Kinetic hindrance during the initial oxidation of Pd(100) at ambient pressures

The oxidation of the Pd(100) surface at oxygen pressures in the 10^-6 to 10^3 mbar range and temperatures up to 1000 K has been studied in-situ by surface x-ray diffraction (SXRD). The results provide direct structural information on the phases present in the surface region and on the kinetics of the oxide formation. Depending on the (T,p) environmental conditions we either observe a thin sqrt(5) x sqrt(5) R27 surface oxide or the growth of a rough, poorly ordered bulk oxide film of PdO predominantly with (001) orientation. By either comparison to the surface phase diagram from first-principles atomistic thermodynamics or by explicit time-resolved measurements we identify a strong kinetic hindrance to the bulk oxide formation even at temperatures as high as 675 K.Comment: 4 pages including 4 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Transfer of Dicamba Tolerance from Sinapis arvensis to Brassica napus via Embryo Rescue and Recurrent Backcross Breeding

Citation: Jugulam M, Ziauddin A, So KKY, Chen S, Hall JC (2015) Transfer of Dicamba Tolerance from Sinapis arvensis to Brassica napus via Embryo Rescue and Recurrent Backcross Breeding. PLoS ONE 10(11): e0141418. https://doi.org/10.1371/journal.pone.0141418Auxinic herbicides (e.g. dicamba) are extensively used in agriculture to selectively control broadleaf weeds. Although cultivated species of Brassicaceae (e.g. Canola) are susceptible to auxinic herbicides, some biotypes of Sinapis arvensis (wild mustard) were found dicamba resistant in Canada. In this research, dicamba tolerance from wild mustard was introgressed into canola through embryo rescue followed by conventional breeding. Intergeneric hybrids between S. arvensis (2n = 18) and B. napus (2n = 38) were produced through embryo rescue. Embryo formation and hybrid plant regeneration was achieved. Transfer of dicamba tolerance from S. arvensis into the hybrid plants was determined by molecular analysis and at the whole plant level. Dicamba tolerance was introgressed into B. napus by backcrossing for seven generations. Homozygous dicamba-tolerant B. napus lines were identified. The ploidy of the hybrid progeny was assessed by flow cytometry. Finally, introgression of the piece of DNA possibly containing the dicamba tolerance gene into B. napus was confirmed using florescence in situ hybridization (FISH). This research demonstrates for the first time stable introgression of dicamba tolerance from S. arvensis into B. napus via in vitro embryo rescue followed by repeated backcross breeding. Creation of dicamba-tolerant B. napus varieties by this approach may have potential to provide options to growers to choose a desirable herbicide-tolerant technology. Furthermore, adoption of such technology facilitates effective weed control, less tillage, and possibly minimize evolution of herbicide resistant weeds

Congenital absence of the external carotid artery: Atherosclerosis without a bifurcation

AbstractWe report the case of a patient with congenital absence of the external carotid artery in whom we performed a carotid endarterectomy. The radiographic features and operative findings are presented. Four similar cases previously reported in the literature are reviewed. A comment on the pathophysiology of atherosclerosis at the carotid bulb in the absence of a bifurcation and a brief discussion on the possible embryologic explanation of this anomaly are discussed. (J Vasc Surg 2002;35:573-5.

Probing molecular ordering in the nematic phases of para-linked bimesogen dimers through NMR studies of flexible prochiral solutes

The quadrupolar splittings of perdeuteriated n-decane dissolved in nematic phases formed by mesogenic dimers of the CBnCB series, for n = 7,9,10,11, are measured throughout the entire temperature range of these phases. These results are reported together with related measurements using the common nematic phase of 5CB as a solvent for n-decane. The data obtained from the 13C spectra of the cyanobiphenyl mesogenic units of the monomeric and dimeric solvent molecules yield the order parameter of those units. The information obtained from this set of experiments is used to elucidate the structure of the low temperature (NX) and the high temperature (N) nematic phases of CBnCB dimers with n = 7,9,11. The polar twisted nematic (NPT) model is found to provide a consistent description not only of our experimental results but also of NMR measurements previously reported in the literature for these phases. These findings suggest that the high temperature nematic (N) is not a common, locally uniaxial and apolar nematic, but rather a nematic phase consisting of NPT clusters. The twist-bend (NTB) model, often identified with the NX phase, is shown to be inadequate to account even qualitatively for crucial features of the experimental findings

Bio-Optics of the Chesapeake Bay from Measurements and Radiative Transfer Calculations

We combined detailed bio-optical measurements and radiative transfer (RT) modeling to perform an optical closure experiment for optically complex and biologically productive Chesapeake Bay waters. We used this experiment to evaluate certain assumptions commonly used when modeling bio-optical processes, and to investigate the relative importance of several optical characteristics needed to accurately model and interpret remote sensing ocean-color observations in these Case 2 waters. Direct measurements were made of the magnitude, variability, and spectral characteristics of backscattering and absorption that are critical for accurate parameterizations in satellite bio-optical algorithms and underwater RT simulations. We found that the ratio of backscattering to total scattering in the mid-mesohaline Chesapeake Bay varied considerably depending on particulate loading, distance from land, and mixing processes, and had an average value of 0.0128 at 530 nm. Incorporating information on the magnitude, variability, and spectral characteristics of particulate backscattering into the RT model, rather than using a volume scattering function commonly assumed for turbid waters, was critical to obtaining agreement between RT calculations and measured radiometric quantities. In situ measurements of absorption coefficients need to be corrected for systematic overestimation due to scattering errors, and this correction commonly employs the assumption that absorption by particulate matter at near infrared wavelengths is zero

