Certified reference material to water content determination in bioethanol fuel

Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This paper presents the results of these studies. The characterization, homogeneity, short-term stability and long-term stability uncertainty contributions values were 0.00500, 0.0166, 0.0355 and 0.0391 mg g-1, respectively. The certificated value for water content of bioethanol fuel was (3.65 ± 0.11) mg g-1. This CRM is the first and up to now the unique in the world.

Acúmulo de cargas elétricas em propelente sólido compósito com matriz de polibutadieno líquido hidroxilado

Composite solid propellants prepared with HTPB prepolymer - Hydroxyl Terminated Polybutadiene, AP - Ammonium Perchlorate as oxidizer and aluminum particles as an additive metal, have characteristics of high electrical resistivity. The loading process of the polymer matrix did not obtain homogeneity, resulting in clusters, mainly of metal particles. The effect of clustering in the composite was studied and observed experimentally, and this effect was one of the factors explaining the phenomenon of electrical charging of the composite. This electrical potential, when discharged abruptly, can generate an electric spark with sufficient energy for sustained ignition of a solid rocket motor.

Hobbes et Gassendi: la psychologie dans le projet mécaniste

L'amitié et l'affinité intellectuelle qui caractérisèrent les rapports de Hobbes avec Gassendi forment un tissu ténu dont il n'est point aisé de démêler la trame. Aux côtés de points de convergence clairement définis, telle la commune aversion envers le dualisme et l'innéisme cartésiens, et par-delà des divergences non moins nettes dans leurs orientations philosophiques particulières, le sens des parcours maintes fois parallèles doit encore être éclairé de façon circonstanciée. Le terrain privilégié sur lequel élever une confrontation étroite entre deux auteurs est sans doute la construction d'une psychologie profondément marquée par des prémisses empiriques et dont l'orientation vise à établir une relation très étroite entre les processus de la perception, du désir (appetitus) et de la volonté avec ce qui les détermine matériellement et mécaniquement. On peut même affirmer que les écrits de Gassendi rédigés au tout début des années 1640 définissent une série d'hypothèses innovatrices sur lesquelles s'inscrit une certaine convergence avec les élaborations de Hobbes à elles contemporaines. Sous ce profil, le groupe de textes remontant aux années 1640-41, et où le philosophe d'Aix s'interroge sur la nature des phénomènes lumineux, est emblématique. L'explication du comportement des corps lumineux en terme de systole et de diastole, l'interprétation de la propagation de la lumière s'inspirant de la pure actualité cinématique (en polémique ouverte et explicite envers les thèses de la Dioptrique de Descartes sur la luminosité comme simple inclinaison au mouvement), le vacuisme (qui est propre à Gassendi, servant justement à rendre compte des phénomènes d'expansion et de contraction des sources lumineuses et qui, à cette époque, n'était pas encore exclu par Hobbes), la représentation, enfin, tout à fait matérielle et mécanique des phénomènes d'irradiation, voilà autant d'aspects de la recherche de Gassendi qui peuvent facilement être confrontés aux écrits de Hobbes.

PLANT GROWTH-PROMOTING MICROBIAL INOCULANT FOR Schizolobium parahyba pv. parahyba

ABSTRACTSchizolobium parahyba pv. amazonicum (Huber ex Ducke) Barneby (paricá) occurs naturally in the Amazon and is significant commercial importance due to its rapid growth and excellent performance on cropping systems. The aim of this paper was to evaluate a microbial inoculants such as arbuscular mycorrhiza fungi (AMF) and Rhizobium sp. that promote plant growth. The inocula was 10 g of root colonized and spores of Glomus clarum and/or 1 mL of cell suspension (107 CFU/mL) of Rhizobium sp. and/or 100 g of chemical fertilizer NPK 20-05-20 per planting hole. The experimental design was complete randomized blocks with five replications and eight treatments (n = 800). Plant height, stem diameter and plant survival were measured. The results were tested for normality and homogeneity of variances and analyzed by ANOVA and Tukey test (p < 0.05). Rhizobium sp and AM fungi showed no effect on plant growth. Environmental factors probably influenced the effectiveness of symbiosis of both microorganisms and plant growth. The chemical fertilizer increased S. parahyba growth. During the first 120 days plants suffered with drought and frost, and at 180 days plants inoculated with microorganism plus chemical fertilizer showed higher survival when compared with control. The results showed that the microbial inoculants used showed an important role on plant survival after high stress conditions, but not in plant growth. Also was concluded that the planting time should be between November to December to avoid the presence of young plants during winter time that is dry and cold.

