Multistage and tandem mass spectrometry of glycosylated triterpenoid saponins isolated from Bacopa monnieri: comparison of the information content provided by different techniques

Whereas all state-of-the-art techniques in mass spectrometry (MS) have been extensively applied to oligosaccharides derived from glycoproteins, less effort has been devoted to the analysis of smaller glycoconjugates. In the present study, the application of a variety of MS techniques for the analysis of two dammarane-type triterpenoid saponins isolated from B. monnieri is reported. The structural information provided by ESI-ion trap (IT)-, AP-MALDI-IT-, and MALDI-IT/reflectron time-of-flight (RTOF)-MS, all utilizing low-energy collision-induced dissociation (CID), and MALDI-TOF/RTOF-MS, facilitating postsource decay and high-energy CID analysis, was compared. The applied desorption/ionization technique does not influence the fragmentation of identical precursor ions in low-energy CID. All three fragmentation techniques clearly yield the sequence and branching of the glycan moiety as well as the molecular mass of the intact aglycon. Cross-ring cleavage of the branching sugar, which gives some information about the sugar linkages, was mainly observed in low-energy CID. High-energy CID, on the other hand, yielded some additional diagnostic fragment ions from the aglycon moiety. Internal cleavage ions are formed by alternative mechanisms in high-energy CID and are assumed to be diagnostic for some linkages. However, none of the applied MS techniques facilitates the identification of those saponins that differ only by their aglycon moiety (i.e., jujubogenin or pseudojujubogenin).     

Finite-size Effects on the Thermal Resistivity of 4He Near the Superfluid Transition

We present measurements of the thermal resistivity () near the superfluid transition temperature of ⁴He at saturated vapor pressure and confined in glass capillary arrays with rectangular capillary cross-sections of spacing L = 1 μm, width m, and length mm. We expect the finite-size effect in this rectangular geometry to provide a good approximation to that in the ideal parallel-plate geometry. The data coincide within our resolution with previous measurements for cylindrical capillaries of 1 m radius, indicating that the finite-size scaling-functions for these two geometries are indistinguishable. This stands in contrast to the scaling functions for static properties which, near the transition temperature, depend on the dimensionality of the confinement. The results are consistent with recent Monte Carlo and spin-dynamics simulations, and with renormalization-group calculations for capillaries with square cross section and .     

Carbon nanotube coating improves neuronal recordings

Implanting electrical devices in the nervous system to treat neural diseases is becoming very common. The success of these brain-machine interfaces depends on the electrodes that come into contact with the neural tissue. Here we show that conventional tungsten and stainless steel wire electrodes can be coated with carbon nanotubes using electrochemical techniques under ambient conditions. The carbon nanotube coating enhanced both recording and electrical stimulation of neurons in culture, rats and monkeys by decreasing the electrode impedance and increasing charge transfer. Carbon nanotube-coated electrodes are expected to improve current electrophysiological techniques and to facilitate the development of long-lasting brain-machine interface devices.     

Critical properties of4He in aerogel near the λ-line

We measured the superfluid fraction _s/ and the isobaric thermal expansion coefficient _P of⁴He confined in an aerogel. Data were obtained near the -line along several isobars. Powerlaw fits to the results for _s/ as a function of tT/T_c–1 (T_c is the transition temperature) give a pressure—independent exponent =0.755 when a confluent singular term is included. Fits to the _P data of power laws yield the specific-heat exponents –0.6 and –1.0 above and below T_c respectively. When an analytic background term a×t is included in the fit, the pressure-independent value =–0.59 is permitted, but the amplitude ratio A/A is found to be near zero and the coefficient of the analytic term is large. The measured values for and or are inconsistent with hyperscaling in three dimensions.     

Modelling natamycin release from alginate/chitosan active films

In antimicrobial active films, the active agent is incorporated in the polymeric matrix and is released from the film to the product surface where most deterioration processes take place. In this study, films structured solely by alginate and by blends of alginate:chitosan (82.5:17.5 and 65:35) were obtained by casting. The film formulations received natamycin (4 and 8 g/100 g biopolymer) as antimicrobial agent. Films were characterised according to their thickness and morphology. Diffusion experiments in water indicated very slow release kinetics of the antimicrobial, being markedly hindered in the alginate and chitosan composite films, probably due to electrostatic interactions between chitosan and natamycin. Fickian diffusion prevailed and the diffusion coefficients found for the films varied from 2.6 × 10^?11 to 2.5 × 10^?12 cm² s^?1.     

中国双低菜粕抗营养因子研究注

对中国培养的3个双低油菜粕和加拿大卡诺拉的1个商品粕和相应的实验室脱脂种籽中寡聚糖、日粮纤维、硫苷和植酸等抗营养成分进行了研究。日粮纤维的组成包括碳水化合物成分－非淀粉多糖（包托中性糖和糖醛酸）和非碳水化合物成分（蛋白质、矿物质、木质素和多酚）。结果表明：4个品种双低菜粕中寡聚糖含量为2.0%－2.5%,品种间差异不大。过热加工显著增加了样品中日粮纤维中蛋白质含量,而非淀粉多糖变化不大。4个品种脱脂种籽中硫苷的种类和含量差异均较大;过热加工显著降低了商品加工的粕4－羟基－3－吲哚甲基硫苷的水平,但105℃的热处理时样品中仍存在黑芥子酶活性,表明热处理温度不足。另外,双低菜粕中还存在2.5%-3.0%的植酸,植酸磷含量为0.8%,占总磷含量的75％－80％。     

The Influence of Feeding Yellow-, Green- and Brown-Seeded Peas on Production Performance of Laying Hens

