. The major focus of the study is the vertical distribution of sub-micron aerosol chemical composition. Vertical profiles are derived from a Quadrupole Aerosol Mass Spectrometer (Q-AMS). Background sub-micron aerosol vertical profiles are identified and are primarily composed of organic matter and sulphate aerosol. Such background conditions occurred predominantly during periods associated with long-range air mass transport across the Atlantic. These instances may serve as useful model input of aerosol to Western Europe. Increased mass concentration episodes are coincident with European outflow and periods of stagnant/recirculating air masses. Such periods are characterised by significantly enhanced concentrations of nitrate aerosol relative to those of organic matter and sulphate. Periods of enhanced ground level PM<sub>2.5</sub> loadings are coincident with instances of high nitrate mass fractions measured on-board the aircraft, indicating that nitrate is a significant contributor to regional pollution episodes. The vertical structure of the sulphate and organic aerosol profiles were shown to be primarily driven by large-scale dynamical processes. The vertical distribution of nitrate is likely determined by both dynamic and thermodynamic processes, with chemical partitioning of gas phase precursors to the particle phase occurring at lower temperatures at the top of the boundary layer. Such effects have profound implications for the aerosol's lifetime and subsequent impacts, highlighting the requirement for accurate representation of the aerosol vertical distribution
Closure between measured and modelled particle hygroscopic growth during TORCH2 implies ammonium nitrate artefact in the HTDMA measurements
International audienceMeasurements of aerosol properties were made in aged polluted and clean background air masses encountered at the North Norfolk (UK) coastline during the second field campaign of the Tropospheric ORganic CHemistry project (TORCH2) in May 2004. Hygroscopic growth factor (GF) measurements were performed at 90% relative humidity (RH) for D0=27?217 nm particles using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA), while the aerosol composition was simultaneously measured with an Aerodyne aerosol mass spectrometer (Q-AMS). During the clean background events the aerosol was characterised by little size dependence of properties with generally large GFs and inorganic sulphate being the dominant compound. In aged polluted air masses the particles were dominated by inorganic sulphate and nitrate at larger sizes, whereas organics were the largest fraction in smaller particles, thus explaining the trend of smaller GFs at smaller sizes. Organics do contribute to the hygroscopic growth, particularly at small sizes, but generally the dominant contribution to growth at 90% RH comes from inorganic salts. The ZSR mixing rule was used to predict GFs based on the chemical composition, theoretical GFs of pure inorganic salts and a "bulk" GF of ~1.20 for the organics. Good quantitative closure with HTDMA measurements as a function of both particle size and time was achieved in the absence of nitrate. However, GFs were clearly overpredicted at times when a significant fraction of nitrate was present. After careful considerations we attribute the overprediction to substantial evaporation losses of ammonium nitrate in the HTDMA instrument. If true, this implies that the ZSR predictions based on composition might be more representative of the actual "bulk" behaviour of undisturbed ambient particles than the HTDMA measurements. The simplified model approach using the ZSR rule and a constant organic growth factor made high size and time resolution possible, which has proven to be essential for a valid closure study. The ZSR mixing rule appears to be sufficiently accurate, as the GF predictions are more sensitive to the exact GFs of the inorganic compounds than to the growth factor of the moderately hygroscopic organics. Therefore a more detailed analysis and modelling of the organic fraction at the expense of time and size resolution is not worth the effort for an aged aerosol and discrepancies in either direction might even be cancelled out by averaging
Coarse-mode mineral dust size distributions, composition and optical properties from AER-D aircraft measurements over the tropical eastern Atlantic
Mineral dust is an important component of the climate system, affecting the radiation balance, cloud properties, biogeochemical cycles, regional circulation and precipitation, as well as having negative effects on aviation, solar energy generation and human health. Dust size and composition has an impact on all these processes. However, changes in dust size distribution and composition during transport, particularly for coarse particles, are poorly understood and poorly represented in climate models. Here we present new in situ airborne observations of dust in the Saharan Air Layer (SAL) and the marine boundary layer (MBL) at the beginning of its transatlantic transport pathway, from the AERosol Properties - Dust (AER-D) fieldwork in August 2015, within the peak season of North African dust export. This study focuses on coarse-mode dust properties, including size distribution, mass loading, shape, composition, refractive indices and optical properties. Size distributions from 0.1 to 100 µm diameter (d) are presented, fully incorporating the coarse and giant modes of dust. Within the MBL, mean effective diameter (deff) and volume median diameter (VMD) were 4.6 and 6.0 µm respectively, giant particles with a mode at 20-30 µm were observed, and composition was dominated by quartz and alumino-silicates at d > 1 µm. Within the SAL, particles larger than 20 µm diameter were always present up to 5 km altitude, in concentrations over 10−5 cm−3, constituting up to 40 % of total dust mass. Mean deff and VMD were 4.0 and 5.5 µm respectively. Larger particles were detected in the SAL than can be explained by sedimentation theory alone. Coarse-mode composition was dominated by quartz and alumino-silicates; the