Outlining precision boundaries among areas with different variability standards using magnetic susceptibility and geomorphic surfaces

There is an increasing demand for detailed maps that represent in a simplified way the knowledge of the variability of a particular area or region maps. The objective was to outline precision boundaries among areas with different accuracy variability standards using magnetic susceptibility and geomorphic surfaces. The study was conducted in an area of 110 ha, which identified three compartment landscapes based on the geomorphic surfaces model. To determinate pH, organic matter, phosphorus, potassium and magnesium, the total sand and clay, 514 soil samples were collected at depths of 0-0.20 m and 0.60-0.80 m. The sum of base, cationic exchange capacity and base saturation were calculated and the magnetic susceptibility was evaluated in the laboratory using a system based on a balance of analytical precision method. Geomorphic surfaces identification allowed setting specific management areas (locations with maximum homogeneity of soil attributes). The map of spatial variability of magnetic susceptibility can be used to validate the precise boundaries among geomorphic surfaces identified in the field and infer the variability of clay content and soil base saturation.

Ultrasonografic changes in the axillary vein of patients with lymphedema after mastectomy

OBJECTIVE: To determine the prevalence of sonographic abnormalities (SA) in the axillary vein of patients with and without post-mastectomy lymphedema. METHODS: We studied a sample of 80 women, divided into two equal groups, with and without lymphedema, with B mode ultrasound, color and pulsed Doppler. The primary variable, SA, is defined as change in the venous diameter, parietal thickening, intraluminal images, compressibility, parietal collapse at inspiration and feature of the axillary venous flow on the operated side. Secondary variables were: stage of lymphedema, surgical technique, number of radio and chemotherapy sessions, limb volume, weight and age. The differences between the proportions in the groups were determined using the Chi-square test and / or Fisher's test. For continuous variables, we used the Mann-Whitney Test. To estimate the magnitude of the associations, we used the prevalence rate of SA in both groups as a measure of frequency, and as a measure of association, the prevalence ratio (PR) obtained as a function of relative risk (RR) and estimated by the test Mantel-Haenszel homogeneity test. We adopted the statistical significance level of 5% (p < 0.05). RESULTS: only the criterion "parietal thickening" was strongly associated with the lymphedema group (p = 0.001). The prevalence of SA was 55% in patients with lymphedema and 17.5% in the group without it, with difference in prevalence of 37.5%. CONCLUSION: the prevalence of SA was higher in patients undergoing mastectomy with lymphedema than in those without lymphedema.

Anatomical and functional characteristics of the pelvic floor in nulliparous women submitted to three-dimensional endovaginal ultrasonography: case control study and evaluation of interobserver agreement

