Development of a bioaerosol single particle detector (BIO IN) for the fast ice nucleus chamber FINCH [Discussion paper]

In this work we present the setup and first tests of our new BIO IN detector. This detector is designed to classify atmospheric ice nuclei (IN) for their biological content. Biological material is identified via its auto-fluorescence (intrinsic fluorescence) after irradiation with UV radiation. Ice nuclei are key substances for precipitation development via the Bergeron–Findeisen process. The level of scientific knowledge regarding origin and climatology (temporal and spatial distribution) of IN is very low. Some biological material is known to be active as IN even at relatively high temperatures of up to –2°C (e.g. pseudomonas syringae bacteria). These biological IN could have a strong influence on the formation of clouds and precipitation. We have designed the new BIO IN sensor to analyze the abundance of IN of biological origin. The instrument will be flown on one of the first missions of the new German research aircraft ''HALO'' (High Altitude and LOng Range)

Incidence of rough and irregular atmospheric ice particles from Small Ice Detector 3 measurements

NERC, NE/E011225/1 © Author(s) 2013. This work is distributed under the Creative Commons Attribution 3.0 LicenseThe knowledge of properties of ice crystals such as size, shape, concavity and roughness is critical in the context of radiative properties of ice and mixed phase clouds. Limitations of current cloud probes to measure these properties can be circumvented by acquiring two-dimensional light scattering patterns instead of particle images. Such patterns were obtained in situ for the first time using the Small Ice Detector 3 (SID-3) probe during several flights in a variety of mid-latitude mixed phase and cirrus clouds. The patterns are analyzed using several measures of pattern texture, selected to reveal the magnitude of particle roughness or complexity. The retrieved roughness is compared to values obtained from a range of well-characterized test particles in the laboratory. It is found that typical in situ roughness corresponds to that found in the rougher subset of the test particles, and sometimes even extends beyond the most extreme values found in the laboratory. In this study we do not differentiate between small-scale, fine surface roughness and large-scale crystal complexity. Instead, we argue that both can have similar manifestations in terms of light scattering properties and also similar causes. Overall, the in situ data is consistent with ice particles with highly irregular or rough surfaces being dominant. Similar magnitudes of roughness were found in growth and sublimation zones of cirrus. The roughness was found to be negatively correlated with the halo ratio, but not with other thermodynamic or microphysical properties found in situ. Slightly higher roughness was observed in cirrus forming in clean oceanic airmasses than in a continental, polluted one. Overall, the roughness and complexity is expected to lead to increased shortwave cloud reflectivity, in comparison with cirrus composed of more regular, smooth ice crystal shapes. These findings put into question suggestions that climate could be modified through aerosol seeding to reduce cirrus cover and optical depth, as the seeding may result in decreased shortwave reflectivity.Peer reviewe

Radiation in medicine: Origins, risks and aspirations.

The use of radiation in medicine is now pervasive and routine. From their crude beginnings 100 years ago, diagnostic radiology, nuclear medicine and radiation therapy have all evolved into advanced techniques, and are regarded as essential tools across all branches and specialties of medicine. The inherent properties of ionizing radiation provide many benefits, but can also cause potential harm. Its use within medical practice thus involves an informed judgment regarding the risk/benefit ratio. This judgment requires not only medical knowledge, but also an understanding of radiation itself. This work provides a global perspective on radiation risks, exposure and mitigation strategies

A quasi-Lagrangian coordinate system based on high resolution tracer observations: implementation for the Antarctic polar vortex

