427 research outputs found
Ultrafast photoinduced enhancement of nonlinear optical response in 15-atom gold clusters on indium tin oxide conducting film
We show that the third order optical nonlinearity of 15-atom gold clusters is
significantly enhanced when in contact with indium tin oxide (ITO) conducting
film. Open and close aperture z-scan experiments together with non-degenerate
pump-probe differential transmission experiments were done using 80 fs laser
pulses centered at 395 nm and 790 nm on gold clusters encased inside
cyclodextrin cavities. We show that two photon absorption coefficient is
enhanced by an order of magnitude as compared to that when the clusters are on
pristine glass plate. The enhancement for the nonlinear optical refraction
coefficient is ~3 times. The photo-induced excited state absorption using
pump-probe experiments at pump wavelength of 395 nm and probe at 790 nm also
show an enhancement by an order of magnitude. These results attributed to the
excited state energy transfer in the coupled gold cluster-ITO system are
different from the enhancement seen so far in charge donor-acceptor complexes
and nanoparticle-conjugate polymer composites.Comment: To appear in Optics Express (2013);
http://dx.doi.org/10.1364/OE.21.00848
In vitro antifungal activity of Turbinaria conoides collected from Mandapam coast, Tamilnadu, India
ABSTRACTÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Marine macroalgae have been used as medicines or drug sources for a great many years, stretching back to the era of folk medicines. Algae have been extensively used in the traditional medicines of maritime nations for treatment of goitre, cancer, hypertension, cough and other diseases. The present work was carried out to find out the antifungal activity of the seaweed Turbinaria conoides collected from Mandapam coastal regions of Tamilnadu. The extracts were tested against Candida albicans, Candida parapsilopsis, Fusarium sp, Aspergillus flavus , Asergillus fumigatus. The hexane, chloroform and ethanolic extracts showed a well profound inhibitory activity against Candida albicans and Candida parapsilopsis. No inhibitory activity was found at Fusarium sp, Aspergillus flavus , Asergillus fumigates under chloroform and ethanolic extracts.Key words: Medicine, antifungal, cancer, Candida albicans, diseases
An interdisciplinary online certificate and masters program in agroforestry
Paper presented at the 12th North American Agroforesty Conference, which was held June 4-9, 2011 in Athens, Georgia.In Ashton, S. F., S.W. Workman, W.G. Hubbard and D.J. Moorhead, eds. Agroforestry: A Profitable Land Use. Proceedings, 12th North American Agroforestry Conference, Athens, GA, June 4-9, 2011.Within a context of rapid technological change and shifting market conditions, the American education system is challenged with providing increased educational opportunities for students and non-traditional clients often at lower cost than in campus-based degree programs. Many educational institutions are answering this challenge by developing distance education graduate programs. These programs can provide working professionals with a chance at a graduate education, reach those disadvantaged by limited time or distance, and update the knowledge base of workers at their places of employment. Agroforestry, as a farming system that integrates crops and/or livestock with trees and shrubs, is gaining recognition as an integral component of a multifunctional working landscape. While agroforestry has been gradually gaining attention, the need for a cadre of well trained professionals in agroforestry is essential to support its continued growth. Short courses and workshops are helpful, but professionals and landowners alike across the U.S., Canada and overseas are seeking more comprehensive graduate degree or certificate programs. A web-based, asynchronous M.S. degree and/or a graduate Certificate will help to fill this void. Presently, there are no comparable comprehensive graduate programs in agroforestry elsewhere in the U.S. To meet the current and future needs of the agroforestry profession, The Center for Agroforestry at the University of Missouri is creating an online graduate certificate and masters degree program in agroforestry. The Center for Agroforestry will begin admitting students and offering online courses beginning Spring semester 2011. The certificate and masters will be fully implemented by the summer of 2013.Michael A. Gold and Shibu Jose ; The Center for Agroforestry and Dept. of Forestry University of Missouri.Includes bibliographical references
Properties of Umbral Dots from Stray Light Corrected Hinode Filtergrams
High resolution blue continuum filtergrams from Hinode are employed to study
the umbral fine structure of a regular unipolar sunspot. The removal of
scattered light from the images increases the rms contrast by a factor of 1.45
on average. Improvement in image contrast renders identification of short
filamentary structures resembling penumbrae that are well separated from the
umbra-penumbra boundary and comprise bright filaments/grains flanking dark
