The relationship between cation exchange capacity, total bases, and exchange acidity in certain Oregon soils

Two soils representative of the coast and three representing the Willamette Valley have been studied for their general chemical characteristics. Exchange capacity and exchangeable cations were determined by the ammonium acetate and the BaCl₂-triethanolamine buffer methods. Exchange capacity was also obtained from conductimetric titrations which were run on each soil before and after destroying the organic matter.Potentiometric titrations were run before and after leaching each soil with HCl. Lime requirement was determined by Woodruff's method and also obtained from the pH-lime curves. The two coastal soils, Astoria and Clatsop, have lower pH and base saturation and higher organic matter content and exchange capacity than the Melbourne, Olympic, and Willamette soils from the valley. The Melbourne soil had the highest base saturation percentage and Astoria had the lowest. The amount of exchangeable aluminum was also higher in the coastal soils. The amount of exchange capacity contributed to the organic fraction was 65 per cent in the Olympic and Willamette soils and 50 per cent in the other three. The value for exchange capacity by the different methods was in good agreement in the three valley soils before and after the organic matter was destroyed. In the coastal soils there was no agreement between methods in any case. This would indicate that in the latter two soils, type of clay mineral present may be more of an influence than in the former soils. The potentiometric titration curves showed that the two coastal soils were well buffered and the valley soils were only slightly buffered. After the soils were leached with HCl the Melbourne soil was the only one which indicated a strong acid property. The exchange properties of the soils as affected by additions of lime were studied by incubating the soils for four weeks with added increments of lime. With each added increment of lime the pH increased and exchangeable acidity decreased in each soil. The amount of lime to bring the soils to any given degree of base saturation appeared to be proportional to the magnitude of the exchange capacity and inversely proportional to the degree of base saturation. At any given pH value there was a considerable difference in the degree of base saturation for these soils. This might well be a reflection of the type of minerals present in the different soils. More lime was required to bring the two coastal soils up to pH 6.5 as indicated by the pH-lime relationship curve than that estimated by the Woodruff method. Consistent results were observed in the three valley soils. This suggests that the buffer solution at pH 7 as recommended by Woodruff was not strong enough to neutralize the acidity in the coastal soils. There was good agreement between the two methods in the determination of the exchangeable bases. The BaCl₂-buffer method gave much higher values of exchangeable acidity than did the ammonium acetate method. These values, when converted to tons of calcium carbonate, agree fairly closely with the amount of lime required to bring the soils to pH 7 when added directly to the soil. When lime was added above the saturation point the amount of exchangeable calcium as determined by the ammonium acetate method increased but remained relatively constant for the BaCl₂-buffer method. The various analysis seem to indicate that the Astoria and Clatsop soils contain predominantly 2:1 type clay minerals while the Olympic and Willamette soils contain predominantly the 1:1 type. The Melbourne soil exhibits properties more closely associated with the coastal soils

Resveratrol activates antioxidant protective mechanisms in cellular models of Alzheimer’s disease inflammation

Resveratrol is a natural phenolic compound with known benefits against neurodegeneration. We analyzed in vitro the protective mechanisms of resveratrol against the proinflammatory monomeric C-reactive protein (mCRP). mCRP increases the risk of AD after stroke and we previously demonstrated that intracerebral mCRP induces AD-like dementia in mice. Here, we used BV2 microglia treated with mCRP for 24 h in the presence or absence of resveratrol. Cells and conditioned media were collected for analysis. Lipopolysaccharide (LPS) has also been implicated in AD progression and so LPS was used as a resveratrol-sensitive reference agent. mCRP at the concentration of 50 µg/mL activated the nitric oxide pathway and the NLRP3 inflammasome pathway. Furthermore, mCRP induced cyclooxygenase-2 and the release of proinflammatory cytokines. Resveratrol effectively inhibited these changes and increased the expression of the antioxidant enzyme genes Cat and Sod2. As central mechanisms of defense, resveratrol activated the hub genes Sirt1 and Nfe2l2 and inhibited the nuclear translocation of the signal transducer NF-ĸB. Proinflammatory changes induced by mCRP in primary mixed glial cultures were also protected by resveratrol. This work provides a mechanistic insight into the protective benefits of resveratrol in preventing the risk of AD induced by proinflammatory agents

The establishment of the infant intestinal microbiome is not affected by rotavirus vaccination