In order to quantitatively analyse the chemical and dynamical evolution of the polar vortex it has proven extremely useful to work with coordinate systems that follow the vortex flow. We propose here a two-dimensional quasi-Lagrangian coordinate system {X i, delta X i}, based on the mixing ratio of a long-lived stratospheric trace gas i, and its systematic use with i = N2O, in order to describe the structure of a well-developed Antarctic polar vortex. In the coordinate system {X i, delta X i} the mixing ratio X i is the vertical coordinate and delta X i = X i(theta) - X i vort(theta) is the meridional coordinate (X i vort(theta) being a vertical reference profile in the vortex core). The quasi-Lagrangian coordinates {X i, delta X i} persist for much longer time than standard isentropic coordinates, potential temperature theta and equivalent latitude Phi e, do not require explicit reference to geographic space, and can be derived directly from high-resolution in situ measurements. They are therefore well-suited for studying the evolution of the Antarctic polar vortex throughout the polar winter with respect to the relevant chemical and microphysical processes. By using the introduced coordinate system {X N2O, delta X N2O} we analyze the well-developed Antarctic vortex investigated during the APE-GAIA (Airborne Polar Experiment – Geophysica Aircraft in Antarctica – 1999) campaign (Carli et al., 2000). A criterion, which uses the local in-situ measurements of X i=X i(theta) and attributes the inner vortex edge to a rapid change (delta-step) in the meridional profile of the mixing ratio X i, is developed to determine the (Antarctic) inner vortex edge. In turn, we suggest that the outer vortex edge of a well-developed Antarctic vortex can be attributed to the position of a local minimum of the X H2O gradient in the polar vortex area. For a well-developed Antarctic vortex, the delta X N2O-parametrization of tracer-tracer relationships allows to distinguish the tracer inter-relationships in the vortex core, vortex boundary region and surf zone and to examine their meridional variation throughout these regions. This is illustrated by analyzing the tracer-tracer relationships X i : X N2O obtained from the in-situ data of the APE-GAIA campaign for i = CFC-11, CFC-12, H-1211 and SF6. A number of solitary anomalous points in the CFC-11 : N2O correlation, observed in the Antarctic vortex core, are interpreted in terms of small-scale cross-isentropic dispersion

Confocal microscopy

Chapter focusing on confocal microscopy. A confocal microscope is one in which the illumination is confined to a small volume in the specimen, the detection is confined to the same volume and the image is built up by scanning this volume over the specimen, either by moving the beam of light over the specimen or by displacing the specimen relative to a stationary beam. The chief advantage of this type of microscope is that it gives a greatly enhanced discrimination of depth relative to conventional microscopes. Commercial systems appeared in the 1980s and, despite their high cost, the world market for them is probably between 500 and 1000 instruments per annum, mainly because of their use in biomedical research in conjunction with fluorescent labelling methods. There are many books and review articles on this subject ( e.g. Pawley ( 2006) , Matsumoto( 2002), Wilson (1990) ). The purpose of this chapter is to provide an introduction to optical and engineering aspects that may be o f interest to biomedical users of confocal microscopy

Combining confocal and BSE SEM imaging for bone block surfaces

The present report presents a method for the correlation of qualitative and quantitative BSE SEM imaging with confocal scanning light microscopy (CSLM) imaging modes applied to bone samples embedded in PMMA. The SEM has a proper digital scan generator: we leave the BSE image unchanged, and match the CSLM image to it, because the CSLM scan mechanism is not digital, though the signal is digitised. Our overlapping program uses a linear transformation matrix which projects one system to the other, calculated by finding three corresponding points in BSE and CSLM pictures. BSE images are empty where cells and osteoid are present. Fluorescence mode CSLM fills in these gaps. The combination images enhance our understanding of what is going on - and re-establish the need for good cellular preservation

Sandfish hatchery techniques

Sandfish is arguably the most commercially valuable of the tropical species of sea cucumber that are processed into bΩche-de-mer. It is widely distributed throughout the Indo-Pacific, occurring in shallow inshore areas where it is easily accessible to coastal fishers. A-grade bΩche-de-mer processed from sandfish commands some of the highest prices on the international market. But these same attributes also make it vulnerable to overexploitation. Sadly, this has happened in most places where it occurs. While sandfish was an important component of bΩche-de-mer fisheries 20 to 30 years ago, its contribution to bΩche-de-mer exports is now relatively small, even trivial.Not surprisingly, there is widespread interest in restoring the production of sandfish, especially where it promises to deliver benefits to coastal fishing communities with few other options for earning livelihoods. it promises to deliver benefits to coastal fishing communities with few other options for earning livelihoods. This manual is designed to help government agencies and members of the private sector interested in implementing ways of increasing production of sandfish by outlining the basic methods for spawning and rearing juvenile sandfish. It builds on the pioneering work done in 1988 at the Tuticorin Research Centre of CMFRI (Central Marine Fisheries Research Institute) in India and is based largely on methods developed and applied by the WorldFish Center (formerly ICLARM) in Solomon Islands, Vietnam and New Caledonia.Sea cucumber, Hatching, Rearing, Aquaculture techniques, Brook stocks, Nursery ponds, Aquaculture techniques Holothurioidea

