Permeation of Ternary Mixture Containing H2S, CO2 and CH4 in Aquivion® Perfluorosulfonic Acid (PFSA) Ionomer Membranes

Aquivion (R) E87-12S Perfluorosulfonated acid ionomer material (PFSA) has been studied as a membrane technology for natural gas sweetening from CO2 , H2S due to its interesting chemical and mechanical stability and good separation performance for polar compounds in humid environments. In the present work, permeation of the H2S/CO2/CH4 ternary mixture in this short-side PFSA chain was investigated at pressures up to 10 bar, temperatures up to 50 degrees C, and in a range of relative humidity (RH) from 20% to 90%. The results obtain confirm the strong dependence of Aquivion (R) on water activity and temperature, and its ability to separate gases based on their water solubility without substantial differences between pure and mixed gas experiments. Indeed, even when tested in ternary mixture, the permeation behavior remains similar to that observed for pure components and binary mixtures. In particular, the permeability of H2S is higher than that of CO(2 )and methane CH4, reaching values of 500 Barrer at 50 degrees C and 80% RH, against 450 and 23 Barrer for the other two gases respectively. Additionally, when tested at higher pressures of up to 10 bar under humid conditions, the membrane properties remained largely unchanged, thus confirming the overall stability and durability of Aquivion (R) E87-12S in acid environments

Polyvinylamine membranes containing graphene-based nanofillers for carbon capture applications

In the present study, the separation performance of new self-standing polyvinylamine (PVAm) membranes loaded with few-layer graphene (G) and graphene oxide (GO) was evaluated, in view of their use in carbon capture applications. PVAm, provided by BASF as commercial product named Lupamin\u2122, was purified obtaining PVAm films with two degrees of purification: Low Grade (PVAm-LG) and High Grade (PVAm-HG). These two-grade purified PVAm were loaded with 3 wt% of graphene and graphene oxide to improve mechanical stability: indeed, pristine tested materials proved to be brittle when dry, while highly susceptible to swelling in humid conditions. Purification performances were assessed through FTIR-ATR spectroscopy, DSC and TGA analysis, which were carried out to characterize the pristine polymer and its nanocomposites. In addition, the membranes\u2032 fracture surfaces were observed through SEM analysis to evaluate the degree of dispersion. Water sorption and gas permeation tests were performed at 35 \ub0C at different relative humidity (RH), ranging from 50% to 95%. Overall, composite membranes showed improved mechanical stability at high humidity, and higher glass transition temperature (Tg) with respect to neat PVAm. Ideal CO2/N2 selectivity up to 80 was measured, paired with a CO2 permeability of 70 Barrer. The membranes\u2019 increased mechanical stability against swelling, even at high RH, without the need of any crosslinking, represents an interesting result in view of possible further development of new types of facilitated transport composite membranes

Pebax® 2533/graphene oxide nanocomposite membranes for carbon capture

In this work, the behavior of new GO-based mixed matrix membranes was tested in view of their use as CO2-selective membrane in post combustion carbon capture applications. In particular, the new materials were obtained by mixing of Pebax® 2533 copolymer with different types of graphene oxide (GO). Pebax® 2533 has indeed lower selectivity, but higher permeability than Pebax® 1657, which is more commonly used for membranes, and it could therefore benefit from the addition of GO, which is endowed with very high selectivity of CO2 with respect to nitrogen. The mixed matrix membranes were obtained by adding different amounts of GO, from 0.02 to 1% by weight, to the commercial block copolymers. Porous graphene oxide (PGO) and GO functionalized with polyetheramine (PEAGO) were also considered in composites produced with similar procedure, with a loading of 0.02%wt. The obtained films were then characterized by using SEM, DSC, XPS analysis and permeability experiments. In particular, permeation tests with pure CO2 and N2 at 35°C and 1 bar of upstream pressure were conducted for the different materials to evaluate their separation performance. It has been discovered that adding these GO-based nanofillers to Pebax® 2533 matrix does not improve the ideal selectivity of the material, but it allows to increase CO2 permeability when a low filler content, not higher than 0.02 wt%, is considered. Among the different types of GO, then, porous GO seems the most promising as it shows CO2 permeability in the order of 400 barrer (with an increase of about 10% with respect to the unloaded block copolymer), obtained without reducing the CO2/N2 selectivity of the materials, which remained in the order of 25

Synthesis and characterization of a benzoyl modified Pebax materials for gas separation applications

