926 resultados para Products with antimicrobial action


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Asymmetric heteroatom oxidation of benzo[b]thiophenes to yield the corresponding sulfoxides was catalysed by toluene dioxygenase (TDO), naphthalene dioxygenase (NDO) and styrene monooxygenase (SMO) enzymes present in P. putida mutant and E. coli recombinant whole cells. TDO-catalysed oxidation yielded the relatively unstable benzo[b] thiophene sulfoxide; its dimerization, followed by dehydrogenation, resulted in the isolation of stable tetracyclic sulfoxides as minor products with cis-dihydrodiols being the dominant metabolites. SMO mainly catalysed the formation of enantioenriched benzo[b] thiophene sulfoxide and 2-methyl benzo[b] thiophene sulfoxides which racemized at ambient temperature. The barriers to pyramidal sulfur inversion of 2- and 3-methyl benzo[b] thiophene sulfoxide metabolites, obtained using TDO and NDO as biocatalysts, were found to be ca.: 25-27 kcal mol(-1). The absolute configurations of the benzo[b] thiophene sulfoxides were determined by ECD spectroscopy, X-ray crystallography and stereochemical correlation. A site-directed mutant E. coli strain containing an engineered form of NDO, was found to change the regioselectivity toward preferential oxidation of the thiophene ring rather than the benzene ring.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article describes the trends in analytical techniques for the determination of trichothecene mycotoxins, namely deoxynivalenol, and T-2 and HT-2 toxins in cereals and cereal products with particular emphasis on screening and rapid approaches. The driving force behind the changing methodologies is mainly attributed to legislative demands. However, for commercial and governmental testing laboratories, the need to use validated official methods is ever increasing to ensure quality assurance of results.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Immunoaffinity chromatography (IAC) and affinity chromatography (AC:) are widely used for extraction of drugs from biological samples. Fifteen column types were purchased from five different manufacturers and;their ability to bind specific drugs including beta-agonists and anabolic steroids over a range of analyte concentrations in fortified bovine urine samples was assessed. The performance data obtained from these columns were compared with columns produced in this laboratory (in house columns). The in house columns gave the highest recoveries, ranging from 92 to 100% at the 1 ng spiking concentration, for five of the seven analytes assessed. Forty percent (11 of 27) of all the commercial column assessments recorded recoveries of less than 50% even when the lowest spiking concentration was applied (1 ng). For one manufacturer, only one of seven different columns purchased delivered extraction efficiencies greater than 50%. The extraction efficiencies of the clenbuterol columns were the highest with all commercially prepared columns showing at least 50% binding of radiolabelled tracer. Recoveries of alpha-nortestosterone were the lowest. The variability of these products with respect to quality control requires constant monitoring.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Spray-dried formulations offer an attractive delivery system for administration of drug encapsulated into liposomes to the lung, but can suffer from low encapsulation efficiency and poor aerodynamic properties. In this paper the effect of the concentration of the anti-adherent l-leucine was investigated in tandem with the protectants sucrose and trehalose. Two manufacturing methods were compared in terms of their ability to offer small liposomal size, low polydispersity and high encapsulation of the drug indometacin. Unexpectedly sucrose offered the best protection to the liposomes during the spray drying process, although formulations containing trehalose formed products with the best powder characteristics for pulmonary delivery; high glass transition values, fine powder fraction and yield. It was also found that l-leucine contributed positively to the characteristics of the powders, but that it should be used with care as above the optimum concentration of 0.5% (w/w) the size and polydispersity index increased significantly for both disaccharide formulations. The method of liposome preparation had no effect on the stability or encapsulation efficiency of spray-dried powders containing optimal protectant and anti-adherent. Using l-leucine at concentrations higher than the optimum level caused instability in the reconstituted liposomes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The chemoenzymatic synthesis of a Lewis basic phosphine-phosphine oxide organocatalyst from a cis-dihydrodiol metabolite of bromobenzene proceeds via a palladium-catalysed carbon-phosphorus bond coupling and a novel room temperature Arbuzov [2,3]-sigmatropic rearrangement of an allylic diphenylphosphinite. Allylation of aromatic aldehydes were catalysed by the Lewis basic organocatalyst giving homoallylic alcohols in up to 57% ee. This compound also functioned as a ligand for rhodium-catalysed asymmetric hydrogenation of acetamidoacrylate giving reduction products with ee values of up to 84%.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Being able to predict the properties of granules from the knowledge of the process and formulation variables is what most industries are striving for. This research uses experimental design to investigate the effect of process variables and formulation variables on mechanical properties of pharmaceutical granules manufactured from a classical blend of lactose and starch using hydroxypropyl cellulose (HPC) as the binder. The process parameters investigated were granulation time and impeller speed whilst the formulation variables were starch-to-lactose ratio and HPC concentration. The granule properties investigated include granule packing coefficient and granule strength. The effect of some components of the formulation on mechanical properties would also depend on the process variables used in granulation process. This implies that by subjecting the same formulation to different process conditions results in products with different properties. © 2012 Elsevier B.V. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objectives
To explore the role of evidence of effectiveness when making decisions about over-the-counter (OTC) medication and to ascertain whether evidence-based medicine training raised awareness in decision-making. Additionally, this work aimed to complement the findings of a previous study because all participants in this current study had received training in evidence-based medicine (unlike the previous participants).

