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Search Results: 1 - 10 of 201696 matches for " Nigel P. Brunton "
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Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins
Natalie Heffernan,Nigel P. Brunton,Richard J. FitzGerald,Thomas J. Smyth
Marine Drugs , 2015, DOI: 10.3390/md13010509
Abstract: Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene) unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC) with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast ( Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis). Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM) and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW) phlorotannins were found to have a molecular weight range equivalent to 4–12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs). These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.
Profiling of Phytochemicals in Tissues from Sclerocarya birrea by HPLC-MS and Their Link with Antioxidant Activity
Daniela Russo,Owen Kenny,Thomas J. Smyth,Luigi Milella,Mohammad B. Hossain,Moussoukhoye Sissokho Diop,Dilip K. Rai,Nigel P. Brunton
ISRN Chromatography , 2013, DOI: 10.1155/2013/283462
Abstract: High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to investigate the differences in phytochemicals in roots, bark, and leaf of Sclerocarya birrea (marula) for methanol and water extracts that exhibited the best antioxidant activities. As many as 36 compounds were observed in the extracts of these tissues of which 27 phenolic compounds were tentatively identified. The HPLC-MS/MS results showed flavonoid glycosides were prominent in leaf extracts while the galloylated tannins were largely in bark and root extracts. Four flavonoid glycosides that were reported for the first time in the marula leaf have been identified. The HPLC-MS/MS studies also illustrated different degrees (highest degree = 3) of oligomerisation and galloylation of tannins in the bark and root extracts. 1. Introduction Sclerocarya birrea (A. Rich.) Hochst, more commonly known as marula, is taxonomically derived from the Anacardiaceae plant family. It is an indigenous, fruit-bearing tree of sub-Saharan Africa [1]. It grows mostly at low altitudes and can reach up to 20?m in height and 1.2?m in diameter [2]. Traditionally, marula has multiple uses; the fruits are eaten or processed to make beer and jam, the kernels are eaten or their oils extracted, the leaves are used as forage for livestock, and the wood is carved into utilitarian items such as spoons and plates [2]. The marula tree has been the subject of numerous chemical, biological, and environmental investigations since 1906 [3] and has been identified as one of five fruit tree species that should be integrated in the domestication process in African farming system [4, 5]. This is due to its use as source of food and medicine in rural communities and its potential to generate income through the sale of its derivates. The bark, leaves, and roots of Sclerocarya birrea (S. birrea) have attracted attention because they have been traditionally used to treat an assortment of human ailments such as dysentery, fevers, malaria, diarrhea, stomach ailments, rheumatism, sore eyes, gangrenous rectitis, infertility, headaches, toothache, and body pains [6, 7]. As a result, extracts of this plant have been reported to possess antioxidant, antibacterial, antifungal, astringent anticonvulsant [8–10], antihyperglycemic, anti-inflammatory [11], and antiatherogenic properties [12]. Several of these properties could be attributed to the high content of polyphenols and its antioxidant activity [13–16]. As a result of their high antioxidant activities, extracts from S. birrea could also be used to control
Murray,Nigel P.;
Revista chilena de obstetricia y ginecología , 2003, DOI: 10.4067/S0717-75262003000200010
Abstract: a case of a pregnancy in a woman anti-p1 positive, the effect on the fetus, treatment and follow-up is presented. anti-p1 is associated with placental insuficiency and fetal death. this is the first case in the literature describing intrauterine fetal growth recovery in the second and third trimesters
Nigel P. Murray
Revista Chilena de Obstetricia y Ginecología , 2003,
Abstract: La presentación de un embarazo en una mujer con anticuerpos anti-P1 positivo, los efectos fetales, el tratamiento y seguimiento del feto. Anti-P1 es asociada con insuficiencia de la placenta y la muerte del feto. Este es el primer caso en la literatura donde hubo recuperación del crecimiento durante el segundo y el tercer trimestre A case of a pregnancy in a woman anti-P1 positive, the effect on the fetus, treatment and follow-up is presented. Anti-P1 is associated with placental insuficiency and fetal death. This is the first case in the literature describing intrauterine fetal growth recovery in the second and third trimesters
Nilpotent and abelian Hopf-Galois structures on field extensions
Nigel P. Byott
Mathematics , 2012,
Abstract: Let $L/K$ be a finite Galois extension of fields with group $\Gamma$. When $\Gamma$ is nilpotent, we show that the problem of enumerating all nilpotent Hopf-Galois structures on $L/K$ can be reduced to the corresponding problem for the Sylow subgroups of $\Gamma$. We use this to enumerate all nilpotent (resp. abelian) Hopf-Galois structures on a cyclic extension of arbitrary finite degree. When $\Gamma$ is abelian, we give conditions under which every abelian Hopf-Galois structure on $L/K$ has type $\Gamma$. We also give a criterion on $n$ such that \emph{every} Hopf-Galois structure on a cyclic extension of degree $n$ has cyclic type.
A Valuation Criterion for Normal Basis Generators of Hopf-Galois Extensions in Characteristic p
Nigel P. Byott
Mathematics , 2009,
Abstract: Let S/R be a finite extension of discrete valuation rings of characteristic p>0, and suppose that the corresponding extension L/K of fields of fractions is separable and is H-Galois for some K-Hopf algebra H. Let D_{S/R} be the different of S/R. We show that if S/R is totally ramified and its degree n is a power of p, then any element $\rho$ of L with $v_L(\rho)$ congruent to $-v_L(D_{S/R})-1$ mod n generates L as an H-module. This criterion is best possible. These results generalise to the Hopf-Galois situation recent work of G. Elder for Galois extensions.