PURPOSE: To determine anatomical and functional pelvic floor measurements performed with three-dimensional (3-D) endovaginal ultrasonography in asymptomatic nulliparous women without dysfunctions detected in previous dynamic 3-D anorectal ultrasonography (echo defecography) and to demonstrate the interobserver reliability of these measurements. METHODS: Asymptomatic nulliparous volunteers were submitted to echo defecography to identify dynamic dysfunctions, including anatomical (rectocele, intussusceptions, entero/sigmoidocele and perineal descent) and functional changes (non-relaxation or paradoxical contraction of the puborectalis muscle) in the posterior compartment and assessed with regard to the biometric index of levator hiatus, pubovisceral muscle thickness, urethral length, anorectal angle, anorectal junction position and bladder neck position with the 3-D endovaginal ultrasonography. All measurements were compared at rest and during the Valsalva maneuver, and perineal and bladder neck descent was determined. The level of interobserver agreement was evaluated for all measurements. RESULTS: A total of 34 volunteers were assessed by echo defecography and by 3-D endovaginal ultrasonography. Out of these, 20 subjects met the inclusion criteria. The 14 excluded subjects were found to have posterior dynamic dysfunctions. During the Valsalva maneuver, the hiatal area was significantly larger, the urethra was significantly shorter and the anorectal angle was greater. Measurements at rest and during the Valsalva maneuver differed significantly with regard to anorectal junction and bladder neck position. The mean values for normal perineal descent and bladder neck descent were 0.6 cm and 0.5 cm above the symphysis pubis, respectively. The intraclass correlation coefficient ranged from 0.62-0.93. CONCLUSIONS: Functional biometric indexes, normal perineal descent and bladder neck descent values were determined for young asymptomatic nulliparous women with the 3-D endovaginal ultrasonography. The method was found to be reliable to measure pelvic floor structures at rest and during Valsalva, and might therefore be suitable for identifying dysfunctions in symptomatic patients.

How and why to measure the germination process?

In the last two centuries, papers have been published including measurements of the germination process. High diversity of mathematical expressions has made comparisons between papers and some times the interpretation of results difficult. Thus, in this paper is included a review about measurements of the germination process, with an analysis of the several mathematical expressions included in the specific literature, recovering the history, sense, and limitations of some germination measurements. Among the measurements included in this paper are the germinability, germination time, coefficient of uniformity of germination (CUG), coefficient of variation of the germination time (CVt), germination rate (mean rate, weighted mean rate, coefficient of velocity, germination rate of George, Timson’s index, GV or Czabator’s index; Throneberry and Smith’s method and its adaptations, including Maguire’s rate; ERI or emergence rate index, germination index, and its modifications), uncertainty associated to the distribution of the relative frequency of germination (U), and synchronization index (Z). The limits of the germination measurements were included to make the interpretation and decisions during comparisons easier. Time, rate, homogeneity, and synchrony are aspects that can be measured, informing the dynamics of the germination process. These characteristics are important not only for physiologists and seed technologists, but also for ecologists because it is possible to predict the degree of successful of a species based on the capacity of their harvest seed to spread the germination through time, permitting the recruitment in the environment of some part of the seedlings formed.

Spatial variation in the structure and floristic composition of "restinga" vegetation in southeastern Brazil

We examined large-scale spatial variation of structural parameters and floristic composition in open Clusia scrub, a vegetation type of the Brazilian "restingas" (sandy coastal plain vegetation). This vegetation is organized in islands separated by sandy stretches with sparse herbaceous vegetation. We located 12 sample areas on three consecutive beach ridges, lying parallel to the coastline and at different distances from the ocean, in close proximity to two lagoons (Cabiúnas and Comprida). Each sample area was divided into three strips. We used the line intercept method to sample all woody plants ³ 50 cm tall. We used nested ANOVA to verify structural variation between different sampling scales. TWINSPAN analysis was performed to examine the variation in floristic composition between areas. The overall diversity index was 3.07. Six species are repeatedly dominant throughout the entire sampling area. There was homogeneity in relation to diversity and species richness between beach ridges but not within beach ridges. Floristic composition and structural parameters did not vary in relation to distance from the sea but floristic composition did vary as a function of proximity to Cabiúnas or Comprida lagoon. Differences in plant cover between sample areas may be related to the paleoformation of this sandy coastal plain.

