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Zero-gap liquid alkaline water electrolyzers have great potential for hydrogen production. In order to enhance their actual performance, one of the key components to investigate is the anionic exchange membrane that allows the conduction of anions between the electrodes. This paper reports the preparation and characterization of membranes composed of a polybenzimidazole, either poly(2,5-benzimidazole) (ABPBI) or poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (PBI), crosslinked with different ratios of poly(vinylbenzyl chloride) (PVBC), forming thermally stable and homogeneous films. Quaternization of these films with 1,4-diazabicyclo (2.2.2) octane (DABCO) followed by immersion in an alkaline solution lead to the introduction of quaternary ammonium groups and hydroxide anions respectively. Adequate thermal stability is observed in the temperature range of application (below 100 °C). Measurements of KOH and water and related swelling reflect the higher absorption capacity of ABPBI based membranes relative to PBI based ones. ABPBI-c-PVBC/OH 1:2 membranes at 50 °C are characterized by high ionic conductivity values (48 mS cm−1), reaching 380 mA cm−2 at cell voltage 1.98 V. In conclusion, we consider that these membranes are competitive candidates as anion exchange membranes for zero-gap alkaline water electrolyzers, and can be further enhanced to reach the performance of state of the art AEM’s.

In this study, a thenoyltriflouroacetone ligand (TTA) with a Tb3+ MOF was synthesized (Tb=10 and 50% mol) and its structural and luminescent properties were analyzed. The metalorganic compound was generated in a simple one-pot reaction from terbium nitrate and 2-thenoyltrifluoroacetone precursors at room temperature. By means of FTIR, it was confirmed the presence of carbon groups, which made possible the terbium ion chelation, and also the Tb-O bonds vibration modes. HNMR results confirm that the complex with 10% mol of Tb3+ contains three coordinates molecules of TTA and two waters molecules. The powders exhibit rod-like morphology with size about 170 nm of diameter and a length about 2 {\mu}m, the rod-like nature of powders was confirmed by SEM and TEM analyses. By XRD it was concluded that at higher terbium concentration (TTA-50Tb sample) higher the crystallite size and crystallinity, in fact the TTA-10Tb sample shows a partial-amorphous nature. By photoluminescence analyses, the 5D4-7FJ (J=3, 4, 5 and 6) emissions were recorded for both synthesized samples ({\lambda}exc=376 nm). Furthermore, it was observed that the emission intensity was enhanced in a factor of 3.5 for the TTA-50Tb. The energy transfer efficiency from TTA to Tb3+ (antenna effect) was 0.984 for TTA-10Tb and 0.993 for TTA-50Tb. Decay time analyses indicate effective lifetime of 1.45 and 1.60ms for the samples doped at 10 and 50%, respectively, indicating that the forbidden transition rules are stronger at higher crystallinity. The integrated intensities of the 5D4 - 7F5 (green at 541 nm) and 5D4 - 7F6 (blue at 486 nm) emissions and their intensity ratios IG/IB upon 376 nm excitation have been evaluated for TTA-10Tb andTTA-50Tb samples., Comment: Optical Materials (2018)

Resumen Caso clinico Paciente varon de 10 anos, de raza negra, con antecedente de traumatismo leve en ojo izquierdo; presenta agudeza visual corregida de 0,2 en escala de Snellen, hifema con altura de 1 mm, presion intraocular (PIO) de 12 mmHg en ese ojo, con incremento de PIO a 20 mmHg a las 72 h. Con el resultado positivo del estudio de drepanocitos, se decide tratamiento medico con oxigenoterapia transcorneal. Se logra el aclaramiento de la camara anterior, con agudeza visual corregida de 0,8 y la reduccion de la PIO a 8 mmHg. Discusion En los pacientes con hifema persitente en el contexto de una drepanocitosis, la oxigenoterapia transcorneal es una buena alternativa terapeutica. Se obtienen resultados satisfactorios inmediatos con la disminucion de la PIO y el aclaramiento de la camara anterior.

