A generalist herbivore in a specialist mode Metabolic,sequestrative, and defensive consequences

Adults of a generalist herbivore, the lubber grasshopper,Romalea guttata, can be converted to functional specialists by feeding them exclusively on catnip,Nepeta cataria. No obvious adverse effects on adult development resulted from this enforced monophagy. Notwithstanding the fact thatR. guttata has had no coevolutionary relationship with this Eurasian mint, it readily sequesters compounds that are identical to or derived from the terpenoid lactones that are characteristic ofN. cataria. R. guttata appears to both biomagnify minor allelochemicals and to sequester metabolites of theNepeta terpenes in its paired defensive glands. The levels of autogenously produced phenolics are not affected by feeding onN. cataria and the defensive secretions of catnip-fed grasshoppers are more repellent to ants than those of wild-fed acridids. Metabolites of theN. cataria monoterpenes are sequestered in the defensive glands when catnip is added to the natural diet ofR. guttata. The ability of a generalist,R. guttata, to facilely bioaccumulate a potpourri of foreign allelochemicals when feeding in a specialist mode is analyzed in terms of its biochemical, physiological, and functional significance. Sequestration is examined as a response to the enteric effronteries represented by the phytochemicals that can be characteristic of the overload in a monophagous diet.     

化学分离法分析大型纸浆发电厂废渣中生物质底灰和飞灰成分(英文)

采用三步分离法,其中第一步用水,第二步用乙酸铵,第三步用盐酸,提取纸浆发电厂生物质飞灰和底灰的组分,以评估这些残渣的浸出行为。除了Mo、S、Na以及那些浓度低于检测范围的元素外,在这两种灰份中,对于其他元素这三种浸出剂的浸出能力从弱到强的顺序为:水、乙酸铵和盐酸。采用三步分离法处理的废渣中元素浓度比前期用BCR连续提取法得到的低。     

Chemical composition of shell and flesh of three prawn samples from Lagos lagoon

The protein, ash, fibre and individual mineral ion contents of three species of prawn taken from the Lagos lagoon were determined. The median liveweights of Macrobrachium vollenhovenii (Herklots), Palaemon species A (Powell) and Penaeus notialis were respectively, 25.52 g (shell + head 16.76 g; flesh 9.26 g), 3.15 g (shell + head 1.71 g; flesh 1.44 g) and 5.11 g (shell + head 2.14 g; flesh 2.96 g). All (shell + head) samples had high protein, ash and fibre contents but only the protein content was high in the flesh, which had low or undetectable quantities of fibre. The fat and carbohydrates contents were generally low. In M vollenhovenii the (shell + head) was a better source of Mg, Zn, Cu and K than the flesh, which was a better source of Ca, Ni, P, Fe, Co and Na. In P species A the (shell + head) was a better source of Ca, Mg, P, Cu, Co, Na and K than the flesh (higher in Zn and Ni). In P notialis the (shell + head) was the better source of Ca, Zn, P, Fe and Co and the flesh the better source of Mg, Ni, Fe, Na and K. Copyright © 2004 Society of Chemical Industry     

Magnetic Normal Modes in Squared Antidot Array With Circular Holes: A Combined Brillouin Light Scattering and Broadband Ferromagnetic Resonance Study

We present a combined experimental investigation of magnetic normal modes in an antidot lattice using both Brillouin light scattering and broadband ferromagnetic resonance. It was fabricated on a silicon substrate using optical ultraviolet lithography. The sample consisted of a 30-nm-thick ${rm Ni}_{80}{rm Fe}_{20}$ squared antidot array with circular holes whose diameter and edge-to-edge spacing are 250 and 150 nm, respectively. Experiments were performed as a function of the applied magnetic field $mu_{0}{rm H}_{rm ext}$ in the range from $-$100 to 100 mT, with ${rm H}_{rm ext}$ applied along both the square lattice axis and its diagonal. Several peaks were observed in both the Brillouin light scattering and ferromagnetic resonance spectra, and their evolution with the intensity and the direction of the applied field ${rm H}_{rm ext}$ was measured. Micromagnetic simulations enabled us to identify the modes in terms of their symmetry obtaining a good quantitative agreement with the measured frequencies. In addition, we show how the inhomogeneity of the internal field affected the properties of the magnetic eigenmodes and their localization in different regions of the antidot lattice.      

Phononic and magnonic dispersions of surface waves on a permalloy/BARC nanostructured array

Phononic and magnonic dispersions of a linear array of periodic alternating Ni₈₀Fe₂₀ and bottom anti-reflective coating nanostripes on a Si substrate have been measured using Brillouin light scattering. The observed phononic gaps are considerably larger than those of laterally patterned multi-component crystals previously reported, mainly a consequence of the high elastic and density contrasts between the stripe materials. Additionally, the phonon hybridization bandgap has an unusual origin in the hybridization and avoided crossing of the zone-folded Rayleigh and pseudo-Sezawa waves. The magnonic band structure features near-dispersionless branches, with unusual vortex-like dynamic magnetization profiles, some of which lie below the highly-dispersive fundamental mode branch. Finite element calculations of the phononic and magnonic dispersions of the magphonic crystal accord well with experimental data.     

