Quantum multifractality as a probe of phase space in the Dicke model.

We study the multifractal behavior of coherent states projected in the energy eigenbasis of the spin-boson Dicke Hamiltonian, a paradigmatic model describing the collective interaction between a single bosonic mode and a set of two-level systems. By examining the linear approximation and parabolic correction to the mass exponents, we find ergodic and multifractal coherent states and show that they reflect details of the structure of the classical phase space, including chaos, regularity, and features of localization. The analysis of multifractality stands as a sensitive tool to detect changes and structures in phase space, complementary to classical tools to investigate it. We also address the difficulties involved in the multifractal analyses of systems with unbounded Hilbert spaces.

Phenolic-rich extracts from acerola, cashew apple and mango by-products cause diverse inhibitory effects and cell damages on enterotoxigenic Escherichia coli.

This study aimed to evaluate the inhibitory effects of phenolic-rich extracts from acerola (Malpighia emarginata D.C., PEA), cashew apple (Anacardium occidentale L., PEC) and mango (Mangifera indica L., PEM) by-products on distinct enterotoxigenic Escherichia coli (ETEC) strains. The capability of PEA and PEC of impairing various physiological functions of ETEC strains was investigated with multiparametric flow cytometry. Procyanidin B2 , myricetin and p-coumaric acid were the major phenolic compounds in PEA, PEC and PEM, respectively. PEA and PEC had lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) (MIC: 31·25 mg ml-1 ; MBC: 62·5 mg ml-1 ) on ETEC strains than PEM (MIC and MIC: >1000 mg ml-1 ). PEA and PEC (15·6, 31·2, 62·5 mg ml-1 ) caused viable count reductions (P < 0·05) on ETEC strains after 24 h of exposure, notably the ≥3 log reductions caused by 62·5 mg ml-1 . The 24 h exposure of ETEC strains to PEA and PEC (31·2, 62·5 mg ml-1 ) led to high sizes of cell subpopulations with concomitant impairments in cell membrane polarization and permeability, as well as in enzymatic, respiratory and efflux activities. PEA and PEC are effective in inhibiting ETEC through a multi-target action mode with disturbance in different physiological functions.

Quantum localization measures in phase space.

Measuring the degree of localization of quantum states in phase space is essential for the description of the dynamics and equilibration of quantum systems, but this topic is far from being understood. There is no unique way to measure localization, and individual measures can reflect different aspects of the same quantum state. Here we present a general scheme to define localization in measure spaces, which is based on what we call Rényi occupations, from which any measure of localization can be derived. We apply this scheme to the four-dimensional unbounded phase space of the interacting spin-boson Dicke model. In particular, we make a detailed comparison of two localization measures based on the Husimi function in the regime where the model is chaotic, namely, one that projects the Husimi function over the finite phase space of the spin and another that uses the Husimi function defined over classical energy shells. We elucidate the origin of their differences, showing that in unbounded spaces the definition of maximal delocalization requires a bounded reference subspace, with different selections leading to contextual answers.

Probiotic properties of yeasts isolated from Brazilian fermented table olives.

AIMS: To investigate the probiotic potential of yeasts isolated from naturally fermented Brazilian table olives. METHODS AND RESULTS: Eighteen yeast strains were tested in terms of: safety; survival of gastrointestinal and digestion conditions; antimicrobial activity; cellular hydrophobicity; autoaggregation ability and adhesion to epithelial cells; coaggregation and inhibition of pathogenic bacteria adhesion. Six yeasts showed favourable results for all probiotic attributes: Saccharomyces cerevisiae CCMA 1746, Pichia guilliermondii CCMA 1753, Candida orthopsilosis CCMA 1748, Candida tropicalis CCMA 1751, Meyerozyma caribbica CCMA 1758 and Debaryomyces hansenii CCMA 1761. These yeasts demonstrated resistance to 37°C, pH 2·0 and bile salts, and survived in vitro digestion (≥106  CFU per ml). Furthermore, the yeasts exhibited a hydrophobic cell surface (42·5-92·2%), autoaggregation capacity (41·0-91·0%) and adhesion to Caco-2 (62·0-82·8%) and HT-29 (57·6-87·3%) epithelial cell lines. Also, the strains showed antimicrobial activity against Salmonella Enteritidis as well as the ability to coaggregate and reduce the adhesion of this pathogen to intestinal cells. CONCLUSIONS: Autochthonous yeasts from naturally fermented Brazilian table olives have probiotic properties, with potential for development of new probiotic food products. SIGNIFICANCE AND IMPACT OF STUDY: These data are important and contribute to the knowledge of new potential probiotic yeasts capable of surviving gastrointestinal tract conditions and inhibiting pathogenic bacteria.