Resumen Caso clinico Mujer de 78 anos con antecedentes de cirugia XEN®. A los 18 meses de seguimiento se observa perforacion conjuntival a nivel del implante, decidiendose intervencion quirurgica. En esta se constato un trayecto subconjuntival corto (0,5 mm). Se intenta, sin exito, extraerlo mediante traccion, sin embargo, el XEN® se rompe con facilidad. Finalmente se decide seccionarlo hasta nivel escleral, y suturar la conjuntiva. Durante la primera semana poscirugia existe disminucion de la presion intraocular (6 mmHg), para posteriormente aumentar progresivamente hasta 25, optandose por iniciar tratamiento medico. Discusion La exposicion conjuntival del XEN® es una complicacion rara, pero potencialmente grave. Para evitarla es importante una tecnica quirurgica meticulosa durante su implantacion. En caso de suceder es importante identificar la causa. Si es debida al trayecto subconjuntival corto, una alternativa terapeutica es la seccion del implante a este nivel para evitar nuevas complicaciones.

We developed an innovative polymer blend system composed of polyvinyl alcohol (PVA) and polybenzimidazole as an anionic membrane for application to zero gap alkaline electrolysers. The challenge was to combine PVA with either poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (PBI) or poly (2,5-benzimidazole) (ABPBI) to complement these neutral polymers, which must be doped to conduct, with hydroxyl groups that benefit the OH− transport mechanism. We studied PVA-PBI and PVA-ABPBI membranes with compositions varying between 2:1 and 8:1, with 4:1 being best ratio. PVA is crosslinked inside PVA-PBI 4:1 and PVA-ABPBI 4:1 membranes with glutaraldehyde (GA) by immersion in a reaction solution with different GA contents ranging from 0.5 vol% to 50 vol% to enhance the stability of the membranes. The chemical stability in a KOH environment, thermal and mechanical properties, surface morphology, swelling, water/KOH sorption, and conductivity of the linear alkali-doped (L-PVA-PBI, L-PVA-ABPBI) and crosslinked (C-PVA-PBI, C-PVA-ABPBI) membranes were analysed. The best results were observed for the C-PVA-ABPBI 4:1 membrane crosslinked in 0.5 vol% GA, which exhibited specific conductivities at 90 °C of 50 mS cm−1 and 90 mS cm−1 when doped using 15 wt% and 30 wt% KOH, respectively. In short-term electrolysis tests performed with circulated 15 wt% KOH at 50 °C, this membrane exhibited a current density that was twice that of the commercial porous Zirfon® diaphragm (i.e., 300 mA cm−2 and 140 mA cm−2, respectively) at a cell voltage of 2.0 V. The performance achieved with the C-PVA-ABPBI membrane in a 15 wt% KOH electrolyte at 70 °C was good (i.e., 360 mA cm−2 at a cell voltage of 1.9 V).

A non-noble metal (NNM) catalyst for oxygen reduction reaction (ORR) was synthesized using Fe(II)-phthalocyanine as unique source of Fe, N, and C, and SBA-15 ordered mesoporous silica as templating agent, resulting in a material with an extremely high specific surface area and a high microporosity (around 50%). FESEM, FTIR and Raman analyses were performed to investigate the morphology and the physicochemical properties of the catalyst. The ORR activity and the methanol tolerance were tested in rotating disk electrode (RDE), and the selectivity towards a complete 4-electrons reduction was investigated by rotating ring disk electrode (RRDE) test and hydrogen peroxide reduction test in RDE, showing very promising results. Thus, the Fe-N-C catalyst was tested at the cathode of a DMFC after determination of the optimal electrode formulation regarding catalyst loading and Nafion ® content, showing a maximum power density of 20 mW cm −2 at 90 °C. A short term durability test to assess the behavior of both the Fe-N-C and the Pt/C catalysts was conducted on the DMFC, showing a better performance of the non-noble catalyst. Thus, the Fe-N-C catalyst is a potential good candidate to be used as catalytic material for DMFC cathode, in alternative to Pt. The performance in a H 2 /O 2 PEMFC was tested as well, showing a power density of 105 mW cm −2 at 60 °C.

The activity of carbon supported palladium-based catalysts towards ethanol oxidation reaction in alkaline medium is investigated. To this end, Pd and Pd x Ru (x = 1, 6, 12) materials are synthesized supported on Vulcan XC72R by a modified impregnation method. These materials are characterized physicochemically and their composition varies between 40 and 50 wt. % of metal content. The mean size of nanoparticles is below 4 nm, and the size of the majority of particles ranges from 2 to 6 nm. The catalytic activity of these samples is also tested in half-cell and alkaline membrane direct ethanol fuel cell (AMDEFC). Lower onset potential and higher oxidation current densities is observed in palladium-rich bimetallic catalysts. By using the prepared samples as anode of AMDEFC and a commercial membrane of polybenzimidazole as solid electrolyte, the maximum power density is observed for Pd 12 Ru/C, 97 mW cm −2 , almost doubling the value achieved by the catalyst Pd/C (50 mW cm −2 ), and above the obtained by commercial PtRu/C catalyst (89 mW cm −2 ).

