Sylow P-Subgroups of Abelian Group Rings

2000 Mathematics Subject Classification: Primary 20C07, 20K10, 20K20, 20K21; Secondary 16U60, 16S34.

Zero-Dimensionality and Serre Rings

2000 Mathematics Subject Classification: Primary 13A99; Secondary 13A15, 13B02, 13E05.

Binomial Skew Polynomial Rings, Artin-Schelter Regularity, and Binomial Solutions of the Yang-Baxter Equation

2000 Mathematics Subject Classification: Primary 81R50, 16W50, 16S36, 16S37.

'Growth rings' in crustose lichens:comparison with directly measured growth rates and implications for lichenometry

Some species of crustose lichens, such as Ochrolechia parella (L.) Massal., exhibit concentric marginal rings, which may represent an alternative technique of measuring growth rates and potentially, a new lichenometric dating method. To examine this hypothesis, the agreement and correlation between ring widths and directly measured annual radial growth rates (RaGR, mm a^-1) were studied in 24 thalli of O. parella in north Wales, UK, using digital photography and image analysis. Variation in ring width was observed at different locations around a thallus, between thalli, and from year to year. The best agreement and correlation between ring width and lichen growth rates was between mean width of the outer two rings (measured in 2011) and mean RaGR (in 2009/10). The O. parella data suggest that mean width of the youngest two growth rings, averaged over a sample of thalli, is a predictor of recent growth rates and therefore could be used in lichenometry. Potential applications include as a convenient method of comparing lichen growth rates on surfaces in different environmental settings; and as an alternative method of constructing lichen growth-rate curves, without having to revisit the same lichen thalli over many years. However, care is needed when using growth rings to estimate growth rates as: growth ring widths may not be stable; ring widths exhibit spatial and temporal variation; rings may not represent 1-year's growth in all thalli; and adjacent rings may not always represent successive year's growth.

Smoke rings:towards a comprehensive tobacco free policy for the Olympic Games

Background The tobacco industry has long sought affiliation with major sporting events, including the Olympic Games, for marketing, advertising and promotion purposes. Since 1988, each Olympic Games has adopted a tobacco-free policy. Limited study of the effectiveness of the smoke-free policy has been undertaken to date, with none examining the tobacco industry's involvement with the Olympics or use of the Olympic brand. Methods and Findings A comparison of the contents of Olympic tobacco-free policies from 1988 to 2014 was carried out by searching the websites of the IOC and host NOCs. The specific tobacco control measures adopted for each Games were compiled and compared with measures recommended by the WHO Tobacco Free Sports Initiative and Article 13 of the Framework Convention on Tobacco Control (FCTC). This was supported by semi-structured interviews of key informants involved with the adoption of tobacco-free policies for selected games. To understand the industry's interests in the Olympics, the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu) was systematically searched between June 2013 and August 2014. Company websites, secondary sources and media reports were also searched to triangulate the above data sources. This paper finds that, while most direct associations between tobacco and the Olympics have been prohibited since 1988, a variety of indirect associations undermine the Olympic tobacco-free policy. This is due to variation in the scope of tobacco-free policies, limited jurisdiction and continued efforts by the industry to be associated with Olympic ideals. Conclusions The paper concludes that, compatible with the IOC's commitment to promoting healthy lifestyles, a comprehensive tobacco-free policy with standardized and binding measures should be adopted by the International Olympic Committee and all national Olympic committees.

A note on the propagation of quantized vortex rings through a quantum turbulence tangle:energy transport or energy dissipation?

We investigate quantum vortex ring dynamics at scales smaller than the inter-vortex spacing in quantum turbulence. Through geometrical arguments and high-resolution numerical simulations, we examine the validity of simple estimates for the mean free path and the structure of vortex rings post-reconnection. We find that a large proportion of vortex rings remain coherent objects where approximately 75% of their energy is preserved. This leads us to consider the effectiveness of energy transport in turbulent tangles. Moreover, we show that in low density tangles, appropriate for the ultra-quantum regime, ring emission cannot be ruled out as an important mechanism for energy dissipation. However at higher vortex line densities, typically associated with the quasi-classical regime, loop emission is expected to make a negligible contribution to energy dissipation, even allowing for the fact that our work shows rings can survive multiple reconnection events. Hence the Kelvin wave cascade seems the most plausible mechanism leading to energy dissipation

Synthesis of aromatic monothiols and aromatic dithiols to increase the folding rate and yield of disulfide containing proteins

