971 resultados para engineer to order
Resumo:
Glycoproteins from the total vesicular fluid of Taenia crassiceps (VF-Tc) were prepared using three different purification methods, consisting of ConA-lectin affinity chromatography (ConA-Tc), preparative electrophoresis (SDS-PAGE) (14gp-Tc), and monoclonal antibody immunoaffinity chromatography (18/14-Tc). The complex composition represented by the VF-Tc and ConA-Tc antigens revealed peptides ranging from 101 - to 14-kDa and from 92- to 12-kDa, respectively. Immunoblotting using lectins confirmed glucose/mannose (glc/man) residues in the 18- and 14-kDa peptides, which are considered specific and immunodominant for the diagnosis of cysticercosis, and indicated that these fractions are glycoproteins. Serum antibodies from a patient with neurocysticercosis that reacted to the 14gp band from T. crassiceps (Tc) were eluted from immunoblotting membranes and showed reactivity to 14gp from Taenia solium. In order to determine the similar peptide sequence, the N-terminal amino acid was determined and analyzed with sequences available in public databases. This sequence revealed partial homology between T. crassiceps and T solium peptides. In addition, mass spectrometry along with theoretical M(r) and pI of the 14gp-Tc point suggested a close relationship to some peptides of a 150-kDa protein complex of the T solium previously described. The identification of these common immunogenic sites will contribute to future efforts to develop recombinant antigens and synthetic peptides for immunological assays. (C) 2009 Elsevier Inc. All rights reserved.
Resumo:
Inulin was used as a prebiotic to improve quality of skim milk fermented by pure cultures of Lactobacillus acidophilus Lactobacillus rhamnosus Lactobacillus bulgaricus and Bifidobacterium lactis binary co-cultures with Streptococcus thermophilus or a cocktail containing all them Inulin supplementation to pure cultures lowered the generation time with particular concern to S thermophilus and L acidophilus The generation time of all micro-organisms decreased in the following order mono-cultures co-cultures cocktail It was demonstrated a synergism between S thermophilus and the other strains and a bifidogenic effect of inulin Enumerations of L rhamnosus in cocktail markedly decreased compared to co-cultures likely because of greater competition for the same substrates The results of this work highlight the industrial potential of the cocktail mainly in terms of fermentation acceleration (C) 2010 Elsevier Ltd All rights reserved
Resumo:
Bovine pericardium (BP) tissue is widely used in the manufacture of bioprosthetics. The effects of freeze-drying on the BP tissue have been studied by some researchers in order to decrease their cytotoxicity due to preservation in formaldehyde solution, and to increase the lifetime of the product in storage. This study was undertaken in order to study the effect of freeze-drying in the structure of BP. To perform this study BP samples were freeze-dried in two different types of freeze-dryers available in our laboratory: a laboratory freeze-dryer, in which it was not possible to control parameters and a pilot freeze-dryer, wherein all parameters during freezing and drying were controlled. After freeze-drying processes, samples were analyzed by SEM, Raman spectroscopy, tensile strength, water uptake tests and TEM. In summary, it has been demonstrated that damages occur in collagen fibers by the loss of bulk water of collagen structure implicating in a drastic decreasing of BP mechanical properties due to its structural alterations. Moreover, it was proven that the collagen fibrils suffered breakage at some points, which can be attributed to the uncontrolled parameters during drying. (C) 2011 Elsevier Inc. All rights reserved.
Resumo:
This report focuses on the effects of cholesterol on the expression and function of the ATP-binding cassette (ABCB1, ABCG2 and ABCC2) and solute-linked carrier (SLCO1B1 and SLCO2B1) drug transporters with a particular focus on the potential impact of cholesterol on lipid-lowering drug disposition. Statins are the most active agents in the treatment of hypercholesterolemia. However, considerable interindividual variation exists in the response to statin therapy. Therefore, it would be huge progress if factors were identified that reliably differentiate between responders and nonresponders. Many studies have suggested that plasma lipid concentrations can affect drug disposition of compounds, such as ciclosporin and amphotericin B. Both compounds are able to affect the expression and function of ABC transporters. Although still speculative, these effects might be owing to the regulation of drug transporters by plasma cholesterol levels. Studies with normo- and hyper-cholesterolemic individuals, before and after atorvastatin treatment, have demonstrated that plasma cholesterol levels are correlated with drug transporter expression, as well as being related to atorvastatin`s cholesterol-lowering effect. The mechanism influencing the correlation between cholesterol levels and the expression and function of drug transporters remains unclear. Some studies provide strong evidence that nuclear receptors, such as the pregnane X receptor and the constitutive androstane receptor, mediate this effect. In the near future, pharmacogenomic studies with individuals in a pathological state should be performed in order to identify whether high plasma cholesterol levels might be a factor contributing to interindividual oral drug bioavailability.
