Influence of surface wettability on friction and wear test.

In this work the effect of surface wettability of different materials on friction and wear behaviour with sliding friction of 100% has been studied. The following materials have been chosen: AISI 1050 and AISI 420 steels, pyrex glass, teflon PTFE. and carbon fiber. All have different surface wettability angles u .. Tests with these materials have been carried out with a pin-on-disc tribometer with homogeneous and heterogeneous couplings in dry conditions and with oil and water lubrication. The most important result achieved with the mechanical tests and the SEM examinations is that with couplings of a hydrophillic and a hydrophobic material, water lubrication has a greatly positive effect. Particularly with hydrophobic discs and hydrophillic pins the friction factor and the wear have been lower than those with oil lubrication

New Implications on Genomic Adaptation Derived from the Helicobacter pylori Genome Comparison

BACKGROUND: Helicobacter pylori has a reduced genome and lives in a tough environment for long-term persistence. It evolved with its particular characteristics for biological adaptation. Because several H. pylori genome sequences are available, comparative analysis could help to better understand genomic adaptation of this particular bacterium. PRINCIPAL FINDINGS: We analyzed nine H. pylori genomes with emphasis on microevolution from a different perspective. Inversion was an important factor to shape the genome structure. Illegitimate recombination not only led to genomic inversion but also inverted fragment duplication, both of which contributed to the creation of new genes and gene family, and further, homological recombination contributed to events of inversion. Based on the information of genomic rearrangement, the first genome scaffold structure of H. pylori last common ancestor was produced. The core genome consists of 1186 genes, of which 22 genes could particularly adapt to human stomach niche. H. pylori contains high proportion of pseudogenes whose genesis was principally caused by homopolynucleotide (HPN) mutations. Such mutations are reversible and facilitate the control of gene expression through the change of DNA structure. The reversible mutations and a quasi-panmictic feature could allow such genes or gene fragments frequently transferred within or between populations. Hence, pseudogenes could be a reservoir of adaptation materials and the HPN mutations could be favorable to H. pylori adaptation, leading to HPN accumulation on the genomes, which corresponds to a special feature of Helicobacter species: extremely high HPN composition of genome. CONCLUSION: Our research demonstrated that both genome content and structure of H. pylori have been highly adapted to its particular life style

Archival Document Report on Crater Trip December 1984

December 3-8 crater trip report by Carmelle F. Crivellone to Lloyd L. Loope, research biologist dated December 13, 1984

Status of the silversword in Haleakala National Park: past and present

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The Haleakala silversword, Arhyroxiphium sandwicense DC. ssp. macrocephalum (Gray) Meyrat, declined markedly in the late 1800's and early 1900's due to browsing by goats and cattle and to vandalism by humans. During the 1930's, after protection was provided by the national park, much concern arose over the high level of seed predation by native insects. Nevertheless, following protection, silversword numbers have increased and now total about 50,000 individuals. Although total crater-wide numbers remained stable between censuses in 1971 and 1982, large fluctuations have occurred on individual cinder cones. Plots for long-term study of silversword population dynamics have been established, with data taken annually. Preliminary results after three years suggest that many seedlings establish in some years, few or none in others; that substantial natural mortality occurs in some years; and that wide population fluctuations from year to year are occurring. The greatest threats to the Haleakala silversword today are thought to be the Argentine ant (Iridomyrmex humilis) and the western yellow-jacket (Vespula pensylvanica), aggressive alien predators (of insects) which could disrupt ecosystem processes, especially pollination. Park managers now recognize the need for preservation of the entire complex of organisms belonging to the silversword ecosystem.National Park Servic

THE NATURE OF POTASSIUM FERRATE INACTIVATION OF PORCINE MUSCLE ADENYLATE KINASE AND OF OTHER PHOSPHATE BINDING ENZYMES (ACTIVE-SITE-SPECIFIC)

Potassium ferrate is an analog of phosphate ion and a potent oxidizing agent. The ferrate ion is similar in geometry and electrostatic properties to orthophosphate. Previous studies have demonstrated that ferrate inactivates enzymes in a phosphate-site-specific manner, causing a selective oxidation of key amino acids located in the phosphate binding regions of these enzymes. An examination of the phosphate binding sites of adenylate kinase was undertaken using potassium ferrate. This reagent was found to cause irreversible inactivation of the enzyme. Inhibition could be prevented by the presence of competitive inhibitors or substrates, establishing that the action of ferrate was site-specific. Amino acid and peptide sequence analysis showed that ferrate treatment resulted in the loss of Cys-25 and Tyr-95. Tentative evidence suggests that Tyr-95 is essential for enzyme activity. The involvement of these residues at the phosphate binding sites of adenylate kinase is discussed. The value of potassium ferrate as a general inhibitor of enzymes which recognize compounds possessing phosphoryl groups was investigated. Various types of enzymes which interact with phosphate-containing substances were found to be inactivated by ferrate. Protection by specific substrates and competitive inhibitors indicated that ferrate inactivation was site-specific

“The Italian Job”: How Italy’s Long History of Catholicism has influenced a culture of Maschilismo and Misogyny

Though Italy has been plagued by maschilismo (the Italian word for machismo, or rather, toxic masculinity) and violent misogyny for as long as it has been a country, there has rarely been any appropriate insight as to why Italian men are more violent towards their partners, on average, than other men in the European Union. Italian men have been known as “passionate” and “possessive,” but rarely it is discussed how poorly these “passionate” men treat their female partners. Italy has an astounding prevalence rate of 78 percent across the country for happenstances of domestic violence and an estimated 32 percent of Italian women have been a victim of sexual violence (United Nations), yet there have been few attempts to try to rectify these statistics. Italy has recently elected a known sexual predator, Silvio Berlusconi, former four-time prime minister, into the European Parliament despite his reputation. So, the question is why are women treated this way in Italy and how can it be stopped? My answer to the first part of that question is Catholicism. I am arguing that Italy’s long and sordid history with the Catholic church has affected the general Italian public’s perception of women even if the country is gradually moving away from devout religiosity. This thesis is going to examine how religion becomes deeply entrenched into the collective consciousness and constructs basic morality and points of judgement. Even further, how that constructed morality creates impossible standards for women which can then lead to horrific spiteful violence from their fathers, brothers, and partners. Religion is a safe space for a lot of Italian women, but it is also a tool in their destruction

Dynamic solidification of sand-cast aluminium alloys

The effect of low-frequency mechanical vibration, applied during the solidification process, on the microstructure and mechanical performance of aluminium sand-casting was investigated. Both green-sand moulds and chemically bounded sand moulds were used. The vibration was applied to the moulds along the vertical axe. The investigated acceleration range was included between 0.1g and 15g. The effect of different sections and cooling rate was considered, as well as the influence of using different amplitude at constant acceleration. The microstructure and porosity of the ingots was evaluated by optical microscopy and image analysis. The mechanical properties were investigated by tensile tests performed both on cylindrical and different section flat specimens. Microstructure modification of dynamically solidified castings was achieved, consisting on a refined or a completely non-dendritic microstructure, with a globular aspect and quite rare dendrite fragments. The effective threshold acceleration in order to modify the microstructure of the different section considered was assessed. The ingots presenting modified microstructure revealed interesting mechanical performance, that means mainly higher fracture strain