Enhancing the Permeate Flux Improvement of Direct Contact Membrane Distillation Modules with Inserted S-Ribs Carbon-Fiber Filaments.

Three widths of manufacturing S-ribs carbon-fiber filaments acting as turbulence promoters were implemented into the flow channel of direct contact membrane distillation (DCMD) modules to augment the permeate flux improvement in the present study. Attempts to reduce the disadvantageous temperature polarization effect were made by inserting S-ribs turbulence promoters in improving pure water productivity, in which both heat- and mass-transfer boundary layers were diminished due to creating vortices in the flow pattern and increasing turbulence intensity. The temperature polarization coefficient ttemp was studied and found to enhance device performance (less thermal resistance) under inserting various S-ribs carbon-fiber thicknesses and operating both cocurrent- and countercurrent-flow patterns. The permeate fluxes in the DCMD modules with inserted S-ribs carbon-fiber turbulence promoters were investigated theoretically by developing the mathematical modeling equations and were conducted experimentally with various design and operating parameters. The theoretical predictions and experimental results exhibited a great potential to considerably achieve permeate flux enhancement in the new design of the DCMD system. The DCMD module with inserted S-ribs carbon-fiber turbulence promoters in the flow channel could provide a relative permeate flux enhancement up to 37.77% under countercurrent-flow operations in comparisons with the module of using the empty channel. An economic consideration on both permeate flux enhancement and power consumption increment for the module with inserted S-ribs carbon-fiber filaments was also delineated.

Evidence for an Induced-Fit Process Underlying the Activation of Apoptotic BAX by an Intrinsically Disordered BimBH3 Peptide.

Apoptotic BAX protein functions as a critical gateway to mitochondria-mediated apoptosis. A diversity of stimuli has been implicated in initiating BAX activation, but the triggering mechanism remains elusive. Here we study the interaction of BAX with an intrinsically disordered BH3 motif of Bim protein (BimBH3) using ESR techniques. Upon incubation with BAX, BimBH3 binds to BAX at helices 1/6 trigger site to initiate conformational changes of BAX, which in turn promotes the formation of BAX oligomers. The study strategy is twofold: while BAX oligomerization was monitored through spectral changes of spin-labeled BAX, the binding kinetics was studied by observing time-dependent changes of spin-labeled BimBH3. Meanwhile, conformational transition between the unstructured and structured BimBH3 was measured. We show that helical propensity of the BimBH3 is increased upon binding to BAX but is then reduced after being released from the activated BAX; the release is due to the BimBH3-induced conformational change of BAX that is a prerequisite for the oligomer assembling. Intermediate states are identified, offering a key snapshot of the coupled folding and binding process. Our results provide a quantitative mechanistic description of the BAX activation and reveal new insights into the mechanism underlying the interactions between BAX and BH3-mimetic peptide.

Solution Structure of Apoptotic BAX Oligomer: Oligomerization Likely Precedes Membrane Insertion.

Proapoptotic BAX protein is largely cytosolic in healthy cells, but it oligomerizes and translocates to mitochondria upon receiving apoptotic stimuli. A long-standing challenge has been the inability to capture any structural information beyond the onset of activation. Here, we present solution structures of an activated BAX oligomer by means of spectroscopic and scattering methods, providing details about the monomer-monomer interfaces in the oligomer and how the oligomer is assembled from homodimers. We show that this soluble oligomer undergoes a direct conversion into membrane-inserted oligomer, which has the ability of inducing apoptosis and structurally resembles a membrane-embedded oligomer formed from BAX monomers in lipid environment. Structural differences between the soluble and the membrane-inserted oligomers are manifested in the C-terminal helices. Our data suggest an alternative pathway of apoptosis in which BAX oligomer formation occurs prior to membrane insertion.

Applications of machine learning techniques to a sensor-network-based prosthesis training system.

