Physical properties of a generalized model of multilayer adsorption of dimers.

We investigate the transport properties of a complex porous structure with branched fractal architectures formed due to the gradual deposition of dimers in a model of multilayer adsorption. We thoroughly study the interplay between the orientational anisotropy parameter p_{0} of deposited dimers and the formation of porous structures, as well as its impact on the conductivity of the system, through extensive numerical simulations. By systematically varying the value of p_{0}, several critical and off-critical scaling relations characterizing the behavior of the system are examined. The results demonstrate that the degree of orientational anisotropy of dimers plays a significant role in determining the structural and physical characteristics of the system. We find that the Einstein relation relating to the size scaling of the electrical conductance holds true only in the limiting case of p_{0}→1. Monitoring the fractal dimension of the interface of the multilayer formation for various p_{0} values, we reveal that in a wide range of p_{0}>0.2 interface shows the characteristic of a self-avoiding random walk, compared to the limiting case of p_{0}→0 where it is characterized by the fractal dimension of the backbone of ordinary percolation cluster at criticality. Our results thus can provide useful information about the fundamental mechanisms underlying the formation and behavior of wide varieties of amorphous and disordered systems that are of paramount importance both in science and technology as well as in environmental studies.

Transport properties in multilayer adsorption of dimers.

In this paper, we study the transport properties (percolation and conductivity) of a two-dimensional structure created by depositing dimers on a one-dimensional substrate where multilayer deposition is allowed. Specifically, we are interested in studying how the mentioned properties vary as a function of the height of the multilayer. The critical parameters of the percolation transition are calculated using finite-size scaling analysis, obtaining the scaling laws for the probability of percolation and the conductivity of the system. To calculate the electrical conductivity of the multilayer, we use the Frank-Lobb algorithm.

Unfolding of crumpled thin sheets.

Crumpled thin sheets are complex fractal structures whose physical properties are influenced by a hierarchy of ridges. In this paper, we report experiments that measure the stress-strain relation and show the coexistence of phases in the stretching of crumpled surfaces. The pull stress showed a change from a linear Hookean regime to a sublinear scaling with an exponent of 0.65±0.03, which is identified with the Hurst exponent of the crumpled sheets. The stress fluctuations are studied. The statistical distribution of force peaks is analyzed. It is shown that the unpacking of crumpled sheets is guided by a hierarchical order of ridges.

Saccharomyces boulardii as therapeutic alternative in experimental giardiasis.

AIMS: The objective of this study was to evaluate the effect of treatment with the probiotic Saccharomyces boulardii with or without metronidazole in experimental giardiasis. METHODS AND RESULTS: The effect of treatment with S. boulardii with or without metronidazole on the intestinal mucosa, the antioxidant defence system and the parasitic load was determined in experimental giardiasis. Eight groups of animals with infection and/or treatment with the probiotic and/or drugs for 1 week after infection with Giardia lamblia were used. A reduction of approximately 90% in the parasitic load was observed in all the treated groups. Saccharomyces boulardii attenuated the damage caused by infection in the intestinal mucosa preserving its architecture and inhibiting the oxidative stress induced by parasite and metronidazole. CONCLUSIONS: Saccharomyces boulardii was effective alone or in combination with metronidazole in resolving already established G. lamblia infection. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest the use of S. boulardii as an alternative treatment for giardiasis mainly in cases of resistance or intolerance to conventional treatment.

Weissella paramesenteroides WpK4 ameliorate the experimental amoebic colitis by increasing the expression of MUC-2 and the intestinal epithelial regeneration.