Resumo:
Due to differences in the functional quality of natural extracts, we have also faced differences in their effectiveness. So, it was intended to assess the antioxidant activity of natural extracts in order to attain their functional quality. It was observed that all the extracts (brown and green propolis, Ginkgo biloba and Isoflavin Beta (R)) and the standard used (quercetin) showed antioxidant activity in a dose-dependent manner with IC50 values ranging from 0.21 to 155.28 mu g mL(-1) (inhibition of lipid peroxidation and scavenging of the DPPH center dot assays). We observed a high correlation (r(2)= 0.9913) among the antioxidant methods; on the other hand, the antioxidant activity was not related to the polyphenol and flavonoid content. As the DPPH center dot assay is a fast method, presents low costs and even has a high correlation with other antioxidant methods, it could be applied as an additional parameter in the quality control of natural extracts.
Resumo:
Cyclodextrins (CDs) are annular oligosaccharides containing 6-12 glucose unities joined together by alpha-1,4 bonds. They have a conical-truncated shape with a lipophilic cavity in which different molecules can be included resulting in a stable inclusion complex. The cyclodextrins have been widely applied in pharmaceutical technology with the objective of increasing the solubility, stability and bioavailability of drugs in different pharmaceutical dosage forms, such as tablets. In order to obtain beta-CD tablets, liquid dispersions of drug/beta-CD are usually submitted to different drying processes, like spray-drying, freeze-drying or slow evaporation, being this dry material added to a number of excipients. However, such drying processes can generate particulate materials showing problems of flow and compressibility, needing their conversion into granulates by means of wetting with granulation liquid followed by additional drying. In this work, the main objective was to evaluate the preparation of tablets without the need of this additional drying step. For this purpose an aqueous dispersion containing acetaminophen/beta-CD complex and cornstarch was dried using a spouted bed and the obtained granules were compressed in tablets. Acetaminophen was used as model drug due to its low water solubility and the inexpensive and widely available cornstarch was chosen as excipient. Acetaminophen powder was added into a beta-cyclodextrin solution prepared in distilled water at 70 degrees C. Stirring was kept until this dispersion cooled to room temperature. Then cornstarch was added and the resulting dispersion was dried in spouted bed equipment. This material was compressed into tablets using an Erweka Korsh EKO tablet machine. This innovative approach allowed the tablets preparation process to be carried out with fewer steps and represents a technological reliable strategy to produce beta-cyclodextrin inclusion complexes tablets. (C) 2010 Elsevier By. All rights reserved.
Resumo:
Paracoccidioides brasiliensis infectious process relies on the initial expression of virulence faactors that are assumed to be controlled by molecular mechanisms through which the conidia and/or mycelial fragments convert to yeast cells. In order to analyze the profile of the thermally-induced dimorphic gene expression, 48 h C-L transition cultures which had been incubated at 36 degrees C were studied. By this time approximately 50% of the conidial population had already reverted to yeast form cells. At this transition time, an EST-Orestes library was constructed and characterized. As a result, 79 sequences were obtained, of which 39 (49.4%) had not been described previously in other libraries of this fungus and which could represent novel exclusive C-Y transition genes. Two of these sequences are, among others, cholestanol delta-isomerase, and electron transfer flavoprotein-ubiquinoneoxidoreductase (ETF-QO). The other 40 (50.6%) sequences were shared with Mycelia (M), Yeast (Y) or Mycelia to yest transition (M-Y) libraries. An important component of this group of sequences is a putative response regulator receiver SKN7, a protein of high importance in stress adaptation and a regulator of virulence in some bacteria and fungi. This is the first report identifying genes expressed during the C-Y transition process, the initial step required to understand the natural history of P brasiliensis conidia induced infection.