Most pharmaceutically relevant proteins and many extracellular proteins contain disulfide bonds. Formation of the correct disulfide bonds is essential for stability in almost all cases. Disulfide containing proteins can be rapidly and inexpensively overexpressed in bacteria. However, the overexpressed proteins usually form aggregates inside the bacteria, called inclusion bodies, which contains inactive and non-native protein. To obtain native protein, inclusion bodies need to be isolated and resolubilized, and then the resulting protein refolded in vitro. In vitro protein folding is aided by the addition of a redox buffer, which is composed of a small molecule disulfide and/or a small molecule thiol. The most commonly used redox buffer contains reduced and oxidized glutathione. Recently, aliphatic dithiols and aromatic monothiols have been employed as redox buffers. Aliphatic dithiols improved the yield of native protein as compared to the aliphatic thiol, glutathione. Dithiols mimic the in vivo protein folding catalyst, protein disulfide isomerase, which has two thiols per active site. Furthermore, aromatic monothiols increased the folding rate and yield of lysozyme and RNase A relative to glutathione. By combining the beneficial properties of aliphatic dithiols and aromatic monothiols, aromatic dithiols were designed and were expected to increase in vitro protein folding rates and yields. Aromatic monothiols (1-4) and their corresponding disulfides (5-8), two series of ortho- and para-substituted ethylene glycol dithiols (9-15), and a series of aromatic quaternary ammonium salt dithiols (16-17) were synthesized on a multigram scale. Monothiols and disulfides (1-8) were utilized to fold lysozyme and bovine pancreatic trypsin inhibitor. Dithiols (11-17) were tested for their ability to fold lysozyme. At pH 7.0 and pH 8.0, and high protein concentration (1 mg/mL), aromatic dithiols (16, 17) and a monothiol (3) significantly enhanced the in vitro folding rate and yield of lysozyme relative to the aliphatic thiol, glutathione. Additionally, aromatic dithiols (16, 17) significantly enhance the folding yield as compared to the corresponding aromatic monothiol (3). Thus, the folding rate and yield enhancements achieved in in vitro protein folding at high protein concentration will decrease the volume of renaturation solution required for large scale processes and consequently reduce processing time and cost.

Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn's moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards aromatic compounds in cold environments, such as on Titan or in the interstellar medium.

Synthesis of aromatic monothiols to increase the folding rate and yields of disulfide-containing proteins

Almost all pharmaceutically relevant proteins and many extracellular proteins contain disulfide bonds, which are essential for protein functions. In many cases, disulfidecontaining proteins are produced via in vitro protein folding that involves the oxidation of reduced protein to native protein, a complex process. The in vitro folding of reduced lysozyme has been extensively studied as a model system because native lysozyme is small, inexpensive, and has only four disulfide bonds. The folding of reduced lysozyme is conducted with the aid of a redox buffer consisting of a small molecule disulfide and a small molecule thiol, such as oxidized and reduced glutathione. Herein, in vitro folding rates and yields of lysozyme obtained in the presence of a series of aromatic thiols and oxidized glutathione are compared to those obtained with reduced and oxidized glutathione. Results showed that aromatic thiols significantly increase the folding rate of lysozyme compared to glutathione.

A study of methods used to analyze total oil and polycyclic aromatic hydrocarbons in produced water: steps towards the validation of molecularly imprinted polymers for use in marine environmetns

Produced water is a by-product of offshore oil and gas production, and is released in large volumes when platforms are actively processing crude oil. Some pollutants are not typically removed by conventional oil/water separation methods and are discharged with produced water. Oil and grease can be found dispersed in produced water in the form of tiny droplets, and polycyclic aromatic hydrocarbons (PAHs) are commonly found dissolved in produced water. Both can have acute and chronic toxic effects in marine environments even at low exposure levels. The analysis of the dissolved and dispersed phases are a priority, but effort is required to meet the necessary detection limits. There are several methods for the analysis of produced water for dispersed oil and dissolved PAHs, all of which have advantages and disadvantages. In this work, EPA Method 1664 and APHA Method 5520 C for the determination of oil and grease will be examined and compared. For the detection of PAHs, EPA Method 525 and PAH MIPs will be compared, and results evaluated. APHA Method 5520 C Partition-Infrared Method is a liquid-liquid extraction procedure with IR determination of oil and grease. For analysis on spiked samples of artificial seawater, extraction efficiency ranged from 85 – 97%. Linearity was achieved in the range of 5 – 500 mg/L. This is a single-wavelength method and is unsuitable for quantification of aromatics and other compounds that lack sp³-hybridized carbon atoms. EPA Method 1664 is the liquid-liquid extraction of oil and grease from water samples followed by gravimetric determination. When distilled water spiked with reference oil was extracted by this procedure, extraction efficiency ranged from 28.4 – 86.2%, and %RSD ranged from 7.68 – 38.0%. EPA Method 525 uses solid phase extraction with analysis by GC-MS, and was performed on distilled water and water from St. John’s Harbour, all spiked with naphthalene, fluorene, phenanthrene, and pyrene. The limits of detection in harbour water were 0.144, 3.82, 0.119, and 0.153 g/L respectively. Linearity was obtained in the range of 0.5-10 g/L, and %RSD ranged from 0.36% (fluorene) to 46% (pyrene). Molecularly imprinted polymers (MIPs) are sorbent materials made selective by polymerizing functional monomers and crosslinkers in the presence of a template molecule, usually the analytes of interest or related compounds. They can adsorb and concentrate PAHs from aqueous environments and are combined with methods of analysis including GC-MS, LC-UV-Vis, and desorption electrospray ionization (DESI)- MS. This work examines MIP-based methods as well as those methods previously mentioned which are currently used by the oil and gas industry and government environmental agencies. MIPs are shown to give results consistent with other methods, and are a low-cost alternative improving ease, throughput, and sensitivity. PAH MIPs were used to determine naphthalene spiked into ASTM artificial seawater, as well as produced water from an offshore oil and gas operation. Linearity was achieved in the range studied (0.5 – 5 mg/L) for both matrices, with R² = 0.936 for seawater and R² = 0.819 for produced water. The %RSD for seawater ranged from 6.58 – 50.5% and for produced water, from 8.19 – 79.6%.

