Kinetic modeling of malonylgenistin and malonyldaidzin conversions under alkaline conditions and elevated temperatures

The conversion and degradation of malonylglucosides were kinetically characterized under elevated pH/heat conditions. Malonylgenistin and malonyldaidzin were heated at 60, 80, and 100 degrees C and pH values of 8.5, 9, and 9.5. A simple kinetic model was developed, which adequately predicted the conversion and degradation reactions. The conversion and degradation rates increased as temperature and pH increased. The rates of conversion of both malonylglucosides into their respective beta-glucosides were comparable under all pH/heat treatments. However, at 100 degrees C, the rates of degradation of malonyldaidzin were approximately double those of malonylgenistin, under all pH treatments. When malonlydaidzin was heated at 100 degrees C and pH 9.5, degradation of the produced daidzin occurred. Therefore, an alternative kinetic model was developed to better predict the conversion and degradation of malonyldaidzin occurring at 100 degrees C and pH 9.5. The models developed provide soy food manufacturers with guidelines for better control of the profile and level of isoflavones..     

Action of Clathrodin and Analogues on Voltage-Gated Sodium Channels

Clathrodin is a marine alkaloid and believed to be a modulator of voltage-gated sodium (Na_V ) channels. Since there is an urgent need for small molecule Na_V channel ligands as novel therapeutics, clathrodin could represent an interesting lead compound. Therefore, clathrodin was reinvestigated for its potency and Na_V channel subtype selectivity. Clathrodin and its synthetic analogues were subjected to screening on a broad range of Na_V channel isoforms, both in voltage clamp and patch clamp conditions. Even though clathrodin was not found to exert any activity, some analogues were capable of modulating the Na_V channels, hereby validating the pyrrole-2-aminoimidazole alkaloid structure as a core structure for future small molecule-based Na_V channel modulators.     

Farmland birds and resource protection in the UK: Cross-cutting solutions for multi-functional farming?

Farmland bird declines in Europe are well documented. In the UK, agri-environment schemes are key mechanisms for reversing the declines of birds and other farmland biodiversity, but recent reviews suggest that wet habitats might be a gap in provision by these schemes. Important resources provided by wet habitats include: (i) damp soil, for probing species; (ii) permanent water to provide water-dependent invertebrates, as a source of food; (iii) bare or sparsely vegetated ground in the draw-down zone, to improve access to food; (iv) rank emergent vegetation for nesting. However, wet habitats have been lost from farmland as a result of loss of ponds and filling of ditches, as well as the effective removal of water from fields by surface run-off, itself affected by soil compaction, and extensive under-field drainage. The efficient removal of water from fields can cause problems downstream, both through flooding, and diffuse pollution. Regular farmland pollutants include pesticides, nitrogen, phosphorus and sediment, leading to environmental problems such as eutrophication and reduced quality of drinking water. Major new political instruments, such as the Water Framework Directive, will aim to reduce the impact of this diffuse pollution from agriculture. A variety of solutions to diffuse pollution, such as conservation tillage, buffer strips at field edges, and small constructed wetlands, could simultaneously provide some of the resources required by farmland birds. We suggest that future agri-environment schemes, to be truly multifunctional, could focus on bringing these diverse objectives together.     

Mantle phase changes and deep-earthquake faulting in subducting lithosphere

Inclined zones of earthquakes are the primary expression of lithosphere subduction. A distinct deep population of subduction-zone earthquakes occurs at depths of 350 to 690 kilometers. At those depths ordinary brittle fracture and frictional sliding, the faulting processes of shallow earthquakes, are not expected. A fresh understanding of these deep earthquakes comes from developments in several areas of experimental and theoretical geophysics, including the discovery and characterization of transformational faulting, a shear instability connected with localized phase transformations under nonhydrostatic stress. These developments support the hypothesis that deep earthquakes represent transformational faulting in a wedge of olivine-rich peridotite that is likely to persist metastably in coldest plate interiors to depths as great as 690 km. Predictions based on this deep structure of mantle phase changes are consistent with the global depth distribution of deep earthquakes, the maximum depths of earthquakes in individual subductions zones, and key source characteristics of deep events.     

EXTRACTION OF A HIGHLY POTENT PENICILLIN INACTIVATOR FROM PENICILLIN RESISTANT STAPHYLOCOCCI

A highly potent penicillin inactivator has been extracted from 7 strains of Staph. aureus (coagulase positive), all of which were naturally penicillin resistant. No such inhibitor was present in extracts of 7 penicillin sensitive strains of Staph. aureus.     