Resumo:
Sickle cell disease (SCD) is an inherited disorder caused by a single nucleotide substitution in the P-globin gene. The clinical heterogeneity observed in SCD patients has been attributed to environmental and genetic factors. The patients are subjected to increased oxidative stress, particularly during vaso-occlusive crises and acute chest pain. Another possible cause of oxidative stress in SCD is the high concentration of iron in the patients` plasma. The increase in oxidative stress could be a relevant risk factor for mutagenesis and carcinogenesis. Studies on the frequency of basal chromosomal aberrations in cultured lymphocytes from SCD patients have not been reported so far. In order to contribute to the understanding of the role of the different biomarkers and their relationship with the extremely variable clinical manifestation of SCD, we investigated the frequency of chromosome damage in peripheral lymphocytes from sickle cells patients and healthy controls. We found an increased frequency of chromosome damage and percentage of aberrant metaphases in these patients when compared with control subjects, even at basal values (p < 0.05). In the cytogenetic sensitivity assay, the results showed that these patients presented a marked decrease in the mitotic index values compared with healthy controls. Cisplatin-induced chromosomal damage in lymphocytes from these patients was significantly higher than the frequency measured in healthy controls. The results obtained in the present study showed that more investigations are needed in order to elucidate the susceptibility to genomic instability of SCD patients.
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Vulvovaginal candidiasis, a high prevailing infection worldwide, is mainly caused by Candida albicans. Probiotic Lactobacillus reuteri RC-14 and Lactobacillus rhamnosus GR-1 have been previously shown to be useful as adjuvants in the treatment of women with VVC. In order to demonstrate and better understand the anti-Candida activity of the probiotic microorganisms in an in vitro model simulating vaginal candidiasis, a human vaginal epithelial cell line (VK2/E6E7) was infected with C. albicans 3153a and then challenged with probiotic L. rhamnosus GR-1 and/or L. reuteri RC-14 or their respective CFS (alone or in combination). At each time point (0, 6, 12 and 24 hr), numbers of yeast, lactobacilli and viable VK2/E6E7 cells were determined and, at 0, 6 and 12 hr, the supernatants were measured for cytokine levels. We found that C. albicans induced a significant increase in IL-1 alpha and IL-8 production by VK2/E6E7 cells. After lactobacilli challenge, epithelial cells did not alter IL-6, IL-1 alpha, RANTES and VEGF levels. However, CFS from the probiotic microorganisms up-regulated IL-8 and IP-10 levels secreted by VK2/E6E7 cells infected with C. albicans. At 24 hr of co-incubation, L. reuteri RC-14 alone and in combination with L. rhamnosus GR-1 decreased the yeast population recoverable from the cells. In conclusion, L. reuteri RC-14 alone and together with L. rhamnosus GR-1 have the potential to inhibit the yeast growth and their CFS may up-regulate IL-8 and IP-10 secretion by VK2/E6E7 cells, which could possibly have played an important role in helping to clear VVC in vivo.
Resumo:
Monoamine oxidase is a flavoenzyme bound to the mitochondrial outer membranes of the cells, which is responsible for the oxidative deamination of neurotransmitter and dietary amines. It has two distinct isozymic forms, designated MAO-A and MAO-B, each displaying different substrate and inhibitor specificities. They are the well-known targets for antidepressant, Parkinson`s disease, and neuroprotective drugs. Elucidation of the x-ray crystallographic structure of MAO-B has opened the way for the molecular modeling studies. In this work we have used molecular modeling, density functional theory with correlation, virtual screening, flexible docking, molecular dynamics, ADMET predictions, and molecular interaction field studies in order to design new molecules with potential higher selectivity and enzymatic inhibitory activity over MAO-B.
Resumo:
A Latin square is pan-Hamiltonian if the permutation which defines row i relative to row j consists of a single cycle for every i j. A Latin square is atomic if all of its conjugates are pan-Hamiltonian. We give a complete enumeration of atomic squares for order 11, the smallest order for which there are examples distinct from the cyclic group. We find that there are seven main classes, including the three that were previously known. A perfect 1-factorization of a graph is a decomposition of that graph into matchings such that the union of any two matchings is a Hamiltonian cycle. Each pan-Hamiltonian Latin square of order n describes a perfect 1-factorization of Kn,n, and vice versa. Perfect 1-factorizations of Kn,n can be constructed from a perfect 1-factorization of Kn+1. Six of the seven main classes of atomic squares of order 11 can be obtained in this way. For each atomic square of order 11, we find the largest set of Mutually Orthogonal Latin Squares (MOLS) involving that square. We discuss algorithms for counting orthogonal mates, and discover the number of orthogonal mates possessed by the cyclic squares of orders up to 11 and by Parker's famous turn-square. We find that the number of atomic orthogonal mates possessed by a Latin square is not a main class invariant. We also define a new sort of Latin square, called a pairing square, which is mapped to its transpose by an involution acting on the symbols. We show that pairing squares are often orthogonal mates for symmetric Latin squares. Finally, we discover connections between our atomic squares and Franklin's diagonally cyclic self-orthogonal squares, and we correct a theorem of Longyear which uses tactical representations to identify self-orthogonal Latin squares in the same main class as a given Latin square.
