Membrane Counterparts Research Articles

Polyarylene-Based Anion Exchange Membranes for Fuel Cells.

Anion exchange membrane fuel cell (AEMFC) is an emerging and promising technology that can help realize a carbon-neutral, sustainable economy. Also, compared to the proton exchange membrane counterpart, AEMFC can achieve comparable cell outputs with lower costs due to the applicability of non-platinum group metal electrocatalysts for the reaction on the electrodes' surfaces. However, the wide application of the AEMFCs has been impeded by the unsatisfactory stability and performance of the hydroxide-conductive membranes in the past. Recently researchers have made breakthroughs using polyarylene (PA)-based AEMs. This article summarizes the recent advances of a class of AEMs with aromatic backbone without ether bonds, mainly synthesized by Friedel-Crafts polycondensation. Such PA-based AEMs showed high chemical/mechanical stabilities and ionic conductivity, and even the fuel cell with those AEMs showed impressive peak power density of up to 2.58 W cm-2. In this concept article, we classify major strategies for making PA-based AEMs to show the recent trends, highlight synthesis, characterization, and properties, and provide a brief outlook.

Toward low-emissivity passive heating: a supramolecular-enhanced membrane with warmth retention.

Maintaining a reasonably stable body temperature is vital for a variety of human activities in an energy-conservation strategy. However, it is well-known that metal-like materials, utilized as radiative reflectors, severely restrict wearability properties, thus posing a tremendous obstacle in personal thermal management (PTM) systems. Herein, we designed a supramolecular-enhanced membrane (SupraEM) acting as a mid-infrared (MIR) reflector to solve the conundrum of warmth-wearability performance. Benefiting from the low-emissivity of decorating titanium carbide (MXene) and the formation of supramolecular interactions, the prototyped polyvinylidene difluoride&Polyurethane/MXene (PVDF&PU/MXene) SupraEM demonstrated a low-emissivity of 0.246 and reinforced mechanical performance, resulting in an evenly higher temperature retention of 8 °C in comparison to the pristine hybrid membrane counterpart, and compared with a commercial textile that is three times thicker, it also exhibited higher temperature retention of 6.2 °C. This work demonstrates the wearability of decorated MXene without sacrificing its temperature retention, overcoming a major bottleneck that has plagued MXene as a thermoregulatory material for PTM systems.

Anode-Fed Anion Exchange Membrane Electrolyzers for Hydrogen Generation Tolerant to Anion Contaminants

