Application of nanostructured titanium dioxide pigments in paper coating: a comparison between prepared and commercially available ones

Nano-TiO₂ pigments in pure crystallographic anatase and rutile phases have been successfully prepared by hydrothermal at 120°C and hydrolysis methods, respectively. The laboratory-prepared pigments were characterized parallel to two commercial pigments of the same crystal structure. All pigments were applied in paper coating mixtures, and their influence on coated paper properties was systematically investigated. X-ray diffraction investigation showed that the laboratory-prepared pigments using the hydrothermal method at 120°C were pure anatase, whereas hydrolysis method produced pure rutile phase pigment. The application of the prepared nanopigments and the corresponding commercial TiO₂ phases in paper coating revealed that clay/rutile nano-TiO₂ pigments in paper coating mixture decreased coated paper roughness more than blending clay with anatase nano-TiO₂ pigments. Commercial nano-TiO₂ pigments increased porosity of coated paper at both the 30% and 50% addition of nano-TiO₂ pigments to clay, while laboratory-prepared nano-TiO₂ pigments highly decreased it at 30% addition of nano-TiO₂ to clay, compared to clay only. Blending of clay/nano-TiO₂ pigments improved both brightness and opacity of the coated paper where commercial pigments are more effective. Burst, tensile strength, stretching, and TEA were improved in the case of all pigments. The 50% addition of the prepared and commercial nanopigments in conjunction with clay improved the mechanical coated paper properties more than 30% addition (except the cases of stretching and TEA of the commercial pigments). The coated paper samples were offset printed. It was found that blending of clay/nano-TiO₂ pigments improved print density. Commercial nano-TiO₂ pigments improved print gloss more than the laboratory-prepared ones. This result was found consistent with the results of coated paper roughness.     

Saturated and unsaturated aliphatic side chain-appended naphthalenediimide derivatives: synthesis and structure property relationship

Previous studies have shown influence of aliphatic side chain length and type on the transport properties of naphthalenediimide (NDI) materials by affecting molecular arrangement. There is lack of comparative study on the presence or absence of unsaturation in side chain and its effect on optical and electronic properties of NDI. The present work focuses on the structure–property relationship of four NDI derivatives bearing octyl (C8, OctA-NDI), hexadecyl (C16, HD-NDI), octadecyl (C18, ODA-NDI) and oleyl (C18-un, unsaturated, OLA-NDI) chain on imide-nitrogen. The self-assembling behaviour of the molecules is studied in concentrated solutions as fresh and aged samples in four different solvents by absorbance and emission spectroscopy. With increase in alkyl chain length, the aggregation behaviour is observed to increase. Very interestingly introduction of unsaturation in side chain reduces aggregation and restores the monomeric properties. Self-assembled microstructures formation was studied by scanning electron microscopy where all the four materials show different types of self-assembly formation. Finally, we compared the thermally activated electron conductivity and electron mobility of NDI derivatives, where also the side chain structure clearly influences the electron transport. Electron mobility decreases on increasing chain length from C8 to C18 and again increases in C18-un. A rationale for the structure–property relationship has been given based on the molecular packing and intermolecular π–π interactions. This study contributes significantly towards designing new NDI derivatives bearing long side chains with hampered aggregation for niche applications.

     

An efficient Resource Management to optimize the placement of hardware task on FPGA in the RVC framework

Dynamic partial reconfiguration (DPR) functionality allows implementing multi-tasks applications by exchanging tasks in a design at run-time. It is a promising solution to enhance system performances. But, the effective use of DPR is often hampered by the complexity added to the system design process. In this paper, we investigate the implementation of a multi-tasks applications using the DPR in the RVC framework. We present a resource management method which includes three steps: partitioning the application in HW/SW tasks, divided the FPGA in static and dynamic regions and placement the tasks on FPGA. The proposed method is based on using linear programming strategy to find the optimal placement of hardware tasks. We take into account the heterogeneity aspect of the device. The goal is to minimize the resource utilization and fragmentation. We use RVC technology which is based on a specific language for writing dataflow models called RVC-CAL. This language describes the application as set of blocks called actors connected through a network. To test the efficiency of our approach, we exploit the decoder MPEG-4 SP described in RVC-CAL. We measure the quality of placement in terms of tasks rejection, execution time and resource wastage. Application of different data combinations and a comparison with the state-of-the art method show the high performance of the proposed approach.     

