Low metal loading catalysts used for the selective hydrogenation of styrene

A series of Group VIII metal catalysts was obtained for the semi-hydrogenation of styrene. Catalysts were characterized by Hydrogen Chemisorption, TPR and XPS. Palladium, rhodium and platinum low metal loading prepared catalysts presented high activity and selectivity (ca. 98%) during the semi-hydrogenation of styrene, being palladium the most active catalyst. The ruthenium catalyst also presented high selectivity (ca. 98%), but the lowest activity. For the palladium catalyst, the influence of the precursor salt and of the reduction temperature on the activity and selectivity were studied. The following activity series was obtained: PdN-423 > PdCl-673 > PdCl-373> PtCl-673 > RhCl-673 >> RuCl-673. As determined by XPS, differences in activity could be attributed, at least in part, to electronic effects.

Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse

The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose) and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by increasing surface area. For both materials, glucose concentrations increased with enzyme loading. On the other hand, enzyme loadings higher than 15 FPU/g did not result in any increase in the initial rate, since the excess of enzyme adsorbed onto the substrate restricted the diffusion process through the structure.

METHANE DRY REFORMING OVER Ni SUPPORTED ON PINE SAWDUST ACTIVATED CARBON: EFFECTS OF SUPPORT SURFACE PROPERTIES AND METAL LOADING

The influence of metal loading and support surface functional groups (SFG) on methane dry reforming (MDR) over Ni catalysts supported on pine-sawdust derived activated carbon were studied. Using pine sawdust as the catalyst support precursor, the smallest variety and lowest concentration of SFG led to best Ni dispersion and highest catalytic activity, which increased with Ni loading up to 3 Ni atoms nm-2. At higher Ni loading, the formation of large metal aggregates was observed, consistent with a lower "apparen" surface area and a decrease in catalytic activity. The H2/CO ratio rose with increasing reaction temperature, indicating that increasingly important side reactions were taking place in addition to MDR.

Swine effluent treatment using anaerobic digestion at different loading rates

The industrial swine production is characterized by generation of significant effluent amounts that require treatment. The most adopted practices by Brazilian swine farmers have been wastewater storage in lagoons and its subsequent use as a biofertilizer. Nutrient accumulation in soil and water creates the need for an effective management of these residues. The anaerobic digestion process is an important alternative and low-cost treatment for organic matter reduction. However, its efficiency is limited by the digester capacity of solid degradation, especially at low hydraulic retention times. Thus, the present study aimed to verify the behavior of an upflow anaerobic digester by increasing the organic loading rate. This was accomplished in three stages using, as a parameter, volatile solids at 0.5; 1.0 and 1.5 kgVS m-3 d-1, respectively. This digester model proved to be quite robust and effective in swine manure treatment, achieving high efficiency of volatile solid removal at all stages of the study (stage 1: 61.38%; stage 2: 55.18%; and stage 3: 43.18%). Biogas production was directly related to the increasing organic load, reaching 0.14, 0.85, and 0.86 Nm³ kgVS-1add., respectively, with no significant difference (p<0.05) of biogas methane concentration among the studied stages (73.7, 75.0, and 77.9%).

Mechanical damage during harvest and loading affect orange postharvest quality

Brazil is the world’s largest orange producer; however, part of this production is lost during postharvest. This loss can be minimized by controlling incidence of physical damage throughout the harvest and loading operations. Impacts can negatively modify quantitative and qualitative fruits aspects. The main goal of this study was to measure the impact magnitude in two types of harvest (manual and detachment) and during all steps from picking into bags until loading for transport to the processing industry and additionally evaluating, in laboratory, the physico-chemical quality of the fruit subjected to various impacts, similar to those found in the field. In order to evaluate the impact magnitude, an instrumented sphere was used (760 mm, Techmark, Inc, USA). The following physico-chemical parameters were evaluated during 6-days of storage: weight loss, soluble solids contents, titratable acidity, ascorbic acid content, pH, firmness and peel color. The greatest impacts were observed during harvest, during the detachment practice, and when loading and unloading from bulk storage, with average acceleration values between 249.5 and 531.52G. The impact incidence in oranges were responsible for reducing the soluble solids, titratable acidity, ascorbic acid and weight by to 5.5%; 8.7%; 4.6% and 0.5%, respectively, compared to the control. Impacts during harvest and the various pre-industry manipulation steps must be controlled as they interfere in postharvest quality and physiology of ‘Valência’ oranges.

