An algorithmic analysis of DNA structure

Bilinearity, complementarity and antiparallelism of the double stranded DNA structure are proved, in a general and abstract setting, as requirements of an efficient duplication algorithm for ‘mobile strings’.     

Interbasin Water Transfers: The Brazilian Experience and International Case Comparisons

This paper critically examines Brazil’s transbasin diversion experiences and two select, large-scale transbasin projects outside of Brazil. Rather than simply compare Brazil’s experiences with international cases, the authors explore the historical context of the projects, focusing on the water resources and environmental regulatory and institutional frameworks in place during the initial proposals and how they influenced the projects’ development and completion rates. Huge investments, the lengthy time span between the date of the initial project proposals and the start of construction, the need to garner public and political support, and more recently, the need to fulfill national and regional environmental laws are major factors underlying heated public debates about the proposed projects. After a broad discussion about the subject, the authors examine a recently approved large-scale Brazilian project, the Sao Francisco river transbasin diversion. This river diversion project is considered crucial to the economic development of Brazil’s semi-arid northeastern region. Despite the fact that this government-funded project was debated for several decades among the various stakeholders, it was approved under Brazil’s newly formed water resources regulatory and environmental framework, which enabled improvements in various key technical aspects of the project, and greater involvement of various key social players.     

Synergistic effects in hydrogen production through water sonophotolysis catalyzed by new La2xGa2yIn2(1−x−y)O3 solid solutions

This work presents experimental data regarding hydrogen production by heterogeneous photocatalysis, sonocatalysis and sonophotocatalysis in water/ethanol solutions. Three new metal oxides solid solutions, LaGa_0.5In_0.5O₃, La_0.8Ga_0.2InO₃ and S-doped La_0.8Ga_0.2InO₃ (S:La_0.8Ga_0.2InO₃), have been synthesized and used as catalysts. Their action has been tested in diluted and concentrated suspensions wherein the content of ethanol, acting as sacrificial reagent, has been fixed to 10% in volume. The largest amounts of hydrogen have, always, been achieved from concentrated suspensions and by using S:La_0.8Ga_0.2InO₃ as catalyst. Ultrasounds, generated by 38 kHz and 50 W piezoelectric transducer, were more effective than light coming from a 35 W Xe lamp. Moreover, the hybrid action of light and ultrasounds determined a remarkable synergistic effect on the hydrogen production. Therefore, sonophotocatalysis is a promising way of generating hydrogen from water/ethanol solutions. In the near future, a net hydrogen production is expected to be achieved by improving the proposed process efficiencies.     

Characterization of a 0.13 μm CMOS Link Chip using Time Resolved Emission (TRE)

The Picosecond Imaging Circuit Analysis (PICA) technique using the Superconducting Single-Photon Detector (SSPD) allows the detailed characterization of pulse width variations along the delay chain of a high speed Self Timing Interface (STI). Pulses gradually shrink and finally disappear along the delay chain.     

Influence of farming methods on microbiological contamination and prevalence of resistance to antimicrobial drugs in isolates from beef

The presence of Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Salmonella spp. was determined in 75 samples of conventional beef and in 75 samples of organic beef. All samples came from cattle slaughtered and processed in the same slaughterhouse and quartering room. A total of 180 E. coli, 180 S. aureus and 98 L. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to 11 antimicrobials, for the case of E. coli and S. aureus, or 9 antimicrobials, for the case of L. monocytogenes. Salmonella spp. were not isolated from any of the beef samples. No significant differences in prevalence were obtained for any of the bacterial species tested between organic and conventional beef. E. coli isolated from organic beef exhibited significant differences in antimicrobial resistance against 5 of the 11 antimicrobials tested as compared to isolates recovered from conventional beef. In the case of S. aureus, these differences were only found for 3 of the 11 antimicrobials tested and for L. monocytogenes, no differences were obtained between isolates obtained from organic or conventional beef. Although no significant differences were obtained in microbiological contamination, E. coli and S. aureus isolates from organically farmed beef samples showed significantly lower rates of antimicrobial resistance in E. coli and S. aureus isolates.     

Salted and fermented fish processes evaluation

Fish curing by salting and fermentation is the result of the action of certain enzymes over fresh fish. This study aimed to evaluate and compare three technological processing methods (A, B, C). Coliforms, Escherichia coli , Enterococcus spp ., coagulase-positive Staphylococcus , Salmonella spp., total volatile base (TVB), pH, water activity (Wa), sodium chloride and biogenic amines were evaluated. A significant difference in histamine production ( P  < 0.05) was observed. Escherichia spp ., Klebsiella spp , Proteus spp ., Shigella spp., Citrobacter spp. and Pseudomonas spp. were isolated . Sodium chloride content varied between 15.65 and 18.87% and no significant difference was observed ( P  > 0.05). Wa and pH showed significant differences ( P  < 0.05), with values between 0.71 and 0.75, and 5.54 and 5.93. TVB values varied between 15.1 and 62.1 mg N 100 g⁻¹, showing significant differences ( P  < 0.05) as well. Worrying levels of histamine were found. Processing method A was found to be the most appropriate for the production of this kind of fish.     

