bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutral, Radical [CpNi(dithiolene)] Complexes with Flexible, Nonplanar Seven‐Membered Rings: [CpNi{S2C2S2(CH2)2X}] (X = CH2, CF2, C=CH2, S, C=O)
Authors: Nomura Mitsushiro , Geoffroy Michel , Adkine Prashant , Fourmigué Marc 
Published: October 2006

AbstractNeutral, radical [CpNi(dithiolene)] complexes fused with seven‐membered rings, formulated as [CpNi{S2C2S2(CH2)2X}] (X = CH2, CF2, C=CH2, S), have been synthesized in 30–60 % yields from the reactions of nickelocene with the corresponding neutral, square‐planar, (dithiolene)nickel complexes [Ni{S2C2S2(CH2)2X}2]. [CpNi{S2C2S2(CH2)2X}] (X = C=O) was prepared from nickelocene and [1,3]dithiolo[4,5‐b][1,4]dithiepine‐2,6‐dione under thermal or photochemical conditions. All complexes exhibit reversible oxidation and reduction waves to the cation and anion form, respectively. The terminal groups (X) in the seven‐membered ring shift their redox potentials to anodic potentials in the following order: CF2 > C=O > S > C=CH2 > CH2. The singlet EPR responses of [CpNi{S2C2S2(CH2)2(X)}] appear at g ≈ 2.0514–2.0529 in dichloromethane solution at room temperature. An NIR absorption is observed at λmax ≈ 798–848 nm (ϵ ≈ 1700–2400 M–1 cm–1) in dichloromethane solution. The X‐ray structures of the five complexes show two‐legged piano‐stool geometries around the central nickel atom (formally NiIII) and strong distortions from planarity of the seven‐membered C2S2(CH2)2X rings. In the solid state, those radical (S = 1/2) species adopt either one‐dimensional alternating chain‐like motifs (X = CH2, C=CH2, S) or dimeric entities characterized by a singlet–triplet magnetic behavior (X = CF2, C=O). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Development of a three‐dimensional finite element model of a human mandible containing endosseous dental implants. II. Variables affecting the predictive behavior of a finite element model of a human mandible
Authors: Al‐Sukhun Jehad , Lindqvist Christian , Helenius Miia 
Published: October 2006

AbstractThe purpose of this study was to propose a systematic approach to validate a finite element model (FEM) of the human mandible and to investigate the effects of changing the geometry and orthotropic material properties on the FEM predictions. Thirty‐eight variables affecting the material properties, boundary conditions, and the geometry of a FEM of a human mandible, including two dental implants, were systematically changed, creating a number of FEMs of the mandible. The effects of the variations were quantified as differences in the principal strain magnitudes modeled by the original FEM (gold standard), prior to the sensitivity analyses, and those generated by the changed FEMs. The material properties that had the biggest impact on the predicted cortical principal strain were the shear moduli (up to 31% in difference from the unchanged state), and the absence of cancellous bone (up to 34%). Alterations to the geometry of the mandibular cross section, such as an increase in corpus dimensions, had the greatest effect on principal strain magnitudes (up to 16%). Changes in the cortical thickness in relation to the width of the corpus section modified strain more than alterations to the corpus depth (14% and 5%, respectively). The relatively small difference (up to 13.5%) between the predicted and measured interimplant distances indicates the accuracy of the FEM. Changes in geometry and orthotropic material properties could induce significant changes in strain patterns. These values must therefore be chosen with care when using finite element techniques for predicting stresses, strains, and displacements. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Glutenin structure
Authors: Ewart J. A. D. 
Published: October 2006

AbstractThe fall in viscosity of dispersions of gluten when treated with excess of mercaptoethanol does not exhibit an initial induction period. This finding appears to rule out the idea that glutenin is highly crosslinked in a branching mode. It is compatible with a linear model in which one SS bond, not two, joins adjacent chains, or a model with low levels of branching. However, it is unnecessary to postulate branching crosslinks to explain glutenin properties in the present state of knowledge. The insoluble residue fraction of wheat flour protein is believed to be mainly linear glutenin of high molecular weight. A linear hypothesis can account for the Orth and Bushuk effect, in which baking quality is positively and negatively correlated with insoluble and soluble protein, respectively. It is suggested that gliadin may act as a plasticiser and aid to dispersion of glutenin.
In vitro digestibility of protein from barley and other cereals
Authors: Büchmann Nils B. 
Published: October 2006

