Reactions of the goldfish (Carassius auratus auratus L.) to quantified mechanical and thermal stimuli

Goldfish can differentiate between mechanical and thermal stimuli components in combined stimulations. Reactions to heated thermode (deltaT = + 3 degrees C) differ from those to isotherm thermode by up to 30%. Additional pretension (0.5 p) increases the reaction more than double; at simultaneously varied temperature (deltaT = + 3 degrees C and + 5 degrees C), there is a further increase in reaction of 25% and 35%. The significance for the organism of the two stimuli components is discussed.     

Computational experiences with discrete Lp-Approximation

DiscreteL _p -approximation, especially for 1≤p≤2 is useful for practical purposes. We describe the experience with an algorithm for its numerical computation.     

Protein extraction from activated sludge: an analytical approach

To investigate the efficiency of different methods on exopolymeric substance (EPS) extraction, mechanical and chemical treatments were applied on two activated sludges, regarding the yield of protein extraction as well as their compatibility with usual quantification methods. Mechanical disruption methods do not drastically affect protein measurements by both bicinchoninic acid (BCA) and modified Lowry methods. Chemical compounds such as cationic exchange resin and triton show high interference with modified Lowry method while the protein quantification by BCA method is not affected. In addition, inner sludge compounds were shown to interfere with both methods: BCA and modified Lowry measurement respectively overestimate and underestimate protein content. According to these data, BCA method was chosen in this study as the most appropriate protein quantification method in sludge extracts. Comparison of various extraction protocols, combining mechanical and/or chemical treatments, shows that efficiency can be increased by repeating the same method or by applying a prior mechanical treatment. Proteins are preferably extracted by triton treatments, indicating the importance of hydrophobic interactions linking proteins to the EPS matrix. The amount of extracted proteins reaches 182 and 148 mg eq.BSA g(-1)VSS using triton/triton and ultraturax/triton extractions, respectively. Protease activity/extracted protein ratios vary widely depending on extraction protocols. Protease seemed to be preferably extracted by ultrasound and triton treatments (150-220 U mg(-1)protein). This study underlines that the choice of a relevant coupled quantification/extraction method is of great importance for efficient EPS determination.     

Biologically induced phosphorus precipitation in aerobic granular sludge process

Aerobic granular sludge is a promising process for nutrient removal in wastewater treatment. In this work, for the first time, biologically induced precipitation of phosphorus as hydroxyl-apatite (Ca₅(PO₄)₃(OH)) in the core of granules is demonstrated by direct spectral and optical analysis: Raman spectroscopy, Energy dispersive X-ray (EDX) coupled with Scanning Electron Microscopy (SEM), and X-ray diffraction analysis are performed simultaneously on aerobic granules cultivated in a batch airlift reactor for 500 days. Results reveal the presence of mineral clusters in the core of granules, concentrating all the calcium and considerable amounts of phosphorus. Hydroxyapatite appears as the major mineral, whereas other minor minerals could be transiently produced but not appreciably accumulated. Biologically induced precipitation was responsible for 45% of the overall P removal in the operating conditions tested, with pH varying from 7.8 to 8.8. Major factors influencing this phenomenon (pH, anaerobic phosphate release, nitrification denitrification) need to be investigated as it is an interesting way to immobilize phosphorus in a stable and valuable product.     

Exploring the Potential of Norbornene‐Modified Mannosamine Derivatives for Metabolic Glycoengineering

Metabolic glycoengineering (MGE) allows the introduction of unnaturally modified carbohydrates into cellular glycans and their visualization through bioorthogonal ligation. Alkenes, for example, have been used as reporters that can react through inverse‐electron‐demand Diels–Alder cycloaddition with tetrazines. Earlier, norbornenes were shown to be suitable dienophiles; however, they had not previously been applied for MGE. We synthesized two norbornene‐modified mannosamine derivatives that differ in the stereochemistry at the norbornene (exo/endo linkage). Kinetic investigations revealed that the exo derivative reacts more than twice as rapidly as the endo derivative. Through derivatization with 1,2‐diamino‐4,5‐methylenedioxybenzene (DMB) we confirmed that both derivatives are accepted by cells and incorporated after conversion to a sialic acid. In further MGE experiments the incorporated sugars were ligated to a fluorophore and visualized through confocal fluorescence microscopy and flow cytometry.     