Anion exchange membrane water electrolysis has the ability to produce green hydrogen with high voltage efficiencies at low capital cost with zero CO2 emissions. The alkaline environment of these devices allows for the use of economical metal catalysts and anion exchange membranes (AEMs) that conduct hydroxide ions and are less expensive than their proton exchange membrane counterparts. However, research has shown that anion contamination of hydroxide exchange membranes can lead to significant performance losses in anion exchange membrane fuel cells (AEMFCs), particularly when air fed to the oxygen-reducing cathode contains CO2.1 A similar contamination effect occurs in anion exchange membrane electrolyzers (AEMELs), when dissolved CO2 in the electrolyte reacts to form carbonate (CO3 2-) and bicarbonate (HCO3 2-) anions which compete with the hydroxide (OH-) ions that must be conducted through the AEM and ionomer. The presence of these and other anion contaminants can lower the ionic conductivity of the cell. Under high current density operation, an AEMEL undergoes a self-purging process that uses an ionic potential gradient to push hydroxide and anion contaminants through the membrane to the anode. This creates a significant pH gradient between cathode and anode that can lead to concentration polarization which further lowers performance.2 In this work, we use 1-D CO2 transport modeling and experiments to show how altering the electrolyte feed method allows for CO2-tolerant AEMEL operation in several different electrolytes.The unique advantages of AEMELs over AEMFCs and proton exchange membrane electrolyzers (PEMELs) are that (1) this self-purge occurs during normal operation, and (2) they allow for flexibility in the location of the potentially contaminated water feed. In PEMELs, water is intuitively fed to the anode, and cation contaminants are purged through the entire MEA to the cathode. Although water in AEMELs is intuitively fed to the cathode, where it is consumed in the hydrogen evolution reaction, water can diffuse easily through the membrane, allowing for it to be fed as an anolyte to the oxygen-evolving side of the cell. This allows for better contaminant rejection because anions can be concentrated mostly on the anode side of the electrolyzer.The model described in this paper predicts that an anode-fed AEMEL can more easily purge CO2 without contaminating as much of the AEM or inducing as high of a pH gradient due to more rapid self-purging of anions. We find experimentally that AEMELs with DI water anolyte are more tolerant of forced CO2 contamination than those with DI water catholytes, which is likely one of the major reasons for superior anode-feed performance. Furthermore, electrolyzer operation at high current densities can lead to voltage recoveries greater than 200 mV due to self-purging of anions. Although supporting electrolytes such as potassium hydroxide can mitigate catholyte contamination, the anion self-purging shows that electrolyzer operation in DI water and even tap water (containing fluoride, chloride, and nitrates) can improve when employing an anode feed.1. Y. Zheng et al., Energy Environ. Sci., 12, 2806–2819 (2019).2. B. P. Setzler, L. Shi, T. Wang, and Y. Yan, in ECS Meeting s, vol. MA2019-01, p. 1824–1824, IOP Publishing (2019) https://iopscience.iop.org/article/10.1149/MA2019-01/34/1824.

(Invited) Hydrogen Oxidation Reaction (HOR) on Carbon-Capped Pd/C in Alkaline Media

It is no secret alkaline fuel cells (AFC) using a liquid electrolyte (usually concentrated KOH) have assets over their proton-exchange membrane counterparts, in particular in niche applications where the latter are challenged by too harsh operating/environmental conditions [1]. AFC can also, in theory, use non-Pt catalysts at their electrodes without detrimental durability issues. However, recent studies from our group showed that Pt/C and Pd/C were very sensitive to the metal nanoparticles detachment from the carbon owing to their propensity to catalyze the carbon-support corrosion upon repeated alternation of the potential below/above their metal oxide potential (which is unavoidable at the anode upon start/stop of the fuel cell) [2-5].In this presentation, it is highlighted that more robust hydrogen oxidation catalysts can be prepared by tailoring a carbon cap around the metal nanoparticles, in particular for palladium as the catalyst metal. Such “carbon-capped” Pd/C nanoparticles (ex. PdG2/C) exhibit a good compromise between their HOR activity and long-term stability (Figure 1), evaluated by identical location transmission electron microscopy upon accelerated stress tests (0.1 - 1.23 V vs. RHE stepped by 3 s – 3 s, 1000 times) (Figure 2). Their properties are very advantageous over non-capped (classical) Pd/C nanoparticles, demonstrating the interest of this strategy for the development of active and durable HOR catalysts for AFC anodes.