AIMS: This study evaluates the action of Weissella paramesenteroides WpK4 on amoebic colitis. METHODS AND RESULTS: Weissella paramesenteroides WpK4 was administered in Entamoeba dispar infected and noninfected mice and clinical parameters were evaluated. Following 7 days, the caeca were collected for histopathology, morphometry and immunohistochemical staining of MUC-2, CDC-47 and IgA. The treatment reduced diarrhoea and the presence of blood in the faeces and diminished the area of necrosis, also causing weight gain. Also, the addition of this bacterium enhanced the expression of the mucin (MUC-2). The reduction in necrosis and increased CDC-47 expression indicates significant epithelial regeneration. The negative correlation between CDC-47 and the necrosis area reveals that the bacterium favoured the recovery of the necrotic regions and the positive correlation found between the expression of MUC-2 and CDC-47 indicates that the epithelial regeneration also supports the synthesis of MUC-2. CONCLUSIONS: Weissella paramesenteroides WpK4 was able to increase the protection of the intestinal mucosa against experimental amoebic colitis through the increase of MUC-2 and epithelial regeneration. SIGNIFICANCE AND IMPACT OF THE STUDY: Weissella paramesenteroides WpK4 presents the potential to become a complementary tool in the treatment of amoebic colitis.

Prevalence of enteroparasitic infections and related hormonal and immunological repercussions that may compromise students' physical performance.

The aim of this study was to evaluate the prevalence of enteroparasitic infections in students and their hormonal and immunological repercussions on physical development. Students of basic education of both sexes were evaluated. Parasitological stool tests were performed using the Hoffman and Kato-Katz methods. The students were divided into two groups: a control group (negative parasitological examination, N=25) and an infected group (positive parasitological test, N=25). Anthropometric variables (height, weight, and BMI), concentrations of hormones (melatonin and cortisol), cytokine/chemokine levels (IL-1ß, IL-6, IL-8, IL-10, IL-12, IL-17 and TNF-α) and physical performance (aerobic capacity, upper- and lower-limb muscle strength and abdominal performance) were evaluated. The prevalence of parasitic infection among the students was 7.98%. No anthropometric differences were observed among the groups. IL-2 and TNF-α levels were higher and IL-8 levels were lower in serum from students who were positive for parasitic infection. Serum from students who were positive for parasitic infection showed higher levels of melatonin than that from parasitenegative students. No differences were observed in cortisol levels. Students who were positive for parasitic infection presented greater lower-limb strength and lower abdominal performance than parasite-negative students. In the parasitic infection group, IL-12 was positively correlated with melatonin. In the parasitic infection group, IL-8 showed a positive correlation with aerobic capacity, while IL-17 and TNF-α showed a positive correlation with abdominal performance. These data suggest that parasitic infections determine the profile of inflammatory cytokines and that melatonin may be involved in the control of this process to minimize tissue damage. Additionally, students' difficulty in practising physical exercises can be an indication of enteroparasitic infection.

Probiotic effect of Bifidobacterium longum 51A and Weissella paramesenteroides WpK4 on gerbils infected with Giardia lamblia.

AIMS: The objective of this study was to assess the probiotic potential of genuine strains of Bifidobacterium longum 51A and Weissella paramesenteroides WpK4, in experimental giardiasis. METHODS AND RESULTS: The bacteria were administered orally to gerbils (Meriones unguiculatus) 10 days before oral infection with trophozoites of Giardia lamblia. After 7 days of infection, the animals were euthanized and portions of the duodenum were processed for histopathologic, histochemical and morphometric assessment. The height of the intestinal crypts and crypt/villi ratio were higher in infected groups (P < 0·05) than in noninfected groups. The area of mucus production was higher (P < 0·05) in infected animals pretreated with B. longum 51A than in other groups. The parasitic load of the animals that received both bacteria decreased significantly (P < 0·05) compared to the ones of the control group. CONCLUSIONS: Our results suggest a probiotic function of B. longum 51A and W. paramesenteroides WpK4 and may result in their use as a prophylactic and therapeutic alternative for promoting human and animal health. SIGNIFICANCE AND IMPACT OF THE STUDY: Bifidobacterium longum 51A and W. paramesenteroides WpK4 may constitute prophylactic alternatives, reversing the emergence of side effects and resistance observed in the conventional treatment of giardiasis.

Effect of probiotic Saccharomyces boulardii in experimental giardiasis.