Fluidized beds are found in the energy production industry, and knowing their hydrodynamic conditions, such as local gas holdup or volumetric gas fraction, is important for effective operation. Local measurement probes are commonly used to measure local gas holdup. Although the probes are typically as small as possible to mitigate their influence on the local conditions, the invasive nature of this measurement technique has the potential to alter the fluidized bed behavior. This study used a noninvasive measurement technique, X-ray computed tomography (CT) imaging, to determine the local time-average gas holdup everywhere within a 10.2 cm diameter fluidized bed filled with 500–600 μm glass beads in which simulated probes were inserted. Three different simulated probe tips (pointed, rounded, and flat) and two different orientations (horizontal and vertical) were investigated at four different bed heights and two different fluidization velocities. The results show increases in local time-average gas holdup when the probes were present, but the scale of the effects was dependent upon the height at which the probes were placed; the lower the probe within the fluidized bed, the larger the local effects. The shape of the probe tip did not show any differences in the local gas holdup. On the other hand, probe orientation was an important factor, with the horizontal orientation showing a sustained increase in gas holdup values farther from the probe. The two different flow rates used in this study (1.5 U mf and 3 U mf , where U mf is the minimum fluidization velocity) also showed differences in the amount of variation in gas holdup, but the trends were inconsistent. Overall, the local hydrodynamic effects of the simulated invasive probes of this work were minimized when: (i) the probes were placed in the central part of the bed, outside the aeration region and top of the bed, (ii) the fluidized bed was operated at higher superficial gas velocities, and (iii) the probes were mounted in a vertical orientation.

A Nafion ® membrane has been both electrochemically and chemically modified in-situ to incorporate polyaniline (PANi) into its structure. The proposed objective was to decrease the methanol (MeOH) permeability and thus improve the durability of a direct methanol fuel cell device. Permeability and conductivity of the modified membranes were measured using the unmodified Nafion ® 117 as a reference. The permeability was determined from the electrochemical oxidation of permeated methanol, and the conductivity was determined via electrochemical impedance spectroscopy. To evaluate the effect of these modifications, the performance of a MeOH/O 2 single-cell was measured using different MeOH flows and concentrations. The device durability was evaluated under a constant potential and at different operating times. The power density, p , at high MeOH flows and concentrations was 7 times higher for the PANi-modified membrane than the unmodified Nafion ® 117. The durability of the modified membranes containing small amounts of PANi was 2 times higher using low MeOH flows and concentrations, while the power densities were similar. Impedance measurements were performed before and after the long-term durability tests in order to identify the improvements at the different parts of the fuel cell.

Acoustic vibration in a fluidized bed can be used to enhance the fluidization quality of particulate matter; this particular noninvasive method provides no internal changes to the bed material structure. However, due to the complexity of this multiphase flow system, characterizing the hydrodynamics of a fluidized bed has become critical in understanding this system behavior. The local void fraction behavior in a cold flow 3D fluidized bed with and without acoustic intervention is investigated in this research. Several noninvasive techniques like gamma-ray computed tomography (GRT), X-ray computed tomography (XCT), or electrical capacitance tomography (ECT), can be used to study the void fraction distribution in multiphase flow systems. In this study, XCT imaging is used to determine the time-average local void fraction or gas holdup. Experiments are implemented in a 10.2 cm ID fluidized bed filled with glass beads or ground walnut shell, having a material density of 2500 kg/m 3 and 1440 kg/m 3 , respectively, and particle size ranges between 212 and 600 μm. In this study, three different bed height-to-diameter ratios are examined: H/D = 0.5, 1 and 1.5. The loudspeaker’s frequency, used as the acoustic source, is fixed at 150 Hz with a sound pressure level of 120 dB for glass beads, and 200 Hz and 110 dB for ground walnut shell. Local time-average gas holdup results show that the fluidized bed under the presence of an acoustic field provides a more uniform fluidization, the bed exhibits less channeling, and the jetting phenomena produced by the distributor plate is less prominent when compared to no acoustic field. Thus, acoustic intervention affects the local hydrodynamic behavior of the fluidized bed.

