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Background In the malaria parasite Plasmodium falciparum the expression of ‘var’ virulence genes is regulated through epigenetic mechanisms. P. falciparum sirtuin epigenetic regulators have a direct effect on their var gene expression patterns, are increased in the 3D7 laboratory strain on exposure to heat shock. A Gambia study showed an association with fever, blood lactate and var genes commonly expressed in severe malaria, and between PfSir2A and group B var. A Kenyan study extended this association to between PfSir2A and overall var transcript level. We investigated a causal link between heat shock or lactate levels and sirtuins or var expression. Methods In vitro experiments were conducted using laboratory and recently-laboratory-adapted Kenyan isolates of P. falciparum to follow up the correlative findings of the field study. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after highly synchronous cultured parasites had been exposed to 2h or 6h of heat shock at 40°C or elevated lactate. Results Heat shock was shown to increase the expression of PfSir2B in the trophozoites, whereas exposure to lactate was not. After the ring stages were exposed to heat shock and lactate, there was no alteration in the expression of sirtuins and severe-disease-associated upsA and upsB var genes. The association between high blood lactate and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative. Conclusions This study demonstrates that heat stress in laboratory and recently-laboratory-adapted isolates of P. falciparum results in a small increase in PfSir2B transcripts in the trophozoite stages only. This finding adds to our understanding of how patient factors can influence the outcome of Plasmodium falciparum infections.

Background: In the malaria parasite Plasmodium falciparum the expression of ‘var’ virulence genes is regulated through epigenetic mechanisms. Its sirtuin epigenetic regulators have a direct effect on var gene expression patterns, are increased in a laboratory strain of P. falciparum exposed to heat shock and are positively associated with fever. A Gambia study extended this association to blood lactate and var genes commonly expressed in severe malaria, and between PfSir2A and group B var. A Kenyan study extended this association to between PfSir2A and overall var transcript level. These observations suggest a mechanism through which stress phenotypes in the human host might be sensed via a parasite sirtuin, and virulence gene expression modulated accordingly. Methods: In vitro experiments were conducted using laboratory and recently-laboratory-adapted Kenyan isolates of P. falciparum to follow up the correlative findings of the field study. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after highly synchronous cultured parasites had been exposed to 2h or 6h of heat shock at 40°C or elevated lactate.Results: Heat shock was shown to influence the expression of PfSir2B in the trophozoites, whereas exposure to lactate was not. After the ring stages were exposed to heat shock, sirtuins, severe-disease-associated upsA and upsB var genes and var genes in general were not altered. More biological replicate experiments will be needed to confirm our observations.Conclusions: This study demonstrates that heat stress in laboratory and recently-laboratory-adapted isolates of P. falciparum results in a small increase in PfSir2B transcripts in the trophozoite stages only. We could not establish if heat shock can cause an increased expression of sirtuins or var genes in the ring stages. By contrast, the association between hyperlactataemia and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative.

Background\ud In Plasmodium falciparum the monoallelic expression of var virulence genes is regulated through epigenetic mechanisms. A study in the Gambia showed that an increase in var gene expression is associated with fever, high blood lactate with commonly-expressed var genes expressed in patients with severe malaria. A strong association was demonstrated between the upregulation of PfSir2A and group B var genes. A subsequent study in Kenya extended this association to show a link between elevated expression of PfSir2A and overall var transcript levels. We investigate here the link between heat shock and/or lactate levels on sirtuin and var gene expression levels in vitro.\ud \ud Methods\ud In vitro experiments were conducted using laboratory and recently-laboratory-adapted Kenyan isolates of P. falciparum. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after highly synchronous cultured parasites had been exposed to 2 h or 6 h of heat shock at 40 °C or elevated lactate.\ud \ud Results\ud Heat shock was shown to increase the expression ofPfSir2B in the trophozoites, whereas exposure to lactate was not. After the ring stages were exposed to heat shock and lactate, there was no alteration in the expression of sirtuins and severe-disease-associated upsA and upsB var genes. The association between high blood lactate and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative.\ud \ud Conclusions\ud This study demonstrates that heat stress in a laboratory and recently-laboratory-adapted isolates of P. falciparum results in a small increase in PfSir2B transcripts in the trophozoite stages only. This finding adds to our understanding of how patient factors can influence the outcome of Plasmodium falciparum infections.

