Effects of adding La and Ce to hydrotalcite-type Ni/Mg/Al catalyst precursors on ethanol steam reforming reactions

Catalyst precursors composed of Ni/Mg/Al oxides with added La and Ce were tested in ethanol steam reforming (ESR) reactions. La and Ce were added by anion-exchange. The oxides were characterized by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) analysis. The catalyst precursors consist of a mixture of oxides, with the nickel in the form of NiO strongly interacting with the support Mg/Al. The XPS analysis showed a lanthanum-support interaction, but no interaction of Ce species with the support. The reaction data obtained with the active catalysts showed that the addition of Ce and La resulted in better H(2) production at 550 degrees C. The CeNi catalyst provided the higher ethanol conversion, with lower acetaldehyde production, possibly clue to a favoring of water adsorption on the weakly interacting clusters of CeO(2) on the surface. (C) 2010 Elsevier B.V. All rights reserved.

Deposition of selenium thin layers on gold surfaces from sulphuric acid media: Studies using electrochemical quartz crystal microbalance, cyclic voltammetry and AFM

In this paper we report here new considerations about the relationship between the mass and charge variations (m/z relationship) in underpotential deposition (UPD), bulk deposition and also in the H(2)Se formation reaction. Nanogravimetric experiments were able to show the adsorption of H(2)SeO(3) on the AuO surface prior to the voltammetric sweep and that, after the AuO reduction, 0.40 monolayer of H(2)SeO(3) remains adsorbed on the newly reduced Au surface, which was enough to gives rise to the UPD layer. The UPD results indicate that the maximum coverage with Se(ads) on polycrystalline gold surface corresponds to approximately 0.40 monolayer, in good agreement with charge density results. The cyclic voltammetry experiments demonstrated that the amount of bulk Se obtained during the potential scan to approximately 2 Se monolayers, which was further confirmed by electrochemical quartz crystal microbalance (EQCM) measurements that pointed out a mass variation corresponding of 3 monolayers of Se. In addition, the Se thin films were obtained by chronoamperometric experiments, where the Au electrode was polarized at +0.10V during different times in 1.0 M H(2)SO(4) + 1.0 mM SeO(2). The topologic aspects of the electrodeposits were observed in Atomic Force Microscope (AFM) measurements. Finally, in highly negative potential polarizations, the H(2)Se formation was analyzed by voltammetric and nanogravimetric measurements. These finding brings a new light on the selenium electrodeposition and point up to a proposed electrochemical model for molecule controlled surface engineering. (c) 2009 Elsevier Ltd. All rights reserved.

Ni catalysts with Mo promoter for methane steam reforming

NiO/Al(2)O(3) catalyst precursors were prepared by simultaneous precipitation, in a Ni:Al molar ratio of 3:1, promoted with Mo oxide (0.05, 0.5, 1.0 and 2.0 wt%). The solids were characterized by adsorption of N(2), XRD, TPR, Raman spectroscopy and XPS, then activated by H(2) reduction and tested for the catalytic activity in methane steam reforming. The characterization results showed the presence of NiO and Ni(2)AlO(4) in the bulk and Ni(2)AlO(4) and/or Ni(2)O(3) and MoO(4)(-2) at the surface of the samples. In the catalytic tests, high stability was observed with a reaction feed of 4:1 steam/methane. However, at a steam/methane ratio of 2: 1, only the catalyst with 0.05% Mo remained stable throughout the 500 min of the test. The addition of Mo to Ni catalysts may have a synergistic effect, probably as a result of electron transfer from the molybdenum to the nickel, increasing the electron density of the catalytic site and hence the catalytic activity. (C) 2009 Elsevier Ltd. All rights reserved.

Acupuncture with manual and electrical stimulation for labour pain : a longitudinal randomised controlled trial

