Lipid components and enzymatic hydrolysis of lipids in muscle of Chinese freshwater fish

The lipid and fatty acid composition of muscle of 10 species of freshwater fish obtained from a market of Shanghai City was examined. Total lipids (TL) ranged over 0.9–4.7% of muscle for all samples. The content of triacylglycerol (TG) in muscle ranged over 0.2–3.4% and that of polar lipids (PL) was 0.5–1.3%. Differences of TL content were dependent on TG contents. The predominant important fatty acids (>10% of the total fatty acids in TL) were 16∶0 and 18∶1n−9 with some 16∶1n−7, 18∶2n−6, and 22∶6n−3. The polyunsaturated fatty acids (PUFA) content was 10.2–43.4%, and especially Chinese sea bass contained above 20% of 22∶6n−3 in the total fatty acids. There were higher levels of PUFA such as 20∶5n−3 and 22∶6n−3 in PL than in neutral lipids. Muscle of the silver carp was stored at 20°C, and changes of lipid classes during storage were examined. Free fatty acids increased, and PL decreased during storage. This phenomenon was inhibited by heating the muscle, suggesting that lipid hydrolysis by phospholipase occurred in silver carp muscle.     

Oxidation of Methyl Linoleate in Oil-in-Water Micro- and Nanoemulsion Systems

Oxidation of methyl linoleate in O/W emulsions having droplets of median diameters ranging from 17 nm to 8.0 μm was carried out at 40°C. The oxidation process was analyzed on the basis of a kinetic equation of the autocatalytic type. The induction period was found to be shorter and the oxidation rate constant lower for emulsions with smaller oil droplets. The stoichiometry between methyl linoleate and oxygen was observed to be independent of both the size of oil droplet and the type of the surfactant and was found to be unity during the early stage of the oxidation. However, more oxgen was consumed in the oxidation of the methyl linoleate in the later half of the oxidation process.     

Microstructural and chemical stability of Y-ZrO2 reinforced β″-alumina in molten sodium sulfide and sulfur

The stability of -alumina reinforced with 10 vol% of tetragonal partially stabilized 3 mol% Y₂O₃-ZrO₂ (3Y-ZrO₂) and with 10 vol% of cubic 8 mol% Y₂O₃-ZrO₂ (8Y-ZrO₂) in molten sulfur or molten Na₂S₄ has been examined using scanning electron microscopy (SEM) X-ray diffraction (XRD) and electron probe microanalysis (EPMA) both before and after immersion at 350 °C. Tetragonal partially stabilized 3 mol % Y₂O₃-ZrO₂ was destabilized when reinforced into -alumina and immersed in molten Na₂S₄. Destabilization without incorporation into -alumina or using molten S as the immersion medium was minor. EPMA analyses indicated that the presence of -alumina enhanced zirconia destabilization in that -alumina can react with the molten corrodants to form corrosion products which are known corrosion agents for the leaching of Y₂O₃ from partially stabilized 3Y-ZrO₂. From XRD analyses, changing from partially stabilized 3Y-ZrO₂ to cubic 8Y-ZrO₂ in the composite increased resistance against phase destabilization. EPMA analyses revealed that the depletion was almost halted for cubic 8Y-ZrO₂ suggesting that the change in the zirconia phase used had reduced the chemical reactivity between Y₂O₃ and the corrodants. In order to avoid depletion destabilization of zirconia in -alumina, corrosion resistance can be increased by reducing chemical reactivity by using fully stabilizing zirconia. In addition, partially stabilized tetragonal zirconia may still be considered for use if a less reactive stabilizer such as CeO₂ is used.     

A histological study on tissue responses to titanium implantation in rat maxilla: the process of epithelial regeneration and bone reaction

The present study aimed to establish a titanium implantation model using rat maxillae as well as demonstrate the chronological tissue responses to implantation. Pure titanium implants were inserted in the upper first molar extraction sites of Wistar rats 1 month after tooth extraction. The animals were sacrificed at 1 to 30 days postimplantation, and prepared tissue specimens were processed for light microscopy. The removal of implants from tissue blocks was done using 2 methods: mechanical removal or a cryofracture technique. In the early stages, peri-implant tissues showed severe damage to the oral epithelium and collagen bundles with significant inflammatory cell infiltration. The peri-implant epithelium grew apically along the implant by 10 days postimplantation, and regenerated to show a similar feature of junctional epithelium seen in normal rats at 15 days postimplantation, at which time no signs of inflammation were observed. The regenerated collagen bundles in the connective tissue were arranged circumferentially to the implants in the horizontal sections. New bone formation first appeared around the implants at 5 days postimplantation, covering the entire perimeter of implants by 30 days postimplantation. Scanning electron microscopic observations of the surface texture of the removed implants suggest the probability of an adhesive mechanism between the implants and the peri-implant epithelium and/or the alveolar bone. These findings indicate that this experimental model is useful for detailed analysis of peri-implant tissue because of its easy implantation procedure.     

