Polyurethane and carboxylated polysulfone blend ultrafiltration membranes. I. Preparation and characterization

Polysulfone was functionalized by carboxylation and blended with polyurethane (ether type). Blend membranes were prepared in the presence and absence of the additive poly(ethylene glycol) 600 and subjected to ultrafiltration characterizations such as compaction, pure water flux, water content, and hydraulic resistance. Morphological studies of the membranes were performed with scanning electron microscopy. The effects of the polymer composition and additive concentrations on the above parameters were analyzed and the results compared. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1307–1315, 2005     

Effect of finger millet (Eleusine coracana, Indaf-15) malt esterases on the functional characteristics of non-starch polysaccharides

Acetic acid esterase (AAE) (E.C 3.1.1.6) and ferulic acid esterase (FAE) (E.C 3.1.1.73) cleaves the acetyl groups substituted at O-2/O-3 of the xylan backbone and feruloyl groups substituted at 5′–OH group of arabinosyl residues, respectively of arabinoxylans. These enzymes modulate the functional properties of cereal arabinoxylans such as viscosity, foam stabilization and gelling. In the present study, water-soluble non-starch polysaccharides (WSPs) from ragi, wheat flours were isolated, and their functional characteristics were studied in the presence of purified esterases. Relative viscosities of the enzyme treated WSPs were marginally less than the untreated ones. Untreated WSPs from wheat and ragi were found to stabilize the thermal disruption of protein foams compared to the esterase treated ones. AAE treated WSPs of wheat and ragi showed increased gelation while FAE treated ones showed slight decrease in comparison with their respective controls. Xanthan gum (XG), which was deacetylated by purified AAE, showed improved gelation (ratio of relative viscosities for 0, 1 and 2 h of control and enzyme treated blend is 1:1.16, 1:1.35 and 1:1.20, respectively) when blended with locust bean gum (LBG).     

The Neonatal Fc Receptor Is Elevated in Monocyte-Derived Immune Cells in Pancreatic Cancer

The neonatal Fc receptor (FcRn) is responsible for recycling of IgG antibodies and albumin throughout the body. This mechanism has been exploited for pharmaceutic delivery across an array of diseases to either enhance or diminish this function. Monoclonal antibodies and albumin-bound nanoparticles are examples of FcRn-dependent anti-cancer therapeutics. Despite its importance in drug delivery, little is known about FcRn expression in circulating immune cells. Through time-of-flight mass cytometry (CyTOF) we were able to characterize FcRn expression in peripheral blood mononuclear cell (PBMC) populations of pancreatic ductal adenocarcinoma (PDAC) patients and non-cancer donors. Furthermore, we were able to replicate these findings in an orthotopic murine model of PDAC. Altogether, we found that in both patients and mice with PDAC, FcRn was elevated in migratory and resident classical dendritic cell type 2 (cDC2) as well as monocytic and granulocytic myeloid-derived suppressor cell (MDSC) populations compared to tumor-free controls. Furthermore, PBMCs from PDAC patients had elevated monocyte, dendritic cells and MDSCs relative to non-cancer donor PBMCs. Future investigations into FcRn activity may further elucidate possible mechanisms of poor efficacy of antibody immunotherapies in patients with PDAC.     

Pass Transistor-Based Pull-Up/Pull-Down Insertion Technique for Leakage Power Optimization in CMOS VLSI Circuits

Reduction in leakage power consumption is one of the important issues in the field of VLSI. Numerous techniques have been proposed by several researchers, based on threshold voltage variations and gate modifications. In this paper, a novel pass transistor-based pull-up/pull-down insertion technique is proposed to minimize standby leakage. Experimental results on various ISCAS’89 benchmark circuits show that proposed technique has an improvement up to 20, 36 and 33 % on average in leakage reduction, delay improvement and area savings respectively, compared to the transmission gate-based technique. All benchmark circuits are simulated using H-spice Tool with an 180-nm standard cell library based on BSIM3 transistor model. Finally, the efficacy of the proposed approach in improving various metrics has been compared with present state-of-art methods.     