Background: Acupuncture is commonly used to reduce pain during labour despite contradictory results. The aim of this study is to evaluate the effectiveness of acupuncture with manual stimulation and acupuncture with combined manual and electrical stimulation (electro-acupuncture) compared with standard care in reducing labour pain. Our hypothesis was that both acupuncture stimulation techniques were more effective than standard care, and that electro-acupuncture was most effective.  Methods: A longitudinal randomised controlled trial. The recruitment of participants took place at the admission to the labour ward between November 2008 and October 2011 at two Swedish hospitals. 303 nulliparous women with normal pregnancies were randomised to: 40 minutes of manual acupuncture (MA), electro-acupuncture (EA), or standard care without acupuncture (SC). Primary outcome: labour pain, assessed by Visual Analogue Scale (VAS). Secondary outcomes: relaxation, use of obstetric pain relief during labour and post-partum assessments of labour pain. The sample size calculation was based on the primary outcome and a difference of 15 mm on VAS was regarded as clinically relevant, this gave 101 in each group, including a total of 303 women.  Results: Mean estimated pain scores on VAS (SC: 69.0, MA: 66.4 and EA: 68.5), adjusted for: treatment, age, education, and time from baseline, with no interactions did not differ between the groups (SC vs MA: mean difference 2.6, 95% confidence interval [CI] -1.7-6.9 and SC vs EA: mean difference 0.6 [95% CI] -3.6-4.8). Fewer number of women in the EA group used epidural analgesia (46%) than women in the MA group (61%) and SC group (70%) (EA vs SC: odds ratio [OR] 0.35; [95% CI] 0.19-0.67).  Conclusions: Acupuncture does not reduce women's experience of labour pain, neither with manual stimulation nor with combined manual and electrical stimulation. However, fewer women in the EA group used epidural analgesia thus indicating that the effect of acupuncture with electrical stimulation may be underestimated. These findings were obtained in a context with free access to other forms of pain relief.

Acupuncture with manual and electrical stimulation for labour pain : a two month follow up of recollection of pain and birth experience.

BACKGROUND: In a previous randomised controlled trial we showed that acupuncture with a combination of manual- and electrical stimulation (EA) did not affect the level of pain, as compared with acupuncture with manual stimulation (MA) and standard care (SC), but reduced the need for other forms of pain relief, including epidural analgesia. To dismiss an under-treatment of pain in the trial, we did a long-term follow up on the recollection of labour pain and the birth experience comparing acupuncture with manual stimulation, acupuncture with combined electrical and manual stimulation with standard care. Our hypothesis was that despite the lower frequency of use of other pain relief, women who had received EA would make similar retrospective assessments of labour pain and the birth experience 2 months after birth as women who received standard care (SC) or acupuncture with manual stimulation (MA). METHODS: Secondary analyses of data collected for a randomised controlled trial conducted at two delivery wards in Sweden. A total of 303 nulliparous women with normal pregnancies were randomised to: 40 min of MA or EA, or SC without acupuncture. Questionnaires were administered the day after partus and 2 months later. RESULTS: Two months postpartum, the mean recalled pain on the visual analogue scale (SC: 70.1, MA: 69.3 and EA: 68.7) did not differ between the groups (SC vs MA: adjusted mean difference 0.8, 95 % confidence interval [CI] -6.3 to 7.9 and SC vs EA: mean difference 1.3 CI 95 % -5.5 to 8.1). Positive birth experience (SC: 54.3 %, MA: 64.6 % and EA: 61.0 %) did not differ between the groups (SC vs MA: adjusted Odds Ratio [OR] 1.8, CI 95 % 0.9 to 3.7 and SC vs EA: OR 1.4 CI 95 % 0.7 to 2.6). CONCLUSIONS: Despite the lower use of other pain relief, women who received acupuncture with the combination of manual and electrical stimulation during labour made the same retrospective assessments of labour pain and birth experience 2 months postpartum as those who received acupuncture with manual stimulation or standard care. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01197950.

Material properties under drawing and extrusion with cyclic torsion

A copper bar was drawn while a lead bar was extruded through a cyclically twisting die in a specifically designed experimental rig. The drawing/extrusion load fluctuated at the same frequency as that of die twisting. The load tended to be at a level of monotonic deformation when the die was changing direction. The degree of the reduction in load for both the drawing and extrusion processes depended on the deformation conditions and requires optimisation for industrial application.

Guanylyl cyclase stimulation by homologous and heterologous natriuretic peptides in salmonids

A range of homologous (trout ANP, trout CNP, trout VNP) and heterologous (eel ANP, eel ANP-NH₂, rat ANP, porcine CNP) NPs were tested for their effect on guanylyl cyclase in gill and kidney membrane preparations from freshwater and seawater-acclimated rainbow trout and Atlantic salmon. All NPs stimulated guanylyl cyclase at 1 µmol l^-1in all preparations. ANP was the most potent stimulator of kidney guanylyl cyclase and CNP the most potent stimulator of guanylyl cyclase in gills. Some differences were apparent between the potencies of homologous and heterologous peptides at 1 µmol l^-1: tANP was more potent than rANP in the SW trout kidney and tCNP was more potent than pCNP in FW salmon tissues. While eANP was more potent than tANP in trout gills, it was less potent than tANP in FW salmon gills. However, there was no significant difference between the potencies of eANP and eANP-NH₂ in trout or salmon gills. Salinity did not affect guanylyl cyclase activity with the exception that trout ANP at 1 µmol l^-1was more potent in SW trout kidneys than in FW trout kidneys. These results suggest a predomination of NPR-A in the kidney and NPR-B in the gill. It appears that salmonid NPR-A and NPR-B are relatively promiscuous in their ligand affinity, with few differences in the potencies of trout and mammalian NPs and only small differences in cGMP production where these differences do occur.

