Green synthesis of zinc oxide nanoparticles using Amygdalus scoparia Spach stem bark extract and their applications as an alternative antimicrobial,anticancer, and anti-diabetic agent

For the first time in this study, Zinc oxide nanoparticles were biosynthesized by the eco-friendly and cost-effective procedure using Amygdalus scoparia stem bark extract then used as antibacterial, antifungal, anticancer, and anti-diabetic agents. The characterization techniques confirmed the biosynthesis, crystalline nature, structure, size, elemental composition of ZnO NPs and bioactive compounds that exist in A. scoparia extract accounting for Zn²⁺ ion reduction, capping and stabilization of ZnO NPs. The ZnO NPs displayed remarkable inhibitory activity against E. coli, E. aerigenes, S. aureus, P. oryzae, F. thapsinum, and F. semitectum compared to antibiotic standards. The ZnO NPs showed significant inhibitory effects on cancer cell lines, while it had no toxic effect on Vero normal cell line. The ZnO NPs (30 mg/kg)-treated diabetic rats showed significantly higher levels of insulin and lower AST, ALT and blood glucose compared with the STZ induced diabetic group and other treated groups (P < 0.05). The ZnO NPs- and extract-treated rats showed significantly higher levels of IR, GluT2, and GCK expression and lower TNFα expression compared with the STZ induced diabetic rats. Our findings showed that ZnO NPs represented an outstanding performance for biological applications.     

Temperature/pH/magnetic triple‐sensitive nanogel–hydrogel nanocomposite for release of anticancer drug

Hydrogels, nanogels and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for a long‐term drug release system. In this regard, the design and application of a nanocomposite hydrogel containing entrapped nanogel for drug delivery are demonstrated. To this aim, we first prepared an iron oxide nanocomposite nanogel based on poly(N‐isopropylacrylamide)‐co‐((2‐dimethylaminoethyl) methacrylate) (PNIPAM‐co‐PDMA) grafted onto sodium alginate (NaAlg) as a biocompatible polymer and iron oxide nanoparticles (ION) as nanometric base (PND/ION‐NG). This was then added into a solution of PDMA grafted onto NaAlg. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermal and magnetic responsivity was fabricated. The synthesized samples were fully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy‐dispersive X‐ray analysis, vibrating sample magnetometry and atomic force microscopy. A mechanism for the formation of PNIPAM‐co‐PDMA/NaAlg‐ION nanogel–PDMA/NaAlg‐ION hydrogel and PND/ION nanogel is suggested. Swelling capacity was measured at various temperatures (25 to 45 °C), pH values (from 2 to 11) and magnetic field and under load (0.3 psi) and the dependence of swelling properties of the nanogel–hydrogel nanocomposite on these factors was well demonstrated. The release rate of doxorubicin hydrochloride (DOX) as an anticancer drug was studied at different pH values and temperatures in the presence and absence of a magnetic field. The results showed that these factors have a high impact on drug release from this nanocomposite. The result showed that DOX release could be sustained for up to 12.5 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or nanogel alone (<1 day). The results indicated that the nanogel–hydrogel nanocomposite can serve as a novel nanocarrier for anticancer drug delivery. © 2019 Society of Chemical Industry     

An optimal procedure for minimizing total weighted resource tardiness penalty costs in the resource-constrained project scheduling problem

We present an optimal solution procedure for minimizing total weighted resource tardiness penalty costs in the resource-constrained project scheduling problem. In this problem, we assume the constrained renewable resources are limited to very expensive equipments and machines that are used in other projects and are not available in all periods of time of a project. In other words, for each resource, there is a dictated ready date as well as a due date such that no resource can be available before its ready date but the resources are permitted to be used after their due dates by paying penalty cost depending on the resource type. We also assume that only one unit of each resource type is available and no activity needs more than it for execution. The objective is to determine a schedule with minimal total weighted resource tardiness penalty costs. For this purpose, we present a branch-and-bound algorithm in which the branching scheme starts from a graph representing a set of conjunctions (the classical finish-start precedence constraints) and disjunctions (introduced by the resource constraints). In the search tree, each node is branched to two child nodes based on the two opposite directions of each undirected arc of disjunctions. Selection sequence of undirected arcs in the search tree affects the performance of the algorithm. Hence, we developed different rules for this issue and compare the performance of the algorithm under these rules using a randomly generated benchmark problem set.     