The present article investigates the tolerant effect exerted by a functionalised multi-walled carbon nanotube (MWCNT) support compared with the Vulcan XC-72 support for a nanoparticulate Pt catalyst. The negative effect produced in the hydrogen oxidation reaction (HOR) by the presence of a Pt contaminated with high CO coverage was analysed. This investigation was conducted using a rotating disk electrode (RDE) and a single cell with membrane electrode assemblies (MEAs) with loads of 0.3 mg Pt/cm 2 for the anode and 0.6 mg Pt/cm 2 for the cathode at various poisoning times. To this end, polarisation curves were performed, and electrochemical impedance spectroscopy (EIS) measurements were analysed. In addition, the recovery of the poisoning/de-poisoning process was studied. The –OH groups anchored to the MWCNT support exert a protective effect on the Pt nanoparticles, making the catalyst more efficient in a PEMFC fed with H 2 + CO.

The granular cell tumour is a very rare tumour which originates in the Schwann cells, and is generally benign. It is usually located in the head and neck, and its appearance in the breast is uncommon. Although it is rare tumour, granular cell tumours of the breast have a higher prevalence than previously recognised. This tumour usually imitates breast cancer due to its clinical and imaging data, with its diagnosis being by histopathology. The treatment is a wide local excision, and its prognosis is good with a low recurrence rate. We present two cases of granular tumours of the breast in post-menopausal women that simulated a breast carcinoma in the ultrasound and mammography. The first was detected in the breast cancer screening program, and the second during follow up of an invasive ductal carcinoma.

Fluidized beds are used in a variety of process industries because they provide uniform temperature distributions, low pressure drops, and high heat/mass transfer rates. Minimum fluidization velocity is an important factor in understanding the hydrodynamic behavior of fluidized beds, and this characteristic may be modified through high frequency (sound) vibrations. The effects caused by sound wave frequency and sound pressure level on the minimum fluidization velocity in a 3D fluidized bed are investigated in this study. Experiments are carried out in a 10.2 cm ID cold flow fluidized bed filled with either glass beads or ground walnut shell, and particle sizes ranged between 212 and 600 μm. In this study, four different bed height-to-diameter ratios are examined: H/D = 0.5, 1, 1.5, and 2. Moreover, the sound frequency of the loudspeaker used as the acoustic source ranged between 50 and 200 Hz, and the sound pressure level ranged 90–120 dB. Results show that the minimum fluidization velocity is influenced by the frequency change. As the frequency increases, the minimum fluidization velocity decreases until a specific frequency is reached, beyond which the minimum fluidization velocity increases. With increasing sound pressure level, the minimum fluidization velocity decreases because the additional vibration forces imparted to the bed particles helps to loosen the bed, reducing the interparticle forces, which reduces the required energy for particle fluidization. Thus, acoustic fields provide an improvement in the ease of fluidization of these particles.

Resumen Objetivos Evaluacion del manejo quirurgico, evolucion y complicaciones de pacientes afectados por fractura pertrocanterea de cadera tratados mediante enclavado PFNA. Material y metodo Revision retrospectiva de 200 pacientes intervenidos entre abril de 2010 y febrero de 2012 de forma consecutiva. Se realiza evaluacion radiografica preoperatoria, postoperatoria y durante el seguimiento (reduccion de la fractura, posicion de la espiral, consolidacion o signos de colapso). La evaluacion clinica se realizo en funcion de la autonomia para la marcha. Se comparan los resultados obtenidos con estudio previo, sobre muestra de 700 pacientes y enclavado gamma 3 y TFN. Resultados La posicion de la espiral es centro-centro en el 64% de los pacientes, que disminuye al 53% en el grupo de las complicaciones mecanicas, siendo la distancia punta-vertice menor a 25 mm en el 91,5% de los casos. La estancia hospitalaria media se situa en 9,17 dias con una estancia media postintervencion de 5,95 dias. Las complicaciones (7,5%) fueron: 2 casos de cut out (1%), uno de cut through (0,5%), 4 casos de efecto telescopaje (2%), un fallo en el encerrojado distal (0,5%), 2 casos de molestias en la fascia lata (1%), un retardo en la consolidacion (0,5%), 2 seudoartrosis que condicionaron la rotura del dispositivo (1%), un caso de sangrado relativo al clavo (0,5%) y un caso de necrosis avascular (0,5%). Conclusiones El sistema de espiral cefalica PFNA parece reducir la incidencia de cut out y cut through en el hueso osteoporotico. La posicion de la espiral supone uno de los principales parametros relacionados con las complicaciones mecanicas.