Phase and partitioning behavior of phenols and polycyclic aromatic hydrocarbons in offshore oil and gas produced water

Produced water constitutes the largest volume of waste from offshore oil and gas operations and is composed of a wide range of organic and inorganic compounds. Although treatment processes have to meet strict oil in water regulations, the definition of “oil” is a function of the analysis process and may include aliphatic hydrocarbons which have limited environmental impact due to degradability whilst ignoring problematic dissolved petroleum species. This thesis presents the partitioning behavior of oil in produced water as a function of temperature and salinity to identify compounds of environmental concern. Phenol, p-cresol, and 4-tert-butylphenol were studied because of their xenoestrogenic power; other compounds studied are polycyclic aromatic hydrocarbon PAHs which include naphthalene, fluorene, phenanthrene, and pyrene. Partitioning experiments were carried out in an Innova incubator for 48 hours, temperature was varied from 4ﾟC to 70ﾟC, and two salinity levels of 46.8‰ and 66.8‰ were studied. Results obtained showed that the dispersed oil concentration in the water reduces with settling time and equilibrium was attained at 48 h settling time. Polycyclic aromatic hydrocarbons (PAHs) partitions based on dispersed oil concentration whereas phenols are not significantly affected by dispersed oil concentration. Higher temperature favors partitioning of PAHs into the water phase. Salinity has negligible effect on partitioning pattern of phenols and PAHs studied. Simulation results obtained from the Aspen HYSYS model shows that temperature and oil droplet distribution greatly influences the efficiency of produced water treatment system.

Assessment of anticancer properties of essential oils from aromatic plants of the sand dunes of peniche (portugal)