Nuclear Location Bias of HCAR1 Drives Cancer Malignancy by Multiple Routes

IntroductionG‐Protein Coupled Receptors (GPCR) are virtually involved in all physiological processes. HCAR1 (GPR81), as a GPCR, is endogenously activated by lactate and has been shown to promote cancer malignancy via higher level of glycolysis due to Warburg effect. Its expression level is highly elevated in many cancers and negatively correlates with patient’s prognosis. However, its mechanism of action is not well understood.On the other hand, nuclear localization of several GPCRs have been described albeit it is unusual feature for them. Additionally, it has been shown that nuclear GPCRs can perform functions distinct from their cell surface counterparts in vivo. Here we demonstrate HCAR1 has a nuclear localization and this localization pattern promotes cancer malignancy by multiple routes.Methods and ResultsWe determined HCAR1 nuclear localization pattern by cell fractionation, immunofluorescence confocal imaging and TEM. Site‐directed mutagenesis showed ICL3 and phosphorylation of C‐terminal domains are required for nuclear localization. We also demonstrated that this localization is ligand independent and there is a pool of nuclear HCAR1 (N‐HCAR1) in the cells. We show N‐HCAR1 induces intra‐nuclear signaling through Gi and Gßγ by WB and ELISA leading to increased phosphorylation of nuclear AKT and ERK resulting in increased cancer cell survival and proliferation. Our ChIP‐sequencing data shows N‐HCAR1 binds to the genes regulating transcription and promoting expression of genes involved in cell migration and we validated this in cellulo proving N‐HCAR1 promotes migration. We identified N‐HCAR1 interactome by Bio‐ID coupled with mass spectrometry and found, it interacts with proteins involved in ribosome biogenesis, translation and DNA damage repair and our experimental data demonstrates that specifically the N‐HCAR1 promotes these three process in cellulo. Additionally, we identified the transcriptomic signature of N‐HCAR1 and showed it regulated a larger gene network than its plasma membrane counterpart. Concordantly, our in vivo tumor xenografts and tail vein injections proves that tumors without N‐HCAR1 have smaller size and tumor mass and lower metastatic rate as well.ConclusionHere we show an unusual localization of a GPCR in the nucleus and provide evidence that N‐HCAR1 specifically promotes various hallmarks of cancer malignancy. The effect of N‐HCAR1 is validate in vivo in tumor xenografts as well. Understanding these mechanisms can provide targets and cues for therapeutic developments.

Induced hemocompatibility of polyethersulfone (PES) hemodialysis membrane using polyvinylpyrrolidone: Investigation on human serum fibrinogen adsorption and inflammatory biomarkers released

When blood comes in contact with dialyzer membranes, the interfacial bioactivation reactions occurring at blood/membrane boundaries detect the gross mechanism of thrombogenicity. In the presence of biocompatible polymers, the adhesion and subsequent interactions of platelets, as well as other serum components (e.g., proteins), are altered. It delays thrombus formation. In this study, the hemocompatibility of polyvinylpyrrolidone (PVP) modified polyethersulphone (PES) hemodialysis membrane fabricated using UV-assisted photochemical synthesis was investigated. To obtain varying degrees of PVP modification on each membrane, each coated surface was aged within the viscous polymer suspension for a predetermined duration. The correlation between the membrane induced hemocompatibility with membrane roughness, chemical composition, and surface charge at different aging duration of coating. In our study, we performed a comprehensive investigations on membrane morphology, hydrophilicity and its chemical composition using Atomic Force Microscopy (AFM), Fourier Transform Infra-Red (FTIR) Spectroscopy, Nuclear Magnetic Resonance (NMR), Zeta potential, and Scanning Electron Microscopy (SEM). The coated samples were analyzed using Luminex assays for the inflammatory biomarkers of Serpin/Antithrombin-III, C5a, 1L-1α, 1L-1β, IL6, and C5b-9. Modified membranes showed significant resistance against fibrinogen adsorption compared to their bare membrane counterpart. This inherent antifouling activity against fibrinogen adsorption was observed more on modified membranes that aged longer within the PVP suspension during synthesis. A longer ageing period contributed to the enhanced PVP modification, hence, more stable polymeric hydration layers. In addition, both bare and coated membranes triggered both complement system activation and inflammatory responses, but to a mild degree in the latter case. Coated membranes at longer coating duration, around ∼4 min, had smoother surfaces and lower magnitudes of surface charge and consequently exhibited reduced release of all biomarkers (except IL-1α), indicating enhanced biocompatibility. Higher levels of C5a were observed in membranes coated at 1 and 2 min, promoting modest reduction toward the release of other components.