Solubility Criteria for Hopf-Galois Structures
Nigel P. Byott
Mathematics , 2014,
Abstract: Let $L/K$ be a finite Galois extension of fields with group $\Gamma$. Associated to each Hopf-Galois structure on $L/K$ is a group $G$ of the same order as the Galois group $\Gamma$. The type of the Hopf-Galois structure is by definition the isomorphism type of $G$. We investigate the extent to which general properties of either of the groups $\Gamma$ and $G$ constrain those of the other. Specifically, we show that if $G$ is nilpotent then $\Gamma$ is soluble, and that if $\Gamma$ is abelian then $G$ is soluble. The proof of the latter result depends on the classification of finite simple groups. In contrast to these results, we give some examples where the groups $\Gamma$ and $G$ have different composition factors. In particular, we show that a soluble extension may admit a Hopf-Galois structure of insoluble type.
Book reviews
Brunton, Howard
Graellsia , 2006,
Surveillance of adverse events following H1N1/09 influenza immunisation in Victoria, Australia  [PDF]
David Tran, Hazel Clothier, Jim P. Buttery, Nigel W. Crawford
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.412135
Abstract: BACKGROUND: The H1N1 pandemic in 2009 required a systematic coordinated response, which in Australia included a monovalent (H1N1/09) vaccine (Panvax?). SAEFVIC (Surveillance of Adverse Events Following Vaccination In the Community) is the Victorian, Australia state-based vaccine safety unit. The aim of the study was to review SAEFVIC reports of adverse events following immunisations (AEFI) temporally associated with H1N1/09 vaccines [monovalent and Trivalent Influenza Vaccines (TIV)]. METHODS: 1) Analysis of AEFI related to H1N1/09 vaccines reported to SAEFVIC from September 2009 to December 2010; 2) Review of febrile convulsions (ICD-10 code R56.0), in children under 5 years of age presenting to the Royal Children’s Hospital (RCH) Melbourne, Emergency Department between 1 March-30 April 2010. The presentation details and immunisation history were clarified by a telephone interview. RESULTS: 1) There were 659 reports of 749 adverse events following H1N1 vaccines. Among the TIV group, Fluvax had the most AEFI reported, with 77 per 100,000 doses distributed. Serious AEFI temporally associated with H1N1/09 vaccines included: 3 deaths, 2 anaphylactic reactions, and 3 GuillainBarre Syndrome. There were 7 reports of drug administration error; 2) There were 179 presentations with fever and 67 reported febrile convulsions out of 11025 presentations (0.61%), 11 following H1N1 vaccines. Fluvax? was associated with 55% (6/11) reports. The mean onset time of AEFI was 13.2 hours post vaccination, and there was complete resolution of symptoms in allcases with no significant morbidity. CONCLUSION: Consistent with other Australian states in 2010, there was a TIV brand specific [Fluvax?] increase in febrile convulsions post vaccination. As a result this vaccine is no longer licensed for children <5 years of age. Comprehensive passive and active surveillance for AEFI needs to be incorporated into future pandemic planning.
Fluvial Facies and Provenance of the Early Permian Warchha Sandstone Salt Range, Pakistan
Shahid Ghazi,Nigel P. Mountney
Iranian Journal of Earth Sciences , 2011,
Abstract: Deposits of the Warchha Sandstone in the Salt Range, Pakistan are characterised by a range of fluvial facies and architectural elements that together preserve a record of both the proximal and distal parts of a meandering river system that drained the northern margin of Gondwanaland. Several fining-upward cycles are recognised and completely preserved cycles can be divided in to three parts; a lower part composed of an erosive base with gravel- and coarse sand-grade trough cross-bedded facies, a middle part composed of planar cross-bedded, ripple cross-laminated and horizontally laminated sandstone facies, and an upper part composed predominantly of horizontally laminated and massive mudstone facies. Nine architectural elements are recognised within these cycles and these record the presence of channels, downstream and laterally accreting barforms, laminated sand sheets, crevasse splays, levees, over-bank floodplain units and shallow lakes. A broad range of sedimentary structures is recognised, including different forms of bedding, cross bedding, ripple marks and stratification, channels, flute casts, load casts, desiccation cracks, rain prints, conein- cone structures, a variety of concretions and bioturbation. The occurrence and abundance of these structures varies in a systematic manner throughout the vertical thickness of the succession. Cross bedding is the most prominent and consistent sedimentary structure, including various trough and planar varieties. The clasts are mainly of plutonic and low-grade metamorphic origin, with an additional minor sedimentary component. Textural properties of the sandstone are fine- to coarse-grained, poorly to moderately sorted, sub-angular to sub-rounded and with generally loose packing. Based on modal analyses, the sandstone is dominantly a sub-arkose to arkose. Detrital constituents of this formation are mainly composed of monocrystalline quartz, feldspars (more K-feldspar than plagioclase) and various types of lithic clasts. XRD and SEM studies indicate that kaolinite is the dominant clay mineral. Detailed palaeocurrent analysis reveals a broad unimodal palaeocurrent pattern within each cycle but significant changes in local migration direction between each vertically stacked cycle, supporting the notion of a high-sinuosity system with an overall dominant flow direction to the north-northwest. Petrographic analysis indicates the provenance of the Warchha Sandstone to have been the Aravalli Range to the southeast and the Malani Range to the south of the Salt Range, suggesting northward transport across a broad a
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