The effect of mannitol upon cochlear dysfunction induced by transient local anoxia

Transient local anoxia of the cochlea was induced by pressing the labyrinthine artery, and compound action potential (CAP) or endocochlear potential (EP) was measured before and after transient local anoxia ranging from 5 to 60 min using 106 albino guinea pigs. The complete interruption of the cochlear blood flow by this procedure and its full restoration after releasing the pressure on the artery was confirmed by a laser-Doppler flowmeter. The anoxia of less than 10 min induced no post-anoxic cochlear dysfunction, whereas the anoxia of a longer duration induced an irreversible dysfunction of the cochlea. It was evident that the post-anoxic recovery of the CAP threshold was worse as the anoxia period was prolonged, and CAP was almost completely abolished after 60-min anoxia. In animals which were administered mannitol intravenously just after the restoration of the cochlear blood circulation, the recovery of the CAP threshold was significantly better than that in the control animals, when the animals were subjected to local anoxia of 15- to 30-min duration. No beneficial effect, however, was observed in the 60-min anoxia group. In conclusion, local anoxia of 10 min or longer caused cochlear dysfunction, which was partially but significantly alleviated by mannitol.     

Process Simulation and Economic Feasibility Analysis for a Hydrogen‐Based Novel Suspension Ironmaking Technology

A novel gas‐solid suspension ironmaking process is under development at the University of Utah, which would greatly reduce energy consumption and carbon dioxide emission compared with current blast furnace technology. The proposed process is based on the flash reduction of iron ore concentrate using a gaseous reagent, such as hydrogen, syngas, natural gas or a combination of thereof. A process flow sheet of the proposed ironmaking process using purchased hydrogen was constructed and then simulations were performed at several potential operating conditions. Ironmaking was simulated using two different process configurations. The simulation results show that the required fresh hydrogen would increase with higher excess driving force and operating temperature, but not greatly when hydrogen is preheated. Compared with the average blast furnace process, the proposed process would reduce energy consumption by 57 ‐ 60%, using the higher heating value of hydrogen (71 – 73%, if the lower heating value is used), when hydrogen and coal are considered as the starting materials in the respective processes. The economic feasibility analysis using net present value (NPV) indicates that the proposed process could be economically feasible at elevated hot metal prices and/or if reduction in carbon dioxide emissions has a significant value in a cap and trade scenario.     

Elimination Transformations for Associative–Commutative Rewriting Systems

To simplify the task of proving termination and AC-termination of term rewriting systems, elimination transformations have been vigorously studied since the 1990s. Dummy elimination, distribution elimination, general dummy elimination, and improved general dummy elimination are examples of elimination transformations. In this paper we clarify the essence of elimination transformations based on the notion of dependency pairs. We first present a theorem that gives a general and essential property for elimination transformations, making them sound with AC-termination. Based on the theorem, we design an elimination transformation called the argument filtering transformation. Next, we clarify the relation among various elimination transformations by comparing them with a corresponding restricted argument filtering transformation. Finally, we compare the AC-dependency pair method with the argument filtering transformation. Parts of this work were done while K. Kusakari was completing his Ph.D. thesis, “Termination, AC-Termination and Dependence Pairs of Term Rewriting Systems,” at Japan Advanced Institute of Science and Technology, School of Information Science (March, 2000). A preliminary version of parts of this article appeared in K. Kusakari, M. Nakamura, Y. Toyama, Argument filtering transformation, Proc. of Int. Conf. on Principles and Practice of Declarative Programming, LNCS 1702 (Springer-Verlag, 1999) pp.47–61.     

Support planning and controlling of early quality assurance by combining expert judgment and defect data—a case study

Planning quality assurance (QA) activities in a systematic way and controlling their execution are challenging tasks for companies that develop software or software-intensive systems. Both require estimation capabilities regarding the effectiveness of the applied QA techniques and the defect content of the checked artifacts. Existing approaches for these purposes need extensive measurement data from historical projects. Due to the fact that many companies do not collect enough data for applying these approaches (especially for the early project lifecycle), they typically base their QA planning and controlling solely on expert opinion. This article presents a hybrid method combining commonly available measurement data and context-specific expert knowledge. To evaluate the method’s applicability and usefulness, we conducted a case study in the context of independent verification and validation activities for critical software in the space domain. A hybrid defect content and effectiveness model was developed for the software requirements analysis phase and evaluated with available legacy data. One major result is that the hybrid model provides improved estimation accuracy when compared to applicable models based solely on data. The mean magnitude of relative error (MMRE) determined by cross-validation is 29.6% compared to 76.5% obtained by the most accurate data-based model.     

Effect of asphyxia on the composition of cationic elements in the perilymph

To elucidate the role of free radicals in the cochlea, cationic elements in the perilymph of the scala tympani in normal and asphyxic guinea pigs were measured by an inductively coupled plasma atomic emission spectrometer. The concentrations of 7 cationic elements (i.e., calcium, copper, iron, magnesium, phosphorus, lead and zinc) were measured simultaneously in a sample of the perilymph taken before, during and after asphyxia. There was no significant change in these cationic elements during asphyxia for 3 min. In contrast to the stationary level during asphyxia, the iron concentration was significantly elevated at 5 min after re-ventilation following asphyxia and decreased rapidly toward the pre-asphyxic level thereafter, although no significant change was observed in other cationic elements. These results were comparable to the theory of non-protein-bound iron accumulation produced by an O2-dependent mechanism during re-perfusion.