A multiplicity result for a nonlinear degenerate problem arising in the theory of electrorheological fluids

We study a Dirichlet boundary value problem associated to an anisotropic differential operator on a smooth bounded of $\Bbb R^N$. Our main result establishes the existence of at least two different non-negative solutions, provided a certain parameter lies in a certain range. Our approach relies on the variable exponent theory of generalized Lebesgue-Sobolev spaces, combined with adequate variational methods and a variant of Mountain Pass lemma.Comment: Proceedings A of the Royal Society of London, in pres

Paternity allocation in a mutant Heliothis virescens colony

Tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), females can copulate multiple times creating the possibility for sperm competition. We used a colony lacking wild pigmentation on the wings (albino-type) for an experiment in which females double mated. Females copulated 2 days apart with two, 2-day-old males, one albino-type and one wild-type, or in the opposite sequence. A third of the females produced offspring from the first mate, and this group was significantly biased toward producing albino-type compared to wild-type progeny. A fourth of the females produced offspring from the second male exclusively and within this group was a significant bias toward wild-type compared to albino-type progeny. Almost half of the females produced offspring sired in equal proportions by both males simultaneously or in alternated paternities throughout all the reproductive life. These results suggest that regardless of the order in which moths mated, wild-type sperm had potential superior competitiveness. Therefore, sperm precedence is not the main driving force behind the paternity allocation mechanism in this strain of tobacco budworm

Optimization of mesoporous titanosilicate catalysts for cyclohexene epoxidation via statistically guided synthesis

An efficient approach to improve the catalytic activity of titanosilicates is introduced. The Doehlert matrix (DM) statistical model was utilized to probe the synthetic parameters of mesoporous titanosilicate microspheres (MTSM), in order to increase their catalytic activity with a minimal number of experiments. Synthesis optimization was carried out by varying two parameters simultaneously: homogenizing temperature and surfactant weight. Thirteen different MTSM samples were synthesized in two sequential ‘matrices’ according to Doehlert conditions and were used to catalyse the epoxidation of cyclohexene with 'tert'-butyl hydroperoxide. The samples (and the corresponding synthesis conditions) with superior catalytic activity in terms of product yield and selectivity were identified. In addition, this approach revealed the limiting values of each synthesis parameter, beyond which the material becomes catalytically ineffective. This study demonstrates that the DM approach can be broadly used as a powerful and time-efficient tool for investigating the optimal synthesis conditions of heterogeneous catalysts

Re-designing materials for biomedical applications: from biomimicry to nature-inspired chemical engineering

Gathering inspiration from nature for the design of new materials, products and processes is a topic gaining rapid interest among scientists and engineers. In this review, we introduce the concept of natureinspired chemical engineering (NICE). We critically examine how this approach offers advantages over straightforward biomimicry and distinguishes itself from bio-integrated design, as a systematic methodology to present innovative solutions to challenging problems. The scope of application of the nature-inspired approach is demonstrated via examples from the field of biomedicine, where much of the inspiration is still more narrowly focused on imitation or bio-integration. We conclude with an outlook on prospective future applications, offered by the more systematic and mechanistically based NICE approach, complemented by rapid progress in manufacturing, computation and robotics. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’

Nanoparticles usage tendencies in cementing systems for hydrocarbon wells

In oil and gas wells construction, one of the most critical processes is oil well cementing, whose function is to provide a zonal isolation between the pipe and sedimentary formation. For these reasons, one of the needs in the oil industry, specifically in cementing wells area, is the use of materials with high performance, in order to enhance the useful well's life, and reduce costs associated with their repair or losses due to failures in the cementing. Currently, the efforts in the area of high performance materials for oil wells cementing are focused on the development and use of Nanotechnology, science that study materials at nanoscale (10-9 m) and offers means to obtain substantial changes in the chemical, physical and mechanical properties, due to the increase of their surface that allows them to have a high reactivity. The cement is a complex mixture of inorganic chemical compounds, that contain mainly calcium silicates, aluminates (C3S, C2S, C3A), and gypsum. In the cementitious slurry preparation, the cement is put up in contact with water, producing the C-S-H gel as the main hydration product, with an amorphous initial structure that generate a mixture of solid final crystalline phases sometimes in the nanoscale sizes. This final structure is responsible for providing its mechanical properties. Therefore, their comprehension, modification and size control at nanoscale could enable the production of cementitious systems with improved properties. The present work shows a resume of studies done in PDVSA Intevep on the synthesis and potential use of nanoparticles in diverse faces of oil well cementing and their use as nano-additives. Those papers were focused mainly on the preparation and laboratory-scale study of colloidal solutions of silica nanoparticles (nano-SiO2), Alumina (nano- Al2O3), iron oxides (nano-Fe2O3) and ternary systems of calcium oxide-silica and aluminium (CaO-SiO2-Al2O3). Promising results were obtained on strength and cementing properties by adding nanosilica to the cement slurry formulations, and improvements on the mechanical properties, such as compressive strength at the order of 90% for 0.5% nanosilica concentrations based on weight of cement (BWOC)