Mariner 9 television reconnaissance of Mars and its satellites: preliminary results

At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark, spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes, are at different levels. The largest crater within the southernmost spot is approximately 100 kilometers wide. The craters apparently were formed by subsidence and resemble terrestrial calderas. The south polar cap has a regular margin, suggsting very flat topography. Two craters outside the cap have frost on their floors; an apparent crater rim within the cap is frost free, indicating preferentia loss of frost from elevated ground. If this is so then the curvilinear streaks, which were frost covered in 1969 and are now clear of frost, may be low-relief ridges. Closeup pictures of Phobos and Deimos show that Phobos is about 25 +/-5 by 21 +/-1 kilometers and Deimos is about 13.5 +/- 2 by 12.0 +/-0.5 kilometers. Both have irregular shapes and are highly cratered, with some craters showing raised rims. The satellites are dark objects with geometric albedos of 0.05.     

Evaluation of initial plasma lactate values as a predictor of gastric necrosis and initial and subsequent plasma lactate values as a predictor of survival in dogs with gastric dilatation‐volvulus: 84 dogs (2003–2007)

Objective – To test whether an initial plasma lactate≥6.0 mmol/L is associated with the presence of macroscopic gastric wall necrosis and overall survival in dogs presenting with gastric dilatation‐volvulus (GDV). Additionally, if no association was identified we sought to identify a different predictive initial plasma lactate concentration and to examine whether serial plasma lactate concentrations provide better prediction of survival. Design – Retrospective study over a 5‐year period (2003–2007). Setting – Urban private referral small animal teaching hospital. Animals – Eighty‐four client‐owned dogs with a diagnosis of GDV and plasma lactate measurements. Interventions – None. Measurements and Main Results – There was no statistically significant relationship found between survival and the presence of macroscopic gastric wall necrosis with the initial plasma lactate≥6 mmol/L. There was a significant relationship between the initial plasma lactate >2.9 mmol/L for predicting necrosis and <4.1 mmol/L for predicting survival to discharge. Forty dogs that had an increased initial plasma lactate (>2.5 mmol/L) also had a subsequent plasma lactate measured within 12 hours of presentation, with 37/40 dogs surviving and 70% of these surviving dogs having the subsequent lactate decrease by≥50% within 12 hours. The 3/40 that died failed to decrease their plasma lactate by≥50% from the initial blood lactate. Conclusion – The results of this study indicate that an initial presenting plasma lactate concentration≥6.0 mmol/L is not predictive of macroscopic gastric wall necrosis or survival in dogs presenting with GDV. A decrease in plasma lactate concentrations≥50% within 12 hours may be a good indicator for survival. Limitations to the study include its retrospective nature, the small number of patients, and the number of dogs that were euthanized rather than allowed to progress to a natural outcome.     

Influence of soil strength on root growth: experiments and analysis using a critical-state model

Roots grow thicker in compacted soil, even though it requires greater force for a large object to penetrate soil than it does for a small one. We examined the advantage of thickening in terms of the stresses around a root penetrating with constant shape, rather than the stresses around an expanding cylinder or sphere, as has been studied previously. We combined experiments and simulations of the stresses around roots growing in compacted soils. We measured the diameter of pea roots growing in sandy loam and clay loam at four different densities, and the critical‐state properties of the soils. At a penetration resistance of about 1 MPa the diameter of the roots in the sandy loam was about 40% greater than that at 0.7 MPa, and at 2 MPa it was about 60% greater. In the clay loam, there was less thickening – about 10% greater at 1 MPa and about 20% greater at 1.5 MPa. The maximum axial stresses were predicted using a critical‐state finite‐element model to be at the very tip of the root cap. When there was friction between the root and the soil, shear stresses were predicted with smaller values at the tip than just behind the tip. When the interface between the soil and the root was assumed to be frictionless, there were by definition no shear stresses. In the frictionless case the advantage of root thickening on relieving peak stress at the root tip was diminished. The axial and shear stresses were predicted to be smaller in the clay loam than in the sandy loam and may explain why the roots did not thicken in this soil although its resistance to penetration was similar. Our results suggest that the local values of axial and shear stresses experienced by the root near its tip may be as important in constraining root growth as the total penetration resistance.