Some aspects of the high speed electrodeposition of metals

The literature concerning the fast electrodeposition of metals has been reviewed with particular attention to the electrodeposition of nickel. A study of the electrodeposition of nickel has been carried out in concentrated Ni sulphamate solutions at 50-70°C in parallel plate cells at Reynolds numbers of up to 15,000. The cell design was substantiated by a preliminary study of the electrodeposition of copper. Additional studies have been made of current distribution in both the nickel and acid copper systems using segmented electrodes. Additional studies of mass transport have been made in the nickel system, as have polarisation studies. It has been shown that in the case of acid copper the system performs under mass transport control and that the current distribution is as expected under these conditions. [continues…

Collapse of composite tubes under end moments

Cylindrical tubes of moderate wall thickness such as those proposed for the original space station truss, may fail due to the gradual collapse of the tube cross section as it distorts under load. Sometimes referred to as the Brazier instability, it is a nonlinear phenomenon. This paper presents an extension of an approximate closed form solution of the collapse of isotropic tubes subject to end moments developed by Reissner in 1959 to include specially orthotropic material. The closed form solution was verified by an extensive nonlinear finite element analysis of the collapse of long tubes under applied end moments for radius to thickness ratios and composite layups in the range proposed for recent space station truss framework designs. The finite element analysis validated the assumption of inextensional deformation of the cylindrical cross section and the approximation of the material as specially orthotropic

Sonic hedgehog functions upstream of disrupted-in-schizophrenia 1 (disc1): implications for mental illness

DISRUPTED-IN-SCHIZOPHRENIA (DISC1) has been one of the most intensively studied genetic risk factors for mental illness since it was discovered through positional mapping of a translocation breakpoint in a large Scottish family where a balanced chromosomal translocation was found to segregate with schizophrenia and affective disorders. While the evidence for it being central to disease pathogenesis in the original Scottish family is compelling, recent genome-wide association studies have not found evidence for common variants at the DISC1 locus being associated with schizophrenia in the wider population. It may therefore be the case that DISC1 provides an indication of biological pathways that are central to mental health issues and functional studies have shown that it functions in multiple signalling pathways. However, there is little information regarding factors that function upstream of DISC1 to regulate its expression and function. We herein demonstrate that Sonic hedgehog (Shh) signalling promotes expression of disc1 in the zebrafish brain. Expression of disc1 is lost in smoothened mutants that have a complete loss of Shh signal transduction, and elevated in patched mutants which have constitutive activation of Shh signalling. We previously demonstrated that disc1 knockdown has a dramatic effect on the specification of oligodendrocyte precursor cells (OPC) in the hindbrain and Shh signalling is known to be essential for the specification of these cells. We show that disc1 is prominently expressed in olig2-positive midline progenitor cells that are absent in smo mutants, while cyclopamine treatment blocks disc1 expression in these cells and mimics the effect of disc1 knock down on OPC specification. Various features of a number of psychiatric conditions could potentially arise through aberrant Hedgehog signalling. We therefore suggest that altered Shh signalling may be an important neurodevelopmental factor in the pathobiology of mental illness

Development and testing of a SREX flowsheet for the partitioning of strontium and lead from simulated ICPP sodium-bearing waste

Laboratory experimentation has indicated that the SREX process is effective for partitioning {sup 90}Sr from acidic radioactive waste solutions located at the Idaho Chemical Processing Plant. Previous countercurrent flowsheet testing of the SREX process with simulated waste resulted in 99.98% removal of Sr. With this previous test, however, Pb was extracted by the SREX solvent and was not back-extracted in the dilute nitric acid strip section. The Pb concentration increased in the recycled solvent and in the aqueous phase of the strip section, resulting in the formation of a Pb precipitate. Subsequently, studies were initiated to identify alternative stripping agents which will selectively strip Sr and Pb from the SREX solvent. Based on the results of these studies, a countercurrent flow sheet was developed and tested in the 5.5-cm Centrifugal Contactor Mockup using simulated waste. The flowsheet tested consisted of an extraction section (0.15 M 4{prime},4{prime}(5)-di-(tert-butyldicyclohexo)-18-crown-6 and 1.2 M TBP in Isopar-L{reg_sign}), a 0.05 M nitric acid strip section for the removal of Sr from the SREX solvent, a 0.1 M ammonium citrate strip section for the removal of Pb from the SREX solvent, and a 2.0 M nitric acid equilibration section. The behavior of Sr, Pb, Al, Ca, Hg, Na, Zr, and H{sup +} was evaluated. The described flowsheet successfully extracted and selectively stripped Sr and Pb from the SBW simulant. Removal efficiencies of 97.9% and 99.91% were obtained for Sr and Pb, respectively. Essentially all of the extracted Sr (99.998%) and 1.9% of extracted Pb exited with the 0.05 M nitric acid strip product; whereas, 0.002% of the extracted Sr and 97.9% of the extracted Pb existed with the 0.1 M ammonium citrate strip product. Also, 95% of the Hg and 63% of the Zr were extracted by the SREX solvent

