Binding of heavy metal ions by formaldehyde-polymerized peanut skins

Peanut skin, when treated with formaldehyde to polymerize tannins, is a highly efficient substrate for removal of many heavy metal ions from aqueous waste solutions. The ions Ag¹⁺, Cd²⁺, Cr⁶⁺, Cu²⁺, Hg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, as well as Ca²⁺ and Mg²⁺, were contacted with formaldehyde-treated peanut skin. Quantitative removal could be achieved with Ag¹⁺, Cd²⁺, Cu²⁺, Hg²⁺, Pb²⁺, and Zn²⁺. Capacity of the substrate for ions was promising for Pb²⁺ (2.1 meq/g substrate), Cu²⁺ (3.0 meq/g), and Cd²⁺ (1.3 meq/g). Sorption from a solution containing Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, on a packed column of formaldehyde-treated peanut skin indicated that Hg²⁺, Pb²⁺, and Cu²⁺ were rapidly and completely bound to the packing, while Cd²⁺, Ni²⁺, and Zn²⁺ were poorly bound until the preferred ions had been removed from solution.     

N alpha- and N epsilon-D-galacturonoyl-L-lysine amides: properties and possible occurrence in plant cell walls

Three representatives of a novel class of amide (isopeptide) glycoconjugates have been synthesised: N alpha-D-galacturonoyl-L-lysine and N epsilon-D-galacturonoyl-L-lysine and N epsilon-D-polygalacturonoyl-L-lysine. Galacturonoyl-lysine amide bonds were labile in 2 M trifluoroacetic acid at 120 degrees and in alkali, but relatively stable in cold acid. The amide bonds were resistant to digestion by Driselase, Pronase and trypsin. The polysaccharide backbone of N epsilon-D-polygalacturonoyl-L-lysine was hydrolysed by Driselase to yield two major ninhydrin-positive compounds which were shown by 1H and 13C NMR spectroscopy to be tri- and tetra-alpha-(1-->4)-D-galacturonoyl-L-lysines. To investigate the possible natural occurrence of N-galacturonoyl isopeptide bonds, we fed cell-suspension cultures of spinach and tomato with D-[6-14C]glucuronic acid, which radio-labels pectic polysaccharides. The radioactive cell walls were digested with, sequentially, Driselase, mild acid, and proteinases. On electrophoresis at pH 2.0, several of the radioactive digestion-products were cathodic. Some of the cathodic products yielded [14C]galacturonic acid upon complete acid hydrolysis. The existence of these products is compatible with the presence of novel N-galacturonoyl isopeptide bonds, which could serve as cross-links in plant cell walls.     

Synthesis of GAGG:Ce3+ powder for ceramics using mechanochemical and solution combustion methods

Gadolinium aluminum gallium garnet doped with cerium (Gd_2.99Al_2.00Ga_3.00O_12.00:Ce_0.01, or GAGG:Ce) powders has been synthesized with high‐energy ball milling (HEBM) and solution combustion synthesis (SCS) techniques. The structures and morphologies of the powders were characterized through use of powder X‐ray diffraction (PXRD), photoluminescence (PL) measurements, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV‐decay time measurements. Changes in the mechanochemically produced powders were monitored over time, while the solution combustion synthesis of GAGG:Ce was conducted using various ratios and types of fuels. In both production methods, particle sizes on the order of microns gave evidence of agglomeration.     

Lignin valorization by forming toughened thermally stimulated shape memory copolymeric elastomers: Evaluation of different fractionated industrial lignins

Lignin‐based thermal responsive dual shape memory copolymeric elastomers were prepared with a highly branched prepolymer (HBP, A₂B₃ type) via a simple one‐pot bulk polycondensation reaction. The effect of fractionated lignin type (with good miscibility in the HBP) on copolymer properties was investigated. The thermal and mechanical properties of the copolymers were characterized by DMA, DSC, and TGA. Tensile properties were dominated by HBP <45% lignin content while lignin dominated >45% content. The copolymers glass transition temperature (T_g) increased with lignin content and lignin type did not play a significant role. Thermally stimulated dual shape memory effects (SME) of the copolymers were quantified by cyclic thermomechanical tests. All copolymers had shape fixity rate >95% and >90% shape recovery for all compositions. The copolymer shape memory transition temperature (T_trans) increased with lignin content and T_trans was 20°C higher than T_g. Lignin, a renewable resource, can be used as a netpoint segment in polymer systems with SME behavior. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41389.     

