Comparative Effects of Propylene Oxide, Sodium and Autoclaving on Selected Soil Properties

Samples of soil (25 g) were treated with 1 or 2 ml of propylene oxide, 400 or 800 parts/10? of sodium azide, or autoclaved for 1.5 or 3.0 h. Soil sterilization was achieved by the propylene oxide and autoclaving treatments. Sodium azide inhibited the bacteria and actinomycetes and drastically reduced the fungal population. The autoclaving treatment decreased the soil pH 0.2 unit, while propylene oxide and sodium azide treatments increased it 0.5-1.1 units. Extractable manganous—Mn was increased 2- to 3-fold by all treatments except for a 90- to 120-fold increase in an autoclaved soil; extractable Ca was not affected; and the extractable K changes were slight. Total extractable N was increased 10-20 parts/10?, and available P was generally increased by the treatments. Propylene oxide induced the least chemical alterations upon sterilization and is considered an appropriate sterilant to study chemical transformations in soils; but, germination and growth of wheat and alfalfa were retarded in propylene oxide treated soil

The effect of selected potassium salts on the availability of soil manganese

Incubation experiments with an acid poorly drained soil have shown that the application of neutral soluble salts influenced the level of extractable Mn. The application of a salt which lowered the soil pH either increased the extractable Mn or retarded the oxidation and/or fixation of extractable Mn. This effect was independent of the applied salt, although salts which had the greatest effect on soil pH generally had the largest effect on extractable Mn. Comparisons of K₂SO₄ with KNO₃ at equivalent concentrations of K and with K₂SO₄ at different ionic strengths showed a small but nonsignificant effect of ionic strength on the level of extractable Mn. This indicated that the solubility of the Mn oxides was largely pH dependent and that ionic strength considerations were of secondary importance. The effect of the C1 salt was over and above that of the general salt effect. The application of KC1 always released more extractable Mn than either the KNO₃ or the K₂SO₄ treatment. This was not a strict pH effect since the KNO₃ and KC1 treatments always had the same effect on soil pH. It was also not an ionic strength effect since the relative ionic strength of the K₂SO₄ treatment was 1.5 times greater than that of the KC1 treatment, and biological activity was not a factor in well aerated conditions. To explain the C1 effect, a hypothesis has been presented in which C1 would function in an oxidation-reduction reaction. In these reactions, C1 could act either as the electron donor or as an electron bridge between the reductant and oxidant. Evidence that would support this hypothesis was: 1. The similarity between the effect of KC1 and KBr on extractable Mn, i,e., the KBr treatment released more extractable Mn than the KC1 according to theory. 2, Theoretical considerations of some of the conditions which were possible in the soil system showed that both C1 and Br had the potential to reduce the lower Mn oxides under those conditions. 3. The pH dependence of the C1 effect

Gene Deletion of the Kinin Receptor B1 Attenuates Cardiac Inflammation and Fibrosis During the Development of Experimental Diabetic Cardiomyopathy

Objective: Diabetic cardiomyopathy is associated with increased mortality in patients with diabetes mellitus. The underlying pathology of this disease is still under discussion. We studied the role of the kinin B1 receptor on the development of experimental diabetic cardiomyopathy. Research Design and Methods: We utilized B1 receptor knockout mice and investiged cardiac inflammation, fibrosis and oxidative stress after induction of streptozotocin (STZ)-induced diabetes mellitus. Furthermore, the left ventricular function was measured by pressure-volume loops after 8 weeks of diabetes mellitus. Results: B1 receptor knockout mice showed an attenuation of diabetic cardiomyopathy with improved systolic and diastolic function in comparison with diabetic control mice. This was associated with a decreased activation state of the MAP kinase p38, less oxidative stress as well as normalized cardiac inflammation, shown by fewer invading cells and, no increase in matrix metalloproteinase-9 as well as the chemokine CXCL-5. Furthermore, the pro-fibrotic connective tissue growth factor was normalized, leading to a reduction in cardiac fibrosis despite severe hyperglycemia in mice lacking the B1 receptor. Conclusion: These findings suggest that the B1 receptor is detrimental in diabetic cardiomyopathy in that it mediates inflammatory and fibrotic processes. These insights might have useful implications on future studies utilizing B1 receptor antagonists for treatment of human diabetic cardiomyopathy

Rubber friction: role of the flash temperature

When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 0.01 m/s the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v > 0.01 m/s. This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g., for the tire-road friction, and in particular for ABS-breaking systems.Comment: 22 pages, 27 figure

Chlamydia pecorum Ovine Abortion: Associations between Maternal Infection and Perinatal Mortality.

