2,097 research outputs found
A boronic acid-based fluorescent hydrogel for monosaccharide detection
No full textA boronic acid-based anthracene fluorescent probe was functionalised with an acrylamide unit to incorporate into a hydrogel system for monosaccharide detection. In solution, the fluorescent probe displayed a strong fluorescence turn-on response upon exposure to fructose, and an expected trend in apparent binding constants, as judged by a fluorescence response where d–fructose > d–galactose > d–mannose > d–glucose. The hydrogel incorporating the boronic acid monomer demonstrated the ability to detect monosaccharides by fluorescence with the same overall trend as the monomer in solution with the addition of d–fructose resulting in a 10-fold enhancement (≼0.25 mol/L)
The Bull-James assembly:Efficient iminoboronate complex formation for chiral derivatization and supramolecular assembly
No full textChiral molecules are widely used in many fields of research and so practically simple, accurate methods to measure their enantiopurities are required. This review's initial focus is on one such method, the Bull-James assembly, which employs a three-component protocol combining 2-formylphenyl boronic acid, an amine, and a diol to self-assemble diastereomeric iminoboronate ester (IBE) complexes whose ratio can be used to measure the ee's of amine and diol analytes using 1H and 19F NMR spectroscopic analysis. Examples where this supramolecular IBE assembly approach has been adapted to determine the ee of a range of analytes using other analytical techniques such as circular dichroism, fluorescence, and electrochemistry that are potentially applicable to high-throughput ee analysis are also discussed. Selected examples where this orthogonal self-assembly process has been used as a platform technology to construct boracyles, chiral auxiliaries/ligands, synthesise intelligent polymers/hydrogels, and prepare labelled peptides/proteins/biomolecules are also discussed.</p
Reduced glutathione and cysteine hydrochloride on crossbred bull semen
No full textOver the last few years, good quality freezable semen was not utilized effectively due to less knowledge about the freezability of semen. One reason is the lack of sufficient antioxidants in the seminal plasma and semen extender. The antioxidant content is reduced during the cryopreservation process and causes premature cryo-capacitation and modification of sperm membrane structure upon thawing. So the study of pre-freezing and post thaw seminal parameters like viability, motility, acrosomal integrity, lipid peroxide assay, vanguard distance traveled by sperm, mitochondrial membrane potential, velocity and motility parameters (CASA) and field fertility trial helped to assess the effectiveness of the additives. The conception rate was better in reduced glutathione than the cysteine hydrochloride treated group. The glutathione has improved the poor freezing and maintained the good freezable semen. Thus the field fertility rate was enhanced and in turn helped to prevent waste of good quality germplasm and repeat breeder syndrome in cows
Delphinium cuneatum Steven ex DC.
No full textDelphinium × hybridum Linnaeus, Demonstr. Pl Horto Upsaliensi: 15. 1753. RCN: 3951. Type not designated. Original material: Herb. Linn. No. 218.19 (S); Herb. Linn. No. 694.9 (LINN). Current name: Delphinium cuneatum Steven ex DC. (Ranunculaceae). Note: Burtt (in Kew Bull. 9: 68. 1954) stated "The true D. hybridum, of which there is a specimen in the Linnean herbarium, is the same as D. cuneatum Stev.". Subsequently, Chowdhuri & al. (in Notes Roy. Bot. Gard. Edinburgh 22: 404. 1958) stated that "the specimen in the Linnaean herbarium...must be accepted as the type", but did not distinguish between 694.9 and 694.10 (LINN). They rejected the name as a nomen confusum. It does not appear to be in use and should probably be a candidate for formal rejection.Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part D), pp. 474-489 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 477, DOI: 10.5281/zenodo.29197
Lipid-soluble Vitamins A, D, and E in HIV-Infected Pregnant women in Tanzania.
