A trophic study of the sympatric Amazonian freshwater turtles Podocnemis unifilis and Podocnemis expansa (Testudines, Podocnemidae) using carbon and nitrogen stable isotope analyses

The Yellow-spotted River Turtle (Podocnemis unifilis Troschel, 1848) and the South American River Turtle (Podocnemis expansa (Schweigger, 1812)) are two turtles species that are widely distributed and have ecological, economic, and cultural importance in the Amazon basin. Although sympatric regarding most of their distribution, few studies have addressed the coexistence of these two species. To examine this, we analyzed the trophic level and the primary carbon source from the diets of both species in Baixo Araguaia, Tocantins, Brazil, using stable isotope analyses of carbon (delta C-13) and nitrogen (delta N-15). We also verified possible intraspecific variations (related to sex and body mass) in the trophic levels and primary carbon sources of their diets. Podocnemis unifilis had higher values of delta N-15 than P. expansa, averaging 7.59 parts per thousand and 5.06 parts per thousand, respectively, a difference which may indicate a possible trophic change owing to exploiting different food resources. No differences were found between the two species in relation to delta C-13 (mean values of -26.2 parts per thousand and -26.1 parts per thousand, respectively). The similarity between delta C-13 values suggests that the sources of their basal feeding are the same, consisting mainly of C-3 plants. There was no intraspecific variation in the values of delta C-13 and delta N-15.

STABLE PIECEWISE POLYNOMIAL VECTOR FIELDS

Let N = {y > 0} and S = {y < 0} be the semi-planes of R-2 having as common boundary the line D = {y = 0}. Let X and Y be polynomial vector fields defined in N and S, respectively, leading to a discontinuous piecewise polynomial vector field Z = (X, Y). This work pursues the stability and the transition analysis of solutions of Z between N and S, started by Filippov (1988) and Kozlova (1984) and reformulated by Sotomayor-Teixeira (1995) in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields Z(epsilon), defined by averaging X and Y. This family approaches Z when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002) providing conditions on (X, Y) for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on R-2. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

The effect of acute magnesium loading on the maximal exercise performance of stable chronic obstructive pulmonary disease patients

OBJECTIVE: The potential influence of magnesium on exercise performance is a subject of increasing interest. Magnesium has been shown to have bronchodilatatory properties in asthma and chronic obstructive pulmonary disease patients. The aim of this study was to investigate the effects of acute magnesium IV loading on the aerobic exercise performance of stable chronic obstructive pulmonary disease patients. METHODS: Twenty male chronic obstructive pulmonary disease patients (66.2 +/- 8.3 years old, FEV1: 49.3 +/- 19.8%) received an IV infusion of 2 g of either magnesium sulfate or saline on two randomly assigned occasions approximately two days apart. Spirometry was performed both before and 45 minutes after the infusions. A symptom-limited incremental maximal cardiopulmonary test was performed on a cycle ergometer at approximately 100 minutes after the end of the infusion. ClinicalTrials.gov: NCT00500864 RESULTS: Magnesium infusion was associated with significant reductions in the functional residual capacity (-0.41 l) and residual volume (-0.47 l), the mean arterial blood pressure (-5.6 mmHg) and the cardiac double product (734.8 mmHg.bpm) at rest. Magnesium treatment led to significant increases in the maximal load reached (+8 w) and the respiratory exchange ratio (0.06) at peak exercise. The subgroup of patients who showed increases in the work load equal to or greater than 5 w also exhibited significantly greater improvements in inspiratory capacity (0.29 l). CONCLUSIONS: The acute IV loading of magnesium promotes a reduction in static lung hyperinflation and improves the exercise performance in stable chronic obstructive pulmonary disease patients. Improvements in respiratory mechanics appear to be responsible for the latter finding.

Stable assemblies of cationic bilayer fragments and CpG oligonucleotide with enhanced immunoadjuvant activity in vivo

The cationic lipid dioctadecyldimethylammonium bromide (DODAB) and the CpG oligonucleotide (CpG) have been separately used as potent immunoadjuvants driving Th1 responses. Here DODAB bilayer fragments (BF) and CpG (5 -TTGACGTTCG-3) assemblies have their physical properties and immunoadjuvant activity determined using ovalbumin (OVA) as a model antigen. At 0.1 mg/mL OVA, the dependence of DODAB BF/OVA size and zeta-potential on time and [DODAB] establishes 0.1 mMDODAB as suitable for obtaining stable and cationic DODAB BF/OVA assemblies. At 0.1 mMDODAB, 0.1 mg/mL OVA and 0.006 mMCpG, the zeta-potential is zero. At [CpG]>0.006 mM, good colloidal stability for the anionic assemblies is due to charge overcompensation. At 0.020 mM CpG, these DODAB BF/OVA/CpG assemblies are highly effective in vivo generating responses similar to those elicited by the stable and cationic DODAB BF/OVA. The anti-OVA DTH reaction and the secretion of IFN-gamma and IL-12 are 6, 42 and 9 times larger for the DODAB BF/OVA/CpG-immunized mice than the same responses by OVA-immunized mice, respectively. This work shows for the first time that charge of small assemblies is not important to determine the immune response. (C) 2011 Elsevier B. V. All rights reserved.

