Stage-specific activity of the Leishmania major CRK3 kinase and functional rescue of a Schizosaccharomyces pombe cdc2 mutant

The effects of polyamines and related compounds on the development of drug/antibiotic resistance in a variety of bacterial strains were studied. Methods employed included standard toxicity assays, modified Ames tests for mutation frequencies and antimutagenic effects, prophage induction assays, and recA-lacZ and ada-lacZ induction assays. Using these methods, we have shown that the polyamines produce strong antimutagenic effects against EMS and MMS-induced antibiotic resistance. Spermidine also seems to have antimutagenic potential against 4NQO-induced mutations. DNA fidelity assays suggest that polyamines play a vital role in DNA synthesis, and several polyamines prevent the development of resistance to dihydrostreptomycin. The polyamine putrescine appears to be required for streptomycin action and also enhances the activity of some antibiotics (e.g., neomycin, kanamycin) but shows no enhancing effect on tetracycline or erythromycin. The potential significance of these studies for infectious diseases and tumor therapy is discussed.     

Is the public willing to pay for hydrogen buses? A comparative study of preferences in four cities

This paper presents results from the international AcceptH2 study (http://www.accepth2.com) of acceptability and preferences for hydrogen fuel cell (FC) buses. Using the contingent valuation method, this paper compares public willingness to pay (WTP) for the air pollution reductions associated with a scenario of large-scale introduction of hydrogen (H₂) FC buses in four cities: Berlin, London, Luxembourg and Perth. Results indicate that bus users in all cities have a positive WTP for H₂ buses, and that values (adjusted to the cost of living in each city) are very similar across geographical locations (ranging from WTP an extra €0.29 to €0.35 per single bus fare). Non-bus users were also interviewed in London and Perth, in order to capture values for the whole populations in these cities. Combined results for bus users and non-bus users confirm that overall residents in these cities are willing to pay extra (in taxes) to support the large-scale introduction of H₂-buses.     

Unique regulation of carbohydrate chemotaxis in Bacillus subtilis by the phosphoenolpyruvate-dependent phosphotransferase system and the methyl-accepting chemotaxis protein McpC

The phosphoenolpyruvate-dependent phosphotransferase system (PTS) plays a major role in the ability of Escherichia coli to migrate toward PTS carbohydrates. The present study establishes that chemotaxis toward PTS substrates in Bacillus subtilis is mediated by the PTS as well as by a methyl-accepting chemotaxis protein (MCP). As for E. coli, a B. subtilis ptsH null mutant is severely deficient in chemotaxis toward most PTS carbohydrates. Tethering analysis revealed that this mutant does respond normally to the stepwise addition of a PTS substrate (positive stimulus) but fails to respond normally to the stepwise removal of such a substrate (negative stimulus). An mcpC null mutant showed no response to the stepwise addition or removal of D-glucose or D-mannitol, both of which are PTS substrates. Therefore, in contrast to E. coli PTS carbohydrate chemotaxis, B. subtilis PTS carbohydrate chemotaxis is mediated by both MCPs and the PTS; the response to positive stimulus is primarily McpC mediated, while the duration or magnitude of the response to negative PTS carbohydrate stimulus is greatly influenced by components of the PTS and McpC. In the case of the PTS substrate D-glucose, the response to negative stimulus is also partially mediated by McpA. Finally, we show that B. subtilis EnzymeI-P has the ability to inhibit B. subtilis CheA autophosphorylation in vitro. We hypothesize that chemotaxis in the spatial gradient of the capillary assay may result from a combination of a transient increase in the intracellular concentration of EnzymeI-P and a decrease in the concentration of carbohydrate-associated McpC as the cell moves down the carbohydrate concentration gradient. Both events appear to contribute to inhibition of CheA activity that increases the tendency of the bacteria to tumble. In the case of D-glucose, a decrease in D-glucose-associated McpA may also contribute to the inhibition of CheA. This bias on the otherwise random walk allows net migration, or chemotaxis, to occur.     

An electromyographical study of subvocal speech and recall in preschool children.