Disrupted-in-schizophrenia-1 is essential for normal hypothalamic-pituitary-interrenal (HPI) axis function

Psychiatric disorders arise due to an interplay of genetic and environmental factors, including stress. Studies in rodents have shown that mutants for Disrupted-In-Schizophrenia-1 (DISC1), a well-accepted genetic risk factor for mental illness, display abnormal behaviours in response to stress, but the mechanisms through which DISC1 affects stress responses remain poorly understood. Using two lines of zebrafish homozygous mutant for disc1, we investigated behaviour and functioning of the hypothalamic-pituitary-interrenal (HPI) axis, the fish equivalent of the hypothalamic-pituitary-adrenal (HPA) axis. Here, we show that the role of DISC1 in stress responses is evolutionarily conserved and that DISC1 is essential for normal functioning of the HPI axis. Adult zebrafish homozygous mutant for disc1 show aberrant behavioural responses to stress. Our studies reveal that in the embryo, disc1 is expressed in neural progenitor cells of the hypothalamus, a conserved region of the vertebrate brain that centrally controls responses to environmental stressors. In disc1 mutant embryos, proliferating rx3þ hypothalamic progenitors are not maintained normally and neuronal differentiation is compromised: rx3-derived ff1bþ neurons, implicated in anxiety-related behaviours, and corticotrophin releasing hormone (crh) neurons, key regulators of the stress axis, develop abnormally, and rx3-derived pomcþ neurons are disorganised. Abnormal hypothalamic development is associated with dysfunctional behavioural and neuroendocrine stress responses. In contrast to wild type siblings, disc1 mutant larvae show altered crh levels, fail to upregulate cortisol levels when under stress and do not modulate shoal cohesion, indicative of abnormal social behaviour. These data indicate that disc1 is essential for normal development of the hypothalamus and for the correct functioning of the HPA/HPI axis

Effect of the direction of m. psoas major fibres on the results of tensile test - can we model meat as a material?

The aim of this study was to examine the possibility of tensile-test application at three strain rates (0.01/s and 0.001/s and 0.001/s) on suitable samples of grilled pork meat (musculus psoas major). Differences in the stress-strain curves were observed between the two directions of the muscle fibres (i.e. strain parallel to and transverse to the fibres). However, the strain rate of 0.001/s resulted in the most linear stress-strain curves for strain in both muscle fibre directions. Also, results confirmed that specimens tested transversally to the muscle fibre direction required less stress to fracture. We also concluded that specimens stretch more in the direction transverse to the muscle fibre direction for strain rates of 0.01/s and 0.001/s. Gaining knowledge from different methods of empirical mechanical testing of meat should enhance the possibility of forming material constitutive laws to be used as input to finite element simulations of industrial processes of meat such as cutting or of human oral processing