The microbial colonization of the intestine during the first months of life constitutes the most important process for the microbiota-induced host-homeostasis. Alterations in this process may entail a high-risk for disease in later life. However, the potential factors affecting this process in the infant are not well known. Moreover, the potential impact of orally administered vaccines upon the establishing microbiome remains unknown. Here we assessed the intestinal microbiome establishment process and evaluated the impact of rotavirus vaccination upon this process. Metagenomic, PCR-DGGE and faecal short chain fatty acids analyses were performed on faecal samples obtained from three infants before and after the administration of each dose of vaccine. We found a high inter-individual variability in the early life gut microbiota at microbial composition level, but a large similarity between the infants' microbiomes at functional level. Rotavirus vaccination did not show any major effects upon the infant gut microbiota. Thus, the individual microbiome establishment and development process seems to occur in a defined manner during the first stages of life and rotavirus vaccination appears to be inconsequential for this process.This work was funded by a CSIC intramural project (Ref. 201370E019) and Spanish Ministry of Economy and Competitiveness project AGL2013-43770R.Peer Reviewe

Correlation-induced insulating topological phases at charge neutrality in twisted bilayer graphene

Twisted bilayer graphene (TBG) provides a unique framework to elucidate the interplay between strong correlations and topological phenomena in two-dimensional systems. The existence of multiple electronic degrees of freedom -- charge, spin, and valley -- gives rise to a plethora of possible ordered states and instabilities. Identifying which of them are realized in the regime of strong correlations is fundamental to shed light on the nature of the superconducting and correlated insulating states observed in the TBG experiments. Here, we use unbiased, sign-problem-free quantum Monte Carlo simulations to solve an effective interacting lattice model for TBG at charge neutrality. Besides the usual cluster Hubbard-like repulsion, this model also contains an assisted hopping interaction that emerges due to the non-trivial topological properties of TBG. Such a non-local interaction fundamentally alters the phase diagram at charge neutrality, gapping the Dirac cones even for infinitesimally small interaction. As the interaction strength increases, a sequence of different correlated insulating phases emerge, including a quantum valley Hall state with topological edge states, an intervalley-coherent insulator, and a valence bond solid. The charge-neutrality correlated insulating phases discovered here provide the sought-after reference states needed for a comprehensive understanding of the insulating states at integer fillings and the proximate superconducting states of TBG.Comment: 15 pages, 9 figures, 2 table

The potential of construction robotics to reduce airborne virus transmission in the construction industry in the UK and China

This paper aims to identify construction robotics' potential to reduce airborne virus transmission, review factors limiting the technology's adoption and highlight how similar barriers have been addressed in other industries. Construction robotics were identified and classified into 8 themes with 25 categories through a critical literature review. We undertook interviews with 4 construction contractors and conducted an online questionnaire with 32 experts from the UK (n=14) and China (n=18) who reviewed the robotic systems we identified and ranked the potential ability of each to reduce airborne virus transmission within the construction industry. The results of this study showed that construction robotics is not only beneficial to reduce airborne virus transmission, but may also help to reduce the spread of future contagious viruses. We found no significant difference (P>0.05) in practical usage and implementation barriers to construction robotics between the UK and China. Cost, training and limited awareness of robotic technologies were the main implementation barriers we identified in both countries. Both the UK and China may need to adopt strategies such as providing more financial support to small construction industries and skill training which are utilised successfully in other sectors to realise the potential of construction robotic technologies

IKZF1/3 and CRL4-CRBN E3 ubiquitin ligase mutations and IMiD resistance in multiple myeloma

The work was supported by the Deutsche Forschungsgemeinschaft (KFO216), the IZKF, the BTHA and the CDW Stiftung (KMK). UM was supported by a grant of the German Excellence Initiative to the Graduate School of Life Sciences, University of Würzburg.S

Engineering alternative butanol production platforms in heterologous bacteria

Alternative microbial hosts have been engineered as biocatalysts for butanol biosynthesis. The butanol synthetic pathway of Clostridium acetobutylicum was first re-constructed in Escherichia coli to establish a baseline for comparison to other hosts. Whereas polycistronic expression of the pathway genes resulted in the production of 34 mg/L butanol, individual expression of pathway genes elevated titers to 200 mg/L. Improved titers were achieved by co-expression of Saccharomyces cerevisiae formate dehydrogenase while overexpression of E. coli glyceraldehyde 3-phosphate dehydrogenase to elevate glycolytic flux improved titers to 580 mg/L. Pseudomonas putida and Bacillus subtilis were also explored as alternative production hosts. Polycistronic expression of butanol biosynthetic genes yielded butanol titers of 120 and 24 mg/L from P. putida and B. subtilis, respectively. Production in the obligate aerobe P. putida was dependent upon expression of bcd-etfAB. These results demonstrate the potential of engineering butanol biosynthesis in a variety of heterologous microorganisms, including those cultivated aerobically.Synthetic Biology Engineering Research CenterNational Science Foundation (Grant no. 0540879)Massachusetts Institute of Technology. Energy Initiative (Grant no. 6917278)Natural Sciences and Engineering Research Council of CanadaKorea Research Foundation (Grant