The aim of the study was to assess the efficacy of Saccharomyces boulardii in experimental treatment of giardiasis and its impact on intestinal integrity and some functions of gerbils infected with Giardia lamblia. 28 gerbils (Meriones unguiculatus), aged 4-6 weeks, were divided into four groups: untreated and uninfected control (CT); infected with G. lamblia (IGL); treated with S. boulardii (SB); and infected with G. lamblia and treated with S. boulardii (ITSB). The SB and ITSB groups received S. boulardii 15 days prior to being infected with G. lamblia. The treatment continued until completion of the experiment (22nd day). The IGL and ITSB groups were gavage-inoculated with G. lamblia ensuring one-week infection. 4 h before euthanasia, all animals were gavaged with a solution containing diethylenetriamine-pentaacetic acid (DTPA) marked with technetium-99mTc DTPA to determine intestinal permeability. The small intestine was removed for histopathological, morphometric analysis and count of trophozoites adhered to the mucosa. The selected probiotic caused an approximate reduction of 70% of parasite load, which was determined by attached trophozoites (P<0.01) and immune-marked trophozoites (P<0.05). Treatment with S. boulardii (SB and ITSB groups) also increased the height of the intestinal villi and crypt depth compared to the CT and IGL groups (P<0.05). The area of mucus production and the number of goblet cells of the SB and ITSB groups were higher compared to the CT and IGL groups (P<0.01). The animals treated with S. boulardii also exhibited a significant increase of intraepithelial lymphocytes counts (P<0.01). There was no difference in the intestinal permeability between the groups studied. The efficacy of S. boulardii in reducing damages caused by Giardia was demonstrated, with an approximate reduction of 70% of the parasite load, suggesting its use as a coadjuvant in giardiasis treatment.

Packing loops into annular cavities.

The continuous packing of a flexible rod in two-dimensional cavities yields a countable set of interacting domains that resembles nonequilibrium cellular systems and belongs to a new class of lightweight material. However, the link between the length of the rod and the number of domains requires investigation, especially in the case of non-simply connected cavities, where the number of avoided regions emulates an effective topological temperature. In the present article we report the results of an experiment of injection of a single flexible rod into annular cavities in order to find the total length needed to insert a given number of loops (domains of one vertex). Using an exponential model to describe the experimental data we quite minutely analyze the initial conditions, the intermediary behavior, and the tight packing limit. This method allows the observation of a new fluctuation phenomenon associated with instabilities in the dynamic evolution of the packing process. Furthermore, the fractal dimension of the global pattern enters the discussion under a novel point of view. A comparison with the classical problems of the random close packing of disks and jammed disk packings is made.

Crumpling Damaged Graphene.

Through molecular mechanics we find that non-covalent interactions modify the fractality of crumpled damaged graphene. Pristine graphene membranes are damaged by adding random vacancies and carbon-hydrogen bonds. Crumpled membranes exhibit a fractal dimension of 2.71 ± 0.02 when all interactions between carbon atoms are considered, and 2.30 ± 0.05 when non-covalent interactions are suppressed. The transition between these two values, obtained by switching on/off the non-covalent interactions of equilibrium configurations, is shown to be reversible and independent on thermalisation. In order to explain this transition, we propose a theoretical model that is compatible with our numerical findings. Finally, we also compare damaged graphene membranes with other crumpled structures, as for instance polymerised membranes and paper sheets, that share similar scaling properties.

Scaling, crumpled wires, and genome packing in virions.

The packing of a genome in virions is a topic of intense current interest in biology and biological physics. The area is dominated by allometric scaling relations that connect, e.g., the length of the encapsulated genome and the size of the corresponding virion capsid. Here we report scaling laws obtained from extensive experiments of packing of a macroscopic wire within rigid three-dimensional spherical and nonspherical cavities that can shed light on the details of the genome packing in virions. We show that these results obtained with crumpled wires are comparable to those from a large compilation of biological data from several classes of virions.