Two experiments were conducted to evaluate the feeding value of yellow-, green- and brown-seeded peas as protein and energy supplements in laying hen diets. In experiment 1, all three types of peas were included in laying hen diets at 0, 200, 400 and 600 g kg^-1 replacing wheat and soya bean meal. Layers fed diets containing peas at 200 g kg^-1 produced more (P⩽0·05) eggs, had higher (P⩽0·05) egg mass output and better (P⩽0·01) feed conversion than those fed the wheat soya bean meal control diet. With 400 g peas kg^-1 in diets, egg production, egg mass and feed conversion were similar (P⩾0·05) to the control diet. Total replacement of soya bean meal with peas (600 g peas kg^-1 in diets) reduced (P⩽0·01) egg production, egg mass and feed conversion. A progressive (P⩽0·01) improvement in yolk colour as the level of peas in the diet increased was observed. Shell quality decreased (P⩽0·05) with increasing levels of yellow or brown peas in the diets, however, it seemed not to be affected by green peas. Daily feed intake, egg weight and mortality rates were not affected by dietary treatments. The influence of feeding diets containing yellow or brown peas supplemented with varied levels of methionine on production performance of laying hens was investigated in experiment 2. The dietary treatments consisted of a 400 g kg^-1 yellow or brown pea diet supplemented with three levels of methionine to 100, 115 and 130% of the NRC requirements. Methionine supplementation to either 15 or 30% above NRC requirement for laying hens had no significant (P⩾0·05) effect on all production parameters. It can be concluded that the inclusion of yellow, green or brown peas into laying hen diets up to 400 g kg^-1 does not affect production performance. The NRC recommendation of methionine requirement for laying hens is adequate to support maximum egg production for diets containing moderate quantities of peas. © 1997 SCI.     

Physicochemical characteristics of bio-based thermoplastic polyurethane/graphene nanocomposite for piezoresistive strain sensor

Herein, we report the physicochemical characteristics and piezoresistive strain sensing performance of flexible thin film comprising graphene and bio-based thermoplastic polyurethane (TPU) prepared by solution cast method. A detailed analysis was carried to study the influence of graphene nanoplatelets on the morphological, thermal, mechanical, and electrical properties of TPU nanocomposite. Upon increasing the graphene nanoplatelets loading, the thermal stability and tensile properties improved remarkably, while glass transition temperature decreased slightly. Owing to better dispersion of graphene, the electrical conductivity was significantly increased, which broaden the utilization of the nanocomposite for various applications. The piezoresistive sensor was able to respond to various stress modes such as tapping, bending, and finger touch. The piezoresistive sensor was sensitive and achieved a gauge factor of 11. Sensor attached to finger, showed distinctive response upon bending at different angles and showed high stability and reproducibility even after >10,000 cycles under repetitive constant load. Also, the nanocomposite was able to detect any breakage or fracture in the form of change in electrical resistance. A combination of bio-based TPU and graphene offered improved physical properties and high sensing performance, which could be a potential material in flexible electronics and structural health monitoring systems.     

Spinal Stroke: Outcome Attenuation by Erythropoietin and Carbamylated Erythropoietin and Its Prediction by Sphingosine-1-Phosphate Serum Levels in Mice

Spinal strokes may be associated with tremendous spinal cord injury. Erythropoietin (EPO) improves the neurological outcome of animals after spinal cord ischemia (SCI) and its effects on ischemia-induced endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are considered possible molecular mechanisms. Furthermore, sphingosin-1-phosphate (S1P) is suggested to correlate with SCI. In this study, the effect of recombinant human EPO (rhEPO) and carbamylated EPO (cEPO-Fc) on the outcome of mice after SCI and a prognostic value of S1P were investigated. SCI was induced in 12-month-old male mice by thoracic aortal cross-clamping after administration of rhEPO, cEPO-Fc, or a control. The locomotory behavior of mice was evaluated by the Basso mouse scale and S1P serum levels were measured by liquid chromatography-tandem mass spectrometry. The spinal cord was examined histologically and the expressions of key UPR proteins (ATF6, PERK, and IRE1a, caspase-12) were analyzed utilizing immunohistochemistry and real-time quantitative polymerase chain reaction. RhEPO and cEPO-Fc significantly improved outcomes after SCI. The expression of caspase-12 significantly increased in the control group within the first 24 h of reperfusion. Animals with better locomotory behavior had significantly higher serum levels of S1P. Our data indicate that rhEPO and cEPO-Fc have protective effects on the clinical outcome and neuronal tissue of mice after SCI and that the ER is involved in the molecular mechanisms. Moreover, serum S1P may predict the severity of impairment after SCI.     

Single- and Multievent Optimization in Combined Sewer Flow and Water Quality Model Calibration

Over the last three decades, storm-water quality modeling has been used increasingly commonly to describe the general system behavior and assess the pollution loads transferred in and spilled out of combined sewer systems. The calibration of quality models is, in most cases, based on conventionally obtained calibration data, e.g., by automated sampling. Long-term high-resolution online measurement data are available for the Graz West catchment (Graz, Austria), allowing an assessment of the full dynamics of discharge and pollution concentrations. This paper focuses on the application and comparison of single-event and two different multievent optimization schemes for sewer-water quality model calibration. While both single- and multievent optimization lead to satisfying results for the calibration events in discharge calibration, it is shown that validation events are better reproduced by using multievent calibration. Single- and multievent autocalibration of pollution concentration is based on the best dataset obtained from the discharge calibration. As for discharge, the pollutographs are reproduced satisfactorily, and multievent calibration is more stable. In all cases, the two multievent approaches performed equally well.