Investigated the relationship of subvocal speech to recall for 46 4- and 5-yr-olds. The electromyographical activity on 5 memory trials, consisting of nonlabel pictures' names, was used as a control for nonspeech artifactual activity for 5 labial trials. Electromyographical activity was recorded from 3 muscle sites: lip, chin, and a nonspeech control. A more sensitive measurement procedure than is commonly employed was used to quantify electromyographical activity. Results indicate that (a) significant amounts of subvocalization occurred both during picture presentation and a prerecall delay; (b) amount of subvocalization was significantly related to recall; and (c) younger, less bright Ss subvocalized less than older, brighter Ss during a prerecall delay period. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and measurement of a SAW three-phase unidirectional transducer reflector

A novel reflector made from the highly unidirectional structure of the three-phase interdigital transducer resulting in high reflection coefficients from extremely short transducer lengths is presented. Such a reflector only requires a single phasing component. The dependency of the reflection on the unidirectionality yields frequency tuning capabilities via the phasing component. Such a reflector was fabricated and measured to determine the reflection from a short transducer. Two independent methods for determining the reflection coefficient from the measurements are presented.<>     

Simulation of buried power transmission systems: Some computer graphics options

This paper discusses some computer graphics options useful for both computation and display of three-dimensional motions within buried high-voltage power transmission lines as they undergo temperature changes (load cycling).     

Rheological behaviors exhibited by soy protein systems under dynamic aqueous environments

In this study, rheological behaviors of soy protein and soy flour as powders, pastes, and dispersions are characterized over a range of water contents and temperature to understand their processing in adhesives or paints. At ambient temperature, soy protein samples were characterized by low critical strain values (<0.1%), whereas soy flour samples exhibit linear viscoelastic regions >1% strain with 30–90% water content. On heating, the aqueous soy protein and soy flour compositions have complex rheological behaviors due to plasticization by water and the thermal denaturing and crosslinking of protein and carbohydrate with increasing temperature. Below 100 °C, soy protein rheological behaviors were attributable to the glass transition of the 7S and 11S soy globulin fractions, polymer flow, and plasticization by residual moisture. Above 100 °C, the onset of protein crosslinking was observed with this shifting to higher temperatures for samples still dehydrating. With soy flour samples, the residual moisture present above 100 °C similarly increase protein crosslinking to higher temperatures (125–148 °C) for samples with initial water contents of 30–90%. These results provide a basis for understanding why soy systems undergoing heat processing and rapid dehydration will require higher temperature and longer processing time to attain a cured, crosslinked state. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45513.     

Evergreen Agriculture: a robust approach to sustainable food security in Africa

Producing more food for a growing population in the coming decades, while at the same time combating poverty and hunger, is a huge challenge facing African agriculture. The risks that come with climate change make this task more daunting. However, hundreds of thousands of rain fed smallholder farmers in Zambia, Malawi, Niger, and Burkina Faso have been shifting to farming systems that are restoring exhausted soils and are increasing food crop yields, household food security, and incomes. This article reviews these experiences, and their broader implications for African food security, as manifestations of Evergreen Agriculture, a fresh approach to achieving food security and environmental resilience. Evergreen Agriculture is defined as the integration of particular tree species into annual food crop systems. The intercropped trees sustain a green cover on the land throughout the year to maintain vegetative soil cover, bolster nutrient supply through nitrogen fixation and nutrient cycling, generate greater quantities of organic matter in soil surface residues, improve soil structure and water infiltration, increase greater direct production of food, fodder, fuel, fiber and income from products produced by the intercropped trees, enhance carbon storage both above-ground and below-ground, and induce more effective conservation of above- and below-ground biodiversity. Four national cases are reviewed where farmers are observed to be applying these principles on a major scale. The first case involves the experience of Zambia, where conservation farming programmes include the cultivation of food crops within an agroforest of the fertilizer tree Faidherbia albida. The second case is that of the Malawi Agroforestry Food Security Programme, which is integrating fertilizer, fodder, fruit, fuel wood, and timber tree production with food crops on small farms on a national scale. The third case is the dramatic expansion of Faidherbia albida agroforests in millet and sorghum production systems throughout Niger via assisted natural regeneration. The fourth case is the development of a unique type of planting pit technology (zai) along with farmer-managed natural regeneration of trees on a substantial scale in Burkina Faso. Lastly, we examine the current outlook for Evergreen Agriculture to be further adapted and scaled-up across the African continent.