filaments. Such fine structures were recently detected from ground based
telescopes and have now been observed with Hinode. A multi-level tracking
algorithm was used to identify umbral dots in both the uncorrected and
corrected images and to track them in time. The distribution of the values
describing the photometric and geometric properties of umbral dots are more
easily affected by the presence of stray light while it is less severe in the
case of kinematic properties. Statistically, umbral dots exhibit a peak
intensity, effective diameter, lifetime, horizontal speed and a trajectory
length of 0.29 I_QS, 272 km, 8.4 min, 0.45 km/s and 221 km respectively. The 2
hr 20 min time sequence depicts several locations where umbral dots tend to
appear and disappear repeatedly with various time intervals. The correction for
scattered light in the Hinode filtergrams facilitates photometry of umbral fine
structure which can be related to results obtained from larger telescopes and
numerical simulations.Comment: Accepted for publication in ApJ : 10 pages, 10 figures, 3 table
Creating the knowledge infrastructure to enhance landowner adoption of agroforestry through an agroforestry academy
Paper presented at the 13th North American Agroforesty Conference, which was held June 19-21, 2013 in Charlottetown, Prince Edward Island, Canada.In Poppy, L., Kort, J., Schroeder, B., Pollock, T., and Soolanayakanahally, R., eds. Agroforestry: Innovations in Agriculture. Proceedings, 13th North American Agroforestry Conference, Charlottetown, Prince Edward Island, Canada, June 19-21, 2013.Agroforestry offers a novel approach to land management that provides opportunities to combine productivity and profitability with environmental stewardship, resulting in healthy and sustainable agricultural systems that can be passed on to future generations. In spite of significant advances in both the science and practice of US agroforestry over the past 20 years, adoption has been limited. In the US, natural resource professionals and other educators are currently not equipped to help landowners adopt agroforestry. To advance adoption of agroforestry as a cornerstone of productive land use, a week-long agroforestry academy is being developed by a regional consortium of experts from Missouri, Iowa, Nebraska, Minnesota and Wisconsin. The academy is designed to train natural resource professionals, extension agents, and other agricultural educators who work with landowners. Advanced training will be provided on the five recognized temperate zone agroforestry practices integrated with options for bioenergy, marketing, economic, social dimensions, and environmental services. The cornerstone of the academy will be an applied planning and design exercise. Academy trainees will work in small groups to gain hands on practice in agroforestry design based on the needs of a working farm. Academy trainers and graduates will form the core of the knowledge infrastructure needed to enhance landowner adoption of agroforestry, resulting in increased sustainability of rural communities and the food and agricultural system.Michael A. Gold (1), Mihaela M. Cernusca (1) and Shibu Jose (1) ; 1. University of Missouri Center for Agroforestry, 203 ABNR Bldg., Columbia, MO 65211.Includes bibliographical references
Influence of pH adjustment on physicochemical properties of microfiltration retentates of skim milk and rehydration properties of resulting powders
Effects of pH adjustment on physicochemical properties of microfiltration retentates of skim milk and rehydration of resulting micellar casein concentrate (MCC) powders were investigated. Aliquots of retentate (pH 6.9) were adjusted to pH 7.3, 7.6 or 7.6 followed by readjustment to pH 6.9 (6.9R) prior to powder preparation. The retentates with pH 6.9, 7.3, and 7.6 had casein micelle size of 179, 189 and 197 nm, respectively, while sample 6.9R had size of 183 nm, similar to retentate at pH 6.9. Higher retentate pH resulted in lower ionic calcium and higher conductivity, with sample 6.9R having higher values for both parameters than the pH 6.9 sample. The MCC powders displayed poorer wettability and enhanced dispersibility with increasing retentate pH. Interestingly, the 6.9R powder had the best wettability and dispersibility. This study demonstrated that pH-mediated modifications of the physicochemical properties of retentates improve the rehydration properties of resultant MCC powders
IMPACTS OF AN EXOTIC DISEASE AND VEGETATION CHANGE ON FOLIAR CALCIUM CYCLING IN APPALACHIAN FORESTS