accumulation mode showed a strong contribution from sulfate-rich and sea salt particles. In the SAL, measured single scattering albedos (SSAs) at 550 nm representing d < 2.5 µm were 0.93 to 0.98 (mean 0.97). Optical properties calculated for the full size distribution (0.1 < d < 100 µm) resulted in lower SSAs of 0.91-0.98 (mean 0.95) and mass extinction coefficients of 0.27-0.35 m2 g−1 (mean 0.32 m2 g−1). Variability in SSA was mainly controlled by variability in dust composition (principally iron) rather than by variations in the size distribution, in contrast with previous observations over the Sahara where size is the dominant influence. It is important that models are able to capture the variability and evolution of both dust composition and size distribution with transport in order to accurately represent the impacts of dust on climate. These results provide a new SAL dust dataset, fully representing coarse and giant particles, to aid model validation and development
Closure study between chemical composition and hygroscopic growth of aerosol particles during TORCH2
International audienceMeasurements of aerosol properties were made in aged polluted and clean background air masses encountered at the North Norfolk (UK) coastline as part of the TORCH2 field campaign in May 2004. Hygroscopic growth factors (GF) at 90% relative humidity (RH) for D0=27?217 nm particles and size-resolved chemical composition were simultaneously measured using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA) and an Aerodyne aerosol mass spectrometer (Q-AMS), respectively. Both hygroscopic properties and chemical composition showed pronounced variability in time and with particles size. With this data set we could demonstrate that the Zdanovskii-Stokes-Robinson (ZSR) mixing rule combined with chemical composition data from the AMS makes accurate quantitative predictions of the mean GF of mixed atmospheric aerosol particles possible. In doing so it is crucial that chemical composition data are acquired with high resolution in both particle size and time, at least matching the actual variability of particle properties. The closure results indicate an ensemble GF of the organic fraction of ~1.20±0.10 at 90% water activity. Thus the organics contribute somewhat to hygroscopic growth, particularly at small sizes, however the inorganic salts still dominate. Furthermore it has been found that most likely substantial evaporation losses of NH4NO3 occurred within the HTDMA instrument, exacerbated by a long residence time of ~1 min. Such an artefact is in agreement with our laboratory experiments and literature data for pure NH4NO3, both showing similar evaporation losses within HTDMAs with residence times of ~1 min. Short residence times and low temperatures are hence recommended for HTDMAs in order to minimise such evaporation artefacts
Cloud Ice Properties: In Situ Measurement Challenges
Baumgardner D., S.J. Abel, D. Axisa, R. Cotton, J. Crosier, P. Field, C. Gurganus, A. Heymsfield, A. Korolev, M. Krämer, P. Lawson, G. McFarquhar, Z. Ulanowski, and J. Um, 'Cloud ice properties: in situ measurement challenges', Meteorological Monographs, Vol. 58, pp. 9.1–9.23, April 2017. The version of record is available online at doi: 10.1175/AMSMONOGRAPHS-D-16-0011.1.1 © 2017 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).Understanding the formation and evolution of ice in clouds requires detailed information on the size, shape, mass and optical properties of individual cloud hydrometeors and their bulk properties over a broad range of atmospheric conditions. Since the 1960s, instrumentation and research aircraft have evolved providing increasingly more accurate and larger quantities of data about cloud particle properties. In this chapter we review the current status of electrical powered, in situ measurement systems with respect to their strengths and weaknesses and document their limitations and uncertainties. There remain many outstanding challenges. These are summarized and accompanied by recommendations for moving forward. through new developments that fill the remaining information gaps. Closing these gaps will remove the obstacles that continue to hinder our understanding of cloud processes in general and the evolution of ice in particular.Peer reviewe
South African guideline for the use of chronic opioid therapy for chronic non-cancer pain
Chronic pain may have a significant impact on health-related quality of life and can be difficult to manage. In carefully selected patients,
and as part of a comprehensive pain management strategy, opioid analgesia may help to achieve long-term pain control with a manageable
side-effect profile and a low risk of serious adverse effects. However, appropriate evaluation, including biopsychosocial screening and risk
screening is essential before initiating an opioid and during continued therapy. This guideline aims to assist practitioners in screening and
selecting appropriate patients with chronic non-cancer pain to initiate, monitor and continue pain management with opioid therapy.The development of this guideline was supported by
an unrestricted grant from Mundipharma who did not participate in the
development or writing of the guideline. Dr M Raff has received honoraria
for consultancies and non-restricted research grants from Mundipharma,
Pfizer, Janssen Pharmaceutica, AstraZeneca, MSD, Eli Lilly, Aspen
and Abbott Laboratories. Drs J Crosier and S Eppel have received
honoraria from Mundipharma. Prof. H Meyer has received honoraria
for consultancies and non-restricted research grants from Janssen
Pharmaceutica, Eli Lilly, MSD and Mundipharma. Dr B Sarembock has
received honoraria for consultancies and non-restricted research grants
from MSD, AstraZeneca, Pfizer and Mundipharma. Dr D Webb has
received professional fees for services to Abbott Laboratories, Adcock
Ingram, Alcon Laboratories, AstraZeneca, Eli Lilly, Janssen Pharmaceutica,
Mundipharma, Novartis, and Reckitt Beckiser Pharmaceuticals.http://www.samj.org.zaam201
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