Sc-strengthened commercial purity aluminum under high pressure

Abstract Aluminum alloyed with approximately 1,000 at. ppm Sc was studied by high-pressure energy dispersive X-ray diffraction in two different states, homogenized and aged to peak microhardness. The microhardness of the aged sample is about three times higher than the microhardness of the homogenized sample (as a result of the formation of nanosize Al 3 Sc precipitates in the aged sample). The results, which were refined using the Rietveld analysis technique, indicate a single cubic phase with no phase transition up to a pressure of 32 GPa. The Vinet equation was used to fit the volume-pressure curve to the equation-of-state. The bulk modulus (B 0 ) is found to be 73 ± 5 GPa, and is equal to the value measured for an unalloyed aluminum sample. The fact that the bulk modulus does not change, despite a large difference in microhardness between the samples, is the result of the different origins of the two quantities

On scrimshaw precursors: a 13th-century carved and engraved sperm whale tooth

In der einschlägigen Forschung zur Walfängervolkskunst des "Scrimshaw" - den seit den 1820er Jahren populär gewordenen Seemannsarbeiten speziell auf und aus Pottwal- und Walroßzahn, Barten und Walknochen - werden künstlerisch bearbeitete Gegenstände anderer Kulturen aus denselben Materialien als "Scrimshaw"-Vorläufer bezeichnet. Aus dem europäischen Mittelalter sind zwar zahlreiche Beispiele von Schnitzereien aus Walroßzahn und Walknochen bekannt, nicht jedoch aus Pottwalzahn, dem beinah stereotypen Werkstoff der "Scrimshander" des 19. und 20. Jahrhunderts. Der "Königsspiegel", ein um 1250/60 in Norwegen geschriebener pädagogischer Text, erwähnt gleichwohl Schnitzereien aus Pottwalzahn. Auch aus dem 16. und 17. Jahrhundert sind textliche Hinweise auf skandinavisches Kunstgewerbe aus den Zähnen dieses Meeressäugers bekannt. Im Anschluß an die Präsentation dieser Quellen wird ein konkretes Beispiel vorgestellt: Es handelt sich um ein beschnitztes und graviertes Salbenhorn aus Pottwalzahn, das sich in der Sammlung christlicher Kunst und Kultur des Museums der Universität Bergen, Norwegen, lnv. MA 437, befindet. Aus dem massiven Dentin wurde ein Greif herausgeschnitzt, der Ausguß wurde wie der Kopf eines gotischen Wasserspeiers gestaltet. Auf einer glatten Seitenfläche wurde später ein kleines Tondo mit Pflanzen- und Vogelmotiv eingraviert. Es trägt eine Inschrift, die vom Bergenser Museum als griechisch, hier aber als russisch identifiziert wurde, deren Sinn aber unklar bleibt. Anlass, die vom Museum vorgenommene Datierung des Zahns in das 13. Jahrhundert zu revidieren, besteht allerdings nicht

Genome-Scale Model Reveals Metabolic Basis of Biomass Partitioning in a Model Diatom

Diatoms are eukaryotic microalgae that contain genes from various sources, including bacteria and the secondary endosymbiotic host. Due to this unique combination of genes, diatoms are taxonomically and functionally distinct from other algae and vascular plants and confer novel metabolic capabilities. Based on the genome annotation, we performed a genome-scale metabolic network reconstruction for the marine diatom Phaeodactylum tricornutum. Due to their endosymbiotic origin, diatoms possess a complex chloroplast structure which complicates the prediction of subcellular protein localization. Based on previous work we implemented a pipeline that exploits a series of bioinformatics tools to predict protein localization. The manually curated reconstructed metabolic network iLB1027_lipid accounts for 1,027 genes associated with 4,456 reactions and 2,172 metabolites distributed across six compartments. To constrain the genome-scale model, we determined the organism specific biomass composition in terms of lipids, carbohydrates, and proteins using Fourier transform infrared spectrometry. Our simulations indicate the presence of a yet unknown glutamine-ornithine shunt that could be used to transfer reducing equivalents generated by photosynthesis to the mitochondria. The model reflects the known biochemical composition of P. tricornutum in defined culture conditions and enables metabolic engineering strategies to improve the use of P. tricornutum for biotechnological applications

Designer diatom episomes delivered by bacterial conjugation.