Effect of ion-irradiation on the microstructure and microhardness of the W-2Y2O3 composite materials fabricated by sintering and hot forging

A W-2Y₂O₃ material was developed in collaboration with the Plansee Company (Austria). An ingot of the material having approximate dimension of 95 mm × 20 mm was fabricated by mixing the elemental powders followed by pressing, sintering and hot forging. The microstructure of the W-2Y₂O₃ composite was investigated using transmission electron microscopy (TEM). The microhardness was studied using nano-indentation technique. We observed that the W-grains having a mean size of about 1 μm already formed and these grains contain very low density of dislocations. The size of the yttria particles was between 300 nm and 1 μm and the Berkovich hardness was about 4.8 GPa. The specimens were irradiated/implanted with Fe and He ions at JANNuS facility located at Orsay/Saclay, France. The TEM disks kept were irradiated/implanted at 300 and 700 °C using Fe and He ions with an energy of 24 and 2 MeV, respectively. The calculated radiation dose was about 5 dpa produced by Fe ions and total He content is 75 appm at both 300 and 700 °C. From the TEM investigation of irradiated samples, few radiation loops are present on the W grains, whereas on yttria particles, the radiation induced damages appear as voids. Berkovich hardness of the irradiated sample is higher than that of the non-irradiated sample. Results on the microstructure and microhardness of the ion-irradiated W-2Y₂O₃ composites are presented in detail.     

A detailed experimental study of the effects of pre-bond contamination with a hydraulic fluid,thermal degradation,and poor curing on fracture toughness of composite-bonded joints

Adhesive bonding is applied by the aircraft industry both for assembling composite structural parts and implementing composite patch repairs in damaged structural parts. In both applications, there exist several scenarios, related to surface contamination and processing, that could affect bonding quality and thus, degrade bond strength. In this paper, the detailed effects of pre-bond contamination with a hydraulic fluid, thermal degradation of the composite substrate, as well as poor curing (lower curing temperature) on strength of composite-bonded joints were studied experimentally by conducting mode I fracture toughness tests on double-cantilever beam specimens. These three application scenarios are possible to appear in the implementation of a composite patch repair in a damaged composite structural part. The experimental results showed a contradictory effect as the presence of the hydraulic fluid and poor curing degrades the fracture toughness whereas thermal degradation enhances fracture toughness of the composite-bonded joints. These findings are explained by means of extended non-destructive inspection, surface analysis, and evaluation of fracture surfaces.     

1H NMR study of temperature-induced phase transitions in aqueous solutions of poly(N-isopropylmethacrylamide)/poly(N-vinylcaprolactam) mixtures

¹H NMR spectroscopy was used to investigate the temperature-induced phase transitions in aqueous solutions of poly(N-isopropylmethacrylamide)/poly(N-vinylcaprolactam) (PIPMAm/PVCL) mixtures to find out if the phase transition of the given component (PIPMAm or PVCL) is affected by the presence of the second component. Our results that PVCL and PIPMAm transitions are in polymer mixtures shifted by ~2 K towards higher temperatures in comparison with neat polymers and depend on polymer concentration show that such effect exists. Spin–spin relaxation times of water (HDO) indicate that in solutions with c ≥ 1 wt% a portion of water is predominantly bound in PVCL mesoglobules even at temperatures above the LCST transition of PIPMAm component. Water is with time released from these mesoglobules without any induction period so indicating that it is mostly indirectly bound water. We assume that there is a direct connection between character of the bound water and the transition temperatures.     

Phenolics from Winemaking By‐Products Better Decrease VLDL‐Cholesterol and Triacylglycerol Levels than Those of Red Wine in Wistar Rats

Winemaking by‐products account for more than 30% of the grape production, but this inexpensive feedstock has not yet been fully exploited. Accordingly, we evaluated the potential biological activity of winemaking by‐products produced with Syrah grapes in comparison with those of the wine produced using the same grape cultivar. Winemaking by‐products showed higher contents of total anthocyanins, flavonols, stilbenes, and flavanols than red wine as evaluated by HPLC‐DAD‐FD (on a dry weight basis). In contrast, red wine was a better source of phenolic acids. However, the contribution of phenolic acids was minor for both samples. Furthermore, equivalent concentration of winemaking by‐products (100 mg/kg/d) showed greater biological activity by than that of red wine by decreasing the levels of VLDL‐cholesterol and triacylglycerols in Wistar rats. Therefore, this study supports the use of winemaking by‐products as an economical source of bioactive phenolics with potential use in the food and nutraceutical industries.