Because of the high calcium content of its foliage, Cornus florida (flowering dogwood) has been described as a calcium "pump" that draws calcium from deeper mineral soil and enriches surface soil horizons. However, over the last two decades an exotic fungal disease (dogwood anthracnose, Discula destructiva) has decimated populations of this once-common understory species. Its loss, combined with forest stand development, could alter intra-stand calcium cycling. We used data from long-term vegetation monitoring plots to examine the ecological role of C. florida in calcium cycling and to identify changes in annual foliar calcium cycling over a 20-year period between two sampling intervals, 1977-1979 (preanthracnose) and 1995-2000 (post-anthracnose). Published equations were used to estimate foliar biomass per species for five forest types: alluvial, typic cove, acid cove, oak-hickory, and oak-pine. Calcium concentrations derived from foliage samples were used to estimate annual foliar calcium production per species for understory woody stems ( or =20 cm dbh). At a given level of soil calcium availability, C. florida foliage contained greater concentrations of calcium than three other dominant understory species (Tsuga canadensis, Acer rubrum, and Rhododendron maximum). Between 1977-1979 and 1995-2000, the annual calcium contributions of understory woody vegetation declined across all forest types, ranging from 26% in oak-pine stands to 49% in acid coves. Loss of C. florida was responsible for only 13% of this decline in oak-pine stands, but accounted for 96% of the decline in typic coves. In oak-hickory and oak-pine stands, we observed large increases in the foliar biomass of T. canadensis, a species whose calcium-poor foliage increases soil acidity. Increases in overstory foliar biomass and calcium offset understory losses in three forest types (alluvial, typic coves, and oak-pine) but not in oak-hickory and acid cove stands. Overall, calcium cycling in oak-hickory stands was more negatively affected by the loss of C. florida than the other forest types. Oak-hickory forests comprise over a third of the total forest cover in the eastern United States, and decreases in annual calcium cycling could have cascading effects on forest biota
Stalking the Fourth Domain in Metagenomic Data: Searching for, Discovering, and Interpreting Novel, Deep Branches in Marker Gene Phylogenetic Trees
BACKGROUND: Most of our knowledge about the ancient evolutionary history of organisms has been derived from data associated with specific known organisms (i.e., organisms that we can study directly such as plants, metazoans, and culturable microbes). Recently, however, a new source of data for such studies has arrived: DNA sequence data generated directly from environmental samples. Such metagenomic data has enormous potential in a variety of areas including, as we argue here, in studies of very early events in the evolution of gene families and of species. METHODOLOGY/PRINCIPAL FINDINGS: We designed and implemented new methods for analyzing metagenomic data and used them to search the Global Ocean Sampling (GOS) expedition data set for novel lineages in three gene families commonly used in phylogenetic studies of known and unknown organisms: small subunit rRNA and the recA and rpoB superfamilies. Though the methods available could not accurately identify very deeply branched ss-rRNAs (largely due to difficulties in making robust sequence alignments for novel rRNA fragments), our analysis revealed the existence of multiple novel branches in the recA and rpoB gene families. Analysis of available sequence data likely from the same genomes as these novel recA and rpoB homologs was then used to further characterize the possible organismal source of the novel sequences. CONCLUSIONS/SIGNIFICANCE: Of the novel recA and rpoB homologs identified in the metagenomic data, some likely come from uncharacterized viruses while others may represent ancient paralogs not yet seen in any cultured organism. A third possibility is that some come from novel cellular lineages that are only distantly related to any organisms for which sequence data is currently available. If there exist any major, but so-far-undiscovered, deeply branching lineages in the tree of life, we suggest that methods such as those described herein currently offer the best way to search for them
Recommended from our members
Transcription cofactor GRIP1 differentially affects myeloid cell-driven neuroinflammation and response to IFN-β therapy.
Macrophages (MФ) and microglia (MG) are critical in the pathogenesis of multiple sclerosis (MS) and its mouse model, experimental autoimmune encephalomyelitis (EAE). Glucocorticoids (GCs) and interferon β (IFN-β) are frontline treatments for MS, and disrupting each pathway in mice aggravates EAE. Glucocorticoid receptor-interacting protein 1 (GRIP1) facilitates both GR and type I IFN transcriptional actions; hence, we evaluated the role of GRIP1 in neuroinflammation. Surprisingly, myeloid cell-specific loss of GRIP1 dramatically reduced EAE severity, immune cell infiltration of the CNS, and MG activation and demyelination specifically during the neuroinflammatory phase of the disease, yet also blunted therapeutic properties of IFN-β. MФ/MG transcriptome analyses at the bulk and single-cell levels revealed that GRIP1 deletion attenuated nuclear receptor, inflammatory and, interestingly, type I IFN pathways and promoted the persistence of a homeostatic MG signature. Together, these results uncover the multifaceted function of type I IFN in MS/EAE pathogenesis and therapy, and an unexpectedly permissive role of myeloid cell GRIP1 in neuroinflammation
- …