AbstractAn in vitro method for measuring barley protein digestibility is presented. Samples were first incubated with pepsin in HCl; pancreatin was then added concomitantly with a bacteriostatic borate buffer. After TCA‐precipitation, soluble nitrogen was measured. The digestion was unaffected by accumulated free amino acids. There were no free amino acids following pepsin treatment, but the essential ones were well liberated by pancreatin. Results for barley grown in the field or in pots, and for decortified barley fractions agreed with true digestibility values determined with rats. Of these samples, the field‐grown barleys per se differed too little for the accuracy to be confirmed. The other cereals tested, oats, rye, maize, wheat, and rice, gave unsatisfactory results with pepsin/pancreatin, and also with pepsin, pancreatin, or pronase used separately. The ranking of the cereals according to in vitro digestibility depended on the type of enzyme and on the enzyme‐to‐substrate ratio.
High performance liquid chromatography of cider procyanidins
Authors: Lea Andrew G. H. 
Published: October 2006

AbstractCider procyanidins were successfully separated by h.p.l.c on hydrocarbon bonded reverse‐phase packings with acidified water‐methanol eluents. Adsorptive separations were useful for low molecular weight procyanidins but generally suffered from excessive k values, whilst gel‐permeation separations provided less resolution than might be expected from consideration of the molecular weight range present.
Correlation of bitterness thresholds of amino acids and peptides with molecular connectivity
Authors: Gardner Ronald J. 
Published: October 2006

AbstractMolecular connectivity values are easily calculated topological indices related to the degree of branching (hence the size and shape) of any chemical structure considered. These structural parameters are significantly correlated with literature values for the bitterness thresholds of amino acids, peptides and their derivatives. The quantitative correlation of flavour thresholds with structural parameters may prove useful for predicting thresholds of untested compounds; the potential and disadvantages of this approach are discussed.
Effects of waterlogging at different stages of development on the growth and yield of peas (Pisum sativum L.)
Authors: Belford Robert K. , Cannell Robert Q. , Thomson Robert J. , Dennis Colin W. 
Published: October 2006

AbstractThe effects of waterlogging, for up to 8 days at different stages of development, on the growth and yield of peas have been examined. The peas were grown outdoors subject to field conditions in lysimeters containing monolith sandy loam or clay soils, in facilities where drainage and rainfall could be controlled. The experiments, made during 2 years, involved waterlogging treatments likely to be the most extreme occurring in the pea‐growing areas of the UK. During each waterlogging treatment the oxygen concentration at 20 cm depth in the soil declined to less than 2% within 2 days. On average, when the soil was waterlogged to the surface for 5 days at the 1–2, 3–4 and 6–7 leaf stages (the latter being just before flowering), the losses of yield of seeds (peas) at the freezing stage were 6, 15 and 42%, respectively. The severity of the effect depended on the duration of the treatment and the height of the water‐table; at the 6–7 leaf stage either 2 days waterlogging to the surface or 5 days with the water‐table at 50 cm below the soil surface had little effect on seed yield. Waterlogging restricted leaf expansion and internode extension. After waterlogging at the pre‐flowering stage, leaves usually senesced prematurely and the shoot apex became prematurely quiescent. In all experiments the yield of haulm was more affected by waterlogging than were the yields of pods and seeds. The losses in yield were mainly a consequence of fewer pods per plant. Waterlogging before flowering for 5 days depressed the concentrations of nitrogen, phosphorus and potassium in the haulm grown on both soils and of nitrogen in the seeds (peas) of plants in 1 year on the clay. Other treatments had little effect on nutrient concentration. After waterlogging to the surface for 5 days before flowering the uptake of water by roots was restricted, but other treatments had only a small effect, being least in the early treatments.
Properties of some protein fractions from bambara groundnut [Voandzeia subterranea (L.) Thouars]
Authors: Poulter Nigel H. 
Published: October 2006

