Literacy Research: Issues of Authority, Ownership, and Representation

With the “social turn” of language in the past decade within English studies, ethnographic and teacher research methods increasingly have acquired legitimacy as a means of studying student literacy. And with this legitimacy, graduate students specializing in literacy and composition studies increasingly are being encouraged to use ethnographic and teacher research methods to study student literacy within classrooms. Yet few of the narratives produced from these studies discuss the problems that frequently arise when participant observers enter the classroom. Recently, some researchers have begun to interrogate the extent to which ethnographic and teacher research methods are able to construct and disseminate knowledge in empowering ways (Anderson & Irvine, 1993; Bishop, 1993; Fine, 1994; Fleischer. 1994; McLaren, 1992). While ethnographic and teacher research methods have oftentimes been touted as being more democratic and nonhierarchical than quantitative methods—-which oftentimes erase individuals lived experiences with numbers and statistical formulas—-researchers are just beginning to probe the ways that ethnographic and teacher research models can also be silencing, unreflective, and oppressive. Those who have begun to question the ethics of conducting, writing about, and disseminating knowledge in education have coined the term “critical” research, a rather vague and loose term that proposes a position of reflexivity and self-critique for all research methods, not just ethnography or teacher research. Drawing upon theories of feminist consciousness-raising, liberatory praxis, and community-action research, theories of critical research aim to involve researchers and participants in a highly participatory framework for constructing knowledge, an inquiry that seeks to question, disrupt, or intervene in the conditions under study for some socially transformative end. While critical research methods are always contingent upon the context being studied, in general they are undergirded by principles of non-hierarchical relations, participatory collaboration, problem-posing, dialogic inquiry, and multiple and multi-voiced interpretations. In distinguishing between critical and traditional ethnographic processes, for instance, Peter McLaren says that critical ethnography asks questions such as “[u]nder what conditions and to what ends do we. as educational researchers, enter into relations of cooperation. mutuality, and reciprocity with those who we research?” (p. 78) and “what social effects do you want your evaluations and understandings to have?” (p. 83). In»the same vein, Michelle Fine suggests that critical researchers must move beyond notions of the etic/emic dichotomy of researcher positionality in order to “probe how we are in relation with the contexts we study and with our informants, understanding that we are all multiple in those relations” (p. 72). Researchers in composition and literacy stud¬ies who endorse critical research methods, then, aim to enact some sort of positive transformative change in keeping with the needs and interests of the participants with whom they work.

Non-invasive brain stimulation for the management of arterial hypertension

The neural control of the cardiovascular system is a complex process that involves many structures at different levels of nervous system. Several cortical areas are involved in the control of systemic blood pressure, such as the sensorimotor cortex, the medial prefrontal cortex and the insular cortex. Non-invasive brain stimulation techniques - repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) - induce sustained and prolonged functional changes of the human cerebral cortex. rTMS and tDCS has led to positive results in the treatment of some neurological and psychiatric disorders. Because experiments in animals show that cortical modulation can be an effective method to regulate the cardiovascular system, non-invasive brain stimulation might be a novel tool in the therapeutics of human arterial hypertension. We here review the experimental evidence that non-invasive brain stimulation can influence the autonomic nervous system and discuss the hypothesis that focal modulation of cortical excitability by rTMS or tDCS can influence sympathetic outflow and, eventually, blood pressure, thus providing a novel therapeutic tool for human arterial hypertension. (C) 2009 Published by Elsevier Ltd.