Acerola (Malpighia glabra L.) and guava (Psidium guayaba L.) industrial processing by-products stimulate probiotic Lactobacillus and Bifidobacterium growth and induce beneficial changes in colonic microbiota.

AIMS: This study evaluated whether by-products from industrial processing of acerola (Malpighia glabra L.; AB) and guava (Psidium guajava L.; GB) fruit may stimulate the growth and metabolism of probiotic Lactobacillus and Bifidobacterium and induce changes in human colonic microbiota. METHODS AND RESULTS: The ability of non-digested and digested AB or GB to stimulate the growth ad metabolism of Lactobacillus acidophilus LA-05, Lactobacillus casei L-26 and Bifidobacterium animalis subsp. lactis BB-12 was evaluated. Changes in populations of distinct bacterial groups of human colonic microbiota induced by digested AB and GB were evaluated using an in vitro colonic fermentation system. Non-digested and digested AB and GB favoured probiotic growth. No difference among counts of probiotics in media with glucose, fructooligosaccharides and non-digested and digested AB and GB was found during a 48-h cultivation. Cultivation of probiotics in media with non-digested and digested AB and GB resulted in decreased pH, increased organic acid production and sugar consumption over time. Digested AB and GB caused overall beneficial changes in abundance of Bifidobacterium spp., Lactobacillus-Enterococcus, Eubacterium rectall-Clostridium coccoides and Bacteroides-Provotella populations, besides to decrease the pH and increase the short-chain fatty acid production during a 24-h in vitro colonic fermentation. CONCLUSION: AB and GB could be novel prebiotic ingredients because they can stimulate the growth and metabolism of probiotics and induce overall beneficial changes in human colonic microbiota. SIGNIFICANCE AND IMPACT OF THE STUDY: AB and GB stimulated the growth and metabolism of probiotics, in addition to induce beneficial alterations in human colonic microbiota composition and increase short-chain fatty acid production. These results characterize AB and GB as potential prebiotic ingredients and fruit processing by-products as sources of added-value compounds.

Efficacy of oregano and rosemary essential oils to affect morphology and membrane functions of noncultivable sessile cells of Salmonella Enteritidis 86 in biofilms formed on stainless steel.

AIMS: This study evaluated the efficacy of essential oil from Origanum vulgare L. (oregano; OVEO) and Rosmarinus officinalis L. (rosemary; ROEO) to inactivate sessile cells of Salmonella enterica serovar Enteritidis 86 (SE86) in young and mature biofilms formed on stainless steel. METHODS AND RESULTS: Ultrastructural alterations and damage in different physiological functions caused by OVEO and ROEO in noncultivable sessile cells of SE86 were investigated using scanning electron microscopy and flow cytometry. OVEO (2·5 µl ml-1 ) and ROEO (40 µl ml-1 ) were effective to eradicate young and mature biofilms formed by SE86 sessile cells on stainless steel surfaces; however, the efficacy varied with exposure time. OVEO and ROEO caused alterations in morphology of SE86 sessile cells, inducing the occurrence of bubbles or spots on cell surface. OVEO and ROEO compromised membrane polarization, permeability and efflux activity in noncultivable SE86 sessile cells. These findings show that OVEO and ROEO act by a multitarget mechanism on SE86 membrane functions. CONCLUSIONS: ROEO and OVEO showed efficacy to eradicate SE86 sessile cells in preformed biofilms on stainless steel, displaying a time-dependent effect and multitarget action mode on bacterial cell membrane. SIGNIFICANCE AND IMPACT OF THE STUDY: The study provides for the first time the effects of OVEO and ROEO on morphology and physiological functions of noncultivable sessile cells of S. Enteritidis biofilms preformed on stainless steel surfaces.

Dynamical signatures of quantum chaos and relaxation time scales in a spin-boson system.

Quantum systems whose classical counterparts are chaotic typically have highly correlated eigenvalues and level statistics that coincide with those from ensembles of full random matrices. A dynamical manifestation of these correlations comes in the form of the so-called correlation hole, which is a dip below the saturation point of the survival probability's time evolution. In this work, we study the correlation hole in the spin-boson (Dicke) model, which presents a chaotic regime and can be realized in experiments with ultracold atoms and ion traps. We derive an analytical expression that describes the entire evolution of the survival probability and allows us to determine the time scales of its relaxation to equilibrium. This expression shows remarkable agreement with our numerical results. While the initial decay and the time to reach the minimum of the correlation hole depend on the initial state, the dynamics beyond the hole up to equilibration is universal. We find that the relaxation time of the survival probability for the Dicke model increases linearly with system size.