In the past, the utilization of the limb prosthesis has improved the daily life of amputees or patients with movement disorders. However, a leg-amputee has to take a series of training after wearing a limb prosthesis, and the training results determine whether a patient can use the limb prosthesis correctly in her/his daily life. Limb prosthesis vendors thus desire to offer the leg-amputee a complete and well-organized training process, but they often fail to do so owing to the factors such as the limited support of human resource and financial condition of the amputee. This work proposes a prosthesis training system that the amputees can borrow or buy from the limb prosthesis vendors and train themselves at home. Instant feedback messages provided by the prosthesis training system are used to correct their walking postures during the self-training process. An embedded chip is used as a core to establish a body area sensor network for the prosthesis training system. RFID readers and tags are employed to acquire the 3D positioning information of the amputee's limbs in this work to assist in diagnosing the amputee's walking problem. A series of simulations were conducted and the simulation results exhibit the effectiveness and practicability of the proposed prosthesis training system.

Proline-rich domain of penaeidin molecule exhibits autocrine feature by attracting penaeidin-positive granulocytes toward the wound-induced inflammatory site.

Antimicrobial peptides (AMPs) are amphipathic structures of low molecular weight that are generally positively charged. Penaeidins are shrimp-specific AMPs that are synthesized and stored in granulocytes and released after stimulation. Penaeidin is composed of an N-terminal proline-rich domain (PRD) and a C-terminal cysteine-rich domain (CRD). Penaeidin and PRD were approved as a cytokine in vitro, but how penaeidin regulates hemocyte adhesion in vivo is unclear. The present study examines penaeidin immunomodulation function in the wound-induced inflammation response in tiger shrimp (Penaeus monodon). Both penaeidin transcript and protein decreased in peripheral hemocytes but increased in the wound tissue. The wounded tissue sections were compared in penaeidin normal and penaeidin knockdown shrimps. Only the shrimps at normal penaeidin expression level present the concentration of hemocytes phenomenon in the wounded tissue at 2h post-wound. This phenomenon was recovered in the penaeidin knockdown shrimps by adding recombinant penaeidin or PRD to the wounded tissue. Penaeidin was also found to be simultaneous expression of integrin in vivo. Penaeidin-positive granulocytes decreased in the peripheral hemolymph post-wound. The hemocytes that concentrated in the wounded tissue were 80% penaeidin-positive granulocytes. We propose that penaeidin acts as a pro-inflammatory cytokine and attracts penaeidin-positive granulocytes toward the inflammatory site by autocrine activity through integrin-dependent cell migration.

Tiger shrimp (Penaeus monodon) penaeidin possesses cytokine features to promote integrin-mediated granulocyte and semi-granulocyte adhesion.

Recent studies indicated that antimicrobial peptides (AMPs) play multiple roles in both innate and adaptive immune functions. The penaeidin of tiger shrimp Penaeus monodon shows an antimicrobial activity against Gram-positive bacteria and filamentous fungi. To study immunomodulation functions of the penaeidin, we transfected shrimp hemocytes in primary culture with penaeidin-specific small interfering RNA (siRNA-3) and observed a concomitant 20% reduction in adhesive hemocytes compared with mock-transfected cells. The addition of biosynthesized or chemically synthesized penaeidin or penaeidin proline-rich domain (PRD) to the culture medium of penaeidin knock-down hemocytes led to a full recovery in the number of adhesive hemocytes. The effect of penaeidin knock-down on the expression of tiger shrimp cell adhesion-associated molecules was examined using real-time Q-PCR. Results demonstrated 91% and 64% decreases in the expression of integrin-beta and collagen, respectively, and a 396% increase in the expression of collagenase. The addition of chemically synthesized penaeidin after penaeidin knock-down hemocytes normalized the expression of these genes. The addition of the integrin-beta ligand competitor RGDS to mock-transfected hemocytes decreased the number of adhesive hemocytes similar to penaeidin knock-down. In conclusion, penaeidin possesses an integrin-beta-mediated cytokine feature that promotes shrimp granulocyte and semi-granulocyte adhesion. This is the first report about functional shrimp cytokine.