Methods
Following ethical approval and an e-mailed invitation, face-to-face, semi-structured interviews were conducted with newly registered pharmacists (who had received training in evidence-based medicine as part of their MPharm degree) to discuss the role of evidence of effectiveness with OTC medicines. Interviews were recorded and transcribed verbatim. Following transcription, all data were entered into the NVivo software package (version 8). Data were coded and analysed using a constant comparison approach.

Key findings
Twenty-five pharmacists (7 males and 18 females; registered for less than 4 months) were recruited and all participated in the study. Their primary focus with OTC medicines was safety; sales of products (including those that lack evidence of effectiveness) were justified provided they did no harm. Meeting patient expectation was also an important consideration and often superseded evidence. Despite knowledge of the concept, and an awareness of ethical requirements, an evidence-based approach was not routinely implemented by these pharmacists. Pharmacists did not routinely utilize evidence-based resources when making decisions about OTC medicines and some felt uncomfortable discussing the evidence-base for OTC products with patients.

Conclusions
The evidence-based medicine training that these pharmacists received appeared to have limited influence on OTC decision-making. More work could be conducted to ensure that an evidence-based approach is routinely implemented in practice

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Chlorination of wheat flour in the EU countries has been replaced in recent years, to some extent, by heat treated flour which is used to produce high ratio cakes. Heat treated flour allows high ratio recipes to be developed which generate products with longer shelf life, finer texture, moist crumb and sweeter taste. The mechanism by which heat treatment improves the flour is not fully understood, but it is known that during the heat treatment process, protein denaturation and partial gelatinisation of the starch granules occurs, as well as an increase in batter viscosity. Therefore, it is important to optimize the flour heat treatment process, in order to enhance baking quality. Laboratory preparation of heat treated base wheat flour (culinary, soft, low protein) was carried out in a fluidised bed drier using a range of temperatures and times. The gluten was extracted from the final product and its quality was tested, to obtain objective and comparative information on the extent of protein denaturation. The results indicated that heat treatment of flour decreases gluten extensibility and partial gelatinisation of the starch granules occurred. After heat treatment the gluten appeared to retain moisture. The optimum time/temperature for the heat treatment of base flour was 120-130°C for 30 min with moisture content of ˜12.5%.© 2012 Elsevier Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Since the UN report by the Brundtland Committee, sustainability in the built environment has mainly been seen from a technical focus on single buildings or products. With the energy efficiency approaching 100%, fossil resources depleting and a considerable part of the world still in need of better prosperity, the playing field of a technical focus has become very limited. It will most probably not lead to the sustainable development needed to avoid irreversible effects on climate, energy provision and, not least, society.
Cities are complex structures of independently functioning elements, all of which are nevertheless connected to different forms of infrastructure, which provide the necessary sources or solve the release of waste material. With the current ambitions regarding carbon- or energy-neutrality, retreating again to the scale of a building is likely to fail. Within an urban context a single building cannot become fully resource-independent, and need not, from our viewpoint. Cities should be considered as an organism that has the ability to intelligently exchange sources and waste flows. Especially in terms of energy, it can be made clear that the present situation in most cities are undesired: there is simultaneous demand for heat and cold, and in summer a lot of excess energy is lost, which needs to be produced again in winter. The solution for this is a system that intelligently exchanges and stores essential sources, e.g. energy, and that optimally utilises waste flows.
This new approach will be discussed and exemplified. The Rotterdam Energy Approach and Planning (REAP) will be illustrated as a means for urban planning, whereas Swarm Planning will be introduced as another nature-based principle for swift changes towards sustainability