Neutron irradiation progressively changes the properties of zirconium alloys: they harden and their average c/a lattice parameter ratio decreases with fluence [1, 2, 3, 4]. The bombardment by neutrons produces point defects, which evolve into dislocation loops that contribute to a non-uniform growth phenomenon called irradiation-induced growth (IIG). To gain insights into these dislocation loops in Zr we studied them using atomistic simulation. We constructed and relaxed dislocation loops of various types. We find that the energies of 〈 a 〉 loops on different habit planes are similar, but our results indicate that they are most likely to form on the 1st prismatic plane and then reduce their energy by rotating onto the 2nd prismatic plane. By simulating loops of different aspect ratios, we find that, based on energetics alone, the shape of 〈 a 〉 loops does not depend on character, and that these loops become increasingly elliptical as their size increases. Additionally, we find that interstitial 〈 c / 2 + p 〉 loops and vacancy 〈 c 〉 loops are both energetically feasible and so the possibility of these should be considered in future work. Our findings offer important insights into loop formation and evolution, which are difficult to probe experimentally.

Background: In the malaria parasite Plasmodium falciparum the expression of ‘var’ virulence genes is regulated through epigenetic mechanisms. Two deacetylase enzymes of the sirtuin family have been implicated in this epigenetic control in laboratory-adapted parasites. A previous study of var gene expression in parasites isolated directly from Gambian malaria patients found that high expression levels of severe-disease-associated var variants correlated with high expression of the PfSir2A sirtuin, and these expression patterns also correlated with patient phenotypes of fever and hyperlactataemia. Together, the observations suggest a mechanism through which stress phenotypes in the human host might be sensed via a parasite sirtuin, and virulence gene expression modulated accordingly. Methods: In vitro experiments were conducted using recently-laboratory-adapted Kenyan isolates of P. falciparum to follow up the correlative findings of the field study. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after cultured parasites had been exposed to 2h or 6h of heat shock at 40°C or elevated lactate at 5mM.Results: Heat shock was shown to influence the expression of both sirtuins and var genes, whereas exposure to lactate was not. Heat shock in the trophozoite stage resulted in modest upregulation of the expression of sirtuins, particularly PfSir2B, by 2-3 fold in all strains tested. Interestingly, when heat shock was applied in ring stages PfSir2A was still upregulated but PfSir2B was downregulated. This correlated with a general upregulation of ring-stage var transcription, and particularly of severe-disease-associated upsA and upsB var genes, but there was no clear pattern in the dominant var gene(s) ultimately expressed by heat-shocked parasites. Conclusions: This study demonstrates for the first time that heat stress in recently-laboratory-adapted isolates of P. falciparum results in altered sirtuin expression – PfSir2B as well as PfSir2A – and also the upregulation of var gene expression. These may be strategies evolved by the parasite to survive heat stress when a human host experiences malarial fevers. By contrast, the association between hyperlactataemia and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative.

Satellites generated by small dislocation loops in polycrystalline proton- or neutron-irradiated Zr alloys are characterized by X-ray line profile analysis. The convolutional multiple whole-profile procedure has been extended to characterize irradiation-induced satellites around fundamental Bragg peaks., This work extends the convolutional multiple whole profile (CMWP) line profile analysis (LPA) procedure to determine the total dislocation density and character of irradiation-induced dislocation loops in commercial polycrystalline Zr specimens. Zr alloys are widely used in the nuclear industry as fuel cladding materials in which irradiation-induced point defects evolve into dislocation loops. LPA has long been established as a powerful tool to determine the density and nature of lattice defects in plastically deformed materials. The CMWP LPA procedure is based on the Krivoglaz–Wilkens theory in which the dislocation structure is characterized by the total dislocation density ρ and the dislocation arrangement parameter M. In commercial Zr alloys irradiation-induced dislocation loops broaden the peak profiles, mainly in the tail regions, and occasionally generate small satellites next to the Bragg peaks. In this work, two challenges in powder diffraction patterns of irradiated Zr alloys are solved: (i) determination of the M values from the long tail regions of peaks has been made unequivocal and (ii) satellites have been fitted separately, using physically well established principles, in order to exclude them from the dislocation determination process. Referring to the theory of heterogeneous dislocation distributions, determination of the total dislocation density from the main peaks free of satellites has been justified. The dislocation loop structure has been characterized by the total dislocation density of loops and the M parameter correlated to the dipole character of dislocation loops. The extended CMWP procedure is applied to determine the total dislocation density, the dipole character of dislocation loops, and the fractions of 〈a〉- and 〈c〉-type loops in proton- or neutron-irradiated polycrystalline Zr alloys used in the nuclear energy industry.