Objective Evaluation of the surgical management, outcome and complications in patients with pertrochanteric fractures treated with PFNA nail. Materials and methods A retrospective study was conducted on 200 patients treated consecutively between April 2010 and February 2012. Radiological assessments were performed before and after the surgery, and during the follow-up (fracture reduction, blade position, consolidation or collapse signs). A clinical evaluation was performed as regards walking capabilities. The results were compared with those of a previous study on 700 patients treated with gamma 3 and TFN nails. Results The blade position was center–center in 64% of patients, and decreased to 53% in the mechanical complications group. Tip-apex distance was less than 25 mm in 91.5%. The average hospital stay was 9.17 days, with a mean post-surgery stay of 5.95 days. Complications (7.5%): 2 cut out (1%), one cut through (0.5%), 4 cases of helical blade sliding (2%), one failure in distal locking procedure (0.5%), 2 cases with painful fasciae latae (1%), one union delay (0.5%), 2 cases of non-union with hardware failure (1%), one case of intense bleeding related to distal locking of the nail (0.5%), and one case of avascular necrosis (0.5%). Conclusions The PFNA helical blade system seems to reduce the incidence of cut out and cut through in osteoporotic bone. Blade position was one of the main parameters associated with mechanical complications.

Four carbonaceous materials (acetylene black, multi-walled carbon nanotubes, and two carbon materials synthesized by hard-template method) were used as a support to synthesize four Fe-N/C non-noble metal (NNM) catalysts for oxygen reduction reaction (ORR) by impregnation with a FeIII–1,10-phenanthroline complex and subsequent pyrolysis in inert atmosphere. The catalysts were characterized by N2 physisorption, XPS, Raman and TGA, and their ORR activity was measured by rotating disk electrode (RDE) in both acidic and alkaline conditions. The catalysts were tested in an acidic direct methanol fuel cell (DMFC) and in an alkaline direct ethanol fuel cell (DEFC). Due to the slower ORR kinetics at low pH, the features of the carbon support have an important influence on the performance in acidic DMFC. Conversely, the enhanced ORR kinetics at high pH, makes the influence of the C-support less evident in alkaline DEFC. Moreover, the short-term durability test in DMFC for our best Fe-N/C catalysts showed better results compared to Pt/C benchmark catalyst. The durability in alkaline DEFC is poor, even though the initial performance can be partially recovered after purge-drying and reactivation.

Nanocrystalline nickel films have been prepared via pulse electrodeposition on steel substrates from an additive-free sulfamate-type bath. The mechanical properties of the films have been analyzed with respect to the parameters of various current programs. The mechanical properties of these films were determined using dynamic microindentation measurements known as the universal microhardness test. The hardness, plastic component, Young's modulus and percent of elastic recovery have been measured. Increasing the peak current density was more effective at improving the mechanical response of the films than varying the pulse-on time. In addition, X-ray diffraction studies have been performed to obtain the preferential orientation and grain size of the electrodeposits and scanning electron microscopy used to evaluate their morphology. All deposits exhibited a preferential orientation, and the highest performing films have been analyzed with respect to their mechanical properties. The effect of grain size, in the nanometer range, has been determined for variations in the microhardness with current density confirming the Hall–Petch relationship. These studies allow films to be tailored with good mechanical performance for various technological applications by simply selecting the appropriate electrodeposition conditions.

The long-term stability of PtCoRu/C to methanol crossover has been evaluated in a direct methanol fuel cell (DMFC) configuration. The DMFC has been subjected to continuous operation under potential step cycles. The degradation of the DMFC with PtCoRu/C has been followed by comparison of the power density curves recorded after 0, 60 and 312 h of continuous operation, and compared to that recorded for a DMFC with Pt/C. Electrochemical Impedance Spectra (EIS) were recorded directly from the DMFCs and used to identify the main degradation phenomena responsible for the loss of performance of the used fuel cell. AC impedance spectra show that the resistance of the anode reaction increases while resistance associated to the cathode reaction decreases after the long-term stability tests; however, the analysis of the power density curves unequivocally show that the performance of the DMFCs goes down during the stability tests. This apparent contradiction can be explained by taking into account the changes between the fresh and used PtCoRu/C observed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. During the potential step cycles Ru dissolves form PtCoRu/C leading to Pt-enriched catalysts which are more active for the oxygen reduction reaction (lower resistance) but less tolerant to methanol (lower power density).

