Performance Characterization of a Capacitive Deionization Water Desalination System With an Intermediate Solution and Low Salinity Water

In recent years, more efforts have been made to improve new and more efficient nonmembrane-based methods for water desalination. Capacitive deionization (CDI), a novel technique for water desalination using an electric field to adsorb ions from a solution to a high-porous media, has the capability to recover a fraction of the energy consumed for the desalination during the regeneration process, which happens to be its most prominent characteristic among other desalination methods. This paper introduces a new desalination method that aims at improving the performance of traditional CDI systems. The proposed process consists of an array of CDI cells connected in series with buffer containers in between them. Each buffer serves two purposes: (1) averaging the outlet solution from the preceding cell and (2) securing a continuous water supply to the following cell. Initial evaluation of the proposed CDI system architecture was made by comparing a two-cell-one-buffer assembly with a two cascaded cells array. Concentration of the intermediate solution buffer was the minimum averaged concentration attained at the outlet of the first CDI cell, under a steady-state condition. The obtained results show that the proposed CDI system with intermediate solution had better performance in terms of desalination percentage. This publication opens new opportunities to improve the performance of CDI systems and implement this technology on industrial applications.

Performance Characterization of a Capacitive Deionization Water Desalination System With an Intermediate Solution and Low Salinity Water

In recent years, more efforts have been made to improve new and more efficient non-membrane-based methods for water desalination. Capacitive deionization (CDI), a novel technique for water desalination using an electric field to adsorb ions from a solution to a high-porous media, has the capability to recover a fraction of the energy consumed for the desalination during the regeneration process, which happens to be its most prominent characteristic among other desalination methods. This paper introduces a new desalination method that aims improving the performance of traditional CDI systems. The proposed process consists of an array of CDI cells connected in series with buffer containers in between them. Each buffer, serve two purposes: 1) average the outlet solution from the preceding cell, and 2) secure a continuous water supply to the following cell. Initial evaluation of the proposed CDI system architecture was made by comparing a two-cell-one-buffer assembly with a two cascaded cells array. Concentration of the intermediate solution buffer was the minimum averaged concentration attained at the outlet of the first CDI cell, under a steady state condition. The obtained results show that proposed CDI system with intermediate solution had better performance in terms of desalination percentage. This publication opens new opportunities to improve the performance of CDI systems and implement this technology on industrial applications.

Kinase activation of ClC-3 accelerates cytoplasmic condensation during mitotic cell rounding

“Mitotic cell rounding” describes the rounding of mammalian cells before dividing into two daughter cells. This shape change requires coordinated cytoskeletal contraction and changes in osmotic pressure. While considerable research has been devoted to understanding mechanisms underlying cytoskeletal contraction, little is known about how osmotic gradients are involved in cell division. Here we describe cytoplasmic condensation preceding cell division, termed “premitotic condensation” (PMC), which involves cells extruding osmotically active Cl− via ClC-3, a voltage-gated channel/transporter. This leads to a decrease in cytoplasmic volume during mitotic cell rounding and cell division. Using a combination of time-lapse microscopy and biophysical measurements, we demonstrate that PMC involves the activation of ClC-3 by Ca2+/calmodulin-dependent protein kinase II (CaMKII) in human glioma cells. Knockdown of endogenous ClC-3 protein expression eliminated CaMKII-dependent Cl− currents in dividing cells and impeded PMC. Thus, kinase-dependent changes in Cl− conductance contribute to an outward osmotic pressure in dividing cells, which facilitates cytoplasmic condensation preceding cell division.

Adjacent positioning of cellular structures enabled by a Cdc42 GTPase-activating protein–mediated zone of inhibition

Cells of the budding yeast Saccharomyces cerevisiae are born carrying localized transmembrane landmark proteins that guide the subsequent establishment of a polarity axis and hence polarized growth to form a bud in the next cell cycle. In haploid cells, the relevant landmark proteins are concentrated at the site of the preceding cell division, to which they recruit Cdc24, the guanine nucleotide exchange factor for the conserved polarity regulator Cdc42. However, instead of polarizing at the division site, the new polarity axis is directed next to but not overlapping that site. Here, we show that the Cdc42 guanosine triphosphatase–activating protein (GAP) Rga1 establishes an exclusion zone at the division site that blocks subsequent polarization within that site. In the absence of localized Rga1 GAP activity, new buds do in fact form within the old division site. Thus, Cdc42 activators and GAPs establish concentric zones of action such that polarization is directed to occur adjacent to but not within the previous cell division site.