Towards the detection of human papillomavirus infection by a reagentless electrochemical peptide biosensor

In the present work, we report first results about a technology using a conjugated copolymer poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-2-carboxyethyl-1,4-naphthoquinone) acting both as immobilizing and transducing element for reagentless immunosensor, and its application for the detection of HPV infection. It was shown that the reagentless immunosensor was able to detect the interaction between antigenic peptide L1 from HPV-16 major capsid protein, a dominant epitope involved in viral infection as well as in prophylactic vaccine, and the relevant antibody.     

Validation of a UV Spectrophotometric Method for Determination of Proteolytic Activity of Enzymatic Detergents

Enzymatic detergents are widely used in health services. These products should be controlled to ensure their activity. In this paper, a UV spectrophotometric method for the determination of proteolytic activity in enzymatic detergents was validated. An artificial substrate (azocasein) was used to quantify the enzyme activity at 340 nm. The results showed that the method was satisfactory in respect to its specificity, linearity, precision, accuracy and robustness. This method fulfills both ICH’s and Brazilian criteria, demonstrating its suitability for routine analysis as well as its potential application for regulatory purposes.     

In Vitro Simultaneous Transfer of Lipids to HDL in Coronary Artery Disease and in Statin Treatment

The exchange of lipids with cells and other lipoproteins is a crucial process in HDL metabolism and for HDL antiatherogenic function. Here, we tested a practical method to quantify the simultaneous transfer to HDL of phospholipids, free-cholesterol, esterified cholesterol and triacylglycerols and to verify the lipid transfer in patients with coronary artery disease (CAD) or undergoing statin treatment. Twenty-eight control subjects without CAD, 27 with CAD and 25 CAD patients under simvastatin treatment were studied. Plasma samples were incubated with a donor nanoemulsion prepared by ultrasonication of the constituent lipids and labeled with radioactive lipids; % lipids transferred to HDL were quantified in the HDL-containing supernatant after chemical precipitation of non-HDL fractions and the nanoemulsion. The assay was precise and reproducible. Increase of temperature (4–37 °C), of incubation period (5 min to 2 h), of HDL-cholesterol concentration (33–244 mg/dL) and of mass of nanoemulsion lipids (0.075–0.3 mg/μL) resulted in increased lipid transfer from the nanoemulsion to HDL. In contrast, increasing pH (6.5–8.5) and albumin concentration (3.5–7.0 g/dL) did not affect lipid transfer. There was no difference between CAD and control non-CAD with regard to the lipid transfer, but statin treatment reduced the transfer to HDL of all four lipids. The test herein described is a valid and practical tool for exploring an important aspect of HDL metabolism.     

A novel method to dope diamond — Ion Beam Nuclear Transmutation Doping (IBNTD)

Using MeV-range protons to transmute a small fraction of host nuclei into n- or p-type dopants, we have demonstrated a novel method to dope challenging wide bandgap semiconductors. In particular, we have doped isotopically-enriched ¹³C diamond and AlGaN films using this method focusing on the ¹³C + ¹H → ¹⁴N + γ, radiative proton capture resonance at 1.75 MeV and ²⁷Al + ¹H → ²⁸Si + γ proton capture resonance at 0.997 MeV. Both samples sustained primarily end-of-range damage which was annealable in AlGaN. We have performed a variety of measurements to characterize the doped samples including Raman spectroscopy, STM, and X-ray diffraction on the doped samples which suggest the viability of IBNTD as a doping method. Calculations indicate that doping layer thicknesses of the order of 10 nm are achievable. Possible doping concentrations using this technique are also estimated.     

The uncapacitated hub location problem in networks under decentralized management

We propose a new hub location model defined by the minimization of costs. The main contribution of this work is to permit the analysis of a hub-and-spoke network operated under “decentralized management”. In this type of network, various transport companies act independently, and each makes its route choices according to its own criteria, which can include cost, time, frequency, security and other factors, including subjective ones. Therefore, due to the diversity of the various companies’ criteria, one can expect that between each origin–destination pair, a fraction of the flow will be carried through hubs and a fraction will be carried by the direct route. to resolve this problem, it becomes necessary to determine the probability that any network user will choose the hub route for each trip to be made (or for each load to be carried). We present an integer programming formulation, subject the new model to experiments with an intermodal general cargo network in Brazil and address questions regarding the solution of the problem in practice.     