Effect of polymeric thickeners on pigment coatings: Adsorption, rheological behaviour and surface structures

Polymeric thickeners play a vital role in controlling water retention in paper coating processes. In this work, the interactions between various polymer water retention agents (i.e., thickeners) and coating pigments were investigated, in an attempt to improve the understanding of the thickening mechanisms. Adsorption isotherms of the polymeric thickeners, up to four types of commercial thickeners based mainly on copolymers of acrylate and acrylic acid, onto mineral pigments (clay pigment and ground calcium carbonate, GCC) were determined. It was found that the adsorption behaviour was strongly affected by the surface structure of the pigment. All the selected thickeners showed greater affinity towards clay pigment than calcium carbonate. The influence of the selected thickeners on coating mixtures behaviour at low shear rate was also investigated. In coating mixture based on clay, it was found that HASE (hydrophobically modified alkali swellable emulsion) thickener that has the highest adsorption led to more effective thickening. All the selected thickeners showed moderate effect on the viscosity of the coating mixture based on GCC. The presence of thickeners also produced the coated paper with smooth and homogeneous surfaces, revealed by SEM observation.     

Genetic algorithms to solve the cover printing problem

Inspired by successful application of evolutionary algorithms to solving difficult optimization problems, we explore in this paper, the applicability of genetic algorithms (GAs) to the cover printing problem, which consists in the grouping of book covers on offset plates in order to minimize the total production cost. We combine GAs with a linear programming solver and we propose some innovative features such as the “unfixed two-point crossover operator” and the “binary stochastic sampling with replacement” for selection. Two approaches are proposed: an adapted genetic algorithm and a multiobjective genetic algorithm using the Pareto fitness genetic algorithm. The resulting solutions are compared. Some computational experiments have also been done to analyze the effects of different genetic operators on both algorithms.     

Metal-Based Catalytic Drug Development for Next-Generation Cancer Therapy

Considering the high increase in mortality caused by cancer in recent years, cancer drugs with novel mechanisms of anticancer action are urgently needed to overcome the drawbacks of platinum-based chemotherapeutics. Recently, in the area of metal-based cancer drug development research, the concept of catalytic cancer drugs has been introduced with organometallic Ru^II, Os^II, Rh^III and Ir^III complexes. These complexes are reported as catalysts for many important biological transformations in cancer cells such as nicotinamide adenine dinucleotide (NAD(P)H) oxidation to NAD⁺, reduction of NAD⁺ to NADH, and reduction of pyruvate to lactate. These unnatural intracellular transformations with catalytic and nontoxic doses of metal complexes are known to severely perturb several important biochemical pathways and could be the antecedent of next-generation catalytic cancer drug development. In this concept, we delineate the prospects of such recently reported organometallic Ru^II, Os^II, Rh^III and Ir^III complexes as future catalytic cancer drugs. This new approach has the potential to deliver new cancer drug candidates.     

Cholesterol: A Key in the Pathogenesis of Alzheimer's Disease

Herein we highlight recent advances in our understanding of the role of cholesterol in Alzheimer′s disease (AD). It has been proposed that cholesterol could enhance the risk of AD, and the interaction between cholesterol and amyloid‐β peptide 42 (Aβ42) has been studied extensively, yet until recently, the specific interaction mechanisms between them and how this affects Aβ42 aggregation had not yet been fully explored and had remained ambiguous. Vendruscolo and co‐workers addressed these issues in their recent article entitled “Cholesterol catalyses Aβ42 aggregation through a heterogeneous nucleation pathway in the presence of lipid membranes” (Habchi et al., Nat. Chem. 2018 , 10, 673). In this article, the authors revealed the mechanism behind cholesterol‐catalyzed Aβ42 aggregation, providing the potential to address the molecular origins of AD, thereby opening a new avenue for effective AD therapy.     

Polypyridyl Ruthenium(II) Complexes with Red-Shifted Absorption: New Promises in Photodynamic Therapy

In the field of cancer photodynamic therapy (PDT) research, development of metal-based PDT drugs that can be used under red light exposure is the “holy grail” to achieve. This highlight highlighted few current literatures on polypyridyl-based Ru(II) complexes with significantly red-shifted absorption to achieve in-vitro and in-vivo PDT effect in 540–600 nm light. The enormous potential of judicial ligand choice and in-silico optimization to achieve the red light, metal-based PDT drugs are discussed.     

Recent Advances in the Design of Targeted Iridium(III) Photosensitizers for Photodynamic Therapy

Photodynamic therapy (PDT) is a noninvasive treatment for certain types of cancer, bacterial, fungal and viral infections, and skin diseases. In recent years, adaptation of this treatment so as to achieve more specific targeted cancer therapy in particular has attracted significant attention. We focus herein on the design of novel iridium‐based photosensitizers (PSs) with tunable photophysical and photobiological properties as efficient PDT agents. We highlight the ability of some Ir^III photosensitizers to target specific cellular components, including their activation by one‐ and two‐photon irradiation.