Using Porous Liquids to Perform Liquid-Liquid Separations.

Porous liquids are new types of fluid sorbent investigated mainly for the separation of gas mixtures. Here, we explore their application to the separation of miscible liquids, MEG (monoethylene glycol)/water and EtOH/water) as proof of principle. Recovery of used MEG is industrially important but its extraction from water is difficult. PLs ZIF 8@PDMS (PL1, PDMS = polydimethylsilicone) or ZIF-8@sesame oil (PL2) each consisting of 25wt% of the hydrophobic microporous material ZIF-8 dispersed in PDMS/sesame oil, were formulated and found to be exceedingly physically stable. 5 nm PEEK membranes were used to provide permeable barriers between the PL and the alcohol/water phase. MEG was selectively extracted through the membrane from 50wt% MEG/water mixtures into the PL phase. It was effective for MEG/water mixtures as dilute as 3:97wt%. The PL could be regenerated and re-used, suggesting its potential for continuous cyclic extraction. Furthermore, PL3 (silicalite-1@PDMS) has demonstrated effectiveness in achieving selective alcohol extraction from beverages. It shows great potential for lowering the alcohol concentration in gin/wine due to its excellent chemical stability and nontoxicity. Overall, the enhanced adsorption properties of PLs due the presence of empty pores, which provides unusually high gas solubilities, also makes them, in principle, applicable to liquid-liquid separations.

Effects of Particle Size on the Gas Uptake Kinetics and Physical Properties of Type III Porous Liquids.

Type III porous liquids (PLs) consist of porous solid particles dispersed in a size-excluded liquid phase and are attracting much attention as novel media for applications such as gas separation. However, the effects of fundamental variables such as particle size on their physical properties are currently largely unknown. Here we study the effects of particle size in a series of porous liquids based on solid Al(OH)(fumarate) (a microporous metal-organic framework, MOF) with particle sizes of 60 nm, 200-600 nm, or 800-1000 dispersed in liquid polydimethylsiloxane (PDMS). Properties examined include physical stability of the dispersion, viscosity, total CO2 uptake, and kinetics of CO2 uptake. As expected, both physical stability and viscosity decreased with increasing particle size. Unexpectedly, total gravimetric gas uptake also varied with particle size, being greatest for the largest particles, which we ascribe to larger particles having a lower relative content of surface-bound FMA ligands. Various models for the gas uptake kinetic data were considered, specifically adsorption reaction models such as pseudo-first-order, pseudo-second-order, and Elovich models. In contrast to pure PDMS, which showed first-order kinetics, all PLs fit best to the Elovich model confirming that their uptake mechanism is more complex than for a simple liquid. Adsorption diffusion models, specifically Weber and Morris' intraparticle model and Boyd's model, were also applied which revealed a three-step process in which a combination of diffusion through a surface layer and intraparticle diffusion were rate-limiting. The rate of gas uptake follows the order PDMS < PL1 < PL2 < PL3, showing that the porous liquids take up gas more rapidly than does PDMS and that this rate increases with particle size. Overall, the study suggests that for high gas uptake and fast uptake kinetics, large particles may be preferred. Also, the fact that large particles resulted in low viscosity may be advantageous in reducing the pumping energy needed in flow separation systems. Therefore, the work suggests that finding ways to stabilize PLs with large particles against phase separation could be advantageous for optimizing the properties of PLs toward applications.

Liquids with High Compressibility.

Compressibility is a fundamental property of all materials. For fluids, that is, gases and liquids, compressibility forms the basis of technologies such as pneumatics and hydraulics and determines basic phenomena such as the propagation of sound and shock waves. In contrast to gases, liquids are almost incompressible. If the compressibility of liquids could be increased and controlled, new applications in hydraulics and shock absorption could result. Here, it is shown that dispersing hydrophobic porous particles into water gives aqueous suspensions with much greater compressibilities than any normal liquids such as water (specifically, up to 20 times greater over certain pressure ranges). The increased compressibility results from water molecules being forced into the hydrophobic pores of the particles under applied pressure. The degree of compression can be controlled by varying the amount of porous particles added. Also, the pressure range of compression can be reduced by adding methanol or increased by adding salt. In all cases, the liquids expand back to their original volume when the applied pressure is released. The approach shown here is simple and economical and could potentially be scaled up to give large amounts of highly compressible liquids.