Separated growth of Bi-Cu bimetallic electrocatalysts on defective copper foam for highly converting CO2 to formate with alkaline anion-exchange membrane beyond KHCO3 electrolyte

Tuning the geometric and electronic structure of bimetallic electrocatalyst to facilitate a specific reaction pathway and offer more active sites is a promising avenue for enhancing activity and selectivity of electrocatalytic CO2 reduction reaction (eCO2RR). Owing to formation of Bi-Cu interface through the separated growth of Bi and Cu atoms on defective copper foam, the Bi-Cu bimetallic electrode converts CO2 to formate with an allured Faradaic efficiency (94.37%) and partial current density (27.85 mA cm−2) at -0.91 Vversus reversible hydrogen electrode (RHE). Notably, such electrode with tight moss-like structure delivers the excellent durability under 58 h electrolysis, outperforming most of the current Bi-based catalysts. Moreover, we have experimentally shown that KOH is a better electrolyte than KHCO3 due to the lower solution resistance and more confinement of free CO2 gas, and the alkaline anion-exchange membrane is more ideal than the cation-exchange membrane counterpart, owing to the enhancement of formate selectivity by suppressing the evolution of H2. This study inspires a complete set of concepts for highly converting CO2 to formate that contains the design of effective electrocatalysts, the role of growth substrate, the effect of different electrolytes and membranes.

Soluble Membrane Attack Complex: Biochemistry and Immunobiology.

The soluble membrane attack complex (sMAC, a.k.a., sC5b-9 or TCC) is generated on activation of complement and contains the complement proteins C5b, C6, C7, C8, C9 together with the regulatory proteins clusterin and/or vitronectin. sMAC is a member of the MACPF/cholesterol-dependent-cytolysin superfamily of pore-forming molecules that insert into lipid bilayers and disrupt cellular integrity and function. sMAC is a unique complement activation macromolecule as it is comprised of several different subunits. To date no complement-mediated function has been identified for sMAC. sMAC is present in blood and other body fluids under homeostatic conditions and there is abundant evidence documenting changes in sMAC levels during infection, autoimmune disease and trauma. Despite decades of scientific interest in sMAC, the mechanisms regulating its formation in healthy individuals and its biological functions in both health and disease remain poorly understood. Here, we review the structural differences between sMAC and its membrane counterpart, MAC, and examine sMAC immunobiology with respect to its presence in body fluids in health and disease. Finally, we discuss the diagnostic potential of sMAC for diagnostic and prognostic applications and potential utility as a companion diagnostic.

Identification of an ATP-Sensitive Potassium Channel in the Inner Mitochondrial Membrane

ATP-sensitive potassium channels (KATP) are widely distributed ion channels acting as sensors of cellular metabolism. In the plasma membrane (pmKATP) they couple cell excitability with energy availability. They are also reported to be located to intracellular membranes, in particular in mitochondria, but in this context even their existence is still a matter of debate. Here, we unambiguously identify a mitochondria-localized protein complex that mediates ATP-sensitive potassium currents, referred to as mitoKATP. We show that similarly to its plasma membrane counterpart, mitoKATP is composed of a pore-forming subunit (MITOK) and an ATP-binding subunit (MITOSUR). In vitro reconstitution of MITOK together with MITOSUR recapitulates the main electrophysiological properties and pharmacological profile of mitoKATP. Overexpression of MITOK alone causes loss of mitochondrial membrane potential (▵Ψm), decrease of mitochondrial Ca2+ uptake, organelle fragmentation and disruption of cristae, in line with an increased cation permeability of the inner mitochondrial membrane. However, the concomitant overexpression of the MITOSUR subunit restores the correct channel gating and rescues organelle injury. Conversely, MITOK ablation causes mitochondrial dysfunction characterized by instability of mitochondrial membrane potential, widening of intracristal space and decreased performance of oxidative phosphorylation. Most importantly, loss of MITOK in mice suppresses cardioprotection elicited by diazoxide-induced pharmacological preconditioning. Overall, our data indicate that the hereby-identified novel components forming mitoKATP control organelle volume, thereby representing key players in shaping mitochondrial physiology with a potential impact on several pathological processes.