Evaluating Responses of Sugar Beet Cultivars to Fusarium Species in Greenhouse and Field Conditions

Fusarium yellows of sugar beet (Beta vulgaris L.) is becoming an important disease in Minnesota and North Dakota in the United States. One of the best ways to manage Fusarium yellows is to develop and use resistant cultivars. Responses of eight sugar beet cultivars to three Fusarium species were determined in the greenhouse and compared to the responses of the same eight cultivars grown in a field already infected by Fusarium yellows. There were significant and appreciable relationships between greenhouse and field studies for responses of eight sugar beet cultivars on Fusarium yellows. The estimated correlation coefficient for area under disease progress curve (AUDPC) between observations in fields and those in greenhouses was 0.987 (p<0.01). The mean AUDPC were significantly different among cultivars (p<0.01) in the greenhouse and in the field studies. Of the cultivars, Van der Have 46177 was the most susceptible, but Crystal R434 the most resistant. Crystal 820, Van der Have 66561, and Beta 4797R were resistant, and Beta 4818R, Seedex Magnum, and Hilleshog 2463Rz were moderately resistant. There was a strong negative relationship between the AUDPC and recoverable sucrose yield in the field experiments and the estimated coefficient of determination was 0.939 (p<0.01). It was concluded that greenhouse screening can act as a useful and reliable means to evaluate and select beet germplasms and/or accessions for resistance to Fusarium yellows.Peer reviewe

Alternative Computational Protocols for Supercharging Protein Surfaces for Reversible Unfolding and Retention of Stability

Bryan S. Der, Ron Jacak, Brian Kuhlman, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of AmericaChristien Kluwe, Aleksandr E. Miklos, Andrew D. Ellington , Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas, United States of AmericaChristien Kluwe, Aleksandr E. Miklos, George Georgiou, Andrew D. Ellington, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of AmericaAleksandr E. Miklos, Andrew D. Ellington , Applied Research Laboratories, University of Texas at Austin, Austin, Texas, United States of AmericaSergey Lyskov, Jeffrey J. Gray, Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States of AmericaBrian Kuhlman, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of AmericaReengineering protein surfaces to exhibit high net charge, referred to as “supercharging”, can improve reversibility of unfolding by preventing aggregation of partially unfolded states. Incorporation of charged side chains should be optimized while considering structural and energetic consequences, as numerous mutations and accumulation of like-charges can also destabilize the native state. A previously demonstrated approach deterministically mutates flexible polar residues (amino acids DERKNQ) with the fewest average neighboring atoms per side chain atom (AvNAPSA). Our approach uses Rosetta-based energy calculations to choose the surface mutations. Both protocols are available for use through the ROSIE web server. The automated Rosetta and AvNAPSA approaches for supercharging choose dissimilar mutations, raising an interesting division in surface charging strategy. Rosetta-supercharged variants of GFP (RscG) ranging from −11 to −61 and +7 to +58 were experimentally tested, and for comparison, we re-tested the previously developed AvNAPSA-supercharged variants of GFP (AscG) with +36 and −30 net charge. Mid-charge variants demonstrated ~3-fold improvement in refolding with retention of stability. However, as we pushed to higher net charges, expression and soluble yield decreased, indicating that net charge or mutational load may be limiting factors. Interestingly, the two different approaches resulted in GFP variants with similar refolding properties. Our results show that there are multiple sets of residues that can be mutated to successfully supercharge a protein, and combining alternative supercharge protocols with experimental testing can be an effective approach for charge-based improvement to refolding.This work was supported by the Defense Advanced Research Projects Agency (HR-0011-10-1-0052 to A.E.) and the Welch Foundation (F-1654 to A.E.), the National Institutes of Health grants GM073960 (B.K.) and R01-GM073151 (J.G. and S.L.), the Rosetta Commons (S.L.), the National Science Foundation graduate research fellowship (2009070950 to B.D.), the UNC Royster Society Pogue fellowship (B.D.), and National Institutes of Health grant T32GM008570 for the UNC Program in Molecular and Cellular Biophysics. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Center for Systems and Synthetic BiologyCellular and Molecular BiologyApplied Research LaboratoriesEmail: [email protected]