A proper choice of inelastic parameters is one of the most important aspects for a successful simulation of metal forming processes. Several issues must be observed when choosing such parameters, amongst which the compatibility between the magnitude of the plastic deformation of the target forming operation and the mechanical test employed to obtain those parameters. Within this context, the present work addresses the suitability of selected phenomenological hardening models and identification of the corresponding inelastic parameters based on curve-fitting strategies (logarithmic-based equations) and optimization methods (non-logarithmic models) for the AISI 304 austenitic stainless steel. Tensile tests were performed using specimens of different sizes. Based on a combined assessment of all types of specimens, it was observed that the curve-fitting technique was able to describe with excellent accuracy deformations up to maximum load. In order to contemplate larger plastic deformations, an inverse problem strategy based on optimization methods was used to account for material response up to macroscopic failure of the specimens. Numerical simulation of the tensile tests shows that the latter technique associated with non-logarithmic hardening equations provided the best approximation to the experimental data.

β-glucans are frequently included in the diet of healthy common carp Cyprinus carpio as a pre-emptive measure for combatting disease. In order to study the effect this has on the relationship between the gut bacteria and host immune response, carp were maintained on either a β-glucan free diet or feed containing 0.1% MacroGard®, a β-1/3, 1/6-glucan, for up to 7 weeks and analysis of innate immune gene expression and molecular analysis of the gut bacteria was performed. The data reveals feeding of MacroGard® to healthy carp does not induce bactericidal innate immune gene expression in the gut but does appear to alter bacterial species richness that did not have a negative effect on overall health. Analysis of innate immune gene expression within the upper midgut revealed that there were significant changes over time in the expression of Interleukin (il)-1β, inducible nitric oxide synthase (inos), mucin (muc2) and C-reactive protein (crp2). Diet did not affect the number of copies of the bacterial 16s rDNA gene in the gut, used as a as a measure of total bacteria population size. However, PCR-denaturing gradient gel electrophoresis (DGGE) analysis revealed a shift in bacterial species richness with MacroGard feeding. Bactericidal immune gene expression of crp2, muc2 and il-1β was weakly correlated with gut bacteria population size indicating a potentially limited role of these genes in interacting with the gut bacteria in healthy carp in order to maintain gut homeostatic conditions. These findings highlight the importance of considering both host immunity and the microbiome together in order to fully elucidate the effeect of immunomodulants, such as β-glucans, upon gut health.

Background: This present research was conducted to evaluate the efficacy of a clinical simulation where senior nursing students cared for a standardized patient with Autism Spectrum Disorder (ASD). The goal of the simulation was to teach the nursing students how to work with children with autism. In addition, the study aimed to determine if individual differences in personality affect students’ abilities to complete the simulation and how a student’s personality may affect their perceptions of the simulation. Projected outcomes included learning the use of appropriate communication strategies, improved assessment skills, prioritization of care, development of problem-solving skills, and decision-making abilities when dealing with children with ASD.Methods: Simulations are verified as effective training mechanisms to increase students’ self-efficacy in multiple nursing settings. Therefore, seventy-five senior baccalaureate nursing students completed the standardized patient simulation for care of an individual with ASD. The effect on the students’ self-efficacy was measured using the Occupational and Academic Self-Efficacy for Nursing Measure, the IPEP-NEO short form, and an ASD simulation study questionnaire.Results and conclusions: Logistic regression was used to investigate the relationship between personality measures and experience with ASD. The higher the openness and extraversion scores the more likely respondents were to disclose positive benefits in relation to expectations, communication strategies, teamwork, and reflection.

Since the discovery of ruffe Gymnocephalus cernuus in the St. Louis River in 1987, state, federal, and tribal management agencies have sought to slow its spread to areas outside the western end of Lake Superior. A debate over control strategies highlighted uncertainties about seasonal movements of this species between Lake Superior and its western tributaries. One strategy called for eliminating reproducing populations in tributaries on the periphery of the range using chemical piscicides. That strategy rested on the assumption that ruffe congregate in tributaries during a predictable time of year. This study was designed to explore that assumption. Ruffe collections from the Iron and Sand rivers during 1995 indicated that ruffe were present in those tributaries throughout the summer but that abundance was not highest at the predicted time: June 19–22. Maximum abundance in the Iron River did not coincide with that in the Sand River and did not occur during June 19–22 in either river. The timing o...