Nutritional and sensory characteristics of Minas fresh cheese made with goat milk, cow milk, or a mixture of both.

This study aimed to assess and compare the nutritional, technological, and sensory characteristics of Minas fresh cheese made with goat milk, cow milk, or a mixture of the two stored in cold conditions for 21d. The yield and centesimal composition of the cheeses were not affected by the type of milk used in their preparation. Reductions were observed in the moisture content, pH, proteolysis index, and instrumental hardness; moreover, increases were observed in the syneresis, acidity index, and depth of proteolysis index in all cheeses. The percentages of caprylic, capric, oleic, and linoleic fatty acids were higher in goat milk cheese and cheese made with a mixture of goat and cow milk compared with cow milk cheese, and a sensory evaluation revealed differences in color, flavor, and aroma between the cheeses. The preparation of Minas fresh cheese with a mixture of goat and cow milk can be a viable alternative for dairy products in the market that can be characterized as high-quality products that meet consumer demands.

Evaluation of root resorption associated with orthodontic movement in stressed rats.

AIM: The aim of this study was to investigate the effects of acute and chronic systemic stress response on orthodontically induced root resorption. METHODS: Male Wistar rats were restrained during 1 hour a day by stress models of short (3 days) and long duration (40 days), while control group was not submitted to restraint (N.=10/group). The upper left first molars of all rats were moved mesially by a fixed orthodontic appliance exerting 50 g force upon insertion during the last 14 days of the experiment. Then, animals were killed for blood collection and mensuration of plasmatic corticosterone by radioimmunoassay; the tissues around mesial root of the first molar were processed for histological and histochemical techniques with tartrate-resistant acid phosphatase. The degree of root resorption and the number of odontoclasts were evaluated, being the contralateral side of each animal serving as its control (split-mouth design). RESULTS: The results revealed that the plasmatic levels of corticosterone were significantly higher in both the stressed groups than in the control one. There were no significant differences in the degree of root resorption and in the number of odontoclasts on the root between the 3 groups studied. CONCLUSIONS: These results indicate that systemic stress alone can not be considered a risk factor for root resorption induced by orthodontic tooth movement.

Histological analysis of orthodontic root resorption in rats treated with the cyclooxygenase-2 (COX-2) inhibitor celecoxib.

INTRODUCTION: It has been reported that anti-inflammatory drugs used for treatment of pain and discomfort related to orthodontic treatment could slow down tooth movement. However, the effect of these drugs on orthodontic root resorption is not well understood. OBJECTIVES: The aim of this study was to investigate whether the COX-2 inhibitor celecoxib offers some protection against orthodontically induced root resorption. DESIGN: Male Wistar rats were divided into four groups: Groups I and II were treated with saline and celecoxib (10 mg / kg), respectively for 3 days. Groups III and IV were treated with saline and celecoxib for 14 days. The upper left first molars of all rats were moved mesially for 14 days with 50 g of force. An area including the disto-apical aspect of the mesial root of the first molar was processed for histological and histochemical techniques with tartarate-resistant acid phosphatase (TRAP). OUTCOME MEASURE: The degree of root resorption was measured using an image analysis system with a grid-sheet superimposed in the root were resorption lacunae were counted. The number of TRAP-positive cells on the tooth root surface defined as odontoclasts were also evaluated. RESULTS: The results revealed that there were no significant differences in the degree of root resorption and in the number of odontoclasts on the root between the four groups studied. CONCLUSION: The short and long-term celecoxib administration did not suppress the root resorption in case of experimental orthodontic force application.

Effect of oral vanadyl sulfate treatment on serum enzymes and lipids of streptozotocin-diabetic young rats.

In this work we investigate the possible toxicity of vanadyl sulfate (VOSO4), a compound capable of reducing hyperglycemia, on the following serum enzymes of diabetic young rats: alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LD) and creatine kinase (CK), as well as its effects on serum lipids. We find that at a concentration of 1 mg/mL VOSO4 has no toxic effect on the liver and muscles of diabetics young rats. These findings suggest that VOSO4 may be an alternative to insulin in the near future, due to its low cost, low toxicity and ready availability.