Understanding ring strain and ring flexibility in six - and eight-membered cyclic organometallic group 14 oxides

A simple model was developed for the approximation of ring strain energies of homo- and heterometallic, six- and eight-membered cyclic organometallic group 14 oxides and the degree of puckering of their ring conformations. The conformational energy of a ring is modelled as the sum of its angular strain components. The bending potential energy functions for the various endocyclic M–O–M′ and O–M–O linkages (M, M′=Si, Ge, Sn) were calculated at the B3LYP/(v)TZ level of theory using H3MOM′H3 and H2M(OH)2 as model compounds. For the six-membered rings, the minimum total angular contribution to ring strain, ERSGmin was calculated to decrease in the order: cyclo-(H2SiO)3 (13.0 kJ mol−1)>cyclo-H2Sn(OSiH2)2O (7.0 kJ mol−1)>cyclo-H2Ge(OSiH2)2O (4.9 kJ mol−1)>cyclo-H2Si(OSnH2)2O (3.4 kJ mol−1)>cyclo-(H2SnO)3 (1.7 kJ mol−1)>cyclo-H2Si(OGeH2)2O (0.8 kJ mol−1)≈cyclo-H2Ge(OSnH2)2O (0.7 kJ mol−1)>cyclo-H2Sn(OGeH2)2O (0.1 kJ mol−1)≈cyclo-(H2GeO)3 (0 kJ mol−1). All of the six-membered rings were predicted to adopt (nearly) planar conformations (a=0.996<a<1). By contrast, all eight-membered rings were predicted to adopt strainless, but puckered conformations. The degree of puckering was predicted to increase in the order: cyclo-(H2SiO)4 (a=0.983)<cyclo-H2Sn(OSiH2O)2SiH2 (a=0.959)<cyclo-(H2SiO)2(H2SnO)2 (a=0.942)< cyclo-H2Si(OSnH2O)2SiH2 (a=0.935)<cyclo-(H2SnO)4 (a=0.916)<cyclo-(H2GeO)4 (a=0.885). The differences in ring strain and the degree of puckering were linked to the different electronegativities of Si, Ge and Sn. The results obtained are consistent with experimental ring strain energies; reactivities towards ring opening polymerizations or ring expansion reactions and observed ring conformations of cyclic organometallic group 14 oxides.

Pituitary adenylate cyclase-activating polypeptide induces translocation of its G-protein-coupled receptor into caveolin-enriched membrane microdomains, leading to enhanced cyclic AMP generation and neurite outgrowth in PC12 cells

Pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the secretin/glucagon/vasoactive intestinal peptide family expressed throughout the nervous system, binds to the PACAP-specific G-protein-coupled receptor family members to promote both neuronal differentiation and survival. Although the PACAP receptor is known to activate its effector protein, adenylate cyclase (AC), and thus enhance cAMP generation, the molecular mechanism utilized by the receptor to activate AC is lacking. Here, we show that PACAP induces neurite outgrowth in PC12 cells by induction of translocation of the PACAP type 1 receptor (PAC1R) into caveolin-enriched Triton X-100-insoluble microdomains, leading to stronger PAC1R-AC interaction and elevated cAMP production. Moreover, we demonstrate that translocation of PAC1R is blocked by various treatments that selectively disrupt caveolae. As a result, intracellular cAMP level is decreased and consequently the PACAP-induced neurite outgrowth retarded. In contrast, addition of exogenous ganglioside GM1 to the cells shows the opposite effects. These results therefore identify the PACAP-induced translocation of its G-protein-coupled receptor into caveolae, where both AC and the regulating G-proteins reside, as the key molecular event in activating AC and inducing cAMP-mediated differentiation of PC12 cells.

