Optimal proportional-integral-derivative control of shape memory alloy actuators using genetic algorithm and the Preisach model

Shape memory alloy (SMA) actuators, which have the ability to return to a predetermined shape when heated, have many potential applications in aeronautics, surgical tools, robotics, and so on. Although the number of applications is increasing, there has been limited success in precise motion control owing to the hysteresis effect of these smart actuators. The present paper proposes an optimization of the proportional-integral-derivative (PID) control method for SMA actuators by using genetic algorithm and the Preisach hysteresis model.

BcsK(C) Is an Essential Protein for the Type VI Secretion System Activity in Burkholderia cenocepacia That Forms an Outer Membrane Complex with BcsL(B)

The type VI secretion system (T6SS) contributes to the virulence of Burkholderia cenocepacia, an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. BcsK(C) is a highly conserved protein among the T6SSs in Gram-negative bacteria. Here, we show that BcsK(C) is required for Hcp secretion and cytoskeletal redistribution in macrophages upon bacterial infection. These two phenotypes are associated with a functional T6SS in B. cenocepacia. Experiments employing a bacterial two-hybrid system and pulldown assays demonstrated that BcsK(C) interacts with BcsL(B), another conserved T6SS component. Internal deletions within BcsK(C) revealed that its N-terminal domain is necessary and sufficient for interaction with BcsL(B). Fractionation experiments showed that BcsK(C) can be in the cytosol or tightly associated with the outer membrane and that BcsK(C) and BcsL(B) form a high molecular weight complex anchored to the outer membrane that requires BcsF(H) (a ClpV homolog) to be assembled. Together, our data show that BcsK(C)/BcsL(B) interaction is essential for the T6SS activity in B. cenocepacia.

Construction and biochemical characterization of recombinant cytoplasmic forms of the IucD protein (lysine:N6-hydroxylase) encoded by the pColV-K30 aerobactin gene cluster

The aerobactin gene cluster in pColV-K30 consists of five genes (iucABCD iutA); four of these (iucABCD) are involved in aerobactin biosynthesis, whereas the fifth one (iutA) encodes the ferriaerobactin outer membrane receptor. iucD encodes lysine:N6-hydroxylase, which catalyzes the first step in aerobactin biosynthesis. Regardless of the method used for cell rupture, we have consistently found that IucD remains membrane bound, and repeated efforts to achieve a purified and active soluble form of the enzyme have been unsuccessful. To circumvent this problem, we have constructed recombinant IucD proteins with modified amino termini by creating three in-frame gene fusions of IucD to the amino-terminal amino acids of the cytoplasmic enzyme beta-galactosidase. Two of these constructs resulted in the addition to the iucD coding region of a hydrophilic leader sequence of 13 and 30 amino acids. The other construct involved the deletion of the first 47 amino acids of the IucD amino terminus and the addition of 19 amino acids of the amino terminus of beta-galactosidase. Cells expressing any of the three recombinant IucD forms were found to produce soluble N6-hydroxylysine. One of these proteins, IucD439, was purified to homogeneity from the soluble fraction of the cell lysates, and it was capable of participating in the biosynthesis of aerobactin, as determined in vitro by a cell-free system and in vivo by a cross-feeding bioassay. A medium ionic strength of 0.25 (250 mM NaCl) or higher was required to maintain the protein in a catalytically functional, tetrameric state.(ABSTRACT TRUNCATED AT 250 WORDS)

Inorganic arsenic and trace elements in Ghanaian grain staples

A total of 549 samples of rice, maize, wheat, sorghum and millet were obtained from markets in Ghana, the EU, US and Asia. Analysis of the samples, originating from 21 countries in 5 continents, helped to establish global mean trace element concentrations in grains: thus placing the Ghanaian data within a global context. Ghanaian rice was generally low in potentially toxic elements, but high in essential nutrient elements. Arsenic concentrations in rice from US (0.22 mg/kg) and Thailand (0.15 mg/kg) were higher than in Ghanaian rice (0.11 mg/kg). Percentage inorganic arsenic content of the latter (83%) was, however, higher than for US (42%) and Thai rice (67%). Total arsenic concentration in Ghanaian maize, sorghum and millet samples (0.01 mg/kg) was an order of magnitude lower than in Ghanaian rice, indicating that a shift from rice-centric to multigrain diets could help reduce health risks posed by dietary exposure to inorganic As. (C) 2011 Elsevier Ltd. All rights reserved.