Optical Separation of Cells on Potential Energy Landscapes: Enhancement With Dielectric Tagging

We review the emergent techniques of microfluidic sorting of colloidal and cellular samples using optical forces. We distinguish between what we term as passive and active forms of particle sorting where we can sort either with the use of a fluorescent marker (active) or based on physical attributes alone (passive). We then examine cell sorting with optical potential landscapes such as a Bessel light beam and a multibeam interference pattern. For both forms of optical potential energy landscape, we further present the possibility of enhancing the optical sorting process by tagging dielectric microspheres onto the cells. The results suggest that the methodology of tagging can enhance the sorting of cells as they subsequently respond more strongly to an applied optical field or potential energy landscape. This technique presents a simple method to enhance the sorting process.     

Short answers to deep questions: supporting teachers in large‐class settings

In large class settings, individualized student–teacher interaction is difficult. However, teaching interactions (e.g., formative feedback) are central to encouraging deep approaches to learning. While there has been progress in automatic short‐answer grading, analysing student responses to support formative feedback at scale is arguably some way from being widely applied in practice. However, analysing student written responses can provide insights into student conceptions, thus directly informing teacher actions. Indeed, we argue that analysing student responses to provide feedback directly to teachers is as worthy a goal as providing individualized feedback to students and is achievable given the current state‐of‐the‐art in natural language processing. In this paper, we analyse student written responses to short‐answer questions posed in the context of a large first year health sciences course. Each question was designed to elicit deep responses. Our qualitative analysis illustrates the variability in student responses and reveals multiple relationships between these responses, course materials and the questions posed. Such information can be invaluable for teacher praxis. We conclude with a conceptual ‘dashboard’ that categorizes student responses and reveals relationships between responses, course resources and the questions. Such a dashboard could provide timely, actionable insights for teachers and help foster deep learning approaches for students.     

When Deceitful Chats Look Truthful

The amount of deception taking place via electronic text-based communication is increasing. Research has sought to automatically detect deception by analyzing the text from the communicator. However, the deceptive intent of the communication partner is being ignored. We compare the text from subjects who are trying to deceive each other, subjects trying to deceive truth tellers, subjects telling the truth to truth tellers, and subjects telling the truth to deceivers. We hypothesize that despite the intent of the partner, deceitful text will cluster closest to deceitful text. We cluster each of the four conditions using the text content. The cluster algorithm placed subjects trying to deceive each other closest to subjects telling the truth to each other. In this analysis, the language that led subjects to choose the same outcomes had a stronger effect than the language tied to being deceitful or truthful.     

Mapping intertidal estuarine sediment grain size distributions through airborne remote sensing

The intertidal environments of estuaries represent critical exchange environments of sediment and sediment bound contaminants. Ecological and sedimentological related investigations of these environments require monitoring methods that provide rapid spatially representative data on sediment grain size distribution. Remote sensing has the potential to provide synoptic information of intertidal environments. Previous in situ and laboratory-based reflectance investigations have demonstrated that for effective quantification of sediment grain size distributions, remote sensing platforms must include measurements within the short-wave infrared (SWIR). In addition, the timing of image acquisition, in relation to tidal cycles and sediment moisture content, is critical in optimising the spectral differences between the coarser sand and finer ‘mud’ fraction of sediments. Daedalus 1268 Airborne Thematic Mapper (ATM) has been identified as an appropriate platform and sensor for providing accurate synoptic maps of estuarine sediment distributions. This paper presents the results from the application of ATM 1.75 m resolution data to the mapping of surface sediment grain-size distributions across intertidal areas of Ribble Estuary, Lancashire, UK. ATM imagery was acquired after the intertidal area was exposed to strong summer drying conditions. Pre-processing and linear unmixing of the imagery collected of the intertidal zone following a period of drying allowed accurate sub-pixel determinations (1.75 m resolution) of sediment clay (r²=0.79) but less accurate for sand (r²=0.60). The results also demonstrate deterioration in the image calibration with increasing sediment moisture content and microphytobenthos cover. However, recombining the subpixel end member abundances through multivariate regression analysis improved the image calibration significantly for both sediment clay and sand content (r²>0.8) for imagery collected in both dryer and wetter conditions. These results demonstrate that ATM data, or similar, can be used to gain quantitative information on intertidal sediment distributions and such data has application to a wide variety of estuarine research.     

An automated technique for real-time production of lifelike animations of American Sign Language

Generating sentences from a library of signs implemented through a sparse set of key frames derived from the segmental structure of a phonetic model of ASL has the advantage of flexibility and efficiency, but lacks the lifelike detail of motion capture. These difficulties are compounded when faced with real-time generation and display. This paper describes a technique for automatically adding realism without the expense of manually animating the requisite detail. The new technique layers transparently over and modifies the primary motions dictated by the segmental model and does so with very little computational cost, enabling real-time production and display. The paper also discusses avatar optimizations that can lower the rendering overhead in real-time displays.