Preparation and characterization of Pr0.6Sr0.4FeO3-δ-Ce0.9Pr0.1O2-δ nanofiber structured composite cathode for IT-SOFCs

In this work, Pr_0.6Sr_0.4FeO_3-δ -Ce_0.9Pr_0.1O_2-δ (PSFO-CPO) nanofibers were synthesized by a one-step electrospin technique for use in intermediate-temperature solid oxide fuel cell (IT-SOFC) applications. PSFO-CPO nanofibers were produced with a diameter of about 100nm and lengths exceeding tens of microns. The thermal expansion coefficient (TEC) matches with standard GDC electrolytes and the resulting conductivity also satisfies the needs of IT-SOFCs cathodes. EIS analysis of the nanofiber structured electrode gives a polarization resistance of 0.072Ωcm² at 800°C, smaller than that from the powdered cathode with the same composition. The excellent electrochemical performance can be attributed to the well-constructed microstructure of the nanofiber structured cathode, which promotes surface oxygen diffusion and charge transfer processes. All the results imply that the one-step electrospin method is a facile and practical way of improving the cathode properties and that PSFO-CPO is a promising cathode material for IT-SOFCs.

Synthesis of Pr0.6Sr0.4FeO 3-δ -xCe0.9Pr0.1O 2-δ cobalt-free composite cathodes by a one-pot method for intermediate-temperature solid oxide fuel cells

Cobalt-free composite cathodes consisting of Pr_0.6Sr_0.4FeO _3-δ -xCe_0.9Pr_0.1O _2-δ (PSFO-xCPO, x = 0-50 wt%) have been synthesized using a one-pot method. X-ray diffraction, scanning electron microscopy, thermal expansion coefficient, conductivity, and polarization resistance (R _P ) have been used to characterize the PSFO-xCPO cathodes. Furthermore the discharge performance of the Ni-SSZ/SSZ/GDC/PSFO-xCPO cells has been measured. The experimental results indicate that the PSFO-xCPO composite materials fully consist of PSFO and CPO phases and posses a porous microstructure. The conductivity of PSFO-xCPO decreases with the increase of CPO content, but R _P of PSFO-40CPO shows the smallest value amongst all the samples. The power density of single cells with a PSFO-40CPO composite cathode is significantly improved compared with that of the PSFO cathode, exhibiting 0.43, 0.75, 1.08 and 1.30 W cm^-2 at 650, 700, 750 and 800 °C, respectively. In addition, single cells with the PSFO-40CPO composite cathode show a stable performance with no obvious degradation over 100 h when operating at 750 °C.

Formación de adherencias peritoneales comparando el uso de lactato de Ringer y solución salina al 0.9 a 37 grados Celsius en la cavidad abdominal de ratas wistar

Después de una laparotomía del 70 al 95de pacientes tienen algún grado de adherencias, las que se manifestarán dependiendo de su consistencia y ubicación con cuadros clínicos de obstrucción intestinal agudos o crónicos, dolor abdominal crónico de casa no bien definido, dispareunias, infertilidad. El tratar la causa y el lavado de cavidad peritoneal son puntales principales en el tratamiento de la inflamación peritoneal desencadenante de la formación de adherencias. Para el lavado los cristaloides son los más indicados y de ellos la solución salñina y el lactato de Ringer los más usados. El objetivo fue conocer la capacidad para disminuir la formación de adherencias intraabdominales con el uso de lactato de ringer en comparación con la solución salina al contacto con el peritoneo, en ausencia de patología abdominal, en ratas Wistar. Para esto se realizó un estudio experimental clínico controlado aleatorizado en ratas wistar de laboratorio, formando dos grupos de 38 especímenes en cada uno, que cumplan los criterios de inclusión y exclusión, a las cuales les introdujo 5cc, de lactato de ringer y el otro grupo 5cc de solución salina al 0.9a 37 grados Celsius en la cavidad abdominal por punción con aguja Verres. A las 6 semanas se sacrificó a los animales y se realizó una valoración de las adherencias con clasificación macroscópica y estudio microscópico. De 75 casos, 35 del grupo de Lactato de Ringer y 36 del grupo de Solución salina, solamente 3 (8,10) ratas del grupo de Lactato de Ringer y 3 (7,89) del grupo de Solución Salina presentaron adherencias intraperitoneales. RR: 0,97 (0,18-5,15)

Cardiopulmonary effects and eyeball centralization with low-dose atracurium in spontaneously breathing, anesthetized dogs