Crumpled states of a wire in a cubic cavity with periodic obstacles.

In this paper, we study experimentally the configurations of a plastic wire injected into a cubic cavity containing periodic obstacles placed along a fixed direction. The wire moves in a wormlike manner within the cavity until it becomes jammed in a crumpled state. The maximum packing fraction of the wire depends on the topology of the cavity, which in turn depends on the number of obstacles. The experimental results exhibit scaling laws and display similarities as well as differences with a recently reported two-dimensional version of this complex packing problem. We discuss in detail several aspects of this problem that seem as intricate as the problem of a self-avoiding random walk. Analogies between the experiment reported and some statistical aspects of the bond-percolation problem, as well as of the interacting electron gas at finite temperature, and other physical issues are also discussed.

Mobile health in emerging countries: a survey of research initiatives in Brazil.

OBJECTIVE: To conduct a comprehensive survey of mobile health (mHealth) research initiatives in Brazil, discussing current challenges, gaps, opportunities and tendencies. METHODS: Systematic review of publicly available electronic documents related to mHealth, including scientific publications, technical reports and descriptions of commercial products. Specifically, 42 projects are analyzed and classified according to their goals. This analysis considers aspects such as security features provided (if any), the health condition that are focus of attention, the main providers involved in the projects development and deployment, types of devices used, target users, where the projects are tested and/or deployed, among others. RESULTS: The study shows a large number (86%) of mHealth solutions focused on the following categories: health surveys, surveillance, patient records and monitoring. Meanwhile, treatment compliance, awareness raising and decision support systems are less explored. The main providers of solutions are the universities (56%) and health units (32%), with considerable cooperation between such entities. Most applications have physicians (55%) and Community Health Agents (CHAs) (33%) as targeted users, the latter being important elements in nation-wide governmental health programs. Projects focused on health managers, however, are a minority (5%). The majority of projects do not focus on specific diseases but rather general health (57%), although solutions for hearth conditions are reasonably numerous (21%). Finally, the lack of security mechanisms in the majority of the surveyed solutions (52%) may hinder their deployment in the field due to the lack of compliance with general regulations for medical data handling. CONCLUSION: There are currently many mHealth initiatives in Brazil, but some areas have not been much explored, such as solutions for treatment compliance and awareness raising, as well as decision support systems. Another research trend worth exploring refers to creating interoperable security mechanisms, especially for widely explored mHealth categories such as health surveys, patient records and monitoring. Challenges for the expansion of mHealth solutions, both in number and coverage, include the further involvement of health managers in the deployment of such solutions and in coordinating efforts among health and research institutions interested in the mHealth trend, possibly exploring the widespread presence of CHAs around the country as users of such technology.

[Churg-Strauss syndrome: a disabling disease]. / Síndrome de churg-strauss: uma doença incapacitante.

Churg-Strauss syndrome (CSS) is an infrequent vasculitis that affects small to medium-sized vessels. We describe a 51 year-old-female admitted to our inpatient unit with bullae on her right foot and forearm with pain, paresthesias and impotence of the foot. There was rapid clinical deterioration with lost of gait and peripheral eosinophilia. Histopathology showed many extravascular eosinophils. Bone marrow had an increased number of eosinophils and their precursors with no neoplastic cells infiltration. Electromyogram revealed mononeuritis multiplex with bilateral sciatic and right femoral nerve involvement. She fulfilled the eligibility criteria of American College of Rheumatology (ACR) and Chapell Hill Conference Consensus (CHCC) of CSS so corticosteroids and cyclophosphamide and rehabilitation program were begun with good clinical and laboratorial response. This report illustrates the importance of identifying atypical cutaneous features of CSS for the early diagnosis of this rare condition and the role of a multidisciplinary team in this multissystemic disease.

Histopathological and immunohistochemical study of the hepatic lesions experimentally induced by Entamoeba dispar.

