Development of cellulose nanowhisker-polyacrylamide copolymer as a highly functional precursor in the synthesis of nanometal particles for conductive textiles

Herein we present extensive studies that were undertaken to develop a new copolymer with distinctive characteristics for utilization in different applications particularly in conductive textiles. The copolymer is based on graft polymerization of cellulose nanowhiskers (CNWs) with acrylamide and therefore nominated CNW-polyacrylamide (PAAm) copolymer. Development of this copolymer comprises preparation of CNWs from purified cotton sliver as per the acid hydrolysis method, followed by copolymerization of the freshly prepared CNWs with AAm at different feeding ratios for the sake of product optimization in the presence of K₂S₂O₈ as initiator. Thus, obtained CNW-PAAm copolymers were characterized by making use of the proper instruments and analysis facilities. Following this, the newly prepared and promising copolymer was selected and used as a precursor in the green synthesis of silver and copper nanoparticles. The crystal nature of CNWs as cellulose I remains unaltered after copolymerization, but the crystallinity decreases. According to thermal gravimetric analysis, the copolymer is much more thermally stable than CNWs. The CNW-PAAm copolymer can be used successfully as a highly functional, effective and adequate precursor for green synthesis of silver and copper nanoparticles as shown by UV-Vis spectral analysis and transmission electron microscopy micrographs. A multi-branched shape and hyperbranched shape-like tree involving silver nanoparticles and the PAAm graft of the copolymer are formed. Furthermore, Cu nanoparticles are chosen as a candidate for conductive fabrics application.     

Synthesis and crystal structure of bis(4-methylpiperidine-dithiocarbamato-S,S′)-palladium(II)

The complex bis(4-methylpiperidine-dithiocarbamato-S,S′)-palladium(II) was synthesized by the reaction of 4-methyl-1-piperidine dithiocarbamic acid with palladium(II) chloride. Its structure was determined by X-ray crystal diffraction analysis. It crystallizes in the monoclinic P2₁/c space group with the crystal cell parameters a=8.6491(8) ?, b=18.7305(16) ?, c=11.9933(10) ?, β=107.074(1)°, V=1857.3(3) ?³ and Z=4. The palladium (II) ion is bonded to four sulfur atoms, belonging to two dithiocarbamate ligands, in a distorted square planar geometry. The X-ray data suggest a pronounced electronic delocalization in the two NCS₂ moieties.     

Synthesis, characterization, in vitro cytotoxicity and anti-inflammatory activity of palladium(II) complexes with tertiary phosphines and heterocyclic thiolates: Crystal structure of [PdC28H19N8PS2]

The new four-coordinated mononuclear palladium(II) complexes 1-9 with chelating heterocyclic thiolates and tertiary phosphines with general formula [Pd(L)_nCl(R′R₂P)] (L = Pym2SH (pyrimidine-2-thiolate), Pur6SH (purine-6-thiolate), Py2SH (pyridine-2-thiolate), R₃P = PPh₃, P(o-tolyl)₃, PPh₂Cl), n = 1, 2) have been synthesized by the direct reaction of [PdCl₂(R′R₂P)₂] with polyfunctional heterocyclic thiolates which display a wide variety of coordinations. These compounds were characterized by elemental analysis, FT-IR and multinuclear (¹H, ¹³C and ³¹P) NMR. The X-ray diffraction study of non-ionic compound 5 showed that the thiolate acts as unidentate and that the chelating (-N,S) ligand adopts a slightly distorted square planar geometry around the palladium atom. In vitro the anti-inflammatory inhibition of compounds 1-9 was 10-15% greater than that of the standard drug Declofenac. Compounds 1 and 4 showed mostly a moderate to low cytotoxicity against seven human tumor cell lines whereas compound 3 was somewhat more active.     

Development of natural sorbent based micro-solid-phase extraction for determination of phthalate esters in milk samples

In the present study, a natural sorbent based micro-solid phase extraction (μ-SPE) was developed for determination of phthalate esters in milk samples. For the first time, an efficient and cost effective natural material (seed powder of Moringa oleifera) was employed as sorbent in μ-SPE. The sorbent was found to be naturally enriched with variety of functional groups and having a network of interconnected fibers. This method of extraction integrates different steps such as removal of proteins and fatty stuff, extraction and pre-concentration of target analytes into a single step. Thirteen phthalate esters were selected as target compounds for the development and evaluation of method. Some key parameters affecting the extraction efficiency were optimized, including selection of membrane, selection and amount of sorbent, extraction time, desorption solvent, volume of desorption solvent, desorption time and effect of salt addition. Under the optimum conditions, very good linearity was achieved for all the analytes with coefficient of determinations (R²) ranging between 0.9768 and 0.9977. The limits of detection ranged from 0.01 to 1.2 μg L⁻¹. Proposed method showed satisfactory reproducibility with relative standard deviations ranging from 3.6% to 10.2% (n = 7). Finally, the developed method was applied to tetra pack and bottled milk samples for the determination of phthalate esters. The performance of natural sorbent based μ-SPE was better or comparable to the methods reported in the literature.     