The objective was to determine the cardiopulmonary effects and eyeball centralization time obtained with 15 or 30µg kg-1 of atracurium in anesthetized dogs under spontaneous breathing. Eighteen healthy adult mixed-breed dogs were used, which received 0.1mg kg-1 acepromazine and 0.5mg kg-1 morphine IM, followed by 4mg kg-1 propofol IV and maintained on isoflurane anesthesia with spontaneous breathing. Animals received 1mL 0.9% NaCl IV (CG), 15µg kg-1 (G15) or 30µg kg-1 (G30) of atracurium IV. Eyeball centralization time was measured; heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, respiratory rate (RR), tidal volume (Vt) and minute volume (Vm) were determined every 5min, and pH, arterial CO2 pressure (PaCO2 ), arterial O2 pressure (PaO2 ), hemoglobin oxygen saturation (SaO2 ), bicarbonate (HCO3-) and base excess (BE) every 15min until 60min. Both doses of atracurium produced a similar period of eyeball centralization. Vt in groups treated with atracurium was lower than in CG up to 15min. Vm in G15 differed from CG up to 10min and in G30 up to 25min. No differences were observed for cardiovascular parameters, RR, SaO2, PaO2, HCO3- and BE. pH decreased in CG between 30 and 60min and in G15 and G30 at 15min. G30 differed from CG between 15 and 30min. PaCO2 in GC differed from baseline between 30 and 60min and in G15 differed at 15min. Atracurium at the dose of 15µg kg-1 is adequate for short corneal procedures in inhalant-anesthetized dogs under spontaneous breathing.

In vitro and in vivo antileishmanial activities of a Brazilian green propolis extract

The in vitro antileishmanial activity of Brazilian green propolis hydroalcoholic extract (BPE) were carried out on Leishmania (Viannia) braziliensis against both promastigote (doses ranging from 1 to 750 mu g mL(-1)) and amastigote (10, 100, and 250 mu g mL(-1)) assays in comparison with the positive (amphotericin B) and negative (dimethyl sulfoxide at 1% in physiologic solution) control groups. BPE displayed in vitro antileishmanial activities against promastigote forms of the parasite (p<0.05). However, it was inactive against its amastigote ones. In the in vitro cytotoxicity assay against Vero cells, BPE showed no cytotoxicity in the maximum doses tested. The high-performance liquid chromatography analysis allowed the identification of caffeic acid, p-coumaric acid, aromadendrine-4`-methyl-ether, 3-prenyl-p-coumaric acid (drupanin), and 3,5-diprenil-p-cumarico acid (artepillin C) as major compounds of BPE. In the in vivo assay, using a Balb/C lineage of Mus musculus male mice, groups of ten animals each were treated (1.5 mg kg day(-1)) with BPE orally (group 1), BPE topically (group 2), BPE orally and topically (group 3), and glucantime (group 4), using NaCl 0.9% (group 5) as the negative control group. Groups 1, 2, and 3 displayed a decrease on lesion development, after 90 days of treatment, by 78.6%, 84.3%, and 90.0%, respectively, while the glucantime-treated group showed 57.7% of decrease, all in comparison with the negative control group. It is the first time that the in vivo antileishmanial activity has been reported for Brazilian green propolis.

Timing-dependent protection of hypertonic saline solution administration in experimental liver ischemia/reperfusion injury

Background. Diving liver ischemia, the decrease in mitochondrial energy causes cellular damage that is aggravated after reperfusion. This injury can trigger a systemic inflammatory syndrome, also producing remote organ damage. Several substances have been employed to decrease this inflammatory response during liver transplantation, liver resections, and hypovolemic shock. The aim of this study was to evaluate the effects of hypertonic saline solution and the best timing of administration to prevent organ injury during experimental liver ischemia/reperfusion. Methods. Rats underwent 1 hr of warm liver ischemia followed by reperfusion. Eighty-four rats Were allocated into 6 groups: sham group, control of ischemia group) (C), pre-ischemia treated NaCl 0.9% (ISS) and NaCl 7.5% (HTS) groups, pre-repefusion ISS, and HTS groups. Blood and tissue samples were collected 4 hr after reperfusion. Results. HTS showed beneficial effects in prevention of live ischemia/reperfusion injury. HTS groups developed increases in AST and ALT levels that were significantly less than ISS groups; however, the HTS pre-reperfusion group showed levels significantly less than the HTS pre-ischemia group. No differences in IL-6 and IL-10 levels, were observed. A significant decrease in mitochondrial dysfunction as well as hepatic edema was observed in the HTS pre-reperfusion group. Pulmonary vascular permeability Was significantly less in the pre-reperfusion HTS group compared to the ISS group. No differences in myeloperoxidase activity were observed. The liver histologic score was significantly less in the pre-reperfusion HTS group compared to the pre-ischemia I-ITS group. Conclusion. HTS ameliorated local and systemic injuries in experimental liver ischemia/reperfusion. Infusion of HTS in the pre-reperfusion period may be an important adjunct to accomplish the best results. (Surgery 2010;147:415-23.)