Nanoparticles usage tendencies in cementing systems for hydrocarbon wells

In oil and gas wells construction, one of the most critical processes is oil well cementing, whose function is to provide a zonal isolation between the pipe and sedimentary formation. For these reasons, one of the needs in the oil industry, specifically in cementing wells area, is the use of materials with high performance, in order to enhance the useful well's life, and reduce costs associated with their repair or losses due to failures in the cementing. Currently, the efforts in the area of high performance materials for oil wells cementing are focused on the development and use of Nanotechnology, science that study materials at nanoscale (10-9 m) and offers means to obtain substantial changes in the chemical, physical and mechanical properties, due to the increase of their surface that allows them to have a high reactivity. The cement is a complex mixture of inorganic chemical compounds, that contain mainly calcium silicates, aluminates (C3S, C2S, C3A), and gypsum. In the cementitious slurry preparation, the cement is put up in contact with water, producing the C-S-H gel as the main hydration product, with an amorphous initial structure that generate a mixture of solid final crystalline phases sometimes in the nanoscale sizes. This final structure is responsible for providing its mechanical properties. Therefore, their comprehension, modification and size control at nanoscale could enable the production of cementitious systems with improved properties. The present work shows a resume of studies done in PDVSA Intevep on the synthesis and potential use of nanoparticles in diverse faces of oil well cementing and their use as nano-additives. Those papers were focused mainly on the preparation and laboratory-scale study of colloidal solutions of silica nanoparticles (nano-SiO2), Alumina (nano- Al2O3), iron oxides (nano-Fe2O3) and ternary systems of calcium oxide-silica and aluminium (CaO-SiO2-Al2O3). Promising results were obtained on strength and cementing properties by adding nanosilica to the cement slurry formulations, and improvements on the mechanical properties, such as compressive strength at the order of 90% for 0.5% nanosilica concentrations based on weight of cement (BWOC)

Early holocene human burials from Fa Hien-lena and Kuragala, Sri Lanka

<p>Few human burials from Sri Lankan archaeological contexts have been described. Here we report on the analysis of two early Holocene skeletons, FH8, a young adult female skeleton excavated from Fa Hien-lena and dated to 10,640-10,139 cal BP, and BK1, a middle adult male skeleton excavated at Kuragala and dated to 7,170-6,950 cal BP.  The skeletons are both highly fragmentary, which poses challenges for their thorough analysis. However, this paper describes the archaeological context, mortuary treatment and archaeothanatology of the burials, post-mortem taphonomy of human remains, the osteobiography of both individuals, and some general observations on their morphology relative to one another and a broader range of late Pleistocene and Holocene foragers. The results demonstrate common elements of funerary treatment between these two burials, such as interment on the left side with right hands placed near or over the face. The FH8 individual died at a young age and shows some signs of early childhood stress. Both skeletons show moderate to high degrees of tooth wear for their relative ages, and no evidence for dental disease. The body size estimates of FH8 and BK1 fall in the range that would be expected of tropical or temperate forest foragers, although BK1 has a relatively low body mass relative to stature, which aligns his phenotype with populations of more arid environments. We demonstrate that much can be potentially learned about human populations and prehistoric behaviours from skeletal analyses. </p>Introduction Fa Hien-lena Kuragala Mortuary Context and Archaeothanatology Fa Hien-lena FH8 Kuragala (BK1) Common elements of each burial Skeletal and Dental Inventories and Taphonomy Osteobiographic analyses Morphology and other observations Discussio

Mass spectrometry based metabolomics comparison of liver grafts from donors after circulatory death (DCD) and donors after brain death (DBD) used in human orthotopic liver transplantation

Use of marginal liver grafts, especially those from donors after circulatory death (DCD), has been considered as a solution to organ shortage. Inferior outcomes have been attributed to donor warm ischaemic damage in these DCD organs. Here we sought to profile the metabolic mechanisms underpinning donor warm ischaemia. Non-targeted Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry metabolomics was applied to biopsies of liver grafts from donors after brain death (DBD; n = 27) and DCD (n = 10), both during static cold storage (T1) as well as post-reperfusion (T2). Furthermore 6 biopsies from DBD donors prior to the organ donation (T0) were also profiled. Considering DBD and DCD together, significant metabolic differences were discovered between T1 and T2 (688 peaks) that were primarily related to amino acid metabolism, meanwhile T0 biopsies grouped together with T2, denoting the distinctively different metabolic activity of the perfused state. Major metabolic differences were discovered between DCD and DBD during cold-phase (T1) primarily related to glucose, tryptophan and kynurenine metabolism, and in the post-reperfusion phase (T2) related to amino acid and glutathione metabolism. We propose tryptophan/kynurenine and S-adenosylmethionine as possible biomarkers for the previously established higher graft failure of DCD livers, and conclude that the associated pathways should be targeted in more exhaustive and quantitative investigations

A hybrid soft solar cell based on the mycobacterial porin MspA linked to a sensitizer-viologen diad

A prototype of a nano solar cell containing the mycobacterial channel protein MspA has been successfully designed. MspA, an octameric transmembrane channel protein from Mycobacterium smegmatis, is one of the most stable proteins known to date. Eight Ruthenium(II) aminophenanthroline-viologen maleimide Diads (Ru-Diads) have been successfully bound to the MspA mutant MspAA96C via cysteine-maleimide bonds. MspA is known to form double layers in which it acts as nanoscopic surfactant. The nanostructured layer that is formed by (Ru-Diad)(8)MspA at the TiO2 electrode is photochemically active. The resulting "protein nano solar cell" features an incident photon conversion efficiency of 1% at 400 nm. This can be regarded as a proof-of-principle that stable proteins can be successfully integrated into the design of solar cells