AbstractEight cultivars of bambara groundnut [Voandzeia subterranea (L.) Thouars] were examined for their protein, non‐protein nitrogen, starch, reducing sugar, tannin and trypsin inhibitor contents. Protein (N × 5.71), starch and reducing sugar contents showed little inter‐cultivar variation giving mean values of 18.7, 42.1 and 1.26 g 100 g−1 whole seed, respectively. Tannin contents ranged from 0.36 to 0.94 g 100 g−1 whole seed and trypsin inhibitory activity from 6.75 to 15.44 units mg−1. The majority of the protein nitrogen present was extractable in water or dilute salt solution. Trypsin inhibitory activity was directly correlated with the quantity of protein nitrogen extracted from each of the cultivars, which in turn, was found to be inversely related to their tannin contents. This latter effect was modified by both the pH and the molarity of the extractant used.
Influence of isoelectric precipitation on the solubility of soya bean proteins
Authors: Lillford Peter J. , Wright David J. 
Published: October 2006

AbstractThe factors controlling the solubility characteristics of soya bean proteins consequent upon acid precipitation were investigated. Two processes of protein insolubilisation, fundamentally different in their effects, were identified. One, termed ‚pH sensitivity’︁, involved principally haemagglutinin and low molecular weight (2S) proteins, and was affected by exposure to low pH (4.5) in the presence of reducing agents; resolubilisation could be achieved by adjusting the pH to 7.6, but only at low ionic strength. The second process concerned a precipitation‐induced aggregation of the globulins which was produced in the absence of, and largely eliminated in the presence of, reducing agent. In this case, complete resolubilisation was afforded by readjustment of the pH to 7.6, either by back titration or dialysis against a phosphate buffer, but was not dependent upon the presence of reducing agent. The mechanisms underlying these insolubilisation processes were concluded to be mainly of an electrostatic nature, rather than ones involving disulphide exchange reactions.
A rapid screening method for the estimation of total glycoalkaloids in potato tubers
Authors: Coxon David T. , Jones P. Geraint 
Published: October 2006

AbstractA rapid method for estimating the total glycoalkaloid (TGA) content of potato tubers is described which allows TGA content to be classified into three groups: (i) low TGA containing (< 15 mg TGA 100 g−1 fresh weight); (ii) high TGA containing (< 15‐35 mg TGA 100 g−1 fresh weight); and (iii) very high TGA (> 35 mg TGA 100 g−1 fresh weight). The method is intended for use by plant breeders, particularly when high TGA content might be expected in hybrid clones where one or both parents is derived from a wild species. The TGA concentration in juice expressed from potato periderm and cortex tissue was assayed by thin layer chromatography. The method utilises a direct relationship which was established between the glycoalkaloid concentration in expressed juice and the TGA content of the whole tuber and enables up to 50 analyses to be completed in 1 day by one operator without the need for expensive equipment.
Protein quality in seed meals of Phaseolus vulgaris and heat‐stable factors affecting the utilisation of protein
Authors: Phillips David E. , Eyre Michael D. , Thompson Alan , Boulter Donald 
Published: October 2006

AbstractThe polyphenol content of several cultivars of Phaseolus vulgaris was measured. The true digestibility (TD) and biological value (BV) of the cooked meals of two high‐polyphenol cultivars and one low‐polyphenol cultivar were determined by nitrogen‐balance experiments with growing rats. Removal of the testa caused a significant (P<0.05) increase in TD of Canadian Wonder and Masterpiece (high‐polyphenol) of 7.2 and 8.4%, respectively, but no significant increase in that of Processor (low‐polyphenol). Testa removal caused no significant change in BV. Supplementation of the three cultivars with methionine and cystine raised the BV to values similar to those obtained with egg albumin. Supplementation of Masterpiece with tryptophan caused no further increase in BV. The polyphenol content of the bean meals did not appear to affect the utilisation of their sulphur‐containing amino acids. Isolated Masterpiece globulins were found to be highly digestible (TD 95.4%) but with a low BV (28.36%) which was caused by a low sulphur‐containing amino acid content. The effects measured by rat feeding experiments could not be accounted for by trypsin inhibitors of phytohemagglutinin activity as the heat treatment used prior to the N‐balance studies was sufficient to destroy their activity. For the samples Masterpiece, Canadian Wonder and Processor, both with and without testa, and the isolated globulin fraction, the BV was highly correlated (P<0.001) with the total protein sulphur‐containing amino acid content.
The replacement value of sugarcane molasses for maize in sheep‐fattening rations
Authors: Umunna Nnanyelum N. , Maisamari Bala A. 
Published: October 2006