Pebax copolymers produced by Arkema are widely employed for different applications, including active molecular carriers and membranes for gas separation. In the present work, a new modification approach for Pebax®2533 is presented, along with the characterization of the newly obtained materials. Pebax was modified by grafting, through a nucleophilic acyl substitution, a benzoyl group on Polyamide12 block. The yield of the reaction was confirmed by FTIR and NMR analysis, while thermal DSC and TGA characterizations were then carried out on the polymeric products characterized by different degrees of substitution to understand their properties. Finally, self-standing films were obtained by casting and gas permeation tests were conducted at 35 °C using CO2, N2, CH4, O2 and He, in order to understand the potentiality of the new material as membrane for gas separation. DSC showed that in the modified Pebax, named “Benzoyl-P2533” (BP2533), the crystalline phase of the Nylon block was canceled, as expected, but at the same time the degree of crystallinity of the block of Polytetramethyleneoxide increased from 19%, measured for the unmodified Pebax, to a max of 35% for the fully substituted material. For this reason, gas permeability showed small but consistent increment, in the order of 10–11% for most of the gas tested, with the only exception being helium, where the increment resulted to be around 48%. As a consequence, the overall selectivity of CO2 against helium dropped with respect to pristine Pebax. For all the other gases, on the other hand the selectivity with respect to CO2 remained substantially constant, resulting in slight but neat improvement of the ability of the new material to separate this gas

Highly CO2-permeable membranes derived from a midblock-sulfonated multiblock polymer after submersion in water

To mitigate the effect of atmospheric CO2 on global climate change, gas separation materials that simultaneously exhibit high CO2 permeability and selectivity in gas mixtures must be developed. In this study, CO2 transport through midblock-sulfonated block polymer membranes prepared from four different solvents is investigated. The results presented here establish that membrane morphology and accompanying gas transport properties are sensitive to casting solvent and relative humidity. We likewise report an intriguing observation: submersion of these thermoplastic elastomeric membranes in liquid water, followed by drying prior to analysis, promotes not only a substantial change in membrane morphology, but also a significant improvement in both CO2 permeability and CO2/N2 selectivity. Measured CO2 permeability and CO2/N2 selectivity values of 482 Barrer and 57, respectively, surpass the Robeson upper bound, indicating that these nanostructured membranes constitute promising candidates for gas separation technologies aimed at CO2 capture

Enterotoxin genes, enterotoxin production, and methicillin resistance in Staphylococcus aureus isolated from milk and dairy products in Central Italy

AbstractA total of 227 Staphylococcus aureus colonies, isolated from 54 samples of raw milk and dairy products of bovine, ovine, caprine and bubaline origin were tested for the presence of genes coding for staphylococcal enterotoxins (SEs/SEls) and for methicillin resistance. Ninety-three colonies, from 31 of the 54 samples (57.4%) and from 18 (69.2%) of the 26 farms of origin tested positive for SEs/SEls genes. Most isolates harboured more than one toxin gene and 15 different toxinotypes were recorded. The most frequent were “sec” gene alone (28.6%), “sea, sed, ser, selj” (20%), “seg, sei” and “seh” (8.6%). The 77 colonies harbouring “classical enterotoxins” genes (sea-sed) were further tested for enterotoxin production, which was assessed for 59.2% of the colonies. Three methicillin-resistant S. aureus (MRSA) isolates were detected in three different ovine milk/dairy product samples (1.3%). All isolates belonged to spa type t127, sequence type 1, clonal complex 1, SCCmec type IVa

The long helical jet of the Lighthouse nebula, IGR J11014-6103

Jets from rotation-powered pulsars have so far only been observed in systems moving subsonically trough their ambient medium and/or embedded in their progenitor supernova remnant (SNR). Supersonic runaway pulsars are also expected to produce jets, but they have not been confirmed so far. We investigated the nature of the jet-like structure associated to the INTEGRAL source IGR J11014-6103 (the "Lighthouse nebula"). The source is a neutron star escaping its parent SNR MSH 11-61A supersonically at a velocity exceeding 1000 km/s. We observed the Lighthouse nebula and its jet-like X-ray structure through dedicated high spatial resolution observations in X-rays (Chandra) and radio band (ATCA). Our results show that the feature is a true pulsar's jet. It extends highly collimated over >11pc, displays a clear precession-like modulation, and propagates nearly perpendicular to the system direction of motion, implying that the neutron star's spin axis in IGR J11014-6103 is almost perpendicular to the direction of the kick received during the supernova explosion. Our findings suggest that jets are common to rotation-powered pulsars, and demonstrate that supernovae can impart high kick velocities to misaligned spinning neutron stars, possibly through distinct, exotic, core-collapse mechanisms.Comment: 8 pages, 6 figures, 1 table. Discussion (sec.3) expanded and typos fixed; results unchanged. Published on A&