An experimental investigation on the bearing failure load of glass fibre/epoxy laminates

This paper deals with an experimental investigation on the bearing failure load of glass fibre/epoxy (GFRP) laminates. The effects of fibre-to-load inclination angle and laminate stacking sequence on the bearing load capacity have been determined experimentally on two different type of laminates: unidirectional and bi-directional (cross-ply). Significant reductions in bearing failure load when fibre inclination angle increases are highlighted. Bearing design formulas are also proposed based on the results of the experiments.     

Modelling and experimental analysis of the effects of tool wear on form errors in stainless steel blanking

The main defects that characterize the quality and accuracy of blanked parts are the form errors which can be found on the blanked surface. These defects are basically related to tool wear and process parameters. This work presents theoretical modelling of the effects of tool wear on the shearing mechanism and resulting form errors. To this end, a new parameter denominated effective clearance, which characterizes the distance between a punch and the die cutting edge when a tool is worn, is defined. An experimental analysis of form errors as a function of this new parameter is made, using 6 and 8 mm AISI A2 steel punches and 1 mm thick AISI 304 stainless steel sheet. Finally, design criteria are proposed for the process parameters to fulfil the quality requirements of blanked parts.     

Efficacy of n-3 polyunsaturated fatty acids after myocardial infarction: Results of GISSI-prevenzione trial

Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardio (GISSI)-Prevenzione was conceived as a population, pragmatic trial on patients with recent myocardial infarctions conducted in the framework of the Italian public health system. In GISSI-Prevenzione, patients were invited to follow Mediterranean dietary habits, and were treated with up-to-date preventive pharmacological interventions. Long-term n-3 PUFA (1 g daily) but not vitamin E (300 mg daily), was beneficial for death and for combined death, nonfatal myocardial infarction, and stroke. All the benefit, however, was attributable to the decrease in risk for overall, cardiovascular, cardiac, coronary, and sudden death.At variance with the orientation of a scientific scenario largely dominated by the “cholesterol-heart hypothesis”, GISSI-Prevenzione results indicate n-3 PUFA (virtually devoid of any cholesterol-lowering effect) as a relevant pharmacological treatment for secondary prevention after myocardial infarction.As to the relevance and comparability of GISSI-Prevenzione results, up to 5.7 lives could be saved every 1000 patients with previous myocardial infarction treated with n-3 PUFA (1 g daily) per year. Such a result is comparable to that observed in the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) trial, where 5.2 lives could be saved per 1000 hypercholesterolemic, coronary heart disease patients treated with pravastatin for 1 yr.The choice of a relatively low-dose regimen (1-g capsule daily) more acceptable for long-term treatment in a population of patients following Mediterranean dietary habits, and the pattern of effects seen in GISSI-Prevenzione (namely, reduction of overall mortality with no decrease in the rate of nonfatal myocardial infarction) all strongly suggest that n-3 PUFA treatment should be considered a recommended new component of secondary prevention. The importance of this combined/additive effect is further suggested by the analyses of the interplay between diet and n-3 PUFA: There is an interesting direct correlation between size of the effect and “correctness” of background diets. It can be anticipated that a conceptual barrier must be overcome: A “dietary drug” should be added to “dietary advice”, which remains fundamental to allow this statement to become true in clinical practice.     

Evaluation of lignans and free and linked hydroxy‐tyrosol and tyrosol in extra virgin olive oil after hydrolysis processes

We describe chemical hydrolytic procedures to evaluate the total amount of tyrosol and hydroxy‐tyrosol free and/or linked to secoiridoidic molecules (acid hydrolysis). At the same time a rapid determination of the lignans in complex minor polar compound (MPC) extracts is proposed (alkaline hydrolysis). High‐performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/MS were applied as reference methods to evaluate the quantitative results from the hydrolysis experiments. The optimized acid hydrolysis procedures were first applied to an oleuropein standard and then to MPC fractions extracted from several commercial extra virgin olive oils. The results confirm the applicability of the method, consisting in the acid hydrolysis of complex mixtures of secoiridoidic derivatives, to determine the antioxidant potential in terms of MPC. These data can contribute to forecasting the potential ageing resistance of an extra virgin olive oil in terms of antioxidant potency. Finally, alkaline hydrolysis allows confirmation and easy determination of the amount of lignans, especially in those MPC fractions which are particularly complex. Copyright © 2006 Society of Chemical Industry