Eukaryotic microalgae hold great promise for the bioproduction of fuels and higher value chemicals. However, compared with model genetic organisms such as Escherichia coli and Saccharomyces cerevisiae, characterization of the complex biology and biochemistry of algae and strain improvement has been hampered by the inefficient genetic tools. To date, many algal species are transformable only via particle bombardment, and the introduced DNA is integrated randomly into the nuclear genome. Here we describe the first nuclear episomal vector for diatoms and a plasmid delivery method via conjugation from Escherichia coli to the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. We identify a yeast-derived sequence that enables stable episome replication in these diatoms even in the absence of antibiotic selection and show that episomes are maintained as closed circles at copy number equivalent to native chromosomes. This highly efficient genetic system facilitates high-throughput functional characterization of algal genes and accelerates molecular phytoplankton research

Naturally Embedded Query Languages

We investigate the properties of a simple programming language whose main computational engine is structural recursion on sets. We describe a progression of sublanguages in this paradigm that (1) have increasing expressive power, and (2) illustrate robust conceptual restrictions thus exhibiting interesting additional properties. These properties suggest that we consider our sublanguages as candidates for "query languages". Viewing query languages as restrictions of our more general programming language has several advantages. First, there is no "impedance mismatch" problem; the query languages are already there, so they share common semantic foundation with the general language. Second, we suggest a uniform characterization of nested relational and complex-object algebras in terms of some surprisingly simple operators; and we can make comparisons of expressiveness in a general framework. Third, we exhibit differences in expressive power that are not always based on complexity arguments..

The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study

BACKGROUND: Obesity causes or exacerbates a host of medical conditions, including cardiovascular, pulmonary, and endocrine diseases. Recently obesity in elderly women was associated with greater risk of dementia, white matter ischemic changes, and greater brain atrophy. The purpose of this study was to determine whether body type affects global brain volume, a marker of atrophy, in middle-aged men and women. METHODS: T1-weighted 3D volumetric magnetic resonance imaging was used to assess global brain volume for 114 individuals 40 to 66 years of age (average = 54.2 years; standard deviation = 6.6 years; 43 men and 71 women). Total cerebrospinal fluid and brain volumes were obtained with an automated tissue segmentation algorithm. A regression model was used to determine the effect of age, body mass index (BMI), and other cardiovascular risk factors on brain volume and cognition. RESULTS: Age and BMI were each associated with decreased brain volume. BMI did not predict cognition in this sample; however elevated diastolic blood pressure was associated with poorer episodic learning performance. CONCLUSION: These findings suggest that middle-aged obese adults may already be experiencing differentially greater brain atrophy, and may potentially be at greater risk for future cognitive decline

Reduced clinical and postmortem measures of cardiac pathology in subjects with advanced Alzheimer's Disease

Background. Epidemiological studies indicate a statistical linkage between atherosclerotic vascular disease (ATH) and Alzheimer\u27s disease (AD). Autopsy studies of cardiac disease in AD have been few and inconclusive. In this report, clinical and gross anatomic measures of cardiac disease were compared in deceased human subjects with and without AD. Methods. Clinically documented cardiovascular conditions from AD (n = 35) and elderly non-demented control subjects (n = 22) were obtained by review of medical records. Coronary artery stenosis and other gross anatomical measures, including heart weight, ventricular wall thickness, valvular circumferences, valvular calcifications and myocardial infarct number and volume were determined at autopsy. Results. Compared to non-demented age-similar control subjects, those with AD had significantly fewer total diagnosed clinical conditions (2.91 vs 4.18), decreased coronary artery stenosis (70.8 vs 74.8%), heart weight (402 vs 489 g for males; 319 vs 412 g for females) and valvular circumferences. Carriage of the Apolipoprotein E-ε4 allele did not influence the degree of coronary stenosis. Group differences in heart weight remained significant after adjustment for age, gender, body mass index and apolipoprotein E genotype while differences in coronary artery stenosis were significantly associated with body mass index alone. Conclusions. The results are in agreement with an emerging understanding that, while midlife risk factors for ATH increase the risk for the later development of AD, once dementia begins, both risk factors and manifest disease diminish, possibly due to progressive weight loss with increasing dementia as well as disease involvement of the brain\u27s vasomotor centers. © 2011 Beach et al; licensee BioMed Central Ltd

Pre-Operative Cognitive Functioning and Inflammatory and Neuroendocrine Responses to Cardiac Surgery.

BACKGROUND: Cognitive functioning is linked to cardiac mortality and morbidity, but the mechanisms underlying this relationship are unclear. PURPOSE: To examine the relationship between pre-operative cognitive functioning and post-operative inflammatory and neuroendocrine responses in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: One-hundred ninety-three outpatients were screened to assess their cognitive function using the Montreal Cognitive Assessment (MoCA) on average 30 days prior to CABG surgery and provided blood samples for the measurement of interleukin (IL)-6 and C-reactive protein (CRP) and saliva samples for the measurement of diurnal cortisol. Participants were followed-up 4-8 days following surgery for the repeat measurement of IL-6 and CRP and 60 days after surgery for the measurement of diurnal salivary cortisol. RESULTS: Patients with low cognitive function (MoCA < 26) prior to surgery reached higher IL-6 concentrations in the days after surgery (β = -0.212, p = 0.021) and had greater cortisol output across the day 2 months after surgery (β = -0.179, p = 0.044). CONCLUSIONS: Low cognitive functioning is associated with a more negative pattern of biological response to surgery, indicative of poorer physical recovery. These pathways may contribute to the links between cognitive function and cardiovascular pathology