Fabrication of low-cost ceramic hollow fiber membranes from aluminium dross waste for water purification

In this study, alumina-spinel composite hollow fibre membranes were fabricated from abundantly available aluminium dross waste, which can be commonly obtained from aluminium-producing factory. The hollow fibre membranes were successfully fabricated by using a combine phase inversion method and sintering technique. The effects of sintering temperatures on morphology, mechanical strength, and permeability of the hollow fibre membranes were systematically investigated. X-ray fluorescence (XRF) was used to analyze the composition of the aluminium dross waste, while x-ray diffraction analysis (XRD) were further studied to characterize the major crystalline phase of the sintered hollow fibre membranes. An increase in sintering temperatures resulted in densification of hollow fibre membrane, consequently induced the flux reduction. The presence of spinel in microstructural of hollow fibre assisted in decreasing the sintering temperature. As comparison to pure alumina membrane counterparts, this alternative ceramic hollow fibre membrane exhibited a comparable mechanical strength of 78.3-155.1 MPa with lower sintering temperatures ranging from 1350 ˚C to 1400 ˚C at ceramic loading of 40%.

Chorion laeve accreta – Another manifestation of morbid adherence

IntroductionSmooth muscle in the decidua of fetal membranes (membrane myofibers, MMF) is not mentioned in standard textbooks. MethodsThe current report presents collected observations on 52 patients with MMF at 2 institutions between 2004 and 2017 - including placentas, postpartum curettages, and hysterectomies. ResultsClinical presentations include observation of adherent membranes during delivery, disrupted and incomplete membranes in placentas submitted for examination, postpartum bleeding associated with retained fetal membranes, association with membrane hematomas and membrane hemosiderin, morbidly adherent fetal membranes in hysterectomies; and association with grossly adherent pieces of tissue or nodules in fetal membranes. DiscussionAlthough MMF can be an incidental microscopic observation in a routine placenta, the suggested diagnostic terminology when there are clinical and/or gross presentations is Chorion Laeve Accreta (ChLA). Further study is needed but MMF appears to be the fetal membrane counterpart of BPMF(basal plate myofibers), possibly due to damage of subjacent myometrium by trophoblastic proteases, so that shear stress during delivery causes myofibers to come out attached to the decidua of fetal membranes. Neither the prevalence of MMF, nor its reliability as a marker for placenta accreta is addressed in this collection. Association of MMF with BPMF, and recurrence of MMF, are documented; but the true frequency of these phenomena remains to be established.

Modeling Water Management and Carbon-Dioxide Contamination Effects in Anion-Exchange Membrane Fuel Cells

Anion-exchange membrane fuel cells (AEMFCs) offer a potential advantage over their traditional proton-exchange membrane counterparts in that AEMFCs can operate with non-precious metal catalysts [1]. Recently, high-power operation of AEMFCs has been demonstrated in laboratory-scale cells [2]. The performance of AEMFCs, however, can be highly sensitive to small changes in relative humidity due to the critical role of water in both the alkaline oxygen reduction reaction and in hydrating the membrane. Additionally, carbon-dioxide absorption and conversion to carbonate anions reduces membrane conductivity and worsens fuel-cell performance. In this work, we use our previously developed two-dimensional model [3] to illustrate and explore the effects of membrane and ionomer properties, relative-humidity changes, and absorption of carbon dioxide on cell performance. We model local current density changes in large-area cells by stepping the two-dimensional model along the flow channel, updating it at each step to account for changes in gas concentration and relative humidity. Finally, we show how performance limitations from carbon-dioxide absorption, flooding, and dry-out could be alleviated through changes in operating parameters or ionomer properties. Acknowledgements The work was funded by the Assistant Secretary for Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U.S. Department of Energy under contract number DE-AC02-05CH11231. We thank Bryan Pivovar and the members of the Fuel Cells group of the National Renewable Energy Laboratory for helpful discussion and model validation data.