The sequence of hepatic necrotic-inflammatory events produced by Entamoeba dispar are originally described in this work. For the first time were described in details the experimental lesions produced by E. dispar, as well as the distribution of the trophozoites detected by the immunohistochemistry. Animals experimentally infected with E. dispar presented necrosis, thrombosis and chronic granulomatous inflammation. Immunoreactive products derived from trofozoites were observed close or associated with trophozoites, epithelioid cells, leucocytes and hepatocytes. Few are the articles on the literature about virulence of E. dispar, which is approximately 9 times more frequent than to E. histolytica. Variation in the virulence is, therefore expected and signalizing the need of the continuity of studies with E. dispar strains from different places in the world. Taking into account that E. dispar is a closely related species to E. histolytica, these studies could determine new elements involved with E. histolytica pathogenesis, helping us to understand better the disease.

Crumpled states of a wire in a two-dimensional cavity with pins.

In this paper, we report an extensive experimental study of the configurations of a plastic wire injected into a two-dimensional planar cavity populated with fixed pins. The wire is not allowed to cross any pin, but it can move in a wormlike manner within the cavity until to become jammed in a crumpled state. The jammed packing fraction depends heavily on the topology of the cavity, which depends on the number of pins. The experiment reveals nontrivial entanglement effects and scaling laws which are largely independent of the details of the distribution of pins, the symmetry of the cavity or the type of the wire. A mean-field model for the process is presented and analogies with some basic aspects of statistical thermodynamics are discussed.

Giardia duodenalis: kinetics of cyst elimination and the systemic humoral and intestinal secretory immune responses in gerbils (Meriones unguiculatus) experimentally infected.

This study aimed to determine the pre-patent period and to evaluate the kinetics of cyst elimination and the systemic humoral (IgA, IgG(1), IgG(2a), IgM, IgE) and intestinal secretory (IgA) immune responses in gerbils (Meriones unguiculatus) experimentally innoculated with different doses of Giardia duodenalis trophozoites. Forty-eight animals aged 6-8 weeks were used, equally distributed among six groups, five groups innoculated with different doses of trophozoites (10(1), 10(2), 10(3), 10(4), 10(5)) and one control (non-infected) group. Coproparasitological examinations were carried out daily up to 91 days after inoculation (d.a.i.) to determine the pre-patent period and the kinetics of cyst elimination. Blood and stool samples were weekly collected for antibody assays. The pre-patent period was observed from the 9 d.a.i. onwards, with intermittent elimination of variable quantities of cysts up to 27 d.a.i.. All infected gerbils, irrespective of the dose received, were able to mount systemic humoral immune responses as evidenced by specific IgM titers from 7 to 28 d.a.i., corresponding to the peak of cyst elimination, followed by high and persistent IgG1 titers. Intestinal secretory responses were also seen with two peaks of fecal IgA titers, corresponding to IgM and IgG1 response peaks, respectively. In conclusion, systemic and intestinal humoral immune responses were related to the control of giardiasis in this experimental model.

Metformin inhibits inflammatory angiogenesis in a murine sponge model.

To investigate the effects of metformin on angiogenesis, on inflammatory cell accumulation and on production of endogenous cytokines in sponge implant in mice. Polyester-polyurethane sponges were implanted in Swiss mice and metformin (40 or 400mg/kg/day) was given orally for six days. The implants collected at day 7 postimplantation were processed for the assessment of hemoglobin (Hb), myeloperoxidase (MPO), N-acetylglucosaminidase (NAG) e collagen used as indexes for angiogenesis, neutrophil and macrophage accumulation and extracellular matrix deposition, respectively. Relevant inflammatory, angiogenic and fibrogenic cytokines were also determined. Metformin treatment attenuated the main components of the fibrovascular tissue, wet weight, vascularization (Hb content), macrophage recruitment (NAG activity), collagen deposition and the levels of transforming growth factor (TGF-beta1) intraimplant. A regulatory function of metformin on multiple parameters of main components of inflammatory angiogenesis has been revealed giving insight into the potential therapeutic underlying the actions of metformin.