AbstractTwenty‐eight Yankasa rams, about 1.5 years old and each weighing on average 27.9 kg, were individually fed one of four experimental diets, formulated to differ in the level of cane molasses which replaced maize in the diet: 0 (control), 10 (low), 20 (medium) and 30% (high). The diet comprised on a dry matter (DM) basis, 30% native hay (Andropogon and Hyparrhenia spp. predominating) and 70% concentrate and provided a dietary crude protein level of approximately 12.5%. The results (average daily gain, feed intake and feed conversion efficiency) showed that molasses replaced 30% maize (DM basis) in fattening rations without detrimental effects. Carcass data showed that rams which received the low and medium molasses diets had better dressing percentage and wholesale cuts. Dry matter and protein digestibilities were not significantly affected by the treatments. The economic advantages in the use of molasses in fattening rations is attractive given the wide price differential (in Nigeria) between maize and molasses.
Determination of carboxyl groups in wheat and barley flour proteins
Authors: Ewart John A. D. 
Published: October 2006

AbstractThe method of Hoare and Koshland for the estimation of free carboxyl groups in proteins has been scaled down and applied to wheat proteins. With standard proteins, provided the carboxyl groups were not inaccessible (as in lysozyme), the error was as large as 19%. This level of error is acceptable for estimating by difference amide contents when these are high, as in gluten proteins, because the error is greatly reduced by the molar ratio of side‐chain CONH2:COOH—a ‚leverage’︁ effect. About 95% of the side‐chain COOH groups appear to be amidated in the prolamins and about 50% in the albumins. The proportion of Glx + Asx in the amide form seems to decrease slightly as the electrophoretic mobility of a prolamin increases. The errors in calculating the numbers of positive and negative charges that a protein bears at pH 8.9 become serious when superimposed on the net charge, which is the small difference between these numbers. The net charge at pH 8.9, therefore, could not be obtained accurately by calculation. The polarity of the net charge can be determined by electrophoresis using a marker for electroendosmosis.
Constitution of leguminous seeds. A note on protein‐phytic acid interactions during isolation of acid‐soluble protein from phaseolus beans
Authors: Alli Inteaz , Baker Bruce E. 
Published: October 2006

AbstractAcid‐soluble proteins isolated from three types of Phaseolus beans (white kidney beans, navy beans and lima beans) were found to contain phytic acid. The amount of phytic acid complexed by the proteins was unaffected by the phytic acid content of the bean extracts from which the proteins were isolated but depended on the number of positively charged basic groups which were available for reaction with the phytate anion. It was found that the Neuberg formula for phytic acid (C6H24O27P6) represents more accurately the molecular formula of phytic acid associated with the isolated proteins, than does the Anderson formula (C6H18O24P6).
Fractionation and determination of the carbohydrate components from microbial products
Authors: Longe O. Grace , Norton Grenville , Lewis Dyfed 
Published: October 2006

AbstractA routine procedure was developed which enabled a complete quantitative analysis of the carbohydrate components of microbial products to be achieved within a few days. Using the procedure, the complete carbohydrate composition of two yeasts grown on hydrocarbons and a filamentous fungus grown on carbohydrate waste was determined. Glucose was the predominant sugar contained in the polysaccharide fractions from all samples. Mannose was present to a lesser extent and glucosamine was present in trace amounts. Galactose was found in trace amounts in one of the yeasts but was found in slightly higher amounts in the fungus grown on carbohydrate. Carbohydrates accounted for 22.4‐23.6% of the dry matter of hydrocarbon grown yeasts and 21.7% for the filamentous fungus.
Starch and sugar transformation during the ripening of plantains and bananas
Authors: Marriott John , Robinson Michael , Karikari Simon K. 
Published: October 2006