Modelling of mechanical properties of CRFC composites under flexure loading

Carbon Fibre Reinforced Carbon (CFRC) Composites are increasing their applications due to their high strength and Young’s Modulus at high temperatures in inert atmosphere. Although much work has been done on processing and structure and properties relationship, few studies have addressed the modelling of mechanical properties. This work is divided in two parts. In the first part, a modelling of mechanical properties was carried out for two bi-directional composites using a model based on the Bernoulli-Euler theory for symmetric laminated beams. In the second part, acoustic emission (AE) was used as an auxiliary technique for monitoring the failure process of the composites. Differences in fracture behaviour are reflected in patterns of AE.

Instability of a square sheet under symmetric biaxial loading

An early experiment found that a square rubber sheet under symmetric biaxial loading may not remain square. This curious result has been one of the most instructive examples in finite elasticity. Here thermodynamic considerations are used to analyze this instability.

Synaptic vesicle pool size, release probability and synaptic depression are sensitive to Ca2+ buffering capacity in the developing rat calyx of Held

The calyx of Held, a specialized synaptic terminal in the medial nucleus of the trapezoid body, undergoes a series of changes during postnatal development that prepares this synapse for reliable high frequency firing. These changes reduce short-term synaptic depression during tetanic stimulation and thereby prevent action potential failures during a stimulus train. We measured presynaptic membrane capacitance changes in calyces from young postnatal day 5-7 (p5-7) or older (p10-12) rat pups to examine the effect of calcium buffer capacity on vesicle pool size and the efficiency of exocytosis. Vesicle pool size was sensitive to the choice and concentration of exogenous Ca2+ buffer, and this sensitivity was much stronger in younger animals. Pool size and exocytosis efficiency in p5-7 calyces were depressed by 0.2 mM EGTA to a greater extent than with 0.05 mM BAPTA, even though BAPTA is a 100-fold faster Ca2+ buffer. However, this was not the case for p10-12 calyces. With 5 mM EGTA, exocytosis efficiency was reduced to a much larger extent in young calyces compared to older calyces. Depression of exocytosis using pairs of 10-ms depolarizations was reduced by 0.2 mM EGTA compared to 0.05 mM BAPTA to a similar extent in both age groups. These results indicate a developmentally regulated heterogeneity in the sensitivity of different vesicle pools to Ca2+ buffer capacity. We propose that, during development, a population of vesicles that are tightly coupled to Ca2+ channels expands at the expense of vesicles more distant from Ca2+ channels.

Validation of psychosocial scales for physical activity in university students

OBJECTIVE Translate the Patient-centered Assessment and Counseling for Exercise questionnaire, adapt it cross-culturally and identify the psychometric properties of the psychosocial scales for physical activity in young university students.METHODS The Patient-centered Assessment and Counseling for Exercise questionnaire is made up of 39 items divided into constructs based on the social cognitive theory and the transtheoretical model. The analyzed constructs were, as follows: behavior change strategy (15 items), decision-making process (10), self-efficacy (6), support from family (4), and support from friends (4). The validation procedures were conceptual, semantic, operational, and functional equivalences, in addition to the equivalence of the items and of measurements. The conceptual, of items and semantic equivalences were performed by a specialized committee. During measurement equivalence, the instrument was applied to 717 university students. Exploratory factor analysis was used to verify the loading of each item, explained variance and internal consistency of the constructs. Reproducibility was measured by means of intraclass correlation coefficient.RESULTS The two translations were equivalent and back-translation was similar to the original version, with few adaptations. The layout, presentation order of the constructs and items from the original version were kept in the same form as the original instrument. The sample size was adequate and was evaluated by the Kaiser-Meyer-Olkin test, with values between 0.72 and 0.91. The correlation matrix of the items presented r < 0.8 (p < 0.05). The factor loadings of the items from all the constructs were satisfactory (> 0.40), varying between 0.43 and 0.80, which explained between 45.4% and 59.0% of the variance. Internal consistency was satisfactory (α ≥ 0.70), with support from friends being 0.70 and 0.92 for self-efficacy. Most items (74.3%) presented values above 0.70 for the reproducibility test.CONCLUSIONS The validation process steps were considered satisfactory and adequate for applying to the population.