Effect of farm and industrial processing on the amino acid profile of cocoa beans

An investigation into the amino acid profiles of unfermented and fermented cocoa nibs, as well as process-line cocoa nibs (P-LCN) and processed cocoa cake samples (PCCS) was carried out. In the unfermented cocoa nibs, Glu (128 mg/g crude protein i.e. 128 mg/gcp) was the most abundant amino acid whilst the most concentrated essential amino acid in the same sample was Leu (72.2 mg/g crude protein); in the fermented cocoa nibs, a similar trend was observed, with respective values of Glu (153 mg/gcp) and Leu (62.4 mg/gcp). Lys (181 mg/gcp) was most abundant amino acid in P-LCN and Ile (63.3 mg/gcp) was the second most abundant; also, in PCCS, Lys (52.7 mg/gcp) was the most abundant amino acid but Asp (43.7 mg/gcp) was the second most abundant. The total amino acid content was (mg/gcp), 641 (unfermented nibs), 708 (fermented nibs), 635 (P-LCN) and 368 (PCCS), with corresponding essential amino acids of 300, 287, 478 and 185 (all with His), respectively. Based on whole hen’s egg, the limiting amino acids for the samples were: Ser (unfermented nibs), Met (fermented nibs), Ala (P-LCN) and Val (PCCS), whereas under provisional amino acid scoring pattern, they were: Met + Cys (unfermented nibs), Met + Cys (fermented nibs), Thr (P-LCN) and Val (PCCS). Prolonged and high heat treatments appeared to have reduced the essential amino acids of the PCCS as compared to the P-LCN. Significant differences existed between contents of essential amino acids and non-essential amino acids at p < 0.05 in unfermented cocoa nibs, fermented cocoa nibs and P-LCN.     

Nanostructured magnonic crystal with magnetic-field tunable bandgap

Most experimental investigations into magnonic bandgaps are based on structures composed of single-constituent magnetic materials. Here we report Brillouin and numerical studies of the spin dynamics of a bi-component magnonic crystal, viz. a one-dimensional periodic array of alternating permalloy and cobalt 150 nm-wide nanostripes. Our measurements, together with those for a similar crystal composed of 250 nm-wide nanostripes, suggest that for a stripe width ratio of 1:1, the bandgap width of such magnonic arrays increases with crystal lattice constant. The bandgap parameters are strongly dependent on external magnetic field. This magnetic-field tunability of the bandgap is expected to be a crucial property of devices based on magnonic crystals. The agreement between numerical calculations, based on finite element analysis, and the experimental data is generally good.     

In vitro multienzyme digestibility of protein of six varieties of African yam bean flours

The in vitro multienzyme protein digestibilities of the flours of six varieties of African yam bean (Sphenostylis stenocarpa), made from both whole seeds and dehulled seeds were investigated. The multienzyme system consisted of trypsin, chymotrypsin and peptidase. Digestibilities were determined for a 10 min digestion period. Both dehulling and heat treatment improved digestibility. Comparison of flours from raw whole seeds with those from dehulled seeds showed that digestibility was better in the latter, with an increase of 6.78%. Heat-treated whole seed flcurs gave a digestibility increase of 6.06% compared with raw flours whereas in the dehulled samples the digestibility increase of heat-treated flours over raw was 5.19%. Heat-treated dehulled seeds were better, with a digestibility increase of 5.90% over the heat-treated whole seed flours. No significant differences (P < 0.05) were observed in the digestibilities among the whole seed flours but significant differences were observed in the dehulled seed flours.     

Effect of non-ionic surfactant concentration and type on the formation and stability of W/O/W multiple emulsions: Microscopic and conductometric evaluations

W/O/W multiple emulsions with sodium salicylate as a model drug were prepared and evaluated for the effect of surfactant concentration and type on stability using microscopic and conductometric methods. Primary (W/O) emulsions were prepared with lipophilic surfactants (2-31% W/W relative to the oily phase). W/O/W emulsions were formed by mixing the primary emulsions with solutions containing 0.5 to 2% W/V hydrophilic surfactants. Optimum concentration of the lipophilic surfactant was 26% W/W. The optimum hydrophilic surfactant concentration was 1% W/V. Best stability was achieved with HLB 3.7 lipophilic and HLB 15.6 hydrophilic surfactants.     

Magnetoresistance behavior of ferromagnetic nanorings in a ring-wire hybrid configuration

We present a technique for probing the magnetic configurations in ferromagnetic rings electrically without placing the electrical contact leads directly on the nanorings, but on wires attached to the ring structures. The magnetic configurations in pseudo spin valve rectangular and elliptical rings of width in the range from 60 to 300?nm have been systematically mapped using this technique. The giant magnetoresistance (GMR) responses for both the rings exhibit distinct switching fields and features corresponding to identifiable magnetization states in different segments of the nanostructures.