Effect of Complete Revascularization on 10-Year Survival of Patients With Stable Multivessel Coronary Artery Disease MASS II Trial

Background-The importance of complete revascularization remains unclear and contradictory. This current investigation compares the effect of complete revascularization on 10-year survival of patients with stable multivessel coronary artery disease (CAD) who were randomly assigned to percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). Methods and Results-This is a post hoc analysis of the Second Medicine, Angioplasty, or Surgery Study (MASS II), which is a randomized trial comparing treatments in patients with stable multivessel CAD, and preserved systolic ventricular function. We analyzed patients who underwent surgery (CABG) or stent angioplasty (PCI). The survival free of overall mortality of patients who underwent complete (CR) or incomplete revascularization (IR) was compared. Of the 408 patients randomly assigned to mechanical revascularization, 390 patients (95.6%) underwent the assigned treatment; complete revascularization was achieved in 224 patients (57.4%), 63.8% of those in the CABG group and 36.2% in the PCI group (P = 0.001). The IR group had more prior myocardial infarction than the CR group (56.2% X 39.2%, P = 0.01). During a 10-year follow-up, the survival free of cardiovascular mortality was significantly different among patients in the 2 groups (CR, 90.6% versus IR, 84.4%; P = 0.04). This was mainly driven by an increased cardiovascular specific mortality in individuals with incomplete revascularization submitted to PCI (P = 0.05). Conclusions-Our study suggests that in 10-year follow-up, CR compared with IR was associated with reduced cardiovascular mortality, especially due to a higher increase in cardiovascular-specific mortality in individuals submitted to PCI.

SUFFICIENT CONDITIONS ON DIFFUSIVITY FOR THE EXISTENCE AND NONEXISTENCE OF STABLE EQUILIBRIA WITH NONLINEAR FLUX ON THE BOUNDARY

A reaction-diffusion equation with variable diffusivity and non-linear flux boundary condition is considered. The goal is to give sufficient conditions on the diffusivity function for nonexistence and also for existence of nonconstant stable stationary solutions. Applications are given for the main result of nonexistence.

Cwc24p Is a General Saccharomyces cerevisiae Splicing Factor Required for the Stable U2 snRNP Binding to Primary Transcripts

Splicing of primary transcripts is an essential process for the control of gene expression. Specific conserved sequences in premature transcripts are important to recruit the spliceosome machinery. The Saccharomyces cerevisiae catalytic spliceosome is composed of about 60 proteins and 5 snRNAs (U1, U2, U4/U6 and U5). Among these proteins, there are core components and regulatory factors, which might stabilize or facilitate splicing of specific substrates. Assembly of a catalytic complex depends on the dynamics of interactions between these proteins and RNAs. Cwc24p is an essential S. cerevisiae protein, originally identified as a component of the NTC complex, and later shown to affect splicing in vivo. In this work, we show that Cwc24p also affects splicing in vitro. We show that Cwc24p is important for the U2 snRNP binding to primary transcripts, co-migrates with spliceosomes, and that it interacts with Brr2p. Additionally, we show that Cwc24p is important for the stable binding of Prp19p to the spliceosome. We propose a model in which Cwc24p is required for stabilizing the U2 association with primary transcripts, and therefore, especially important for splicing of RNAs containing non- consensus branchpoint sequences.

Expression Analysis of Wound Healing Genes in Human Periapical Granulomas of Progressive and Stable Nature

Introduction: Wound healing process involves the activation of extracellular matrix components, remodeling enzymes, cellular adhesion molecules, growth factors, cytokines and chemokines genes. However, the molecular patterns underlying the healing process periapical environment remain unclear. Here we hypothesized that endodontic infection might result in an imbalance in the expression of wound healing genes involved in the pathogenesis of periapical lesions. Furthermore, we suggest that differential expression of wound healing markers in active and latent granulomas could account for different clinical outcomes for such lesions. Methods: Study samples consisted of 93 periapical granulomas collected after endodontic surgeries and 24 healthy periodontal ligament tissues collected from premolars extracted for orthodontic purposes as control samples. Of these, 10 periapical granulomas and 5 healthy periapical tissues were used for expression analysis of 84 wound healing genes by using a pathway-specific real-time polymerase chain reaction array. The remaining 83 granulomas and all 24 control specimens were used to validate the obtained array data by real-time polymerase chain reaction. Observed variations in expression of wound healing genes were analyzed according to the classification of periapical granulomas as active/progressive versus inactive/stable (as determined by receptor activator for nuclear factor kappa B ligand/osteoprotegerin expression ratio). Results: We observed a marked increase of 5-fold or greater in SERPINE1, TIMP1, COL1A1, COL5A1, VTN, CTGF, FGF7, TGFB1, TNF, CXCL11, ITGA4, and ITGA5 genes in the periapical granulomas when compared with control samples. SERPINE1, TIMP1, COL1A1, TGFB1, and ITGA4 mRNA expression was significantly higher in inactive compared with active periapical granulomas (P < .001), whereas TNF and CXCL11 mRNA expression was higher in active lesions (P < .001). Conclusions: The identification of novel gene targets that curb the progression status of periapical lesions might contribute to a more accurate diagnosis and lead to treatment modalities more conducive to endodontic success. (J Endod 2012;38:185-190)