Phase II study of epirubicin, oxaliplatin and docetaxel combination in metastatic gastric or gastroesophageal junction adenocarcinoma

<p>Abstract</p> <p>Background</p> <p>This phase II study was designed to evaluate the activity and safety of a combination of epirubicin, oxaliplatin and docetaxel in metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma.</p> <p>Methods</p> <p>Forty patients with measurable distant metastases received epirubicin 50 mg/m², docetaxel 60 mg/m²followed by oxaliplatin 100 mg/m²on day 1 of each 21-day cycle. Primary end point was response rates (RR).</p> <p>Results</p> <p>All patients were evaluable. The overall RR was 47.5% (95% confidence interval (CI) 32–63). The disease control was 80%. Median time for response was 6 weeks. Median time to progression was 6.3 months (95% CI 5.4–7.2) and the median overall survival time was 12.1 months (95% CI 10.7–13.5). Grade 3/4 neutropenia occurred in 50% of patients with two episodes of febrile neutropenia (5%). Other non-hematological grade 3 toxicities included sensory neuropathy in two patiens (5%), vomiting and mucositis in two patients (5%) and diarrhea in one patient (2.5%).</p> <p>Conclusion</p> <p>The combination of epirubicin, oxaliplatin and docetaxel was found to be effective and well tolerated in patiens with metastatic gastric or GEJ adenocarcinoma and maybe an appropriate regimen to be used in the neoadjuvant setting and with molecularly targeted agents.</p

Search for Anisotropy of Ultra-High Energy Cosmic Rays with the Telescope Array Experiment

We study the anisotropy of Ultra-High Energy Cosmic Ray (UHECR) events collected by the Telescope Array (TA) detector in the first 40 months of operation. Following earlier studies, we examine event sets with energy thresholds of 10 EeV, 40 EeV, and 57 EeV. We find that the distributions of the events in right ascension and declination are compatible with an isotropic distribution in all three sets. We then compare with previously reported clustering of the UHECR events at small angular scales. No significant clustering is found in the TA data. We then check the events with E>57 EeV for correlations with nearby active galactic nuclei. No significant correlation is found. Finally, we examine all three sets for correlations with the large-scale structure of the Universe. We find that the two higher-energy sets are compatible with both an isotropic distribution and the hypothesis that UHECR sources follow the matter distribution of the Universe (the LSS hypothesis), while the event set with E>10 EeV is compatible with isotropy and is not compatible with the LSS hypothesis at 95% CL unless large deflection angles are also assumed. We show that accounting for UHECR deflections in a realistic model of the Galactic magnetic field can make this set compatible with the LSS hypothesis.Comment: 10 pages, 9 figure

Immunodetection of retinoblastoma-related protein and its phosphorylated form in interphase and mitotic alfalfa cells

Plant retinoblastoma-related (RBR) proteins are primarily considered as key regulators of G1/S phase transition, with functional roles in a variety of cellular events during plant growth and organ development. Polyclonal antibody against the C-terminal region of the Arabidopsis RBR1 protein also specifically recognizes the alfalfa 115 kDa MsRBR protein, as shown by the antigen competition assay. The MsRBR protein was detected in all cell cycle phases, with a moderate increase in samples representing G2/M cells. Antibody against the human phospho-pRb peptide (Ser807/811) cross-reacted with the same 115 kDa MsRBR protein and with the in vitro phosphorylated MsRBR protein C-terminal fragment. Phospho-MsRBR protein was low in G1 cells. Its amount increased upon entry into the S phase and remained high during the G2/M phases. Roscovitine treatment abolished the activity of alfalfa MsCDKA1;1 and MsCDKB2;1, and the phospho-MsRBR protein level was significantly decreased in the treated cells. Colchicine block increased the detected levels of both forms of MsRBR protein. Reduced levels of the MsRBR protein in cells at stationary phase or grown in hormone-free medium can be a sign of the division-dependent presence of plant RBR proteins. Immunolocalization of the phospho-MsRBR protein indicated spots of variable number and size in the labelled interphase nuclei and high signal intensity of nuclear granules in prophase. Structures similar to phospho-MsRBR proteins cannot be recognized in later mitotic phases. Based on the presented western blot and immunolocalization data, the possible involvement of RBR proteins in G2/M phase regulation in plant cells is discussed