O cancro é um problema de saúde crescente no mundo e é a segunda causa de morte depois das doenças cardíacas. De acordo com a Agência Internacional de Investigação em Cancro (IARC) existem atualmente mais de 10 milhões de casos de cancro por ano no mundo. Os produtos naturais oferecem oportunidades de inovação na descoberta de novos fármacos. Neste sentido, os compostos naturais isolados a partir de plantas medicinais, como potenciais fontes de novas drogas anticancerígenas, têm tido um interesse crescente. Os Óleos Essenciais (OEs) são sintetizados pelas plantas e têm sido estudados pelas suas inúmeras atividades biológicas, incluindo anticancerígena, anti-inflamatória, antimicrobiana, antiviral, antioxidante e repelente de insetos. Este estudo tem como objetivos determinar a eficácia de OEs de seis espécies de plantas das dunas de Peniche (Portugal), como potenciais agentes terapêuticos anticancerígenos em linhas celulares de cancro da mama (MCF7) e do colo-rectal (RKO), assim como perceber o mecanismo de ação destes OEs. Neste estudo, partes aéreas de Artemisia campestris subsp. maritima, Crithmum maritimum, Eryngium maritimum, Juniperus turbinata subsp. turbinata, Otanthus maritimus e Seseli tortuosum foram colhidas na praia da Consolação, em Peniche (Portugal), e os seus OEs isolados através de hidrodestilação. A composição química dos OEs foi investigada por cromatografia gasosa (GC) e por cromatografia gasosa com espetrofotometria de massa (GC-MS) e os compostos maioritários foram descritos para cada óleo. Para avaliar a atividade anticancerígena nas linhas celulares MCF7 e RKO, o método MTS (3- (4, 5-dimethyl- 2 -thiazolyl) - 2, 5-dyphenyl-2H-tetrazolium bromide) foi usado e a viabilidade celular avaliada, através de diluições sucessivas, a concentrações iniciais de 5 μL/mL e 1 μL/mL, com diluição de 1:2 e 1:10, respetivamente, comparando com o controlo (DMSO). De todos os OEs testados, a atividade anticancerígena foi descrita, em ambas as linhas celulares, como observado pela diminuição da viabilidade/proliferação celular – exceto o OE Eryngium maritimum a uma concentração inicial de 5 μL/mL.Com o objetivo de avaliar o mecanismo biológico de ação dos OEs, foi realizado um western blot para marcadores relativos ao bloqueio do ciclo celular e apoptose (p53, p21 e caspase 3 clivada), para Seseli tortuosum e Otanthus maritimus. Foi observado um aumento do nível proteína p53 nas células tratadas com estes OEs, sugerindo a indução de stress celular nas células cancerígenas testadas. No entanto, não foi observada caspase 3 clivada, sugerindo que a apoptose não terá sido a causa para a diminuição da viabilidade/proliferação celular observada. Foi ainda observado o aumento da expressão da p21 com os OEs selecionados, sugerindo que o tratamento com OE está associado ao bloqueio do ciclo celular. Para validar estas observações, a análise realizada por FACS, depois do tratamento indica um possível bloqueio do ciclo celular na fase G1. Concluindo, a concentração inicial de 5 μL/mL revelou ser muito tóxica para as linhas celulares testadas. No entanto, a uma concentração final de 1 μL/mL foi demonstrada uma diminuição da viabilidade/proliferação celular para todos os OEs. No estudo preliminar do mecanismo de ação dos OEs, foi demonstrado, face à presença da p21, que os óleos de Seseli tortuosum e Otanthus maritimus atuam bloqueando o ciclo celular. Para comprovar estes resultados, o FACS realizado (apenas no OE de Seseli tortuosum) revelou que este bloqueio pode ocorrer, pelo aumento da percentagem de células observadas, na fase G1. Estes resultados demonstram o interesse destes OEs de Peniche na procura de novos agentes quimo preventivos contra a progressão do cancro da mama e colo-rectal.

Bullion rings in Viking Age Britain and Ireland

This paper examines a simple type of silver ring, here termed the ‘bullion-ring’, that occurs in several Viking Age contexts in Britain and Ireland. It is proposed that the type may be dated to the later ninth and early to mid-tenth century, and that it developed in Ireland as a convenient way of storing silver as a result of inspiration from southern Scandinavia. Its distribution patterns suggest that it may have developed in one of Munster’s Scandinavian settlements rather than in Dublin, the core of the Hiberno-Scandinavian silver-working tradition.

Investigation of additive effects in enantioselective copper-catalysed C-H insertion and aromatic addition reactions of α-diazocarbonyl compounds

Significant enhancements in enantioselectivities and reaction efficiencies in asymmetric copper-catalysed C-H insertion and aromatic addition reactions of α-diazocarbonyl compounds in the presence of various group I salts are reported. For the first time in carbenoid chemistry, evidence for the critical role of the metal cation is described.

FtsZ Protofilament Curvature is the Opposite of Tubulin Rings

Bacterial tubulin homolog FtsZ assembles straight protofilaments (pfs) that form the scaffold of the cytokinetic Z ring. These pfs can adopt a curved conformation forming a miniring or spiral tube 24 nm in diameter. Tubulin pfs also have a curved conformation, forming 42 nm tubulin rings. We have previously provided evidence that FtsZ generates a constriction force by switching from straight pfs to the curved conformation, generating a bending force on the membrane. In the simplest model the membrane tether, which exits from the C terminus of the globular FtsZ, would have to be on the outside of the curved pf. However, it is well established that tubulin rings have the C terminus on the inside of the ring. Could FtsZ and tubulin rings have the opposite curvature? In the present study we explored the direction of curvature of FtsZ rings by fusing large protein tags to the N or C terminus of the FtsZ globular domain. FtsZ with a protein tag on the N terminus did not assemble tubes. This was expected if the N terminus is on the inside, because the protein tags are too big to fit in the interior of the tube. FtsZ with C-terminal tags assembled normal tubes, consistent with the C terminus on the outside. The FN extension was not visible in negative stain, but thin section EM gave definitive evidence that the C-terminal tag was on the outside of the tubes. This has interesting implications for the evolution of tubulin. It seems likely that tubulin began with the curvature of FtsZ, which would have resulted in pfs curving toward the interior of a disassembling MT. Evolution not only eliminated this undesirable curvature, but managed to reverse direction to produce the outward curving rings, which is useful for pulling chromosomes.