Exogenous Cx43 expression decrease cell proliferation rate in rat hepatocarcinoma cells independently of functional gap junction

Background: Gap junction intercellular communication (GJIC) is considered to play a role in the regulation of homeostasis because it regulates important processes, such as cell proliferation and cell differentiation. A reduced or lost GJIC capacity has been observed in solid tumors and studies have demonstrated that GJIC restoration in tumor cells contribute to reversion of the transformed phenotype. This observation supports the idea that restoration of the functional channel is essential in this process. However, in the last years, reports have proposed that just the increase in the expression of specific connexins can contribute to reversion of the malign phenotype in some tumor cells. In the present work, we studied the effects of exogenous Connexin 43 (Cx43) expression on the proliferative behavior and phenotype of rat hepatocarcinoma cells. Results: The exogenous Cx43 did not increase GJIC capacity of transfected cells, but it was critical to decrease the cell proliferation rate as well as reorganization of the actin filaments and cell flattening. We also observed more adhesion capacity to substrate after Cx43 transfection. Conclusion: Cx43 expression leads to a decrease of the growth of the rat hepatocellular carcinoma cells and it contributes to the reversion of the transformed phenotype. These effects were independent of the GJIC and were probably associated with the phosphorylation pattern changes and redistribution of the Cx43 protein.

Theory of nitride oxide adsorption on transition metal (111) surfaces: a first-principles investigation

In this work, we report a density functional theory study of nitric oxide (NO) adsorption on close-packed transition metal (TM) Rh(111), Ir(111), Pd(111) and Pt(111) surfaces in terms of adsorption sites, binding mechanism and charge transfer at a coverage of Theta(NO) = 0.25, 0.50, 0.75 monolayer (ML). Based on our study, an unified picture for the interaction between NO and TM(111) and site preference is established, and valuable insights are obtained. At low coverage (0.25 ML), we find that the interaction of NO/TM(111) is determined by an electron donation and back-donation process via the interplay between NO 5 sigma/2 pi* and TM d-bands. The extent of the donation and back-donation depends critically on the coordination number (adsorption sites) and TM d-band filling, and plays an essential role for NO adsorption on TM surfaces. DFT calculations shows that for TMs with high d-band filling such as Pd and Pt, hollow-site NO is energetically the most favorable, and top-site NO prefers to tilt away from the normal direction. While for TMs with low d-band filling (Rh and Ir), top-site NO perpendicular to the surfaces is energetically most favorable. Electronic structure analysis show that irrespective of the TM and adsorption site, there is a net charge transfer from the substrate to the adsorbate due to overwhelming back-donation from the TM substrate to the adsorbed NO molecules. The adsorption-induced change of the work function with respect to bare surfaces and dipole moment is however site dependent, and the work function increases for hollow-site NO, but decreases for top-site NO, because of differences in the charge redistribution. The interplay between the energetics, lateral interaction and charge transfer, which is element dependent, rationalizes the structural evolution of NO adsorption on TM(111) surfaces in the submonolayer regime.

Exact nonequilibrium work generating function for a small classical system

We obtain the exact nonequilibrium work generating function (NEWGF) for a small system consisting of a massive Brownian particle connected to internal and external springs. The external work is provided to the system for a finite-time interval. The Jarzynski equality, obtained in this case directly from the NEWGF, is shown to be valid for the present model, in an exact way regardless of the rate of external work.

Composition and screening of antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves and fruits of Piper species

This study investigated the composition and antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves of Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper solmsianum and Piper umbelata and fruits of P. cernuum and P. diospyrifolium. The essentials oils were analyzed by GC-MS and submitted of the antifungal activity tests. The essential oils of fruits from P. cernuum and leaves of P. crassinervium and P. solmsianum showed potential antifungal activity against C. sphaerospermum and C. cladosporioides. In addition, this is the first report of the composition of essential oils of fruits of P. cernuum and P. diospyrifolium.