Ultrastructural study on the morphological changes to male worms of Schistosoma mansoni after in vitro exposure to allicin

INTRODUCTION: Garlic has a wide range of actions, including antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic actions. This antiparasitic activity has been attributed to allicin, which is the main constituent of garlic. The present study aimed to investigate the in vitro activity of allicin on the tegument of adult Schistosoma mansoni worms using scanning electron microscopy. METHODS: Swiss Webster mice were infected with S. mansoni cercariae (100 per mouse) and sacrificed 50 days later to acquire the adult worms. These worms were collected by perfusion and placed in RPMI medium 1,640 at 37°C before transferring to RPMI media containing 0 (control), 5, 10, 15 and 20mg/mL of allicin, where they were incubated for 2h. The worms were fixed in 2.5% glutaraldehyde solution, washed twice, post-fixed in osmium tetroxide, washed twice and then dehydrated with ascending grades of ethanol. The samples were air-dried, mounted on stubs, gold coated in an ion sputtering unit and viewed using a scanning electron microscope. RESULTS: A concentration of 5mg/mL caused wrinkling in the tegument; a concentration of 10mg/mL resulted in changes to tubercles and loss or modification of spines. With 15 and 20mg/mL increasing damage to the tegument could be seen, such as vesicle formation and the presence of ulcers. CONCLUSIONS: These findings demonstrate the effect of allicin on adult S. mansoni worms and indicate that most of the changes occur at concentrations greater than that normally indicated for treatment.

Doppler echocardiographic study in adolescents and young adults with sickle cell anemia

OBJECTIVE: Anatomical and functional assessment of the heart through Doppler and echocardiography in patients with cell anemia (SCA). METHODS: Twenty-five patients with SCA and ages ranging from 14 to 45 years were prospectively studied in a comparison with 25 healthy volunteers. All of them underwent clinical and laboratory evaluation and Doppler echocardiography as well.The measurements were converted into body surface indices. RESULTS: There were increases in all chamber diameters and left ventricle (LV) mass of the SCA patients. It was characterised an eccentric hypertrophy of the left ventricle. The preload was increased (left ventricle end-diastolic volume) and the afterload was decreased (diastolic blood pressure, peripheral vascular resistance and end-systolic parietal stress ESPS). The cardiac index was increased due to the stroke volume. The ejection fraction and the percentage of the systolic shortening , as well as the systolic time intervals of the LV were equivalent. The isovolumetric contraction period of the LV was increased. The mitral E-septum distance and the end-systolic volume index (ESVi) were increased. The ESPS/ESVi ratio,a loading independent parameter, was decreased in SCA, suggesting systolic dysfunction. No significant differences in the diastolic function or in the pulmonary pressure occurred. CONCLUSION: Chamber dilations, eccentric hypertrophy and systolic dysfunction confirm the evidence of the literature in characterizing a sickle cell anemia cardiomyopathy.

Histologia del sistema reproductor masculino de Helobdella hyalina (Hirudinea, Glossiphoniidae) en Argentina

A detailed preliminary histological analysis of Helobdella hyalina Ringuelet, 1942 male system from Los Talas, Buenos Aires, Argentina is described. Six pairs of testisacs, located between the crop caeca, form the male reproductive system. Each testisac is clothed by the mesotelium. Inside it, the germinal cells are connected to the citophore and develop functional unit called poliplast. The spermatozoa are released into testisacs after the reabsortion of the citophore. Five stages of spermatogenesis are described taking into account the successive maturation stages of germinal cells and the changes in the citophore size. Lining cells and gland cells were found in the seminal vesicle. Five different types of gland cells are placed inside the ejaculatory ducts, as well as two kinds of cells are found in its distal portion: type 1, which produces eosinophilic granular secretion, type 2, with amorphous and slightly eosinophilic. Three distinct gland cells are located in the proximal portion of the duct: type 3, which produces a strongly eosinophilic granular secretion; type 4, with a negative eosinophilic amorphous secretion and type 5, with a basophilic granular secretion. Type 5 gland cells are described for the ducts of this species only.