A novel protein refolding protocol for the solubilization and purification of recombinant peptidoglycan-associated lipoprotein from Xylella fastidiosa overexpressed in Escherichia coil

Xylella fastidiosa is a Gram-negative xylem-limited plant pathogenic bacterium responsible for several economically important crop diseases. Here, we present a novel and efficient protein refolding protocol for the solubilization and purification of recombinant X. fastidiosa peptidoglycan-associated lipoprotein (XfPal). Pal is an outer membrane protein that plays important roles in maintaining the integrity of the cell envelope and in bacterial pathogenicity. Because Pal has a highly hydrophobic N-terminal domain, the heterologous expression studies necessary for structural and functional protein characterization are laborious once the recombinant protein is present in inclusion bodies. Our protocol based on the denaturation of the XfPal-enriched inclusion bodies with 8 M urea followed by buffer-exchange steps via dialysis proved effective for the solubilization and subsequent purification of XfPal, allowing us to obtain a large amount of relatively pure and folded protein. In addition, XfPal was biochemically and functionally characterized. The method for purification reported herein is valuable for further research on the three-dimensional structure and function of Pal and other outer membrane proteins and can contribute to a better understanding of the role of these proteins in bacterial pathogenicity, especially with regard to the plant pathogen X. fastidiosa. (C) 2012 Elsevier Inc. All rights reserved.

Changes in the expression of proteins associated with aerobic glycolysis and cell migration are involved in tumorigenic ability of two glioma cell lines

Background: The most frequent and malignant brain cancer is glioblastoma multiforme (GBM). In gliomas, tumor progression and poor prognosis are associated with the tumorigenic ability of the cells. U87MG cells (wild-type p53) are known to be tumorigenic in nude mice, but T98G cells (mutant p53) are not tumorigenic. We investigated the proteomic profiling of these two cell lines in order to gain new insights into the mechanisms that may be involved in tumorigenesis. Results: We found 24 differentially expressed proteins between T98G and U87MG cells. Gene Ontology supports the notion that over-representation of differentially expressed proteins is involved in glycolysis, cell migration and stress oxidative response. Among those associated with the glycolysis pathway, TPIS and LDHB are up-regulated in U87MG cells. Measurement of glucose consumption and lactate production suggests that glycolysis is more effective in U87MG cells. On the other hand, G6PD expression was 3-fold higher in T98G cells and this may indicate a shift to the pentose-phosphate pathway. Moreover, GRP78 expression was also three-fold higher in T98G than in U87MG cells. Under thapsigargin treatment both cell lines showed increased GRP78 expression and the effect of this agent was inversely correlated to cell migration. Quantitative RT-PCR and immunohistochemistry of GRP78 in patient samples indicated a higher level of expression of GRP78 in grade IV tumors compared to grade I and non-neoplastic tissues, respectively. Conclusions: Taken together, these results suggest an important role of proteins involved in key functions such as glycolysis and cell migration that may explain the difference in tumorigenic ability between these two glioma cell lines and that may be extrapolated to the differential aggressiveness of glioma tumors.

Interference of some aqueous two-phase system phase-forming components in protein determination by the Bradford method

The interference of some specific aqueous two-phase system (ATPS) phase-forming components in bovine serum albumin (BSA) determination by the Bradford method was investigated. For this purpose, calibration curves were obtained for BSA in the presence of different concentrations of salts and polymers. A total of 19 salts [Na2SO4, (NH4)(2)SO4, MgSO4, LiSO4, Na2HPO4, sodium phosphate buffer (pH 7.0), NaH2PO4, K2HPO4, potassium phosphate buffer (pH 7.0), KH2PO4, C6H8O7, Na3C6HSO7, KCHO2, NaCHO2, NaCO3, NaHCO3, C2H4O2, sodium acetate buffer (pH 4.5), and NaC2H3O2] and 7 polymers [PEG 4000, PEG 8000, PEG 20000, UCON 3900, Ficoll 70000, PES 100000, and PVP 40000] were tested, and each calibration curve was compared with the one obtained for BSA in water. Some concentrations of salts and polymers had considerable effect in the BSA calibration curve. Carbonate salts were responsible for the highest salt interference, whereas citric and acetic acids did not produce interference even in the maximum concentration level tested (5 wt%). Among the polymers, UCON gave the highest interference, whereas Ficoll did not produce interference when used in concentrations up to 10 wt%. It was concluded that a convenient dilution of the samples prior to the protein quantification is needed to ensure no significant interference from ATPS phase-forming constituents. (C) 2011 Elsevier Inc. All rights reserved.