AbstractRipening changes were studied in plantains of three cultivars, two Horn types and one French type, and compared with those in bananas ripened under the same conditions. Bananas contained 1% starch when fully ripe and none when overripe, whereas plantains contained about 9% starch when fully ripe and 3% when overripe (composition expressed as percentage fresh weight). Total sugar content was 23% in fully ripe and overripe bananas but in plantains it increased from 20% when fully ripe to 27% when overripe. The ratio of glucose:fructose was approximately unity for bananas and plantains at all stages of ripeness. Sucrose comprised more than 70% of the total sugars in fully ripe bananas and plantains and about half of the total sugars in overripe fruits.
Rapid gas‐liquid chromatographic determination of low levels of erucic acid in rapeseed using an internal standard
Authors: Wilson Nancy L. 
Published: October 2006

AbstractA method is described for rapid determination of erucic acid in low erucic rapeseed. The method is suited primarily to erucic acid levels below 1 % and so provides greater sensitivity and accuracy than other procedures adapted to this range. Oil is expressed by means of rollers and the fatty acids are routinely transmethylated before gas‐liquid chromatographic separation isothermally at 215°C. For maximum speed and accuracy the methyl ester of tricosanoic acid (C23:0) is included as internal standard. It elutes after erucic acid (C22:1) and within 15 min of injection. Satisfactory resolution of behenic (C22:0) and erucic acids is achieved, with good separation from other fatty acids and from the internal standard, on a steady baseline. Using one column repeatedly or two columns alternately, approximately 30 samples can be analysed in 1 day. With dual integrators the sample output can be doubled. Within the range below 1 % erucic acid, oils of high (0.9% m/m) and low (0.2% m/m) content returned coefficients of variation (c.v.) of ± 1.1 % and ± 2.5%, respectively. When rapeseed sample variation was included, precision fell away and c.v. changed to ± 7% and ± 12%, respectively. Sample variation is examined briefly and suggestions are made to reduce this source of error.
A pilot‐plant cellulose acetate gel bead column for the removal of limonin from citrus juices
Authors: Johnson Robert L. , Chandler Bruce V. 
Published: October 2006

AbstractA description is given of a pilot‐plant column packed with cellulose acetate gel beads for the removal of the bitter principle limonin from pasteurised citrus juices, at about 20 °C. The column had a bed volume (BV) of 11.5 litres and in a representative run the passage of juice (11 BV) through the column at a flow rate of 2.5 BV h−1 reduced the limonin content of the juice from 19.2 to 10.9 mg litre−1. The adsorptive process can be described by standard mathematical equations and from these equations the theoretical performance of units consisting of two or more columns in series or parallel can be calculated. For example, passage of juice (20 BV) containing 35 mg litre−1 limonin through two columns in series would reduce the limonin content to 14 mg litre−1 compared with 19 mg litre−1 following passage through parallel columns. Treatment of fresh, unpasteurised juice reduced limonin contents by only 15% but treatment of freshly pasteurised juice was almost as successful as that of 1‐day‐old pasteurised juice. Since, like freshly extracted juice, freshly pasteurised juice is not bitter, it is suggested that two non‐bitter limonin precursors are involved in bitterness development, only one of which is adsorbed by cellulose acetate.
Some characteristics of the roots of the winged bean [Psophocarpus tetragonolobus (L.) DC]
Authors: Poulter Nigel H. 
Published: October 2006

AbstractThree accessions of winged bean [Psophocarpus tetragonolobus (L.) DC] tuberous roots from Thailand were examined for their crude protein (N × 6.25), non‐protein nitrogen and starch contents. The roots were further analysed for their trypsin inhibitor and urease activities and for the presence of tannins and cyanogenic compounds. Crude protein was found to be high in comparison with other root crops (5.7–6.7% fresh weight) and this contained a high proportion of non‐protein nitrogen (7.4–15.0%). Amino acid content of the crude protein, when compared with mature winged bean seeds, revealed a deficiency in the sulphur‐containing amino acids but an exceptionally high aspartic acid content. Starch was the major carbohydrate present in the flesh of the roots (21.7–32.1% fresh weight). Root samples were found to contain high levels of trypsin inhibitory activity (13.5–30.1 TIU mg−1 fresh weight). No urease activity or cyanide could be detected in any of the root accessions studied.