Time Decay of the Activity of the Reduction Reaction of NO by CO on a Pd/Al2O3 Catalyst

An experimental study is made of the time decay of activity of the CO–NO reaction on a Pd/Al₂O₃ looking at the effect on reaction order and apparent activation energy. The optimum kinetics parameters fitting the steady state data at moderate pressures are determined. The time decay curves are analyzed through various catalyst deactivation models.     

Progressive scoliosis with vertebral rotation after lumbar intervertebral disc herniation in a 10-year-old girl

A case report of a 10-year old girl with a herniated disc is presented. The most significant symptoms were progressive scoliosis with a flat back and paravertebral muscle spasm. An absent H reflex on the left and an increased latency of the somatosensory-evoked potentials of the left posterior tibial nerve were found. The computed tomographic scan of the lumbar spine showed a large central left-sided disc protrusion at the L5-S1 level. Our case presents the youngest patient with documented intervertebral disc herniation and the only one with severe scoliosis and vertebral rotation. The curve was not structural because it improved with surgery and an orthosis was not necessary.     

Current Understanding of the Structure,Stability and Dynamic Properties of Amyloid Fibrils

Amyloid fibrils are supramolecular protein assemblies represented by a cross-β structure and fibrous morphology, whose structural architecture has been previously investigated. While amyloid fibrils are basically a main-chain-dominated structure consisting of a backbone of hydrogen bonds, side-chain interactions also play an important role in determining their detailed structures and physicochemical properties. In amyloid fibrils comprising short peptide segments, a steric zipper where a pair of β-sheets with side chains interdigitate tightly is found as a fundamental motif. In amyloid fibrils comprising longer polypeptides, each polypeptide chain folds into a planar structure composed of several β-strands linked by turns or loops, and the steric zippers are formed locally to stabilize the structure. Multiple segments capable of forming steric zippers are contained within a single protein molecule in many cases, and polymorphism appears as a result of the diverse regions and counterparts of the steric zippers. Furthermore, the β-solenoid structure, where the polypeptide chain folds in a solenoid shape with side chains packed inside, is recognized as another important amyloid motif. While side-chain interactions are primarily achieved by non-polar residues in disease-related amyloid fibrils, the participation of hydrophilic and charged residues is prominent in functional amyloids, which often leads to spatiotemporally controlled fibrillation, high reversibility, and the formation of labile amyloids with kinked backbone topology. Achieving precise control of the side-chain interactions within amyloid structures will open up a new horizon for designing useful amyloid-based nanomaterials.     

Comparative study of lipogenic enzymes in several vertebrates

The liver lipogenic enzymes are compared among rats, chickens, frogs and fish. Although the apparent Km values of glucose-6-phosphate dehydrogenase for glucose-6-phosphate are not much different among all the species, those of malic enzyme for malate are much higher in chickens and fish than in rats and frogs. Glucose-6-phosphate dehydrogenase showed very high activities compared with malic enzyme in fish liver, and malic enzyme showed high activities in chicken liver. Although the apparent Km values of acetyl-CoA carboxylase and fatty acid synthetase for substrates are in the same range among all the animals, the activity of acetyl-CoA carboxylase seems to be extremely low in fish and frog livers, and that of fatty acid synthetase is low in frog livers only. In addition, the apparent Km values of α-glycerophosphate acyltransferase of fish liver are very high, and the enzyme activity appears to be extremely low compared to the others. Therefore, the enzymes at the first steps of both fatty acid and glycerolipid syntheses of poikilothermos animals appear to be very low. On the other hand, the Ouchterlony double-diffusion patterns showed that the lipogenic enzymes of chickens, frogs and fish are immunologically different from those of rats, with the exception of acetyl-CoA carboxylase in chickens. Therefore, it is suggested that the fatty acid and glycerolipid forming systems of poikilothermos animals are quite different from those of homoiothermos and the lipogenesis is very low in poikilothermos.     