Development and validation of a high-performance liquid chromatography method for quantification of egonol and homoegonol in Styrax species

Styrax camporum Pohl, known in Brazil as estoraque do campo or cuia de brejo, has been used in the treatment of gastrointestinal diseases. The therapeutic action of S. camporum has been attributed to the ethyl acetate fraction, although the chemical composition of this fraction has not yet been analyzed. In this study, a high-performance liquid chromatography photodiode array detection (HPLC-PAD) method for analysis of Brazilian Styrax species has been developed. The compounds egonol (1) and homoegonol (2) were found to be present in all the samples investigated by HPLC. These compounds were isolated by open column chromatography followed by preparative TLC, and were identified by 1H NMR. Compounds 1 and 2 were thus proposed as phytochemical markers for Styrax, owing to their biological properties and presence in other Styrax species. The developed method has been validated and successfully applied for quantification of 1 and 2 in S. camporum dried leaves and crude ethanolic extracts from S. ferrugineus and S. pohlii aerial parts. Copyright (c) 2011 John Wiley & Sons, Ltd.

Sensitive and fast determination of Sudan dyes in chilli powder by partial-filling micellar electrokinetic chromatography-tandem mass spectrometry

A fast and sensitive method for the simultaneous determination of Sudan dyes (I, II, III, and IV) in food samples was developed for the first time using partial filling micellar electrokinectic chromatography-mass spectrometry (MEKC-MS). The use of MEKC was essential to achieve the separation of these neutral analytes, while the partial filling technique was necessary to avoid the contamination of the ion source with non-volatile micelles. MEKC separation and MS detection conditions were optimized in order to achieve a fast, efficient, and sensitive separation of the four dyes. Filling 25% of the capillary with an MEKC solution containing 40 mM ammonium bicarbonate, 25 mM SDS, and 32.5% (v/v) acetonitrile, a baseline separation of the four azo-dyes was obtained in 10 min. Tandem MS was investigated in order to improve the sensitivity and selectivity of the analysis. Limits of detection (LOD) values 5, 8, 15, and 29 times better were obtained for Sudan III, I, II, and IV, respectively, using partial filling MEKC-MS/MS instead of partial filling MEKC-MS. Under optimized conditions, LOD from 0.05 to 0.2 mu g/mL were obtained. The suitability of the developed method was demonstrated through the fast and sensitive determination of Sudan I, II, III, and IV in spiked chilli powder samples. This determination could not be achieved by MEKC-UV due to the existence of several interfering compounds from the matrix.

Translocation capture sequencing: A method for high throughput mapping of chromosomal rearrangements

Chromosomal translocations require formation and joining of DNA double strand breaks (DSBs). These events disrupt the integrity of the genome and are involved in producing leukemias, lymphomas and sarcomas. Translocations are frequent, clonal and recurrent in mature B cell lymphomas, which bear a particularly high DNA damage burden by virtue of activation-induced cytidine deaminase (AID) expression. Despite the ubiquity of genomic rearrangements, the forces that underlie their genesis are not well understood. Here, we provide a detailed description of a new method for studying these events, translocation capture sequencing (TC-Seq). TC-Seq provides the means to document chromosomal rearrangements genome-wide in primary cells, and to discover recombination hotspots. Demonstrating its effectiveness, we successfully estimate the frequency of c-myc/IgH translocations in primary B cells, and identify hotspots of AID-mediated recombination. Furthermore. TC-Seq can be adapted to generate genome-wide rearrangement maps in any cell type and under any condition. (C) 2011 Elsevier B.V. All rights reserved.