Shahidine, a novel and highly labile oxazoline from Aegle marmelos: the parent compound of aegeline and related amides

A rare alkaloid, shahidine (1), having an unstable oxazoline core has been isolated as a major constituent from the fresh leaves of Aegle marmelos. It is moisture-sensitive, and found to be the parent compound of aegeline and other amides, however, it is stable in dimethyl sulfoxide. Its structure was established by spectroscopic analysis. Biogenetically, oxazolines may be considered as the precursor of hydroxy amides and oxazoles found in plants. Shahidine (1) showed activity against a few Gram-positive bacteria.     

Evolving timetabling heuristics using a grammar-based genetic programming hyper-heuristic framework

This paper introduces a Grammar-based Genetic Programming Hyper-Heuristic framework (GPHH) for evolving constructive heuristics for timetabling. In this application GP is used as an online learning method which evolves heuristics while solving the problem. In other words, the system keeps on evolving heuristics for a problem instance until a good solution is found. The framework is tested on some of the most widely used benchmarks in the field of exam timetabling and compared with the best state-of-the-art approaches. Results show that the framework is very competitive with other constructive techniques, and did outperform other hyper-heuristic frameworks on many occasions.     

Bilinearization and soliton solutions of N=1 supersymmetric coupled dispersionless integrable system

An N=1 supersymmetric generalization of coupled dispersionless (SUSY-CD) integrable system has been proposed by writing its superfield Lax representation. It has been shown that under a suitable variable transformation, the SUSY-CD integrable system is equivalent to N=1 supersymmetric sine-Gordon equation. A superfield bilinear form of SUSY-CD integrable system has been proposed by using super Hirota operator. Explicit expressions of superfield soliton solutions of SUSY-CD integrable system have been obtained by using the Hirota method.     

Physiological Flow of Jeffrey Six Constant Fluid Model due to Ciliary Motion

The main purpose of this article is to present a mathematical model of ciliary motion in an annulus. In this analysis, the peristaltic motion of non-Newtonian Jeffrey six constant fluid is observed in an annulus with ciliated tips in the presence of heat and mass transfer. The effects of viscous dissipation are also considered. The flow equations of non-Newtonian fluid for the two-dimensional tube in cylindrical coordinates are simplified using the low Reynolds number and long wave-length approximations. The main equations for Jeffrey six constant fluid are considered in cylindrical coordinates system. The resulting nonlinear problem is solved using the regular perturbation technique in terms of a variant of small dimensionless parameter α. The results of the solutions for velocity, temperature and concentration field are presented graphically. B_k is Brinkman number, ST is soret number, and SH is the Schmidth number. Outcome for the longitudinal velocity, pressure rise, pressure gradient and stream lines are represented through graphs. In the history, the viscous-dissipation effect is usually represented by the Brinkman number.     

Synthesis of tapioca cellulose-based poly(hydroxamic acid) ligand for heavy metals removal from water

A graft copolymerization was performed using free radical initiating process to prepare the poly(methyl acrylate) grafted copolymer from the tapioca cellulose. The desired material is poly(hydroxamic acid) ligand, which is synthesized from poly(methyl acrylate) grafted cellulose using hydroximation reaction. The tapioca cellulose, grafted cellulose and poly(hydroxamic acid) ligand were characterized by Infrared Spectroscopy and Field Emission Scanning Electron Microscope. The adsorption capacity with copper was found to be good, 210 mg g^?1 with a faster adsorption rate (t_1/2 = 10.5 min). The adsorption capacities for other heavy metal ions were also found to be strong such as Fe³⁺, Cr³⁺, Co³⁺ and Ni²⁺ were 191, 182, 202 and 173 mg g^?1, respectively at pH 6. To predict the adsorption behavior, the heavy metal ions sorption onto ligand were well-fitted with the Langmuir isotherm model (R² > 0.99), which suggest that the cellulose-based adsorbent i.e., poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability was checked by the sorption/desorption process for six cycles and the sorption and extraction efficiency in each cycle was determined. This new adsorbent can be reused in many cycles without any significant loss in its original removal performances.     

Thermal Decompositions of Pure and Mixed Manganese Carbonate and Ammonium Molybdate Tetrahydrate

The thermal decompositions of pure and mixed manganese carbonate and ammonium molybdate tetrahydrate in molar ratios of 3:1, 1:1 and1:3 were studied by DTA and TG techniques. The prepared mixed solid samples were calcined in air at 500, 750 or 1000°C and then investigated by means of an XRD technique. The results revealed that manganese carbonate decomposed in the range 300–1000°C, within termediate formation of MnO₂, Mn₂O₃ andMn₃O₄. Ammonium molybdate tetrahydrate first lost its water of crystallization on heating, and then decomposed, yielding water and ammonia. At 340°C,MoO₃ was the final product, which melts at 790°C. The thermal treatment of the mixed solids at 500, 750 or 1000°C led to solid-solid interactions between the produced oxides, with the formation of manganese molybdate. At 1000°C, Mn₂O₃ and MoO₃ were detected, due to the mutual stabilization effect of these oxides at this temperature. This revised version was published online in July 2006 with corrections to the Cover Date.