Modelling Industrial Wastewater Ozonation In Bubble Contactors. 1. Rate Coefficient Determination

A study of the ozonation of distillery and tomato wastewaters was carried out in a small bubble contactor in order to obtain kinetic data for scaling-up. Thus, several parameters, such as chemical oxygen demand (COD), 254 nm absorbance (A₂₅₄) and organic carbon content (OC), were followed during ozonation at different experimental conditions.

For distillery wastewaters all parameters investigated have the highest decreases during the first minutes of ozonation, A₂₅₄ showing the highest disappearance rates. Thus, during the first fifteen minutes of ozonation an important decrease of the 254 nm absorbance (? 75%) was observed. At further reaction times values of all parameters studied decrease slowly, eventually reaching a plateau value. During approximately the first two hours of reaction, dissolved ozone was never found, which suggested that fast or moderate gas-liquid reactions took place in the wastewaters.     

Stability analysis of networked control systems subject to packet-dropouts and finite-level quantization

This paper is concerned with the stability analysis of a networked control system, wherein communication from the controller to the plant input is through a digital channel subject to packet-dropouts and finite-level quantization. No acknowledgments of receipt are available to the controller. To alleviate the effect of packet-dropouts, the controller transmits tentative plant input sequences. Within this setup, we derive a sufficient condition for small ?^∞ signal ?^∞ stability of the networked control system. This condition requires the maximum number of consecutive packet-dropouts to be bounded. We also elucidate the trade-off which exists between the disturbance attenuation and the step size of the quantizer and the maximum number of consecutive packet-dropouts.     

Determination of γ-glutamyl-valyl-glycine in raw scallop and processed scallop products using high pressure liquid chromatography–tandem mass spectrometry

The determination of the kokumi peptide, γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly) in raw scallop and processed scallop products was carried out using high pressure liquid chromatography–tandem mass spectrometry (LC/MS/MS). The detection of γ-Glu-Val-Gly was achieved using a multiple reaction monitoring (MRM) method. The optimised condition enabled the precise determination of γ-Glu-Val-Gly. Raw scallop contained 0.08 μg/g γ-Glu-Val-Gly, and the γ-Glu-Val-Gly levels in processed scallop products, such as dried-scallop and scallop extract, were measured to be 0.64 and 0.77 μg/g, respectively. This is the first report to confirm the existence of γ-Glu-Val-Gly in foodstuff.     

Optimizing location and size of rural schools in Chile

The Chilean Ministry of Education oversees preschool, primary, and secondary education in both urban and rural areas. Many parts of Chile are sparsely populated and there are currently over 4,000 rural schools (almost 38% of all schools in Chile) educating 9.5% of the students in the country. Many of the rural schools are small with only one teacher responsible for instruction of all local students (multigrade schools). The geographical distribution of the rural schools has not been coordinated and this has resulted in unequal utilization of existing schools and some unreasonably long travel distances by students. Good management of the rural schools is fundamental to meeting Chile's goal of providing quality education to its citizens. Seeking to improve the situation, the Ministry of Education ordered a study of the optimal location and size of rural schools with the general goals of reducing the number of lesser quality multigrade schools and reducing student travel distances while maintaining reasonable costs. This paper presents results of this study obtained using an integer linear program that has been embedded in a geographical information system. We present computational results for the entire country. Recommendations include where to open new rural schools as well as where to expand, reduce, close, or leave unchanged existing schools. We show how recommendations are sensitive to key parameters such as the cost of transportation.     

Substitution bias and the construction of a spatial cost of living index*

We estimate the spatial substitution bias based on the difference between a price index (PI) and the true cost of living (COL). This bias is computed at three geographical scales, using several fixed baskets and across different expenditures quartiles. Our results show a significant substitution bias for small geographical units. The choice of the base basket is also relevant for the bias estimation. Finally, the spatial substitution bias is larger for upper side of the expenditure distribution due to the heterogeneity in the consumption basket. This exercise shows that the spatial dimension affects the construction of a price index and that the approach of fixed baskets should be carefully considered in the estimation of spatial price differentials.