Observation on the morphology of Australorbis glabratus

The present morphological study of A. glabratus was based on the observation of shell, radula, renal region and genitalia of 50 specimens having a shell diameter of 18 mm. In this summary we record the data pertaining to the chracteristics that can be used in systematics. The numerals refere to the mean and their standard deviation; no special reference being made, they correspond to length measurements. Shell: 18 mm in diameter, 5.59 ± 0.24 mm in greatest width, 5 to 6 whorls. Right side umbilicated, left one weakly depressed. Last whorl about thrice as tall as the penultimate one at the aperture, the measurements being taken on the right side. Aperture perpendicular or a little oblique. Body, extended: 47.06 ± 3.31 mm. Renal tube: Narrow and elongated, 23.84 ± 1.90 mm, showing a pigmented ridge along its ventral surface. Ovotestis: 12.78 ± 1.50 mm. Mainly trifurcate diverticula attaching in fan-like manner to the collecting canal (this arrangement is seen to best advantage in the cephalic middle of the ovotestis). The collecting canal greatly swells at the cephalic end, narrowing suddenly as it leaves the ovotestis. Ovisperm duct: 13.70 ± 1.68 mm, including the non-unwound seminal vesicle. The latter, situated about 1 mm from the beginning af the ovisperm duct, was 1.14 ± 0.29 mm in greatest diameter, and is beset by numerous short diverticula. Sperm duct: 14.16 ± 1.27 mm, pursuing a sinous course along the oviduct. Prostate: Prostate duct 5.53 ± 0.74 mm, collecting a row of long diverticula, the latter 21.6 ± 3.5 in number. Last diverticulum generally simple or bifurcate, penultimate generally arborescent, bifurcate or simple, antepenultimate nearly always arborescent, the remaining ones arborescent. The arborescent diverticula frequently give off secondary branches. Vas deferens: 17.50 ± 2.05 mm. The ratio vas deferens/vergic sac was 4.7 ± 0.6. Verge: 3.70 ± 0.54 mm long, 0.12 ± 0.03 mm wide. Free end tapering to a point where the sperm canal opens. No penial stylet. Vergic sac: 3.77 ± 0.50 mm long, 0.19 ± 0.01 mm wide. The length ratio vergic sac/preputium was 1 ± 0.02. Preputium: Deeply pigmented, 3.79 ± 0.40 mm long, 0.89 ± 0.12 mm wide in the middle. Muscular diaphragm between it and the vergic sac. Two muscular pilasters along its lateral walls. Oviduct: 10.24 ± 1.29 mm, suddenly swollen at the cephalic end so that it forms a folded pouch capping the beginning of the uterus. Uterus: 10.58 ± 1.18 mm. Vagina: 2.06 ± 0.15 mm long, 0.32 ± 0.05 mm wide, showing a swelling at its caudal portion, just above the opening of the spermathecal duct. Spermatheca: 1.57 ± 0.41 mm long, 0.92 ± 0.23 mm wide. Spermathecal duct 1.15 ± 0.23 mm. Radula: 125 to 163 rows of teeth (mean 141.4 ± 9.8). Radula formula 27-1-27 to 34-1-34 (mean 30.9 ± 1.7).