Sodium phthalamates as corrosion inhibitors for carbon steel in aqueous hydrochloric acid solution

Three compounds of N-alkyl-sodium phthalamates were synthesized and tested as corrosion inhibitors for carbon steel in 0.5 M aqueous hydrochloric acid. Tests showed that inhibitor efficiencies were related to aliphatic chain length and dependent on concentration. N-1-n-tetradecyl-sodium phthalamate displayed moderate efficiency against uniform corrosion, 42–86% at 25 °C and 25–60% at 40 °C. Tests indicated that compounds behave as mixed type inhibitors where molecular adsorption on steel followed Langmuir isotherm, whereas thermodynamic suggested that a physisorption process occurred. XPS analysis confirmed film formation on surface, where Fe⁺² complexes and Fe⁺² chelates with phthalamates prevented steel from further corrosion.     

A genetic programming method for protein motif discovery and protein classification

Proteins can be grouped into families according to some features such as hydrophobicity, composition or structure, aiming to establish common biological functions. This paper presents MAHATMA—memetic algorithm-based highly adapted tool for motif ascertainment—a system that was conceived to discover features (particular sequences of amino acids, or motifs) that occur very often in proteins of a given family but rarely occur in proteins of other families. These features can be used for the classification of unknown proteins, that is, to predict their function by analyzing their primary structure. Experiments were done with a set of enzymes extracted from the Protein Data Bank. The heuristic method used was based on genetic programming using operators specially tailored for the target problem. The final performance was measured using sensitivity, specificity and hit rate. The best results obtained for the enzyme dataset suggest that the proposed evolutionary computation method is effective in finding predictive features (motifs) for protein classification.     

Natural Lignocellulosic Fibers as Engineering Materials—An Overview

Recent investigations on the tensile properties of natural cellulose-based fibers revealed an increasing potential as engineering materials. This is particularly the case of very thin fibers of some species such as sisal, ramie, and curaua. However, several other commonly used fibers such as flax, jute, hemp, coir, cotton, and bamboo as well as less known bagasse, piassava, sponge gourde, and buriti display tensile properties that could qualify them as engineering materials. An overview of the strength limits attained by these fibers is presented. Based on a tensile strength vs density chart, it is shown that natural fibers stand out as a relevant class of engineering materials.     

Functional genomics studies shed light on the nutrition and gene expression of non-typhoidal Salmonella and enterovirulent E. coli in produce

Despite the fact that plants are not traditionally considered as hosts for human enteric pathogens, recent evidence suggests that non-typhoidal Salmonella and enterovirulent Escherichia coli recognize plants and rely on a specific set of genes to multiply in plant-associated environments, eventually causing dramatic outbreaks of illness. The advent of sensitive functional genomics tools, including differential fluorescence induction and in vivo expression technology, set the stage for the characterization of the genes and behaviors used by enterics to colonize, persist and proliferate within plants and the associated microbial communities. Meta-analysis of published data suggests that Salmonella and enterovirulent E. coli persist in plants using strategies that differ from those in phytobacteria. Virulence genes were upregulated in E. coli O157:H7 in the presence of lettuce leaf exudates, however Salmonella SPI-1 genes associated with gastroenteritis were dispensable during plant growth. Microarray and mutant studies of plant responses to human pathogens reveal that plants generally do not recognize Salmonella and enterovirulent E. coli as phytopathogens or beneficial symbionts, although the full spectrum of plant responses to enterics remains to be elucidated. Defining plant responses to human enteric pathogens becomes increasingly important as the feasibility of breeding for resistance to these organisms is being evaluated.     

Nanostructured hematite thin films produced by spin-coating deposition solution: Application in water splitting

Doped and undoped hematite films for photoelectrochemical hydrogen production were prepared by spin-coating deposition solution (SCDS). To understand the influence of the Si-doping and identify the critical parameters of the proposed SCDS method an extensive characterization was conducted. The Si-doped hematite exhibited higher photocurrent response when compared with undoped films. We have shown that the crystallographic orientation degree of the films appears to be a dominant factor affecting the photocurrent. The performance of our hematite electrodes is well below the maximum theoretical efficiency and the conceivable explanation could be given by the high value of recombination phenomena (electron/hole pair).