Arsenic influence on genetic variation in grain trace-element nutrient content in Bengal delta grown rice

It has previously been shown that across different arsenic (As) soil environments, a decrease in grain selenium (Se), zinc (Zn), and nickel (Ni) concentrations is associated with an increase in grain As. In this study we aim to determine if there is a genetic element for this observation or if it is driven by the soil As environment. To determine the genetic and environmental effect on grain element composition, multielement analysis using ICP-MS was performed on rice grain from a range of rice cultivars grown in 4 different field sites (2 in Bangladesh and 2 in West Bengal). At all four sites a negative correlation was observed between grain As and grain Ni, while at three of the four sites a negative correlation was observed between grain As and grain Se and grain copper (Cu). For manganese, Ni, Cu, and Se there was also a significant genetic interaction with grain arsenic indicating some cultivars are more strongly affected by arsenic than others.

Arsenic limits Trace Mineral Nutrition (Selenium, Zinc, and Nickel) in Bangladesh Rice Grain

A reconnaissance of 23 paddy fields, from three Bangladesh districts, encompassing a total of 230 soil and rice plant samples was conducted to identify the extent to which trace element characteristics in soils and irrigation waters are reflected by the harvested rice crop. Field sites were located on two soil physiographic units with distinctly different As soil baseline and groundwater concentrations. For arsenic (As), both straw and grain trends closely fitted patterns observed for the soils and water. Grain concentration characteristics for selenium (Se), zinc (Zn), and nickel (Ni), however, were markedly different. Regressions of shoot and grain As against grain Se, Zn, and Ni were highly significant (P <0.001), exhibiting a pronounced decline in grain trace-nutrient quality with increasing As content. To validate this further, a pot experiment cultivar screening trial, involving commonly cultivated high yielding variety (HYV) rice grown alongside two U.S. rice varieties characterized as being As tolerant and susceptible, was conducted on an As-amended uniform soil. Findings from the trial confirmed that As perturbed grain metal(loid) balances, resulting in severe yield reductions in addition to constraining the levels of Se, Zn, and Ni in the grain.

Thou art a strange fellow:Dissonance and Discordance in Intercultural Shakespeares

Any performance of the intercultural necessarily, and always, advances the question of the cultural since it involves the inter-action and interplay of unique and particular cultural performance styles and modes. Intercultural theatre, according to Pavis, is a hybrid theatrical form “drawing upon performance traditions traceable to distinct cultural areas. The hybridization is very often such that the original forms can no longer be distinguished.” The result of this collaboration of forms is, however, often not a ‘hybrid’ where cultural texts work cohesively and in unison to produce a harmonious mise en scene. Instead, intercultural performances are performances at the interstices and at the intersections of cultures. They raise problems of authorship, authority and performance unities and expose a sense of cultural foreignness. Consequently, intercultural performance can be said to be meta-theatre that queries the construction of culture since it places alongside performance traditions that confront.

Music, as performative unit, is a significant line of action by which the intercultural spectacle is constructed. Integral to Western theatre, and certainly more so in traditional Asian performance forms, the deliberate ‘fusion’ and ‘blending’ of musical styles in intercultural performances underscore not a harmony of diverse sounds but the possible dissonance and discordance already performed by the visual and verbal texts. The paper thus seeks to examine, in particular, the musical elements in intercultural performances such as Ong Keng Sen’s Lear (Theatreworks, 1999) and explore the ways in which music could possibly intensify the confrontation of performative texts resulting in a disruption of performance unities. When watching and listening to Lear, the question of the ‘local’ thus arises not merely with identification and alienation from what is seen but also what is familiar and foreign to one’s ears.