Effect of some essential oils on in vitro methane emission

The objectives of this study were to characterise four essential oils (EO) chemically and to evaluate their effect on ruminal fermentation and methane emission in vitro. The investigated EO were isolated from Achillea santolina, Artemisia judaica, Schinus terebinthifolius and Mentha microphylla, and supplemented at four levels (0, 25, 50 and 75 l) to 75ml of buffered rumen fluid plus 0.5 g of substrate. The main components of the EO were piperitone (49.1%) and camphor (34.5%) in A. judaica, 16-dimethyl 15-cyclooactdaiene (60.5%) in A. santolina, piperitone oxide (46.7%) and cis-piperitone oxide (28%) in M. microphylla, and -muurolene (45.3%) and -thujene (16.0%) in S. terebinthifolius. The EO from A. santolina (at 25 and 50 l), and all levels of A. judaica increased the gas production significantly, but S. terebinthifolius (at 50 and 75 l), A. santolina (at 75 l) and all levels of M. microphylla decreased the gas production significantly in comparison with the control. The highest levels of A. santolina and A. judaica, and all doses from M. microphylla EO inhibited the methane production along with a significant reduction in true degradation of dry matter and organic matter, protozoa count and NH3-N concentration. It is concluded that the evaluated EO have the potential to affect ruminal fermentation efficiency and the EO from M. microphylla could be a promising methane mitigating agent.

Exercise of essential competencies for midwifery care by nurses in Sao Paulo, Brazil

General objective: to analyse the exercise of essential competencies for midwifery care by nurses and/or midwives in the public health system of Sao Paulo (eastern zone), Brazil. Specific objectives: to develop a profile of the public health institutions and of the nurses and/or midwives who care for women before, during and following child birth; to identify the activities performed in providing such care, as well as their frequency; and to specify the possible obstacles or difficulties encountered by them when exercising their competencies. Design: a descriptive and exploratory research design , using a quantitative approach. Setting: the study was conducted in all public health services of Sao Paulo (eastern zone), Brazil, namely 59 basic health-care units and six hospitals, during the period of October 2006-December 2007. Participants: the study population consisted of 272 nurses and/or midwives who provide care for pregnant women and newborns at the primary health-care units and maternity hospitals of the public health system. Participants comprised 100% of hospital nurse coordinators (n = 6), 61% of hospital maternity nursing and/or midwifery staff (n = 62) and 64% (n = 204) of nursing and/or midwifery staff working at primary health-care units. Methods and findings: the data collection was based on a single form given to the coordinators and two questionnaires, one handed out to antenatal and postnatal nursing and/or midwifery staff and another handed out to labour and birth nursing and/or midwifery staff. The results showed that nurses and/or midwives providing care for women during pregnancy, labour, birth and the postnatal period did not put the essential competencies for midwifery care into practice, because they encountered institutional barriers and personal resistance, and lacked protocols based on best practice and on the exercise of essential competencies needed for effective midwifery care. Key conclusions: the model of care in the public health services of Sao Paulo (eastern zone) is based much more on hierarchical positions than on professional competencies or on there commendations of the scientific community. As a result, health authorities need to review their midwifery policies to improve maternal-infant care by nurses and/or midwives in order to ensure the implementation of best midwifery practice. Practical implications: the results of this study support actions to improve the quality of care delivered to women and their families, while integrating nursing and midwifery care in Sao Paulo, Brazil. (C) 2009 Elsevier Ltd. All rights reserved.

The contribution of self-efficacy and depression to disability and work status in chronic pain patients: A comparison between Australian and Brazilian samples

There is evidence that cognitions (beliefs) and mood contribute to physical disability and work status in people with chronic pain. However, most of the current evidence comes from North America and Europe. This study examined the contribution of demographic, pain and psychosocial factors to disability and work status in chronic pain patients in two matched samples from quite different countries (Australia and Brazil). Data were collected from 311 chronic pain patients in each country. The results suggest that although demographic and pain variables (especially pain levels) contribute disability, self-efficacy beliefs made a significant contribution to disability in both samples. Age and educational level also contributed to unemployment in both samples. But there were some differences, with self-efficacy and physical disability contributing to work status only in the Brazilian sample. In contrast, depression was the only psychological risk factor for unemployment in the Australian sample. Catastrophising and pain acceptance did not contribute to disability or unemployment in either sample. These findings confirm key aspects of biopsychosocial models of pain in two culturally and linguistically different chronic pain samples from different countries. They suggest that different chronic pain populations may share more similarities than differences. (C) 2008 European Federation of Chapters of the International Association for the Study of Pain. Published