DETERMINATION OF CHLORFENVINPHOS, FIPRONIL, AND CYPERMETHRIN RESIDUES IN MEAT AND BOVINE FAT USING QUECHERS METHOD AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

Analytic methods were applied and validated to measure residues of chlorfenvinphos, fipronil, and cypermethrin in meat and bovine fat, using the QuEChERS method and gas chromatography-mass spectrometry. For the meat, 2 g of sample, 4mL of acetonitrile, 1.6 g of MgSO4, and 0.4 g of NaCl were used in the liquid-liquid partition, while 80 mg of C18, 80 mg of primary and secondary amine and 150 mg of MgSO4 were employed in the dispersive solid-phase extraction. For the fat, 1 g of sample, 5 mL of hexane, 10 mL of water, 10 mL of acetonitrile, 4 g of MgSO4, and 0.5 g of NaCl were used in the liquid-liquid partition and 50 mg of primary and secondary amine and 150 mg of MgSO4 were used in the dispersive solid-phase extraction. The recovery percentages obtained for the pesticides in meat at different concentrations ranged from 81 to 129% with relative standard deviation below 27%. The corresponding results from the fat ranged from 70 to 123% with relative standard deviation below 25%. The methods showed sensitivity, precision, and accuracy according to EPA standards and quantification limits below the maximum residue limit established by European Union, except for chlorfenvinphos in the fat.

AN EFFICIENT HPLC-UV METHOD FOR THE QUANTITATIVE DETERMINATION OF CEFADROXIL IN HUMAN PLASMA AND ITS APPLICATION IN PHARMACOKINETIC STUDIES

Cefadroxil is a semi-synthetic first-generation oral cephalosporin used in the treatment of mild to moderate infections of the respiratory and urinary tracts, skin and soft tissue infections. In this work a simple, rapid, economic and sensitive HPLC-UV method is described for the quantitative determination of cefadroxil in human plasma samples using lamivudine as internal standard. Sample pre-treatment was accomplished through protein precipitation with acetonitrile and chromatographic separation was performed with a mobile phase consisting of a mixture of sodium dihydrogen phosphate monohydrate solution, methanol and acetonitrile in the ratio of 90:8:2 (v/v/v) at a flow rate of 1.0mL/min. The proposed method is linear between 0.4 to 40.0 mu g/mL and its average recovery is 102.21% for cefadroxil and 97.94% for lamivudine. The method is simple, sensitive, reproducible, less time consuming for determination of cefadroxil in human plasma. The method can therefore be recommended for pharmacokinetics studies, including bioavailability and bioequivalence studies.

Functional Magnetic Resonance Imaging Data Analysis by Autoregressive Estimator

The autoregressive (AR) estimator, a non-parametric method, is used to analyze functional magnetic resonance imaging (fMRI) data. The same method has been used, with success, in several other time series data analysis. It uses exclusively the available experimental data points to estimate the most plausible power spectra compatible with the experimental data and there is no need to make any assumption about non-measured points. The time series, obtained from fMRI block paradigm data, is analyzed by the AR method to determine the brain active regions involved in the processing of a given stimulus. This method is considerably more reliable than the fast Fourier transform or the parametric methods. The time series corresponding to each image pixel is analyzed using the AR estimator and the corresponding poles are obtained. The pole distribution gives the shape of power spectra, and the pixels with poles at the stimulation frequency are considered as the active regions. The method was applied in simulated and real data, its superiority is shown by the receiver operating characteristic curves which were obtained using the simulated data.

Differences in Evolution of Children with Non-severe Acute Lower Respiratory Tract Infection With and Without Radiographically Diagnosed Pneumonia