Characterizing the hydrodynamics of a fluidized bed is of vital importance to understanding the behavior of this multiphase flow system. Minimum fluidization velocity and gas holdup are two of these key characteristics. Experimental studies addressing the effects of bed height and material density on the minimum fluidization velocity and gas holdup were carried out in this study using a 10.2 cm diameter cylindrical fluidized bed. Three different Geldart type-B particles were tested: glass beads, ground walnut shell, and ground corncob, with material densities of 2600, 1300, and 1000 kg/m 3 , respectively. The particle size range was selected to be the same for all three materials and corresponded to 500–600 μm. In this study, five different bed height-to-diameter ratios were investigated: H / D =0.5, 1, 1.5, 2, and 3. Minimum fluidization velocity was determined for each H / D ratio using pressure drop measurements. Local time-average gas holdup was determined using non-invasive X-ray computed tomography imaging. Results show that minimum fluidization velocity is not affected by the change in bed height. However, as the material density increased, the minimum fluidization velocity increased. Finally, local time-average gas holdup values revealed that bed hydrodynamics were similar for all bed heights, but differed when the material density was changed.

Pott's puffy tumor is a rare entity characterized by a swelling of the scalp due to a subperiosteal abscess associated to osteomyelitis in the frontal bone. It is often associated with a complication of frontal sinusitis or trauma. Undiagnosed or partially treated frontal sinusitis can lead to Pott's puffy tumor, which requires rapid medical and surgical intervention to prevent complications that increase morbidity and mortality. Since the advent of antibiotics, Pott's puffy tumor has become rare to the point of almost being forgotten. We present a case of Pott's puffy tumor in a 15-year-old boy. This case is even more unusual because the tumor became complicated with orbital and intracranial involvement. The findings at computed tomography provided the key to the diagnosis in this patient.

Summary. Background: Prostaglandin (PG) E2 induces expression of matrix metalloproteinases and angiogenic factors, thereby contributing to plaque instability. Objective: To study the influence of cyclooxygenase (COX) and PGE synthase (PGES) isoenzyme expression on PGE2 and PGI2 biosynthesis in vascular smooth muscle cells (VSMC) in culture. Methods: Cells were treated with human recombinant IL-1β over different periods of time. Expression of PGI synthase, and COX and PGES isoenzymes was determined by real-time reverse transcriptase polymerase chain reaction and immunoblotting. Biosynthesis of prostanoids from exogenous or endogenous substrate was analyzed by high-performance liquid chromatography or enzyme-immunoassay after incubation of cells with labeled arachidonic acid or thrombin, respectively. Results: Cytosolic PGES and microsomal PGES (mPGES) -1 and -2 were expressed in VSMC. PGES activity was mainly linked to mPGES-1. IL-1β induced COX-2 and mPGES-1 with a different time course. VSMC ability to synthesize PGE2 and PGI2 fitted mPGES-1 and COX-2 expression, respectively. The ability of VSMC to produce PGI2 was downregulated by mPGES-1 expression and was restored when mPGES-1 expression was silenced. Results from COX-1 and COX-2 silencing and selective inhibition showed that both COX-1 and COX-2 were involved in the biosynthesis of PGE2 and their relative contribution depended on the time of incubation with IL-1β. Conclusions: mPGES-1 is the main PGES responsible for PGE2 biosynthesis by VSMC and its induction downregulates VSMC ability to produce PGI2. These results support the concept that under inflammatory conditions VSMC could significantly contribute to plaque instability and that mPGES-1 may be a target for therapeutic intervention in patients with cardiovascular risk.

The effect of sintering pressure and temperature on the corrosion resistance of uniaxially cold-pressed Fe 2 Mo intermetallic alloy in 0.5M H 2 SO 4 has been evaluated using electrochemical techniques at room temperature. The intermetallic Fe 2 Mo powder was sintered at 750 °C at 607, 884 and 1223 MPa and at 900 °C at 480, 540, 822, 873 and 1040 MPa to produce different porosities. Electrochemical techniques included potentiodynamic polarization curves, electrochemical noise in current, evolution of the free corrosion potential ( E corr ) with time and linear polarization resistance to know the change of the corrosion rate with time. Results showed that all the alloys showed a passive region of several hundreds of millivolts wide, and that, regardless the compacting pressure or temperature, practically neither the E corr nor the anodic current density values were affected by these variables, which rapidly reached a steady-state value. At 750 °C, the corrosion rate increased as the sintering pressure decreased, probably due to the retention of electrolyte inside the porous. At T = 900 °C, this was not so evident, but it followed a similar tendency. Thus, the electrochemical noise reading showed that precisely at the lowest compacting pressure for 750 °C, where is expected the highest porosity density, the corrosion type is a localized one, probably pitting, whereas in all the other compacting conditions, where a lower porosity density is expected, the corrosion type is uniform generalized one.