Reduced tillage and crop diversification can improve productivity and profitability of rice-based rotations of the Eastern Gangetic Plains

Intensive rice (Oryza sativa)-based cropping systems in south Asia provide much of the calorie and protein requirements of low to middle-income rural and urban populations. Intensive tillage practices demand more resources, damage soil quality, and reduce crop yields and profit margins. Crop diversification along with conservation agriculture (CA)-based management practices may reduce external input use, improve resource-use efficiency, and increase the productivity and profitability of intensive cropping systems. A field study was conducted on loamy soil in a sub-tropical climate in northern Bangladesh to evaluate the effects of three tillage options and six rice-based cropping sequences on grain, calorie, and protein yields and gross margins (GM) for different crops and cropping sequences. The three tillage options were: (1) conservation agriculture (CA) with all crops in sequences untilled, (2) alternating tillage (AT) with the monsoon season rice crop tilled but winter season crops untilled, and (3) conventional tillage (CT) with all crops in sequences tilled. The six cropping sequences were: rice-rice (R-R), rice-mung bean (Vigna radiata) (R-MB), rice-wheat (Triticum aestivum) (R-W), rice-maize (Zea mays) (R-M), rice-wheat-mung bean (R-W-MB), and rice-maize-mung bean (R-M-MB). Over three years of experimentation, the average monsoon rice yield was 8% lower for CA than CT, but the average winter crops yield was 13% higher for CA than CT. Systems rice equivalent yield (SREY) and systems calorie and protein yields were about 5%, 3% and 6%, respectively, higher under CA than CT; additionally, AT added approximately 1% more to these benefits. The systems productivity gain under CA and AT resulted in higher GM by 16% while reducing the labor and total production cost under CA than CT. The R-M rotation had higher SREY, calorie, protein yields, and GM by 24%, 26%, 66%, and 148%, respectively, than the predominantly practiced R-R rotation. The R-W-MB rotation had the highest SREY (30%) and second highest (118%) GM. Considering the combined effect of tillage and cropping system, CA with R-M rotation showed superior performance in terms of SREY, protein yield, and GM. The distribution of labor use and GM across rotations was grouped into four categories: R-W in low-low (low labor use and low GM), R-M in low-high (low labor use and high GM), R-W-MB and R-M-MB in high-high (high labor use and high GM) and R-R and R-MB in high-low (high labor use and low GM). In conclusion, CA performed better than CT in different winter crops and cropping systems but not in monsoon rice. Our results demonstrate the multiple benefits of partial and full CA-based tillage practices employed with appropriate crop diversification to achieve sustainable food security with greater calorie and protein intake while maximizing farm profitability of intensive rice-based rotational systems

PACE Technical Report Series, Volume 7: Ocean Color Instrument (OCI) Concept Design Studies

Extending OCI hyperspectral radiance measurements in the ultraviolet to 320 nm on the blue spectrograph enables quantitation of atmospheric total column ozone (O3) for use in ocean color atmospheric correction algorithms. The strong absorption by atmospheric ozone below 340 nm enables the quantification of total column ozone. Other applications are possible but were not investigated due to their exploratory nature and lower priority.The first step in the atmospheric correction processing, which converts top-of-the-atmosphere radiances to water-leaving radiances, is removal of the absorbance by atmospheric trace gases such as water vapor, oxygen, ozone and nitrogen dioxide. Details of the atmospheric correction process currently used by the Ocean Biology Processing Group (OBPG) and will be employed for PACE with appropriate modifications, are described by Mobley et al. [2016]. Atmospheric ozone absorbs within the visible to near-infrared spectrum between ~450 nm and 800nm and most appreciably between 530 nm and 650 nm, a spectral region critical for maintaining NASA's chlorophyll-a climate data record and for PACE algorithms planned to characterize phytoplankton community composition and other ocean color products.While satellite-based observations will likely be available during PACE's mission lifetime, the difference in acquisition time with PACE, the coarseness in their spatial resolution, and differences in viewing geometries will introduce significant levels of uncertainties in PACE ocean color data products

Apoptosis screening of human chromosome 21 proteins reveals novel cell death regulators

The functional analysis of chromosome 21 (Chr21) proteins is of great medical relevance. This refers, in particular, to the trisomy of human Chr21, which results in Down’s syndrome, a complex developmental and neurodegenerative disease. In a previous study we analyzed 89 human Chr21 genes for the subcellular localization of their encoded proteins using a transfected-cell array technique. In the present study, the results of the follow-up investigation are presented in which 52 human Chr21 genes were over-expressed in HEK cells using the transfected-cell array platform, and the effect of this protein over-expression on the induction of apoptosis has been analyzed. We found that the over-expression of two Chr21 proteins (claudin-14 and -8) induced cell death independent of the classic caspase-mediated apoptosis. Our results strongly suggest the functional involvement of claudins in the control of the cell cycle and regulation of the cell death induction mechanism