Objective: To identify differences in the evolution of children with non-severe acute lower respiratory tract infection between those with and without radiographically diagnosed pneumonia. Design: Prospective cohort study. Setting: A public university pediatric hospital in Salvador, Northeast Brazil. Patients: Children aged 2-59 months. Methods: By active surveillance, the pneumonia cases were prospectively identified in a 2-year period. Each case was followed-up for changes in various clinical symptoms and signs. Demographic, clinical and radiographic data were recorded in standardized forms. Exclusion was due to antibiotic use in the previous 48 hours, signs of severe disease, refusal to give informed consent, underlying chronic illness, hospitalization in the previous 7 days or amoxicillin allergy. Chest X-ray (CXR) was later read by at least 2 independent pediatric radiologists. Main Outcome Measures: Radiographic diagnosed pneumonia based on agreed detection of pulmonary infiltrate or pleural effusion in 2 assessments. Results: A total of 382 patients receiving amoxicillin were studied, of whom, 372 (97.4%) had concordant radiographic diagnosis which was pneumonia (52%), normal CXR (41%). and others (7%). By multivariate analysis, age (OR=1.03; 95% CI: 1.02-1.05), disease >= 5days (OR = 1.04; 95% CI: 1.001-1.08), reduced pulmonary expansion (OR = 3.3; 95% CI: 1.4-8.0), absence of wheezing (OR = 0.5; 95% CI: 0.3-0.9), crackles on admission (OR = 2.0; 95% CI: 1.2-3.5), inability to drink on day 1 (OR = 4.2; 95% CI: 1.05-17.3), consolidation percussion sign (OR = 7.0; 95% CI: 1.5-32.3), tachypnea (OR = 2.0; 95% CI: 1.09-3.6) and fever (OR = 3.6; 95% CI: 1.4-9.4) on day 2 were independently associated with pneumonia. The highest positive predictive value was at the 2nd day of evolution for tachypnea (71.0%) and fever (81.1%). Conclusion: Persistence of fever or tachypnea up to the second day of amoxicillin treatment is predictive of radiographically diagnosed pneumonia among children with non-severe lower respiratory tract diseases.

Platelet-derived exosomes induce endothelial cell apoptosis through peroxynitrite generation: experimental evidence for a novel mechanism of septic vascular dysfunction

Abstract Introduction Several studies link hematological dysfunction to severity of sepsis. Previously we showed that platelet-derived microparticles from septic patients induce vascular cell apoptosis through the NADPH oxidase-dependent release of superoxide. We sought to further characterize the microparticle-dependent vascular injury pathway. Methods During septic shock there is increased generation of thrombin, TNF-α and nitric oxide (NO). Human platelets were exposed for 1 hour to the NO donor diethylamine-NONOate (0.5 μM), lipopolysaccharide (LPS; 100 ng/ml), TNF-α (40 ng/ml), or thrombin (5 IU/ml). Microparticles were recovered through filtration and ultracentrifugation and analyzed by electron microscopy, flow cytometry or Western blotting for protein identification. Redox activity was characterized by lucigenin (5 μM) or coelenterazine (5 μM) luminescence and by 4,5-diaminofluorescein (10 mM) and 2',7'-dichlorofluorescein (10 mM) fluorescence. Endothelial cell apoptosis was detected by phosphatidylserine exposure and by measurement of caspase-3 activity with an enzyme-linked immunoassay. Results Size, morphology, high exposure of the tetraspanins CD9, CD63, and CD81, together with low phosphatidylserine, showed that platelets exposed to NONOate and LPS, but not to TNF-α or thrombin, generate microparticles similar to those recovered from septic patients, and characterize them as exosomes. Luminescence and fluorescence studies, and the use of specific inhibitors, revealed concomitant superoxide and NO generation. Western blots showed the presence of NO synthase II (but not isoforms I or III) and of the NADPH oxidase subunits p22phox, protein disulfide isomerase and Nox. Endothelial cells exposed to the exosomes underwent apoptosis and caspase-3 activation, which were inhibited by NO synthase inhibitors or by a superoxide dismutase mimetic and totally blocked by urate (1 mM), suggesting a role for the peroxynitrite radical. None of these redox properties and proapoptotic effects was evident in microparticles recovered from platelets exposed to thrombin or TNF-α. Conclusion We showed that, in sepsis, NO and bacterial elements are responsible for type-specific platelet-derived exosome generation. Those exosomes have an active role in vascular signaling as redox-active particles that can induce endothelial cell caspase-3 activation and apoptosis by generating superoxide, NO and peroxynitrite. Thus, exosomes must be considered for further developments in understanding and treating vascular dysfunction in sepsis.