Leptin stimulation of COXIV is impaired in obese skeletal muscle myotubes

Objective
To investigate the effects of leptin on the mRNA abundance of key genes involved in fatty acid oxidation and mitochondrial biogenesis in cultured skeletal muscle myotubes derived from lean and obese individuals.

Research methods and procedures
Rectus abdominus muscle biopsies were obtained from surgical patients to establish primary skeletal muscle cell cultures. Two distinct primary cell culture groups were established (Lean and Obese) n = 7 in each group. Differentiated cultures were then exposed to leptin (2.5 μg/ml) for 6 h. mRNA expression was subsequently measured by real-time PCR analysis.

Results
Basal mRNA expression of βHAD, COXIII, COXIV, PGC-1α and SOCS3 in the cultured human skeletal muscle myotubes were similar, however, PDK4 mRNA was elevated (P < 0.05) in the myotubes derived from obese individuals. The addition of leptin resulted in a 2.5-fold increase in COXIV mRNA expression in the myotubes derived from Lean individuals only (P < 0.05). There was also a tendency for leptin to increase COXIII, βHAD and PDK4 mRNA expression in this same group. Leptin had no impact on the gene expression of all measured transcripts in myotubes derived from obese individuals.

Conclusion
Short-term exposure of human skeletal muscle myotubes to leptin stimulated the expression of the mitochondrial enzyme COXIV in myotubes derived from lean individuals, an effect that was abrogated in myotubes derived from obese individuals. These data demonstrate a novel capacity for leptin to increase mitochondrial biogenesis and thus, a possible increased capacity for lipid oxidation and the persistence of a defect in leptin signalling in human myotubes cultured from obese individuals.

Cyclic GMP modulates stomatal opening induced by natriuretic peptides and immunoreactive analogues

In this paper we demonstrate that compounds that promote stomatal opening such as kinetin, atrial natriuretic peptide (ANP) and plant natriuretic peptide immunoanalogues (irPNP) significantly elevate cGMP in guard cell protoplasts. Stomata opened by irPNP are induced to close in the presence of the guanylate cyclase inhibitor, LY 83583. The effect of cGMP on stomatal opening appears to be linked with Ca2+ levels. ANP, irPNP and 8-Br-cGMP all induce stomatal opening and this is inhibited by compounds that lower intracellular Ca2+ levels such as ethylene glycol bis(β-aminoethyl ether) N,N,N’,N’-tetraacetic acid (EGTA), ruthenium red and procaine.

ß- adrenergic stimulation of skeletal muscle HSL can be overridden by AMPK signaling

Hormone-sensitive lipase (HSL), an important regulatory enzyme for triacylglycerol hydrolysis within skeletal muscle, is controlled by β-adrenergic signaling as well as intrinsic factors related to contraction and energy turnover. In the current study, we tested the capacity of 5′AMP-activated protein kinase (AMPK) to suppress β-adrenergic stimulation of HSL activity. Eight male subjects completed 60 min of cycle exercise at 70% VO2 peak on two occasions: either with normal (CON) or low (LG) pre-exercise muscle glycogen content, which is known to enhance exercise-induced AMPK activity. Muscle samples were obtained before and immediately after exercise. Pre-exercise glycogen averaged 375 ± 35 and 163 ± 27 mmol·kg–1 dm for CON and LG, respectively. AMPK α-2 was not different between trials at rest and was increased (3.7-fold, P<0.05) by exercise during LG only. HSL activity did not differ between trials at rest and increased (0 min: 1.67 ± 0.13; 60 min: 2.60 ± 0.26 mmol·min–1·kg–1 dm) in CON. The exercise-induced increase in HSL activity was attenuated by AMPK α-2 activation in LG. The attenuated HSL activity during LG occurred despite higher plasma epinephrine levels (60 min: CON, 1.96 ± 0.29 vs LG, 4.25 ± 0.60 nM, P<0.05) compared with CON. Despite the attenuated HSL activity in LG, IMTG was decreased by exercise (0 min: 27.1 ± 2.0; 60 min: 22.5 ± 2.0 mmol.kg–1 dm, P<0.05), whereas no net reduction occurred in CON. To confirm the apparent effect of AMPK on HSL activity, we performed experiments in muscle cell culture. The epineprine-induced increase in HSL activity was totally attenuated (P<0.05) by AICAR administration in L6 myotubes. These data provide new evidence indicating that AMPK is a major regulator of skeletal muscle HSL activity that can override β-adrenergic stimulation. However, the increased IMTG degradation in LG suggests factors other than HSL activity are important for IMTG degradation.