Correlation of Modified Natural Rubber Properties by Artificial Neural Networks

Natural rubber (NR) is a raw material largely used by the modern industry; however, it is common that chemical modifications must be made to NR in order to improve properties such as hydrophobicity or mechanical resistance. This work deals with the correlation of properties of NR modified with dimethylaminoethylmethacrylate or methylmethacrylate as grafting agents. Dynamic-mechanical behavior and stress/strain relations are very important properties because they furnish essential characteristics of the material such as glass transition temperature and rupture point. These properties are concerned with different physical principles; for this reason, normally they are not related to each other. This work showed that they can be correlated by artificial neural networks (ANN). So, from one type of assay, the properties that as a rule only could be obtained from the other can be extracted by ANN correlation. POLYM. ENG. SCI., 49:499-505, 2009. (c) 2009 Society of Plastics Engineers

Optimal fermentation conditions for maximizing the ethanol production by Kluyveromyces fragilis from cheese whey powder

Cheese whey powder (CWP) is an attractive raw material for ethanol production since it is a dried and concentrated form of CW and contains lactose in addition to nitrogen, phosphate and other essential nutrients. In the present work, deproteinized CWP was utilized as fermentation medium for ethanol production by Kluyveromyces fragilis. The individual and combined effects of initial lactose concentration (50-150 kg m(-3)), temperature (25-35 degrees C) and inoculum concentration (1-3 kg m(-3)) were investigated through a 2(3) full-factorial central composite design, and the optimal conditions for maximizing the ethanol production were determined. According to the statistical analysis, in the studied range of values, only the initial lactose concentration had a significant effect on ethanol production, resulting in higher product formation as the initial substrate concentration was increased. Assays with initial lactose concentration varying from 150 to 250 kg m(-3) were thus performed and revealed that the use of 200 kg m(-3) initial lactose concentration, inoculum concentration of 1 kg m(-3) and temperature of 35 degrees C were the best conditions for maximizing the ethanol production from CWP solution. Under these conditions, 80.95 kg m(-3) of ethanol was obtained after 44 h of fermentation. (C) 2011 Elsevier Ltd. All rights reserved.

The influence of immobilized biomass and particle size on the fluid dynamics of an anaerobic fluidized bed reactor

Fluid dynamic analysis is an important branch of several chemical engineering related areas, such as drying processes and chemical reactors. However, aspects concerning fluid dynamics in wastewater treatment bioreactors still require further investigation, as they highly influence process efficiency. Therefore, it is essential to evaluate the influence of biofilm on the reactor fluid dynamic behavior, through the analysis of a few important parameters, such as minimum fluidization velocity, bed expansion and porosity, and particle terminal velocity. The main objective of the present work was to investigate the fluid dynamics of an anaerobic fluidized bed reactor, having activated carbon particles as support media for biomass immobilization. Reactor performance was tested using synthetic residual water, which was prepared using the solution employed in BOD determination. The results showed that the presence of immobilized biomass increased particle density and altered the main fluid dynamic parameters investigated.

Evaluation of the geotechnical properties of MSW in two Brazilian landfills

The characteristics of municipal solid waste (MSW) play a key role in many aspects of waste disposal facilities and landfills. Because most of a landfill is made up of MSW, the overall stability of the landfill slopes are governed by the strength parameters and physical properties of the MSW. These parameters are also important in interactions involving the waste body and the landfill structures: cover liner, leachate and gas collection systems. On the other hand, the composition of the waste, which affects the geotechnical behavior of the MSW, is dependent on a variety of factors such as climate, disposal technology, the culture and habits of the local community. It is therefore essential that the design and stability evaluations of landfills in each region be performed based on the local conditions and the geotechnical characteristic of the MSW. The Bandeirantes Landfill, BL, in Sao Paulo and the Metropolitan Center Landfill, MCL, in Salvador, are among the biggest landfills in Brazil. These two disposal facilities have been used for the development of research involving waste mechanics in recent years. Considerable work has been made in the laboratory and in the field to evaluate parameters such as water and organic contents, composition, permeability, and shear strength. This paper shows and analyzes the results of tests performed on these two landfills. The authors believe that these results could be a good reference for certain aspects and geotechnical properties of MSW materials in countries with similar conditions. (C) 2010 Elsevier Ltd. All rights reserved.