Low sclerostin levels: a predictive marker of persistent inflammation in ankylosing spondylitis during anti-tumor necrosis factor therapy?

Abstract Introduction Sclerostin levels have been reported to be low in ankylosing spondylitis (AS), but there is no data regarding the possible role of this Wnt inhibitor during anti-tumor necrosis factor (TNF) therapy. The present study longitudinally evaluated sclerostin levels, inflammatory markers and bone mineral density (BMD) in AS patients under anti-TNF therapy. Methods Thirty active AS patients were assessed at baseline, 6 and 12 months after anti-TNF therapy regarding clinical parameters, inflammatory markers, BMD and baseline radiographic damage (mSASSS). Thirty age- and sex-matched healthy individuals comprised the control group. Patients' sclerostin levels, sclerostin binding low-density lipoprotein receptor-related protein 6 (LRP6) and BMD were evaluated at the same time points and compared to controls. Results At baseline, AS patients had lower sclerostin levels (60.5 ± 32.7 vs. 96.7 ± 52.9 pmol/L, P = 0.002) and comparable sclerostin binding to LRP6 (P = 0.387) than controls. Improvement of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), Ankylosing Spondylitis quality of life (ASQoL) was observed at baseline vs. 6 vs. 12 months (P < 0.01). Concomitantly, a gradual increase in spine BMD (P < 0.001) and a positive correlation between baseline mSASSS and spine BMD was found (r = 0.468, P < 0.01). Inflammatory parameters reduction was observed comparing baseline vs. 6 vs. 12 months (P <0.01). Sclerostin levels progressively increased [baseline (60.5 ± 32.7) vs. 6 months (67.1 ± 31.9) vs. 12 months (72.7 ± 32.3) pmol/L, P <0.001]. At 12 months, the sclerostin levels remained significantly lower in patients compared to controls (72.7 ± 32.3 vs. 96.70 ± 52.85 pmol/L, P = 0.038). Moreover, sclerostin serum levels at 12 months were lower in the 10 patients with high C reactive protein (CRP) (≥ 5 mg/l) compared to the other 20 patients with normal CRP (P = 0.004). Of note, these 10 patients with persistent inflammation also had lower sclerostin serum levels at baseline compared to the other patients (P = 0.023). Univariate logistic regression analysis demonstrated that AS patients with lower sclerostin serum levels had an increased risk to have high CRP at 12 months (odds ratio = 7.43, 95% CI 1.23 to 45.01, P = 0.020) than those with higher sclerostin values. Conclusions Persistent low sclerostin levels may underlie continuous inflammation in AS patients under anti-TNF therapy.

Hands-on experiments in the Practicum: repositioning student teachers' autonomy.

Following a worldwide trend, the Initial Teacher Education (ITE) Programmes in Brazil are recently searching for ways of integrating practice into curriculum. It raises question about what practice must be integrated and how. Notably, university-based courses are disconnected from school and have low commitment with school issues (Zeichner, 2009).The student teacher induction into school daily life is not an easy task, mainly when the practitioners are transforming physics classroom practice toward an active learning. Drawing on cultural-historical framework (Wolff-Michael Roth & Lee, 2007; Vygotsky, 1978) this study addresses the articulation between Practicum in Physics Classes and the Hands-on Experiments (HoE) used throughout the Practicum. Although in a different level, both Practicum and HoE are linked with an idea of practice. Particularly, this study focuses on how HoE might foster student teachers' autonomy and agency in the Practicum. Data was gathered in the course Practice of Physics Teaching at University of São Paulo/Brazil in 2010; in a cohort of 60 student teachers doing a year-long Practicum in urban school in São Paulo city. Data was analysed using qualitative research methods (Roth, 2005), based on 14 interviews and video records of the student teacher preparing the HoE for Practicum we will present in general lines the role of HoE for student teacher autonomy.