The Rowell criteria, commonly used to identify tunneling in magnetic tunnel junctions (MTJ), are scrutinized. While neither the exponential-thickness dependence of the conductivity nor fits of non-linear transport data are found to be reliable tunneling criteria, the temperature-dependent conductivity does remain a solid criterion. Based on experimental studies of the bias and temperature-dependent resistance and magnetoresistance of MTJs, with and without shorted barriers, a new set of criteria is formulated. r 2002 Elsevier Science B.V. All rights reserved.

High yields of graphitic conical nanofibres (5–70 nm OD; 5 μm long) are produced by pyrolysing palladium precursors under Ar at 850–1000°C. The fibres exhibit diamond-shaped Pd particles at their tips, which are responsible for the formation of stacked graphene cones (open, lampshade-type, or closed). The cones observed with apex angles of ca. 30°, 50° and 70° can be explained by an open cone approach, which considers different chiralities. Due to the presence of open edges (dangling bonds), we envisage that these novel nanofibres may find important applications in the fabrication of field emitters, gas storage components and composites.

The gas holdup in laboratory flotation columns was measured using a conductivity probe. Measurements in a 50-cm-diameter flotation column have shown that gas holdup varies radially depending on the sparging system array, surfactants addition, and spargers malfunctions. The column was run in two modes: unbaffled (open), and baffled (vertically). Radial differences in gas holdup are enhanced by using baffles if gas is not uniformly injected through the spargers in the flotation column; however, the gas holdup is the same among the quadrants of the baffled column when the gas is evenly injected. Drift flux analysis was applied to estimate bubble size; it was a bubble size radial distribution in the column that was consistent with the gas holdup.

Resumen Introduccion y Objetivos La presencia de alteraciones del cordon umbilical es relativamente frecuente y las consecuencias de tal anomalia pueden ser variadas; por si solas explican casi un 30% de las situaciones de hipoxias fetales. El objetivo de nuestro estudio es analizar como influye la presencia de circulares, bandoleras o nudos vedaderos de cordon umbilical en los resultados acidobasicos de sangre de cordon en el parto. Material y metodos Se planteo un estudio retrospectivo, partiendo de los registros ya existentes del hospital Arquitecto Marcide de Ferrol, de casos y controles de los cuales incluimos 136 casos y 147 controles a los que se les habia determinado el pH arterial en sangre de cordon. Consideramos como resultados normales de pH los valores mayores o iguales a 7,20, como acidosis los comprendidos entre 7,10 y 7,19 y, finalmente, acidosis intensa los menores de 7,10 Resultados y conclusiones El valor de PH encontrado es de 7,24 para los casos y de 7,25 para los controles. No se han encontrado diferencias estadisticamente significativas en los varones de pH arterial decordon umbilical, con relacion al hecho de existir o no alteraciones en la disposicion funicular.

This communication introduces and discusses the application of flow conductivity cells to measure the solids holdup in mineral-water dispersions. Validation was carried out against independent solids holdup measurements both in the laboratory and in an industrial thickener. Typically, differences were less than 1%. The results suggest the probe has the potential to quantify the solids inventory in a thickener. The probe can operate on line and requires no additional measurements nor assumptions regarding the properties of the phases.

We have measured the thermoelectric power, S (T), of Bi2Sr2CaCu2O8 single crystal in the a-b and c directions, both are positive up to the transition temperature (Tc = 73 K). At high temperature Sc(T) is approximately constant and positive, while S a-b(T) has a negative sign at high temperature, changing sign at around 205 K, it continues increasing until the onset of the transition, and decreases to zero in Tc. A maximum of S a-b(T) is found close to the transition temperature with a value of S a-b(90 K) = 2.75 μV/K. Whereas in the c direction Sc(T) = 1.3 μV/K.