Modeling Water Management and Carbon Dioxide Contamination Effects in Anion-Exchange Membrane Fuel Cells

Anion-exchange membrane fuel cells (AEMFCs) offer a potential advantage over their traditional proton-exchange membrane counterparts in that many non-precious metal catalysts are chemically compatible with the alkaline environment in an AEMFC [1]. Recently, high-power operation of AEMFCs has been demonstrated, including achieving 1 W/cm2 using silver metal cathode catalysts [2], [3]. The performance of AEMFCs, however, can be highly sensitive to small changes in relative humidity, as water is a reactant in the alkaline oxygen reduction reaction. Additionally, performance degradation due to carbon dioxide contamination remains a major issue. The absorption of carbon dioxide and subsequent conversion to carbonate anions reduces membrane conductivity and worsens fuel cell performance. In this work, we use our previously developed two-dimensional model [4] to illustrate and explore the effects of membrane and ionomer properties, relative humidity changes, and absorption of carbon dioxide on AEMFC performance. A 2+1D modeling approach is used, where an external stepping model is used to move along the gas channels. At each step, the 2D cross-section model [4] is used to simulate cell performance. Mass and energy balances are performed at each step to obtain the channel conditions, such as concentration, relative humidity, and temperature, for the subsequent step. The 2+1D model accounts for the performance changes due to concentration and relative humidity changes along the channel, especially at integral cell conditions. Finally, we show how performance limitations from carbon dioxide absorption, flooding, and dry-out could be alleviated through changes in operating parameters or ionomer properties. Acknowledgements The work was funded under the Fuel Cell Performance and Durability Consortium (FC-PAD), by the Fuel Cell Technologies Office (FCTO), Office of Energy Efficiency and Renewable Energy (EERE), of the U.S. Department of Energy under contract number DE-AC02-05CH11231. We thank Bryan Pivovar and the members of the Fuel Cells group of the National Renewable Energy Laboratory for helpful discussion and model validation data. [1] J. R. Varcoe et al., “Anion-exchange membranes in electrochemical energy systems,” Energy Environ. Sci., vol. 7, pp. 3135–3191, 2014. [2] D. R. Dekel, “A mini-review on cell performance in anion exchange membrane fuel cells,” J. Power Sources, p. submitted, 2017, 2017. [3] L. Wang and J. R. Varcoe, “The first anion-exchange membrane fuel cell to exceed 1 W cm-2 at 70 °C with a non-Pt cathode,” Chem. Commun., pp. 1–3, 2017. [4] H.-S. Shiau, I. V. Zenyuk, and A. Z. Weber, “Elucidating Performance Limitations in Alkaline-Exchange- Membrane Fuel Cells,” J. Electrochem. Soc., vol. 164, no. 11, pp. E3583–E3591, 2017.

Influence of thylakoid membrane lipids on the structure of aggregated light-harvesting complexes of the diatom Thalassiosira pseudonana and the green alga Mantoniella squamata.

The study investigated the effect of the thylakoid membrane lipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulphoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) on the structure of two algal light-harvesting complexes (LHCs). In contrast to higher plants whose thylakoid membranes are characterized by an enrichment of the neutral galactolipids MGDG and DGDG, both the green alga Mantoniella squamata and the centric diatom Thalassiosira pseudonana contain membranes with a high content of the negatively charged lipids SQDG and PG. The algal thylakoids do not show the typical grana-stroma differentiation of higher plants but a regular arrangement. To analyze the effect of the membrane lipids, the fucoxanthin chlorophyll protein (FCP) complex of T. pseudonana and the LHC of M. squamata (MLHC) were prepared by successive cation precipitation using Triton X-100 as detergent. With this method, it is possible to isolate LHCs with a reduced amount of associated lipids in an aggregated state. The results from 77 K fluorescence and photon correlation spectroscopy show that neither the neutral galactolipids nor the negatively charged lipids are able to significantly alter the aggregation state of the FCP or the MLHC. This is in contrast to higher plants where SQDG and PG lead to a strong disaggregation of the LHCII whereas MGDG and DGDG induce the formation of large macroaggregates. The results indicate that LHCs which are integrated into thylakoid membranes with a high amount of negatively charged lipids and a regular arrangement are less sensitive to lipid-induced structural alterations than their counterparts in membranes enriched in neutral lipids with a grana-stroma differentiation.