The coupling of mitoproteolysis and oxidative phosphorylation enables tracking of an active mitochondrial state through MitoTimer fluorescence.

The regulation of mitochondria function and health is a central node in tissue maintenance, ageing as well as the pathogenesis of various diseases. However, the maintenance of an active mitochondrial functional state and its quality control mechanisms remain incompletely understood. By studying mice with a mitochondria-targeted reporter that shifts its fluorescence from "green" to "red" with time (MitoTimer), we found MitoTimer fluorescence spectrum was heavily dependent on the oxidative metabolic state in the skeletal muscle fibers. The mitoproteolytic activity was enhanced in an energy dependent manner, and accelerated the turnover of MitoTimer protein and respiratory chain substrate, responsible for a green predominant MitoTimer fluorescence spectrum under the oxidative conditions. PGC1α, as well as anti-ageing regents promoted enhanced mitoproteolysis. In addition, cells with the green predominant mitochondria exhibited lower levels of MitoSox and protein carbonylation, indicating a favorable redox state. Thus, we identified MitoTimer as a probe for mitoproteolytic activity in vivo and found a heightened control of mitoproteolysis in the oxidative metabolic state, providing a framework for understanding the maintenance of active oxidative metabolism while limiting oxidative damages.

Type 3 Porous Liquids for the Separation of Ethane and Ethene.

We assess the potential for formulating a porous liquid that could be used as a selective solvent for the separation of ethane and ethene. Ethane-ethene separation is performed on very large scales by cryogenic distillation, but this uses large amounts of energy. Solvents that are selective to ethane or ethene could potentially enable more efficient liquid-based separation processes to be developed, but to date such solvents have been elusive. Here, Type 3 porous liquids, which consist of microporous solids dispersed in size-excluded liquid phases, were tailored toward the separation of ethane and ethene. A high selectivity for ethene over ethane (25.6 at 0.8 bar) and a high capacity was achieved for zeolite AgA dispersed in an Ag-containing ionic liquid. Unusually for liquid phases, the selectivity for ethane over ethene (2.55 at 0.8 bar) could also be achieved using either the metal-organic framework (MOF) Cu(Qc)2 (Qc = quinoline-5-carboxylate) dispersed in sesame oil or ZIF-7 in sesame oil, the latter showing gated uptake. The efficiency of the Cu(Qc)2 synthesis was increased by developing a mechanochemical method. The regeneration of Cu(Qc)2 in sesame oil and ZIF-7 in sesame oil was also demonstrated, suggesting that these or similar porous liquids could potentially be applied in cyclic separation processes.

Type 3 porous liquids based on non-ionic liquid phases - a broad and tailorable platform of selective, fluid gas sorbents.

We describe a series of Type 3 porous liquids, denoted "T3PLs", based on a wide range of microporous solids including MOFs, zeolites and a porous organic polymer (PAF-1). These solids are dispersed in various non-ionic liquid phases (including silicone oils, triglyceride oils, and polyethylene glycols) which have a range of structures and properties, and that are in many cases sterically excluded from the pores of the solids. Several stable dispersions with high gas uptakes are obtained. We show how these dispersions can be tailored toward important gas separation processes (CO2/CH4, C2H4/C2H6) and applications that require biocompatibility.

Haploinsufficiency of hnRNP U Changes Activity Pattern and Metabolic Rhythms.