A mathematical view of biological complexity

This essay is a trial on giving some mathematical ideas about the concept of biological complexity, trying to explore four different attributes considered to be essential to characterize a complex system in a biological context: decomposition, heterogeneous assembly, self-organization, and adequacy. It is a theoretical and speculative approach, opening some possibilities to further numerical and experimental work, illustrated by references to several researches that applied the concepts presented here. (C) 2008 Elsevier B.V. All rights reserved.

A conserved dibasic site is essential for correct processing of the peptide hormone AtRALF1 in Arabidopsis thaliana

Prohormone proteins in animals and yeast are typically processed at dibasic sites by convertases. Propeptide hormones are also found in plants but little is known about processing. We show for the first time that a dibasic site upstream of a plant peptide hormone, AtRALF1, is essential for processing. Overexpression of preproAtRALF1 causes semidwarfism whereas overexpression of preproAtRALF1(R69A), the propeptide with a mutation in the dibasic site, shows a normal phenotype. RALF1(R69A) plants accumulate only the mutated proprotein and not the processed peptide. In vitro processing using microsomal fractions suggests that processing is carried out by a kexin-like convertase. (C) 2008 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.

Chemical Composition and Antioxidant/Antidiabetic Potential of Brazilian Native Fruits and Commercial Frozen Pulps

Foods provide essential and bioactive compounds with health-promoting properties such as antioxidant, anti-inflammatory, and hypocholesterolemic activities, which have been related to vitamins A, C, and E and phenolic compounds such as flavonoids. Therefore, the aim of this work was to identify potential sources of bioactive compounds through the determination of flavonoids and ellagic acid contents and the in vitro antioxidant capacity and alpha-glucosidase and alpha-amylase inhibitory activities of Brazilian native fruits and commercial frozen pulps. Camu-camu, cambuci, uxi, and tucuma and commercial frozen pulps of cambuci, cagaita, coquinho azedo, and araca presented the highest antioxidant capacities. Cambuci and cagaita exhibited the highest alpha-glucosidase and alpha-amylase inhibitory activities. Quercetin and kaempferol derivatives were the main flavonoids present in most of the samples. Ellagic acid was detected only in umbu, camu-camu, cagaita, araca, and cambuci. According to the results, native Brazilian fruits can be considered as excellent sources of bioactive compounds.

Ascorbic acid metabolism in fruits: activity of enzymes involved in synthesis and degradation during ripening in mango and guava

BACKGROUND: Ascorbic acid is a very important compound for plants. It has essential functions, mainly as an antioxidant and growth regulator. Ascorbic acid biosynthesis has been extensively studied, but studies in fruits are very limited. In this work we studied the influence of five enzymes involved in synthesis (L-galactono-1,4-lactone dehydrogenase, GalLDH, EC 1.3.2.3), oxidation (ascorbate oxidase, EC 1.10.3.3, and ascorbate peroxidase, APX, EC and recycling (monodehydroascorbate reductase, EC 1.6.5.4, and dehydroascorbate reductase, DHAR, EC 1.8.5.1) on changes in ascorbic acid content during development and ripening of mangoes (Mangifera indica L. cv. Keitt) and during the ripening of white pulp guavas (Psidium guayava L. cv. Paloma). RESULTS: It was found that there was a balance between the activities of GalLDH, APX and DHAR, both in mangoes and guavas. CONCLUSIONS: Equilibrium between the enzymatic activities of synthesis, catabolism and recycling is important for the regulation of ascorbic acid content in mango and guava. These results have contributed to understanding some of the changes that occur in ascorbic acid levels during fruit ripening. (C) 2008 Society of Chemical Industry.