Influence of Rotations on the Critical State of Soil Mechanics

The ability of grains to rotate can play a crucial role on the collective behavior of granular media. It has been observed in computer simulations that imposing a torque at the contacts modifies the force chains, making support chains less important. In this work we investigate the effect of a gradual hindering of the grains rotations on the so-called critical state of soil mechanics. The critical state is an asymptotic state independent of the initial solid fraction where deformations occur at a constant shear strength and compactness. We quantify the difficulty to rotate by a friction coefficient at the level of particles, acting like a threshold. We explore the effect of this particle-level friction coefficient on the critical state by means of molecular dynamics simulations of a simple shear test on a poly-disperse sphere packing. We found that the larger the difficulty to rotate, the larger the final shear strength of the sample. Other micro-mechanical variables, like the structural anisotropy and the distribution of forces, are also influenced by the threshold. These results reveal the key role of rotations on the critical behavior of soils and suggest the inclusion of rotational variables into their constitutive equations.Comment: 9 pages, 8 figures, Accepted for publication in Computer Physics Communication

Analysis of travelling waves associated with the modelling of aerosolised skin grafts

A previous model developed by the authors investigates the growth patterns of keratinocyte cell colonies after they have been applied to a burn site using a spray technique. In this paper, we investigate a simplified one-dimensional version of the model. This model yields travelling wave solutions and we analyse the behaviour of the travelling waves. Approximations for the rate of healing and maximum values for both the active healing and the healed cell densities are obtained

Validation of a rapid, saliva-based, and ultra-sensitive SARS-CoV-2 screening system for pandemic-scale infection surveillance

Without any realistic prospect of comprehensive global vaccine coverage and lasting immunity, control of pandemics such as COVID-19 will require implementation of large-scale, rapid identification and isolation of infectious individuals to limit further transmission. Here, we describe an automated, high-throughput integrated screening platform, incorporating saliva-based loop-mediated isothermal amplification (LAMP) technology, that is designed for population-scale sensitive detection of infectious carriers of SARS-CoV-2 RNA. Central to this surveillance system is the “Sentinel” testing instrument, which is capable of reporting results within 25 min of saliva sample collection with a throughput of up to 3840 results per hour. It incorporates continuous flow loading of samples at random intervals to cost-effectively adjust for fluctuations in testing demand. Independent validation of our saliva-based RT-LAMP technology on an automated LAMP instrument coined the “Sentinel”, found 98.7% sensitivity, 97.6% specificity, and 98% accuracy against a RT-PCR comparator assay, confirming its suitability for surveillance screening. This Sentinel surveillance system offers a feasible and scalable approach to complement vaccination, to curb the spread of COVID-19 variants, and control future pandemics to save lives

Book Reviews

Wesleyan Perspectives on the New Creation M. Douglas Meeks, ed. Nashville: Kingswood, 2004, 200 pp., paper, 2004, $30.00 Reviewed by William J Abraham Christ Plays in Ten Thousand Places Eugene H. Peterson Grand Rapids, Michigan: William B. Eerdmans Publishing Company 2005, xii, 368pp. cloth,$25.00 Reviewed by Elaine A. Heath The Evangelical Moment: The Promise of an American Religion By Kenneth J. Collins Grand Rapids: Baker Academic Press 2005, 288 pp., paper, 22.99 Reviewed by Nathan Crawford Theology as History and Hermeneutics: A Post-Critical Evangelical Conversation with Contemporary Theology Laurence W. Wood Lexington: Emeth Publisher 2004, 261 pp. Reviewed by Nathan Crawford Resistance and Theological Ethics Ronald H. Stone and Robert L. Stivers, eds. Lanham, Maryland: Roman & Littlefield Publishers 2004, ri, 334 pp. paper, 28.95 Reviewed by Joerg Rieger The Ripple Church: Multiply Your Ministry by Parenting New Churches Phil Stevenson Indianapolis, IN: Wesleyan Publishing House 2004. pp. 186, $12.99. Reviewed by J.D. Payne The Struggle to Understand Isaiah as Christian Scripture Brevard S. Childs Grand Rapids, Michigan: Wm. B. Eerdmans Publishing Co. 2004, xii, 332 pp. caseboulld,$35.00 Reviewed by John N. Oswalt God is Not Religious, Nice, One of Us, an American, a Capitalist D. Brent Laytham, ed. Grand Rapids, Michigan: Press. 2004, 152 pp., paper, $15.99 Reviewed by Michael Rynkiwitch A Short Introduction to Hermeneutics David Jasper Louisville, KY: Westmilnster John Knox Press 2004, xii, 148 pp. paper,$19.95 Reviewed by Charles M. Woo