Laminated Tubular-channel Ferroelectret Systems from Low-density Polyethylene Films and from Fluoroethylene-propylene Copolymer Films - A Comparison

A template-based lamination technique for the manufacture of ferroelectrets from uniform electret films was recently reported. In the present work, this technique is used to prepare similar ferroelectret structures from low-density polyethylene (LDPE) films and from fluoro-ethylene-propylene (FEP) copolymer films. A comparative analysis of the pressure-, temperature-, and frequency-dependent piezoelectric properties has been performed on the two ferroelectret systems. It is observed that the FEP ferroelectrets exhibit better piezoelectric responses and are thermally more stable. The difference between the piezoelectric d(33) coefficients of the two ferroelectret systems is partially explained here by their different elastic moduli. The anti-resonance peaks of both structures have been investigated by means of dielectric resonance spectroscopy and electroacoustic sound-pressure measurements. A difference of more than 10 kHz is observed between the anti-resonance frequencies of the two ferroelectret systems.

Colibacillosis in lambs is associated to type I heat-stable enterotoxin in a farm in Sao Paulo State, Brazil

Twenty seven (48.2%) culture supernatants of 56 Escherichia coli isolated from diarrheic lamb feces (7 to 10 days old) in Sao Paulo State, Brazil, presented positive results to suckling mice assay (fluid accumulation) but none caused cytopathic effects on Vero and CHO cells, indicating that these strains did not produced LT or VT toxins. PCR assays showed that these 27 E. coli strains harbored estA, that codifies for STa, but not for stx1, stx2 or cnf genes. The positive STa strains were checked for genes that codify for F41, F17 and K99 fimbriae, wich are considered colonization factors in ETEC. Only F17 was detect in two samples (7.4%). Twelve of 27 STa positive carried hlyA gene and presented hemolytic activity in blood Agar. Presence of rotavirus was not detected among the diarrheic feces. These data suggests that STa must be an important diarrheagenic factor to small ruminants in Sao Paulo State.

Sensitivity, specificity and predictive values of linear and nonlinear indices of heart rate variability in stable angina patients

Abstract Background Decreased heart rate variability (HRV) is related to higher morbidity and mortality. In this study we evaluated the linear and nonlinear indices of the HRV in stable angina patients submitted to coronary angiography. Methods We studied 77 unselected patients for elective coronary angiography, which were divided into two groups: coronary artery disease (CAD) and non-CAD groups. For analysis of HRV indices, HRV was recorded beat by beat with the volunteers in the supine position for 40 minutes. We analyzed the linear indices in the time (SDNN [standard deviation of normal to normal], NN50 [total number of adjacent RR intervals with a difference of duration greater than 50ms] and RMSSD [root-mean square of differences]) and frequency domains ultra-low frequency (ULF) ≤ 0,003 Hz, very low frequency (VLF) 0,003 – 0,04 Hz, low frequency (LF) (0.04–0.15 Hz), and high frequency (HF) (0.15–0.40 Hz) as well as the ratio between LF and HF components (LF/HF). In relation to the nonlinear indices we evaluated SD1, SD2, SD1/SD2, approximate entropy (−ApEn), α1, α2, Lyapunov Exponent, Hurst Exponent, autocorrelation and dimension correlation. The definition of the cutoff point of the variables for predictive tests was obtained by the Receiver Operating Characteristic curve (ROC). The area under the ROC curve was calculated by the extended trapezoidal rule, assuming as relevant areas under the curve ≥ 0.650. Results Coronary arterial disease patients presented reduced values of SDNN, RMSSD, NN50, HF, SD1, SD2 and -ApEn. HF ≤ 66 ms2, RMSSD ≤ 23.9 ms, ApEn ≤−0.296 and NN50 ≤ 16 presented the best discriminatory power for the presence of significant coronary obstruction. Conclusion We suggest the use of Heart Rate Variability Analysis in linear and nonlinear domains, for prognostic purposes in patients with stable angina pectoris, in view of their overall impairment.

Isotope determination of sulfur by mass spectrometry in soil samples

Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S) with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS) in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-)), which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2-) concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms) was carried out by isotope ratio mass spectrometry (IRMS). In this work, the labeled material (K2(34)SO4) was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.