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Health claims on food products, which aim at informing the public about the health benefits of the product, represent one type of nutrition communication; the use of these is regulated by the European Union. This paper provides an overview of the research on health claims, including consumers' perceptions of such claims and their intention to buy products that carry health-related claims. This is followed by a discussion on the results from some recent studies investigating public perceptions and willingness to use products with health claims. In these studies, claims are presented in the form of messages of different lengths, types, framing, with and without qualifying words and symbols. They also investigate how perceptions and intentions are affected by individual needs and product characteristics. Results show that adding health claims to products does increase their perceived healthiness. Claim structure was found to make a difference to perceptions, but its influence depended on the level of relevance, familiarity and individuals' need for information. Further, the type of health benefit proposed and the base product used also affected perceptions of healthiness. The paper concludes that while healthiness perceptions relating to products with health claims may vary between men and women, old and young and between countries, the main factor influencing perceived healthiness and intention to buy a product with health claim is personal relevance.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Peak altitudes, hypsometry, geology, and former equilibrium-line altitudes (ELAs) are analyzed across the Sredinny Mountains (Kamchatka). Overall, evidence is found to suggest that the glacial buzzsaw has operated to shape the topography of this mountain range, but the strength of this signature is not spatially uniform. In the southern sector of the mountains, we see evidence that an efficient glacial buzzsaw has acted to impose constraints upon topography, limiting peak altitudes, and concentrating land-surface area (hypsometric maxima) close to palaeo-ELAs. By contrast, in the northern sector of the mountains, a number of peaks rise high above the surrounding topography, and land-surface area is concentrated well below palaeo-ELAs. This deviation from a classic ‘buzzsaw signature’, in the northern sector of the mountains, is considered to reflect volcanic construction during the Quaternary, resulting in a series of high altitude peaks, combined with the action of dynamic glaciers, acting to skew basin topography toward low altitudes, well below palaeo-ELAs. These glaciers are considered to have been particularly dynamic because of their off-shore termination, their proximity to moisture-bearing air masses from the North Pacific, and because accumulation was supplemented by snow and ice avalanching from local high altitude peaks. Overall, the data suggest that the buzzsaw remains a valid mechanism to generally explain landscape evolution in mountain regions, but its signature is significantly weakened in mountain basins that experience both volcanic construction and climatic conditions favouring dynamic glaciation.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Sea bream (Sparus aurata) production plays a significant part in Italian aquaculture, contributing to almost 18% of national pisciculture sales revenue. In recent years, Italian firms faced higher competition from countries with lower production costs. This prompted responses toward both cost reduction and product differentiation. The objective of this study was to investigate the preferences of Italian consumers for sea bream from fish farms, with a focus on aspects of product differentiation as gleaned from the analysis of the market situation: price, product origin, type and place of fish farming, and, in particular, type of feed. Data were collected with a consumers’ survey using personal interviews conducted on a questionnaire that included a choice experiment. Consumer preferences were analyzed with choice models based on stated preference data. The models made it possible to evaluate the potential of products with different combinations of attributes for which there is currently no market information available. In particular, the country of origin emerged as an important element of consumer choice, and to a lesser degree, organic certification and fish farming in marine cages also play a relevant role and may command a price premium.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

It seems there is a positive correlation between rice content and arsenic level in foods. This is of extraordinary importance for infants below 1 y of age because their diet is very limited and in some cases is highly dependent on rice-based products; this is particularly true for infants with the celiac disease because they have no other option than consume gluten-free products, such as rice or corn. Arsenic contents were significantly higher (P <0.001) in gluten-free infant rice (0.057 mg kg-1) than in products with gluten, based on a mixture of cereals (0.024 mg kg-1). Besides, especial precaution must be taken when preparing rice-based products at home, because arsenic content in Spanish rice was high, with levels being above 0.3 mg kg-1 in some cases.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Bacteriovorax marinus SJ is a predatory delta-proteobacterium isolated from a marine environment. The genome sequence of this strain provides an interesting contrast to that of the terrestrial predatory bacterium Bdellovibrio bacteriovorus HD100. Based on their predatory lifestyle, Bacteriovorax were originally designated as members of the genus Bdellovibrio but subsequently were re-assigned to a new genus and family based on genetic and phenotypic differences. B. marinus attaches to gram-negative bacteria, penetrates through the cell wall to form a bdelloplast, in which it replicates, as shown using microscopy. Bacteriovorax is distinct, as it shares only 30% of its gene products with its closest sequenced relatives. Remarkably, 34% of predicted genes over 500 nt in length were completely unique with no significant matches in the databases. As expected, Bacteriovorax shares several characteristic loci with the other delta-proteobacteria. A geneset shared between Bacteriovorax and Bdellovibrio that is not conserved among other delta-proteobacteria such as Myxobacteria (which destroy prey bacteria externally via lysis), or the non-predatory Desulfo-bacteria and Geobacter species was identified. These 291 gene orthologues common to both Bacteriovorax and Bdellovibrio may be the key indicators of host-interaction predatory-specific processes required for prey entry. The locus from Bdellovibrio bacteriovorus is implicated in the switch from predatory to prey/host-independent growth. Although the locus is conserved in B. marinus, the sequence has only limited similarity. The results of this study advance understanding of both the similarities and differences between Bdellovibrio and Bacteriovorax and confirm the distant relationship between the two and their separation into different families.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Recent work of Biedermann and Roendigs has translated Goodwillie's calculus of functors into the language of model categories. Their work focuses on symmetric multilinear functors and the derivative appears only briefly. In this paper we focus on understanding the derivative as a right Quillen functor to a new model category. This is directly analogous to the behaviour of Weiss's derivative in orthogonal calculus. The immediate advantage of this new category is that we obtain a streamlined and more informative proof that the n-homogeneous functors are classified by spectra with an action of the symmetric group on n objects. In a later paper we will use this new model category to give a formal comparison between the orthogonal calculus and Goodwillie's calculus of functors.