Chlamydia pecorum is a common gastrointestinal inhabitant of livestock but infections can manifest in a broad array of clinical presentations and in a range of host species. While C. pecorum is a known cause of ovine abortion, clinical cases have only recently been described in detail. Here, the prevalence and sequence types (STs) of C. pecorum in ewes from a property experiencing high levels of perinatal mortality (PNM) in New South Wales (NSW), Australia, were investigated using serological and molecular methods. Ewes that were PNM+ were statistically more likely to test seropositive compared to PNM- ewes and displayed higher antibody titres; however, an increase in chlamydial shedding from either the rectum, vagina or conjunctiva of PNM+ ewes was not observed. Multilocus sequence typing (MLST) indicated that C. pecorum ST23 was the major ST shed by ewes in the flock, was the only ST identified from the vaginal site, and was the same ST detected within aborted foetal tissues. Whole genome sequencing of C. pecorum isolated from one abortion case revealed that the C. pecorum plasmid (pCpec) contained a unique deletion in coding sequence 1 (CDS1) that was also present in C. pecorum ST23 shed from the ewes. A further unique deletion was noted in a polymorphic membrane protein gene (pmpG) of the C. pecorum chromosome, which warrants further investigation given the role of PmpG in host cell adherence and tissue tropism.This study describes novel infection parameters in a sheep flock experiencing C. pecorum-associated perinatal mortality, provides the first genomic data from an abortigenic C. pecorum strain, and raises questions about possible links between unique genetic features of this strain and C. pecorum abortion

‘‘Lozenge’’ contour plots in scattering from polymer networks

We present a consistent explanation for the appearance of “lozenge” shapes in contour plots of the two dimensional scattering intensity from stretched polymer networks. By explicitly averaging over quenched variables in a tube model, we show that lozenge patterns arise as a result of chain material that is not directly deformed by the stretch. We obtain excellent agreement with experimental data

Submarine permafrost map in the arctic modeled using 1-D transient heat flux (SuPerMAP)

Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 124(6), (2019): 3490-3507, doi:10.1029/2018JC014675.Offshore permafrost plays a role in the global climate system, but observations of permafrost thickness, state, and composition are limited to specific regions. The current global permafrost map shows potential offshore permafrost distribution based on bathymetry and global sea level rise. As a first‐order estimate, we employ a heat transfer model to calculate the subsurface temperature field. Our model uses dynamic upper boundary conditions that synthesize Earth System Model air temperature, ice mass distribution and thickness, and global sea level reconstruction and applies globally distributed geothermal heat flux as a lower boundary condition. Sea level reconstruction accounts for differences between marine and terrestrial sedimentation history. Sediment composition and pore water salinity are integrated in the model. Model runs for 450 ka for cross‐shelf transects were used to initialize the model for circumarctic modeling for the past 50 ka. Preindustrial submarine permafrost (i.e., cryotic sediment), modeled at 12.5‐km spatial resolution, lies beneath almost 2.5 ×106km2 of the Arctic shelf. Our simple modeling approach results in estimates of distribution of cryotic sediment that are similar to the current global map and recent seismically delineated permafrost distributions for the Beaufort and Kara seas, suggesting that sea level is a first‐order determinant for submarine permafrost distribution. Ice content and sediment thermal conductivity are also important for determining rates of permafrost thickness change. The model provides a consistent circumarctic approach to map submarine permafrost and to estimate the dynamics of permafrost in the past.Boundary condition data are available online via the sources referenced in the manuscript. This work was partially funded by a Helmholtz Association of Research Centres (HGF) Joint Russian‐German Research Group (HGF JRG 100). This study is part of a project that has received funding from the European Unions Horizon 2020 research and innovation program under grant agreement 773421. Submarine permafrost studies in the Kara and Laptev Seas were supported by Russian Foundation for Basic Research (RFBR/RFFI) grants 18‐05‐60004 and 18‐05‐70091, respectively. The International Permafrost Association (IPA) and the Association for Polar Early Career Scientists (APECS) supported research coordination that led to this study. We acknowledge coordination support of the World Climate Research Programme (WCRP) through their core project on Climate and Cryosphere (CliC). Thanks to Martin Jakobsson for providing a digitized version of the preliminary IHO delineation of the Arctic seas and to Guy Masters for access to the observational geothermal database. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.2019-10-1

Production and Initial Characterization of Dad1p, a Component of the Dam1-DASH Kinetochore Complex

In all dividing eukaryotic cells, the mitotic spindle (composed primarily of microtubules) must interact with chromosomes through a complex protein assembly called the kinetochore. In Saccharomyces cerevisiae, the Dam1-DASH complex plays an important role in promoting attachment between the kinetochore and the mitotic spindle. It also actively participates in the physical separation of sister chromatids in anaphase. Understanding the biochemical mechanisms used by Dam1-DASH has been facilitated by bacterial co-expression of the ten Dam1-DASH genes, which results in the production of a heterodecameric protein complex that can be studied in vitro. However, individual protein subunits are not soluble when expressed in E. coli, thus precluding analysis of the nature of the interaction between subunits and an examination of the assembly of the functional complex. In this paper, we describe the expression, solubilization, purification and refolding of Dad1p, one of the Dam1-DASH complex subunits. In addition, we show that Dad1p, when isolated in this manner forms dimers and/or tetramers, dependent upon protein concentration. This work provides an important tool for studying the Dam1-DASH complex that was previously unavailable, and provides an avenue of investigation for understanding how the individual heterodecamers associate with each other to facilitate chromosome segregation

On the nature of surface roughness with application to contact mechanics, sealing, rubber friction and adhesion

Surface roughness has a huge impact on many important phenomena. The most important property of rough surfaces is the surface roughness power spectrum C(q). We present surface roughness power spectra of many surfaces of practical importance, obtained from the surface height profile measured using optical methods and the Atomic Force Microscope. We show how the power spectrum determines the contact area between two solids. We also present applications to sealing, rubber friction and adhesion for rough surfaces, where the power spectrum enters as an important input.Comment: Topical review; 82 pages, 61 figures; Format: Latex (iopart). Some figures are in Postscript Level