Resumo:
We give conditions on f involving pairs of lower and upper solutions which lead to the existence of at least three solutions of the two point boundary value problem y" + f(x, y, y') = 0, x epsilon [0, 1], y(0) = 0 = y(1). In the special case f(x, y, y') = f(y) greater than or equal to 0 we give growth conditions on f and apply our general result to show the existence of three positive solutions. We give an example showing this latter result is sharp. Our results extend those of Avery and of Lakshmikantham et al.
Resumo:
A major challenge in successfully implementing transit-oriented development (TOD) is having a robust process that ensures effective appraisal, initiation and delivery of multi-stakeholder TOD projects. A step-by step project development process can assist in the methodic design, evaluation, and initiation of TOD projects. Successful TOD requires attention to transit, mixed-use development and public space. Brisbane, Australia provides a case-study where recent planning policies and infrastructure documents have laid a foundation for TOD, but where barriers lie in precinct level planning and project implementation. In this context and perhaps in others, the research effort needs to shift toward identification of appropriate project processes and strategies. This paper presents the outcomes of research conducted to date. Drawing on the mainstream approach to project development and financial evaluation for property projects, key steps for potential use in successful delivery of TOD projects have been identified, including: establish the framework; location selection; precinct context review; preliminary precinct design; the initial financial viability study; the decision stage; establishment of project structure; land acquisition; development application; and project delivery. The appropriateness of this mainstream development and appraisal process will be tested through stakeholder research, and the proposed process will then be refined for adoption in TOD projects. It is suggested that the criteria for successful TOD should be broadened beyond financial concerns in order to deliver public sector support for project initiation.
Resumo:
The solubilities and dissolution rates of three gypsum sources (analytical grade (AG), phosphogypsum (PG) and mined gypsum (MG)) with six MG size fractions ((mm) > 2.0, 1.0-2.0, 0.5-1.0, 0.25-0.5, 0.125-0.25, and < 0.125) were investigated in triple deionised water (TDI) and seawater to examine their suitability for bauxite residue amelioration. Gypsum solubility was greater in seawater (3.8 g L 1) than TDI (2.9 g L 1) due to the ionic strength effect, with dissolution in both TDI and seawater following first order kinetics. Dissolution rate constants varied with gypsum source (AR > PG > MG) due to reactivity and surface area differences, with 1:20 gypsum:solution suspensions reaching saturation within 15 s (AR) to 30 min (MG > 2.0). The ability of bauxite residue to adsorb Ca from solution was also examined. The quantity of the total solution Ca adsorbed was found to be small (5 %). These low rates of solution Ca adsorption combined with the comparatively rapid dissolution rates preclude the application of gypsum to the residue sand/seawater slurry as a method for residue amelioration. Instead, direct field application to the residue would ensure more efficient gypsum use. In addition, the formation of a sparingly soluble CaCO3 coating around the gypsum particles after mixing in a highly alkaline seawater/supernatant liquor (SNL) solution greatly reduced the rate of gypsum dissolution.
Resumo:
The farming of channel catfish (Ictalurus punctatus) is the largest (by volume and value) and most successful (in terms of market impact) aquaculture industry in the United States of America. Farmed channel catfish is the most consumed (in terms of volume per capita) fish fillet in the U.S. market. Within Australia, it has long been suggested by researchers and industry that silver perch (Bidyanus bidyanus) and possibly other endemic teraponid species possess similar biological attributes for aquaculture as channel catfish and may have the potential to generate a similar industry. The current teraponid industry in Australia, however, shows very little resemblance to the catfish industry, either in production style or market philosophy. A well established budget framework from the literature on U.S. channel catfish farming has been adapted for cost and climate conditions of the Burdekin region, Queensland, Australia. Breakeven prices for the hypothetical teraponid farms were found to be up to 50% higher than those published for catfish farms however were much lower than those reported for silver perch production in Australia using current, endemic styles of production. The breakeven prices for the hypothetical teraponid farms were most sensitive (in order of significance) to feed prices, production rates, interest rates, fingerling prices and electricity prices. At equivalent feed costs the costs of production between the hypothetical catfish farms in the Mississippi, U.S. and the hypothetical teraponid farms in the Burdekin, Australia were remarkably similar. The cost of feeds suitable for teraponid production in Australia are currently around double that of catfish feeds in the U.S. Issues currently hindering the development of a large scale teraponid industry in Australia are discussed.