Observations on the morphology of Australorbis nigricans

A morphological study was done on A. nigricans, based on the observation of shell, radula, renal region and genitalia of 50 specimens measuring 18 mm in diameter. The data obtained are to be compared with those recorded in our previous paper (PARAENSE & DESLANDES, 1955) on A. glabratus. The characteristics common to both species will not be mentioned here. The numerals refere to the means and their standard deviations: no special reference being done, they correspond to length measurementes. Shell - 18 mm in diameter, 6.37 ± 0.29 mm in greatest width, 6 whorls. Prevailing colur ferruginous sepia, a minority of olivaceous, ochreous, nigrescent and deeply black specimens being found. Right side variously depressed, umbilicated, 1.5 to 3.5 mm deep from the bottom of the umblicus to the highest level of the last whorl. Left side more depressed than the right one, broadly concave, 1.5 to 3.5 mm deep. Both sides show a varously distinct keel, that looks sharper at the left. Aperture deltoid, varying in outline and width. Body, extended - 60.26 ± 3.62 mm, less pigmented than in glabratus. Renal tube - 30.68 ± 1.69 mm, showing neither ridge nor pigmented line along its ventral surface, this negative character affording a sure means of separation from glabratus. Ovotestis - 14.48 ± 1.93 mm. Ovisperm duct - 13.04 ± 1.60 mm, including the non-unwound seminal vesicle. The latter was 0.97 ± 0,21 mm in greatest width. Carrefour - Resembling that of glabratus. Sperm duct - 21.36 ± 1.53 mm. Prostate - Prostate duct 7.14 ± 0.74 mm, collecting a row of long diverticula numbering 19.6 ± 3.1 and more separate than in glabratus. Last diverticulum generally bifurcate or arborescent, the remaining ones arborescent. Vas deferens - 28.68 ± 1.38. Ratio vas deferens/vergic sac = 6.8±0.8. Verge - 3.08 ± 0.28 mm long, 0.11 ± 0.02 mm wide. Vergic sac - 3.07 ± 0.28 mm long, about 0.20 mm wide. Ratio vergic sac/preputium = 0.84 ± 0.12. Preputium - 3.69 ± 0.47 mm long, 0.85 ± 0.10 mm wide. Albumen gland - Resembling taht of glabratus. Oviduct - 16.26 ± 1.41 mm, swollen at the cephalic end. Uterus - 13.24 ± 1.19 mm. Vagina - 1.70 ± 0.22 mm, swolen at the caudal portion. Spermatheca - 2.78 ± 0.40 mm long, 0.86 ± 0.16 mm wide. Spermathecal duct 1.11 ± 0.20 mm. Radula - 125 to 168 horizontal rows of teeth (mean 153.9 ± 8.4). Radula formula 28-1-28 to 36-1-36 (mean 31.8 ± 1.9). Mode formula 31-1-31. The morphological characteristics of the renal region and shell, and the great body length in the same condition of shell diameter, distinguish A. nigricans from the most related species A. glabratus, giving support to considering it a good species from a txonomic or phenotypic standpoint (morphospecies).

Physa Marmorata Guilding, 1828 (Pulmonata: Physidae)

A description of Physa marmorata Guilding, 1828, based on material collected at its type-locality, the Caribbean island of Saint Vincent, is presented. The shell is thin, horn-colored, surface very glossy, diaphanous. Spire acute, elevated; protoconch distinct, rounded-conical, reddish-brown; five not shouldered, broadly convex whorls with subobsolete spiral lines and thin growth lines. Aperture elongated, 1.4-2.0 times as long as the remaining shell length, narrow obovate-lunate; upper half acute-angled,lower half oval,narrowly rounded at the base, outer lip sharp, inner lip completely closing the umbilical region; a very distinct callus on the parietal wall; columellar lip with a low ridge gradually merging into the callus. ratios: shell width/shell length = 0.44 - 0.52 (mean 0.47); spire length /shell lenght = 0.33-0.41 (mean 0.39); aperture length/shell lenght = 0.59-0.67 (mean 0.62). Oral lappets laterally mucronate, foot spatulate with deeply pigmented acuminate tail. Mantle reflection with 6-10 short triangular dentations covering nearly half the right surface of the body whorl, and 4-6 covering a part of the ventral wall. Body surface with tiny dots of greenish-yellow pigment besides melanin. Renal tube tightly folded in toa zigzag course. Ovotestis diverticula acinous, laterally pressed against each other around a collecting canal. Ovispermiduct with well-developed seminal vesicle. oviduct highly convoluted, merging into a less convoluted nidamental gland which narrows to a funnel-shaped uterus and a short vagina. Spermathecal body oblong, more or less constricted in the middle and somewhat curved; spermathecal duct uniformly narrow, a little longer than be body. About 20 prostatic diverticula, simple, bifurcate or divided into a few short branches, distalmost ones assembled into a cluster. Penis long, nearly uniformly narrow; penial canal with lateral opening about the junction of its middle and lower thirds. Penial sheath with a bulbous terminal expasion the tip of which isinserted into the caudal end of the prepuce. Prepuce shouldered, much wider than the narrow portion of the penial sheath. Penial sheath/prepuce ratio about 2.08 (1.45-2.75). The main extrinsic muscles of the penial complex are a retractor, with a branch attached to the bulb, and another to the caudal end of the penial sheath; and a protractor, with a branch attached to the shoulder of the prepuce and adjoining area of the penial sheath, and another to the caudal end of the penial sheath. Egg capsule C-shaped, with 10-30 elliptical eggs (snails 10mm long) measuring about 1.10 mm (0.90-1.32) through the long axis and surrounded by an inner and an outer lamellate membranes. Jaw a simple obtusely V-shaped plate. radula will be described separately.