Fluorescent probes for detecting cholesterol-rich ordered membrane microdomains: entangled relationships between structural analogies in the membrane and functional homologies in the cell

This review addresses the question of fluorescent detection of ordered membrane (micro) domains in living (cultured) cells, with a “practical” point of view since the situation is much more complicated than for studying model membranes. We first briefly recall the bases of model membrane structural organization involving liquid-ordered and -disordered phases, and the main features of their counterparts in cell membranes that are the various microdomains. We then emphasize the utility of the fluorescent probes derived from cholesterol, and delineate the respective advantages, limitations and drawbacks of the existing ones. In particular, besides their intra-membrane behavior, their relevant characteristics should integrate their different cellular fates for membrane turn-over, trafficking and metabolism, in order to evaluate and improve their efficiency for in-situ probing membrane microdomains in the cell physiology context. Finally, at the present stage, it appears that Bdp-Chol and Pyr-met-Chol display well complementary properties, allowing to use them in combination to improve the reliability of the current experimental approaches. But the field is still open, and there remains much work to perform in this research area.

N-Functionalised Polyketone Ion Exchange Membranes for Aemfcs

Anion-exchange membrane fuel cells (AEMFCs) provide significant advantages over their proton-exchange membrane counterparts. In the alkaline environment, the oxygen reduction reaction (ORR) is more facile, there is diminished fuel crossover, and a greater flexibility regarding fuel and catalyst choice. The membrane at the heart of AEMFCs not only facilitates the ion exchange but also separates the fuel feedstocks and acts as a support for the membrane-electrode assembly (MEA). However, to date there are still no membrane materials that satisfy all the needs (long-term stability in alkaline environment, high ionic conductivity, low swelling and good structural integrity) for use in AEMFCs and this remains one of the larger obstacles for further AEMFC development. The amination and subsequent quarternisation of polyketone leads to a new family of ionomers containing N-substituted pyrrole moieties. The degree of amination can be controlled by manipulating reaction conditions, allowing the composition and resulting structural properties of the polymer to be tuned. Membrane fabrication results in thermally stable (TD > 250 oC), structurally robust polymer electrolytes that exhibit ionic conductivity ( > 10-3 S cm-1). These new solid-state ion conducting materials have the potential to be used in a variety of applications including AEMFCs. Here we present an in-depth study focusing on the structure-property relationships of this new polypyrrole/polyketone polymer. A variety of analytical techniques are used to probe the thermal and structural properties of the polymers, these include high-resolution thermogravimetric analysis, modulated differential scanning calorimetry, dynamic mechanical analysis, vibrational, NMR and UV-Vis spectroscopies. In addition, broadband electrical spectroscopy is used to gauge the interplay between the structural properties and electrical response. Figure 1

Nanofiber Scaffold-Based Tissue-Engineered Retinal Pigment Epithelium to Treat Degenerative Eye Diseases.

Clinical-grade manufacturing of a functional retinal pigment epithelium (RPE) monolayer requires reproducing, as closely as possible, the natural environment in which RPE grows. In vitro, this can be achieved by a tissue engineering approach, in which the RPE is grown on a nanofibrous biological or synthetic scaffold. Recent research has shown that nanofiber scaffolds perform better for cell growth and transplantability compared with their membrane counterparts and that the success of the scaffold in promoting cell growth/function is not heavily material dependent. With these strides, the field has advanced enough to begin to consider implementation of one, or a combination, of the tissue engineering strategies discussed herein. In this study, we review the current state of tissue engineering research for in vitro culture of RPE/scaffolds and the parameters for optimal scaffold design that have been uncovered during this research. Next, we discuss production methods and manufacturers that are capable of producing the nanofiber scaffolds in such a way that would be biologically, regulatory, clinically, and commercially viable. Then, a discussion of how the scaffolds could be characterized, both morphologically and mechanically, to develop a testing process that is viable for regulatory screening is performed. Finally, an example of a tissue-engineered RPE/scaffold construct is given to provide the reader a framework for understanding how these pieces could fit together to develop a tissue-engineered RPE/scaffold construct that could pass regulatory scrutiny and can be commercially successful.