Calcium handling by vascular myocytes in hypertension

Calcium ions (Ca2+) trigger the contraction of vascular myocytes and the level of free intracellular Ca2+ within the myocyte is precisely regulated by sequestration and extrusion mechanisms. Extensive evidence indicates that a defect in the regulation of intracellular Ca2+ plays a role in the augmented vascular reactivity characteristic of clinical and experimental hypertension. For example, arteries from spontaneously hypertensive rats (SHR) have an increased contractile sensitivity to extracellular Ca2+ and intracellular Ca2+ levels are elevated in aortic smooth muscle cells of SHR. We hypothesize that these changes are due to an increase in membrane Ca2+ channel density and possibly function in vascular myocytes from hypertensive animals. Several observations using various experimental approaches support this hypothesis: 1) the contractile activity in response to depolarizing stimuli is increased in arteries from hypertensive animals demonstrating increased voltage-dependent Ca2+ channel activity in hypertension; 2) Ca2+ channel agonists such as Bay K 8644 produce contractions in isolated arterial segments from hypertensive rats and minimal contraction in those from normotensive rats; 3) intracellular Ca2+ concentration is abnormally increased in vascular myocytes from hypertensive animals following treatment with Ca2+ channel agonists and depolarizing interventions, and 4) using the voltage-clamp technique, the inward Ca2+ current in arterial myocytes from hypertensive rats is nearly twice as large as that from myocytes of normotensive rats. We suggest that an alteration in Ca2+ channel function and/or an increase in Ca2+ channel density, resulting from increased channel synthesis or reduced turnover, underlies the increased vascular reactivity characteristic of hypertension

Neuroendocrine regulation of salt and water metabolism

Neurons which release atrial natriuretic peptide (ANPergic neurons) have their cell bodies in the paraventricular nucleus and in a region extending rostrally and ventrally to the anteroventral third ventricular (AV3V) region with axons which project to the median eminence and neural lobe of the pituitary gland. These neurons act to inhibit water and salt intake by blocking the action of angiotensin II. They also act, after their release into hypophyseal portal vessels, to inhibit stress-induced ACTH release, to augment prolactin release, and to inhibit the release of LHRH and growth hormone-releasing hormone. Stimulation of neurons in the AV3V region causes natriuresis and an increase in circulating ANP, whereas lesions in the AV3V region and caudally in the median eminence or neural lobe decrease resting ANP release and the response to blood volume expansion. The ANP neurons play a crucial role in blood volume expansion-induced release of ANP and natriuresis since this response can be blocked by intraventricular (3V) injection of antisera directed against the peptide. Blood volume expansion activates baroreceptor input via the carotid, aortic and renal baroreceptors, which provides stimulation of noradrenergic neurons in the locus coeruleus and possibly also serotonergic neurons in the raphe nuclei. These project to the hypothalamus to activate cholinergic neurons which then stimulate the ANPergic neurons. The ANP neurons stimulate the oxytocinergic neurons in the paraventricular and supraoptic nuclei to release oxytocin from the neural lobe which circulates to the atria to stimulate the release of ANP. ANP causes a rapid reduction in effective circulating blood volume by releasing cyclic GMP which dilates peripheral vessels and also acts within the heart to slow its rate and atrial force of contraction. The released ANP circulates to the kidney where it acts through cyclic GMP to produce natriuresis and a return to normal blood volume

Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig

We investigated the effects of piperitenone oxide (PO), a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 µg/ml) relaxed basal tonus without significantly altering the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethylammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 µg/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (>30 µg/ml) blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect

Characterization of nerve-induced relaxation of gastrointestinal sphincteric smooth muscle in a South American opossum (Didelphis albiventris)