We have determined the index of refraction of AlxGa−xAs over the wavelength range 0.76–1.15 μm, and the composition range 0≤x

The present concepts for power and particle control in the next generation of tokamak experiments rely upon atomic processes to transfer the power and momentum from the divertor plasma to the divertor chamber walls. These concepts are being evaluated with sophisticated one- and two-dimensional divertor models. We present a survey of some of the candidate atomic processes of impurity radiation, hydrogen radiation and atomic physics and molecular effects to aid the development of the models.

Analysis of infrared images of spatial beats between two discrete modes in a single waveguide is shown to provide a useful consistency check on the thicknesses and refractive indices of the dielectric layers.

Etude des surfaces ondulees d'Ag. L'ondulation joue un role important dans les lois de selections du vecteur d'onde gouvernant le couplage aux phonons de surface. Cet effet est substantiellement different quand le vecteur d'onde effectif est colineaire ou perpendiculaire au plan de diffusion. Le mecanisme de couplage est gouverne par les plasmons de surface qui introduisent une nouvelle interaction de diffusion avec une polarisation inhabituelle

This chapter deals with the theory and derivation of the design equations for shear, bond and torsion. Some of the more practical factors governing the choice and arrangement of the reinforcement are dealt with in the chapters on member design, particularly chapter 7, which contains examples of the design and detailing of shear and torsion reinforcement in beams. Punching shear caused by concentrated loads on slabs is covered in section 8.2 of the chapter on slab design.

The design of an engineering structure must ensure that (1) under the worst loadings the structure is safe, and (2) during normal working conditions the deformation of the members does not detract from the appearance, durability or performance of the structure. Despite the difficulty in assessing the precise loading and variations in the strength of the concrete and steel, these requirements have to be met. Three basic methods using factors of safety to achieve safe, workable structures have been developed; they are (1) The permissible stress method in which ultimate strengths of the materials are divided by a factor of safety to provide design stresses which are usually within the elastic range. (2) The load factor method in which the working loads are multiplied by a factor of safety. (3) The limit state method which multiplies the working loads by partial factors of safety and also divides the materials’ ultimate strengths by further partial factors of safety.

Reinforced concrete beam design consists primarily of producing member details which will adequately resist the ultimate bending moments, shear forces and torsional moments. At the same time serviceability requirements must be considered to ensure that the member will behave satisfactorily under working loads. It is difficult to separate these two criteria, hence the design procedure consists of a series of interrelated steps and checks. These steps are shown in detail in the flow chart in figure 7.1, but may be condensed into three basic design stages (1) preliminary analysis and member sizing (2) detailed analysis and design of reinforcement (3) serviceability calculations.

Reinforced concrete is a strong durable building material that can be formed into many varied shapes and sizes ranging from a simple rectangular column, to a slender curved dome or shell. Its utility and verstatility is achieved by combining the best features of concrete and steel. Consider some of the widely differing properties of these two materials that are listed below.

A satisfactory and economic design of a concrete structure rarely depends on a complex theoretical analysis. It is achieved more by deciding on a practical overall layout of the structure, careful attention to detail and sound constructional practice. Nevertheless the total design of a structure does depend on the analysis and design of the individual member sections.

Reinforced concrete slabs are used in floors, roofs and walls of buildings and as the decks of bridges. The floor system of a structure can take many forms such as in situ solid slabs, ribbed slabs or precast units. Slabs may span in one direction or in two directions and they may be supported on monolithic concrete beams, steel beams, walls or directly by the structure’s columns.

The concept of serviceability limit states has been introduced in chapter 2, and for reinforced concrete structures these states are often satisfied by observing empirical rules which affect the detailing only. In some circumstances, however, it may be desired to estimate the behaviour of a member under working conditions, and mathematical methods of estimating deformations and cracking must be used. The design of water-retaining structures, and prestressed concrete, are both based primarily on the avoidance or limitation of cracking and these are considered separately in other chapters.

The design of foundations and retaining walls is based on the fundamental principles and techiques of analysis which have been discussed in previous chapters. The analysis and design of both forms of structure are presented in this chapter. The reader should however be aware that some of the design values used, which have been extracted from Part 1 of EC2, may not be the design parameters to be used when the definitive EuroCode documents for foundations are eventually published. A building is generally composed of a superstructure above the ground and a substructure which forms the foundations below ground. The foundations transfer and spread the loads from a structure's columns and walls into the ground. The safe bearing capacity of the soil must not be exceeded otherwise excessive settlement may occur, resulting in damage to the building and its service facilities, such as the water or gas mains. Foundation failure can also affect the overall stability of a structure so that it is liable to slide, to lift vertically or even overturn.