Soluble Epidermal Growth Factor Receptors (sEGFRs) in Cancer: Biological Aspects and Clinical Relevance.

The identification of molecules that can reliably detect the presence of a tumor or predict its behavior is one of the biggest challenges of research in cancer biology. Biological fluids are intriguing mediums, containing many molecules that express the individual health status and, accordingly, may be useful in establishing the potential risk of cancer, defining differential diagnosis and prognosis, predicting the response to treatment, and monitoring the disease progression. The existence of circulating soluble growth factor receptors (sGFRs) deriving from their membrane counterparts has stimulated the interest of researchers to investigate the use of such molecules as potential cancer biomarkers. But what are the origins of circulating sGFRs? Are they naturally occurring molecules or tumor-derived products? Among these, the epidermal growth factor receptor (EGFR) is a cell-surface molecule significantly involved in cancer development and progression; it can be processed into biological active soluble isoforms (sEGFR). We have carried out an extensive review of the currently available literature on the sEGFRs and their mechanisms of regulation and biological function, with the intent to clarify the role of these molecules in cancer (and other pathological conditions) and, on the basis of the retrieved evidences, speculate about their potential use in the clinical setting.

Fabrication of hydrophobic flat sheet and hollow fiber membranes from PVDF and PVDF-CTFE for membrane distillation

Hydrophobic polyvinylidene fluoride (PVDF) membranes have been used in membrane distillation, however its performance in terms of permeation flux and salt rejection still needs to be improved. In this study, polyvinylidenedifluoride-co-chlorotrifluoroethylene (PVDF-CTFE), a PVDF based copolymer, was employed to fabricate both flat sheet and hollow fiber membranes. Two pore forming additives (PEG and LiCl) were used in order to examine their effects on the membrane micro-structure and consequently the distillation performance. The crystalline property of the polymers was studied via X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) to reveal its role in the membrane formation. The membrane morphology (SEM), surface property (AFM) and membrane properties (contact angle, pore size, porosity and pore size distribution) were systematically examined and compared among PVDF, PVDF-CTFE membranes as well as their counterparts with pore forming additives. The results revealed that PVDF-CTFE membrane exhibited optimal membrane morphology, pore structure and hydrophobicity, thus delivering better distillation performance (permeation flux up to 62.09kg/m2h, and distillate conductivity as low as 5μS/cm) in comparison with their PVDF membrane counterparts.

Emerging role for PLCβ1 MiRNA and disease

Nuclear inositides are independently regulated and their regulation is totally independent from the plasma membrane counterpart, suggesting that the nucleus constitutes a functionally distinct compartment of inositol lipids metabolism. This suggests that nuclear inositol lipids themselves can modulate nuclear processes as important as transcription and pre-mRNA splicing, growth, proliferation, cell cycle regulation and differentiation. Phospholipase C β1 (PLCβ1) is a key molecule for nuclear inositide signaling. Very recently it has been highlighted that the role of PLCβ1 during erythropoiesis is linked to that of miR-210. Moreover PLCβ1 signaling is linked to gene regulation and changes in microRNAs (miRNAs) occurs with PLCβ1 expression. Molecular targets of PLCβ1 have been found to be important during myogenesis and hematopoiesis. In addition, PLCβ1 signaling has been demonstrated to be impaired in diseases affecting both myogenic differentiation and affecting the hematopoietic system.