The presence of inhibitory nonadrenergic noncholinergic (NANC) intrinsic innervation of the circular muscle of the gastrointestinal sphincters of the South American (SA) opossum was investigated in vitro. Isolated circular muscle strips from the esophagogastric and ileocolonic junctions but not from the gastroduodenal (pylorus) region developed spontaneous tension. Tetrodotoxin (TTX, 1 µM) augmented the spontaneous tension only in the ileocolonic junction strips. Electrical field stimulation of esophagogastric and ileocolonic junction strips caused frequency-dependent responses consisting of a relaxation at lower frequencies (<1 Hz) and a biphasic response or contraction at higher frequencies. In the strips from the pyloric region electrical field stimulation abolished the spontaneous activity at lower frequencies and induced contractions at higher frequencies. The responses elicited by electrical field stimulation in the three sphincters were abolished by TTX (1 µM). Electrical field-induced contractions were reduced while relaxations were enhanced by atropine (1 µM). In the presence of atropine (1 µM) and guanethidine (3 µM), electrical field stimulation, nicotine and ATP induced frequency- or concentration-dependent relaxations of the three sphincters that were abolished by TTX (1 µM). Isoproterenol and sodium nitroprusside caused concentration-dependent relaxations which were TTX-resistant. These findings indicate that the sphincteric circular muscle of the SA opossum gastrointestinal tract is relaxed by the activation of intrinsic NANC nerves and therefore can be used as a model for the study of the mechanisms involved in these responses

Effect of angiotensin-(1-7) on reperfusion arrhythmias in isolated rat hearts

There is increasing evidence that angiotensin-(1-7) (Ang-(1-7)) is an endogenous biologically active component of the renin-angiotensin system (RAS). In the present study, we investigated the effects of Ang-(1-7) on reperfusion arrhythmias in isolated rat hearts. Isolated rat hearts were perfused with two different media, i.e., Krebs-Ringer (2.52 mM CaCl2) and low-Ca2+ Krebs-Ringer (1.12 mM CaCl2). In hearts perfused with Krebs-Ringer, Ang-(1-7) produced a concentration-dependent (27-210 nM) reduction in coronary flow (25% reduction at highest concentration), while only slight and variable changes in contraction force and heart rate were observed. Under the same conditions, angiotensin II (Ang II; 27 and 70 nM) produced a significant reduction in coronary flow (39% and 48%, respectively) associated with a significant increase in force. A decrease in heart rate was also observed. In low-Ca2+ Krebs-Ringer solution, perfusion with Ang-(1-7) or Ang II at 27 nM concentration produced similar changes in coronary flow, contraction force and heart rate. In isolated hearts perfused with normal Krebs-Ringer, Ang-(1-7) produced a significant enhancement of reperfusion arrhythmias revealed by an increase in the incidence and duration of ventricular tachycardia and ventricular fibrillation (more than 30-min duration). The facilitation of reperfusion arrhythmias by Ang-(1-7) was associated with an increase in the magnitude of the decreased force usually observed during the post-ischemic period. The effects of Ang-(1-7) were abolished in isolated rat hearts perfused with low-Ca2+ Krebs-Ringer. The effect of Ang II (27 nM) was similar but less pronounced than that of Ang-(1-7) at the same concentration. These results indicate that the heart is a site of action for Ang-(1-7) and suggest that this heptapeptide may be involved in the mediation of the cardiac effects of the RAS

A new brain metalloendopeptidase which degrades the Alzheimer ß-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects

A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human brain using successive steps of chromatography on DEAE-Trisacryl, hydroxylapatite and Sephacryl S-200. The purified enzyme cleaved the Gly33-Leu34 bond of the 25-35 neurotoxic sequence of the Alzheimer ß-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects. This enzyme activity was only inhibited by divalent cation chelators such as EDTA, EGTA and o-phenanthroline (1 mM) and was insensitive to phosphoramidon and captopril (1 µM concentration), specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. The high affinity of this human brain endopeptidase for ß-amyloid 1-40 peptide (Km = 5 µM) suggests that it may play a physiological role in the degradation of this substance produced by normal cellular metabolism. It may also be hypothesized that the abnormal accumulation of the amyloid ß-protein in Alzheimer's disease may be initiated by a defect or an inactivation of this enzyme.