Effect of Recombinant Bovine Somatotropin on Plasma Concentrations of Insulin-like Growth Factor I, Insulin and Membrane Integrity of Bull Spermatozoa

Contents This study aimed to evaluate the effect of the exogenous recombinant bovine somatotropin (rbST) on plasma concentrations of insulin-like growth factor I (IGF-I), insulin and semen quality of bulls. Twenty bulls (Aberdeen Angus and Brangus) were divided by breed into two groups. Placebo group was injected with NaCl 0.9% (s.c.) and treatment group with rbST (s.c., 500 mg) at days 0 and 14 of the experiment. Immediately after semen collection, blood samples were taken on days 0, 14, 28, 42 and 56 of the experiment. Semen was also collected on day 70 of the experiment. Evaluation of sperm motility was performed at pre-freezing and post-thawing stage, whereas assessment of sperm membrane integrity was performed after freezing and thawing. Analysis of data revealed that the effect of treatment and treatment-by-collection day on plasma concentrations of IGF-I and insulin was not significant. However, mean plasma concentrations of IGF-I and insulin were affected (p < 0.0001) by days of blood sampling. Effect of treatment and treatment-by-collection day on motility of spermatozoa was similar (p > 0.05) at pre-freezing and post-thawing stage. Intactness of plasmalemma and tail membrane of spermatozoa at post-thawing stage was higher (p < 0.05) in rbST-treated group than in control. In conclusion, rbST did not affect plasma concentrations of IGF-I and insulin, however, it did improve post-thaw sperm membrane integrity.

Nephrotoxicity of CCA-treated wood: a comparative study with As2O5 and CrO3 on mice

The purpose of this work was to assess the acute toxicity on male mice to a chromated copper arsenate (CCA) solution, a widespread wood preservative used in building industry until 2002. Animals were subcutaneously injected with CCA (7.2 mg/kg arsenic and 10.2 mg/kg chromium per body weight), CrO3 (10.2 mg/kg), As2O5 (7.2 mg/kg) and NaCl (0.9%) per se, during 48 h and 96 h, for histopathology, histochemistry, chromium and arsenic analysis. The results showed some histopathological changes within renal tubules lumen of CCA exposed animals (during 48 h, and 96 h), and CrO3 (for the period of 96 h). Furthermore, the renal levels of arsenic and chromium in treated animals were statistically more evident than controls. Although, the same contents of pentavalent arsenic and hexavalent chromium were injected into treated animals with CCA and with the prepared solutions of As2O5 and CrO3, a different distribution of the pattern of these compounds was observed in kidneys.

Local heating of human skin causes hyperemia without mediation by muscarinic cholinergic receptors or prostanoids.

RESUME Les changements locaux de la température à la surface de la peau humaine ont une influence importante sur sa perfusion. La chaleur augmente localement le flux sanguin cutané, mais les mécanismes et les médiateurs de cette réponse (réponse thermique d'hyperémie) sont incomplètement élucidés. Dans la présente étude, nous avons examiné la relation possible entre la réponse thermique d'hyperémie, les récepteurs cholinergiques muscariniques et la production des prostaglandines vasodilatatrices. Chez 13 sujets de sexe masculin en bonne santé âgés entre 20 et 30 ans, une chambre métallique (contenant de l'eau) dont la température peut être contrôlée, a été placée sur la face palmaire de leur avant-bras et utilisée pour augmenter la température de surface de 34 à 41°C. L'hyperémie cutanée consécutive a été enregistrée par l'intermédiaire d'un scanner laser-Doppler. Dans une expérience, chacun des 8 sujets a reçu un bolus i.v. de glycopyrolate (agent antimuscarinique) (4 µg/kg) lors d'une visite et de NaCl 0,9% lors de l'autre visite. La réponse thermique d'hyperémie a été déterminée dans l'heure suivant les injections. Les glycopyrolate a efficacement empêché la vasodilation des micro-vaisseaux cutanés induite par iontophorèse d'acétylcholine mais n'a pas influencé la réponse thermique d'hyperémie. Dans une deuxième expérience entreprise avec 5 autres sujets 1 g d'aspirine (inhibiteur de la cyclooxygénase) administrée oralement a totalement supprimé la vasodilatation induite dans la peau par le courant anodique, sans modifier la réponse thermique d'hyperémie. La présente étude confirme l'absence de stimulation des récepteurs muscariniques et la production de prostaglandines vaso-dilatatrices dans la vasodilatation induite chez l'homme par réchauffement local de la peau de l'avant-bras. ABSTRACT Local changes in surface temperature have a powerful influence on the perfusion of human skin. Heating increases local skin blood flow (SkBF), but the mechanisms and mediators of this response (thermal hyperemia response) are incompletely elucidated. In the present study, we examined the possible dependence of the thermal hyperemia response on stimulation of muscarinic cholinergic receptors and on production of vasodilator prostanoids. In 13 male healthy subjects aged 20 - 30 years, a temperature- controlled chamber was positioned on the volar face of one forearm and used to raise surface temperature from 34to41°C. The time-course of the resulting thermal hyperemia response was recorded with a laser-Doppler imager. In one experiment, each of 8 subjects received an i.v. bolus of the antimuscarinic agent glycopyrrolate (4µg/kg) on one visit and saline on the other. The thermal hyperemia response was determined within the hour following the injections. Glycopyrrolate effectively inhibited the skin vasodilation induced by iontophoresis of acetylcholine, but did not influence the thermal hyperemia response. In a second experiment conducted in 5 other subjects, 1 gram of the cyclooxygenase inhibitor aspirin administered orally totally abolished the vasodilation induced in the skin by anodal current, but also failed to modify the thermal hyperemia response. The present study excludes the stimulation of muscarinic receptors and the production of vasodilator prostaglandins as essential and nonredundant mechanisms for the vasodilation induced by local heating in human forearm skin.