The neuropeptides arginine vasopressin (Avp) and vasoactive intestinal polypeptide (Vip) are critical for the communication and coupling of suprachiasmatic nucleus neurons, which organize daily rhythms of physiology and behavior in mammals. However, how these peptides are regulated remains uncharacterized. We found that heterogeneous nuclear ribonucleoprotein U (hnRNP U) is essential for the expression of Avp and Vip. Loss of one copy of the Hnrnpu gene resulted in fragmented locomotor activities and disrupted metabolic rhythms. Hnrnpu+/- mice were more active than wild-type mice in the daytime but more inactive at night. These phenotypes were partially rescued by microinfusion of Avp and Vip into free-moving animals. In addition, hnRNP U modulated Avp and Vip via directly binding to their promoters together with brain and muscle Arnt-like protein-1/circadian locomotor output cycles kaput heterodimers. Our work identifies hnRNP U as a novel regulator of the circadian pacemaker and provides new insights into the mechanism of rhythm output.

CD4+ T cells memorize obesity and promote weight regain.

Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown. In this study, we report that immune cells, especially CD4+ T cells, mediate the 'memory' of previous obese status. In a weight gain-loss-regain model, we found that C57BL/6J mice with an obesity history showed a much faster rate of body weight regain. This obesity memory could last for at least 2 months after previously obese mice were kept at the same body weight as non-obese mice. Surprisingly, such obesity memory was abrogated by dexamethasone treatment, whereas immunodeficient Rag1-/- and H2A-/- mice failed to establish such memory. Rag1-/- mice repossessed the obesity memory when immune cells or CD4+ T cells isolated from previously obese mice were transferred. Furthermore, depletion of CD4+ T cells led to obesity memory ablation. Taken together, we conclude that CD4+ T cells mediate obesity memory and promote weight regain.

Glucose metabolic abnormality is associated with defective mineral homeostasis in skeletal disorder mouse model.

Bone was reported as a crucial organ for regulating glucose homeostasis. In this study, we found that Phex mutant mice (PUG), a model of human X-linked hypophosphatemic rickets (XLH), displayed metabolic abnormality in addition to abnormal phosphate homeostasis, skeletal deformity and growth retardation. Glucose tolerance was elevated with enhanced insulin sensitivity in PUG, though circulating insulin level decreased. Interestingly, bone mineral density defects and glucose metabolic abnormality were both rescued by adding phosphorus- and calcium-enriched supplements in daily diet. Serum insulin level, glucose tolerance and insulin sensitivity showed no differences between PUG and wild-type mice with rescued osteocalcin (OCN) following treatment. Our study suggested that OCN is a potential mediator between mineral homeostasis and glucose metabolism. This investigation brings a new perspective on glucose metabolism regulation through skeleton triggered mineral homeostasis and provides new clues in clinical therapeutics of potential metabolic disorders in XLH patients.

Maged1 co-interacting with CREB through a hexapeptide repeat domain regulates learning and memory in mice.

Maged1 is a member of the type II melanoma antigen (MAGE) family of proteins, which is highly conserved in the brain between mouse and human. Recently, Maged1 has been reported to be involved in depression and impaired sexual behavior. However, the role of Maged1 in learning and memory remains unknown. The aim of the present study was therefore to investigate whether Maged1 deficiency can impair learning and memory formation. By behavioral tests and electrophysiological recording, we observed that 5-6-month-old Maged1 knockout mice displayed the reduced basal synaptic transmission, pronounced hippocampal dysfunction, impaired spatial learning, and a deficit in long-term potentiation induction. Data from immunohistochemical and Western blot showed the reduced dendritic spine density and the number of synapses in the hippocampus of the Maged1 knockout mice, and Maged1 deficiency prevented the interaction of Maged1 with cAMP response element-binding protein (CREB). Furthermore, by chromatin immunoprecipitation and luciferase assay, we observed the downregulated activity of CREB and the suppressed CREB-dependent transcription after deficiency of Maged1, which lead to the decreased levels of brain-derived neurotrophic factor. Taken together, our results provide the evidence that Maged1 is involved in synaptic transmission and hippocampus-dependent learning and memory formation.