Bearing capacity of square footings on geosynthetic reinforced sand

The results from laboratory model tests and numerical simulations on square footings resting on sand are presented. Bearing capacity of footings on geosynthetic reinforced sand is evaluated and the effect of various reinforcement parameters like the type and tensile strength of geosynthetic material, amount of reinforcement, layout and configuration of geosynthetic layers below the footing on the bearing capacity improvement of the footings is studied through systematic model studies. A steel tank of size 900 × 900 × 600 mm is used for conducting model tests. Four types of grids, namely strong biaxial geogrid, weak biaxial geogrid, uniaxial geogrid and a geonet, each with different tensile strength, are used in the tests. Geosynthetic reinforcement is provided in the form of planar layers, varying the depth of reinforced zone below the footing, number of geosynthetic layers within the reinforced zone and the width of geosynthetic layers in different tests. Influence of all these parameters on the bearing capacity improvement of square footing and its settlement is studied by comparing with the test on unreinforced sand. Results show that the effective depth of reinforcement is twice the width of the footing and optimum spacing of geosynthetic layers is half the width of the footing. It is observed that the layout and configuration of reinforcement play a vital role in bearing capacity improvement rather than the tensile strength of the geosynthetic material. Experimental observations are supported by the findings from numerical analyses.     

Simultaneous determination of conductance and thermopower of single molecule junctions

We report the first concurrent determination of conductance (G) and thermopower (S) of single-molecule junctions via direct measurement of electrical and thermoelectric currents using a scanning tunneling microscope-based break-junction technique. We explore several amine-Au and pyridine-Au linked molecules that are predicted to conduct through either the highest occupied molecular orbital (HOMO) or the lowest unoccupied molecular orbital (LUMO), respectively. We find that the Seebeck coefficient is negative for pyridine-Au linked LUMO-conducting junctions and positive for amine-Au linked HOMO-conducting junctions. Within the accessible temperature gradients (<30 K), we do not observe a strong dependence of the junction Seebeck coefficient on temperature. From histograms of thousands of junctions, we use the most probable Seebeck coefficient to determine a power factor, GS(2), for each junction studied, and find that GS(2) increases with G. Finally, we find that conductance and Seebeck coefficient values are in good quantitative agreement with our self-energy corrected density functional theory calculations.     

Dissecting contact mechanics from quantum interference in single-molecule junctions of stilbene derivatives

Electronic factors in molecules such as quantum interference and cross-conjugation can lead to dramatic modulation and suppression of conductance in single-molecule junctions. Probing such effects at the single-molecule level requires simultaneous measurements of independent junction properties, as conductance alone cannot provide conclusive evidence of junction formation for molecules with low conductivity. Here, we compare the mechanics of the conducting para-terminated 4,4'-di(methylthio)stilbene and moderately conducting 1,2-bis(4-(methylthio)phenyl)ethane to that of insulating meta-terminated 3,3'-di(methylthio)stilbene single-molecule junctions. We simultaneously measure force and conductance across single-molecule junctions and use force signatures to obtain independent evidence of junction formation and rupture in the meta-linked cross-conjugated molecule even when no clear low-bias conductance is measured. By separately quantifying conductance and mechanics, we identify the formation of atypical 3,3'-di(methylthio)stilbene molecular junctions that are mechanically stable but electronically decoupled. While theoretical studies have envisaged many plausible systems where quantum interference might be observed, our experiments provide the first direct quantitative study of the interplay between contact mechanics and the distinctively quantum mechanical nature of electronic transport in single-molecule junctions.     

Investigation into Effect of Ceramic Fillers on Mechanical and Tribological Properties of Bamboo-Glass Hybrid Fiber Reinforced Polymer Composites

Silicon - Ceramic fillers (TiO2 and ZrO2) having different morphology were used for reinforcement of bamboo-glass hybrid polymer composites. A particular emphasis is focused on special filler...     

Chemical synthesis of poly(aniline-co-o/m-toluidine)/V2O5 nano composites and their characterizations

Chemical oxidative polymerization of aniline (ANI) and o/m-toluidine (OT or MT) and their nano composites at different experimental conditions were performed using peroxydisulfate (PDS) as a lone chemical initiator and V₂O₅ as a host material in an aqueous HCl medium at 45 °C under nitrogen atmosphere. The nano composites were synthesized under different experimental conditions and were characterized by Fourier transform infra red (FTIR) spectroscopy, conductivity measurements, high resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TGA) like analytical tools. The effect of methyl substituent in the phenyl ring of ANI derivatives on the structure and property relationship of copolymer was studied.