No full textThere is limited published research examining lipid-soluble vitamins in human immunodeficiency virus (HIV)-infected pregnant women, particularly in resource-limited settings. This is an observational analysis of 1078 HIV-infected pregnant women enrolled in a trial of vitamin supplementation in Tanzania. Baseline data on sociodemographic and anthropometric characteristics, clinical signs and symptoms, and laboratory parameters were used to identify correlates of low plasma vitamin A (<0.7 micromol/l), vitamin D (<80 nmol/l) and vitamin E (<9.7 micromol/l) status. Binomial regression was used to estimate risk ratios and 95% confidence intervals. Approximately 35, 39 and 51% of the women had low levels of vitamins A, D and E, respectively. Severe anemia (hemoglobin <85 g/l; P<0.01), plasma vitamin E (P=0.02), selenium (P=0.01) and vitamin D (P=0.02) concentrations were significant correlates of low vitamin A status in multivariate models. Erythrocyte Sedimentation Rate (ESR) was independently related to low vitamin A status in a nonlinear manner (P=0.01). The correlates of low vitamin D status were CD8 cell count (P=0.01), high ESR (ESR >81 mm/h; P<0.01), gestational age at enrollment (nonlinear; P=0.03) and plasma vitamins A (P=0.02) and E (P=0.01). For low vitamin E status, the correlates were money spent on food per household per day (P<0.01), plasma vitamin A concentration (nonlinear; P<0.01) and a gestational age <16 weeks at enrollment (P<0.01). Low concentrations of lipid-soluble vitamins are widely prevalent among HIV-infected women in Tanzania and are correlated with other nutritional insufficiencies. Identifying HIV-infected persons at greater risk of poor nutritional status and infections may help inform design and implementation of appropriate interventions
Bull Threshers and Bindlestiffs
No full textBull Threshers and Bindlestiffs is a panorama on a continental canvas: the Great Plains of North America, stretching from Texas to Alberta. Onto this surface the author lays the large features of regional practice in the harvesting and threshing of wheat during the days before the combined harvester—harvesting with binder and header, threshing with bull thresher and steam engine. Into the picture he places the key figures who accomplished the task of gathering the grain—the farm men and women, the custom threshermen, and the bindlestiffs, or itinerant laborers. Affectionately he sketches the small details of folklife that comprised the everyday work and culture of the wheat belt—building shocks, loading racks, constructing stacks, pitching bundles into the separator, hauling water to the engine, drinking deep from the crockery water jug.Bull Threshers and Bindlestiffs is a profusely illustrated study of a complex, vigorous regional culture concerned with the production of wheat—a culture that centered around the annual harvest and declined with the advent of the combine. This is an examination of the interaction of culture, environment, and technology with import for the fields of agricultural history and regional history. More than that, with its grassroots research, its descriptions of tools and customs, and its lavish illustrations, it is a recreation of a proud phase of regional life previously captured only in yellowed albumen photographs
Dye Displacement Assay for Saccharides using Benzoxaborole Hydrogels
No full textDye displacement assays are a simple but effective method to determine the concentration of target analytes. Previously, we have shown that phenylboronic acid pinacol ester hydrogels (borogels) can be used to develop a boronic acid–Alizarin red S dye displacement assay for the determination of fructose (orange to red). In this work, benzoxaborole hydrogels (BOBgels) were developed, and these BOBgels demonstrated an enhanced apparent binding affinity towards monosaccharides, in particular towards glucose
Biological Diversity in the Northern and Southern Hemispheres
No full text<p>Regular differences between the northern and southern hemispheres in patterns of diversity show up in various groups such as the birds (A) (Adelie Penguin, Pygoscelis adeliae) and seed plant families (B) (King Protea, Protea cynaroides). North–south differences in life histories are also apparent in a diverse array of groups ranging from seaweeds (C) (Bull Kelp, Durvillaea antarctica) and insects (D) (the sub-Antarctic, flightless tineid moth Pringleophaga marioni) to birds (E) (Cape Sugarbird, Promerops cafer) and mammals (F) (Sloggett's Rat, Otomoys sloggetti, from the high Drakensberg in South Africa). (Photos: [A, C, and F] Brent J. Sinclair; [B and D] Steven L. Chown; [E] Mhairi L. McFarlane)</p
Form vs. function in prehistoric typology: the case of the Magdalenian bone bull-roarers
No full textEste trabajo ha sido realizado en el marco del Grupo de Investigación Consolidado GIC 07/21-IT.288.07.[ES] En 1930 D. Peyrony interpretó como ‘churinga’ o ‘bull-roarer’ un objeto en
asta encontrado en el Magdaleniense avanzado de Lalinde (Dordoña). Este holotipo tiene forma fusiforme, alargada y estrecha y una perforación en un extremo. Desde entonces son muy pocos los ejemplares (normalmente sobre placa de costilla animal) recuperados en el sudoeste de Europa (Cantabria, norte del Pirineo, Dordogne) atribuidos a ese mismo
tipo. El autor describe la ‘bramadera’ (esp.), ‘rhombe’(fr.), ‘bull-roarer’ (ing.) y otros tipos formalmente afines (‘elipse’ esp., ‘ellipse’ fr., ‘colgante’ esp., ‘pendeloque’ fr.). Se plantean las dificultades de la taxonomía del utillaje paleolítico (en soporte óseo y, también, lítico) que se asienta, a menudo, en la convergencia de caracteres formales objetivos y funcionales presuntos.[EN] In 1930, an archaeological evidence worked on antler was recovered by D. Peyrony in the Upper Magdalenian level of Lalinde’s cave (Dordogne), and was interpreted as a ‘churinga’ or bull-roarer. The shape of this holotype is fusiform, elongated and narrow, and with a hole in one end. Ever since then, the new evidences recovered (preferably on ribs of animals) in Western Europe (north of Iberian Peninsula, north Pyrenees and Dordogne) have been scarce. The author describes the bull-roarer or rhombus,
and other types with related shapes (such as the ellipse and pendants). Besides, the author puts forward the difficulties of the classification of Paleolithic bone/antler (and, also, lithic) tools, which are based often on the convergence of formal characteristics and assumptions
about the use of the tools
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