Preparation of AgO<Subscript>2</Subscript>/GrO nanocomposites by hydrothermal method and investigation of photoluminescence properties

This paper reports a novel processing route for producing AgO₂/GrO nanocomposites by hydrothermal method. AgO₂/GrO nanocomposites as semiconductor materials have been synthesized via a facile one-step process using AgNO₃ and glucose as starting reagents. We investigated the influence of the thermal decomposition temperature and reaction time, on the morphology and the particle size of AgO₂/GrO nanocomposites. The AgO₂/GrO nanocomposites were characterized by FT-IR, UV–Vis spectra, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. The obtained results exhibited that the synthesized nano product by calcining for 4 h showed excellent uniformity and quality.     

Synthesis and biodegradability assessment of poly(amide-imide)s containing N-trimellitylimido-l-amino acid and 5-(2-benzimidazole)-1,3-phenylenediamine

This paper addressed construction and biodegradability assessment of chiral synthetic poly(amide-imide)s (PAI)s. These polymers were prepared by polycondensation reaction of chiral diacids; N-trimellitylimido-S-valine (7a), and N-trimellitylimido-l-leucine (7b) with 5-(2-benzimidazole)-1,3-phenylenediamine (4) in the presence of tetrabutylammonium bromide as a green media under microwave irradiation. The morphology observations of the aforementioned polymers exhibit that these macromolecules are nanostructured particle and so, good candidate as carrier for biomedical application. Furthermore, in vitro toxicity and soil biodegradability test of the different synthetic diacids (7a, 7b) and the obtained PAIs were employed to evaluate the biological activity of these materials. In Petri plate technique, the monomers and obtained polymers exposed on glass lamels were all colonized by fungal saprophytes and due to this invasion, a weight loss up to 35 % was observed in the material. The soil burial test and measuring dehydrogenase activity revealed that the aforementioned monomers and polymers are biologically active and probably biodegradable under the soil. Normal wheat seedling growth took place in the vials containing the aforesaid monomers and polymers. It could be concluded that the synthesized monomers and their polymers are biologically active, and they are nontoxic to ecosystems and natural environments.     

The impact of baking conditions on physico-chemical characteristics influencing topography and appearance aspects of polyurethane coatings

The appearance aspects of an electrodeposited polyurethane-based coating as a function of baking condition were investigated. Specular gloss and color was measured as a mean to trace the changes of the surface topography due to baking conditions. Atomic force microscopy combined with FTIR spectroscopic investigations showed that the shrinkage occurred due to the high baking temperature results in surface roughness. Films baked at higher temperature form higher-T_g networks. The color was changed to yellow as the baking temperature was raised.     

Effect of light intensity and frequency of flashing light from blue light emitting diodes on astaxanthin production by Haematococcus pluvialis

Flashing light from blue light emitting diodes is an effective method for the reduction of energy consumption in the bioproduction of astaxanthin by Haematococcus pluvialis. We investigated the effects of light intensity and frequency on the final astaxanthin concentration in bioproduction by H. pluvialis grown mixotrophically. The final astaxanthin concentration under illumination with flashing light, with frequencies ranging from 25 to 200 Hz, was dependent on the light intensity and on the duty cycle and was equivalent, or higher, in comparison with that under illumination with continuous light at the same incident intensity. The light intensity determined the maximum attainable concentration of astaxanthin under continuous illumination. Under illumination with flashing light, the ratio of the final astaxanthin concentration to the maximum concentration at a specific light intensity was correlated to the duty cycle in the frequency range from 25 to 200 Hz. The effect of lower frequencies on enhanced astaxanthin production under flashing light was also studied; at levels as low as 1 Hz, higher final astaxanthin concentrations were observed under flashing light compared to concentrations attained under continuous light.     

The odontogenic differentiation of human dental pulp stem cells on hydroxyapatite-coated biodegradable nanofibrous scaffolds

The authors aimed to design nanofibrous (NF) scaffolds that facilitate odontogenic and osteogenic differentiation of human dental pulp-derived mesenchymal stem cells (DPSCs) in vitro. For this purpose, hydroxyapatite (HA)–loaded poly (L-lactic acid)/poly (?-caprolactone) (PLLA:PCL 2;1) blend NFs were prepared using the electrospinning method. Alizarin red activity and cell viability were evaluated by MTT assay, and SEM revealed the proliferation properties of NF scaffolds. QRT-PCR results demonstrated that HA-loaded PLLA/PCL can lead to osteoblast/odontoblast differentiation in DPSCs through the up-regulation of related genes, thus indicating that electrospun biodegradable PCL/PLA/HA has remarkable prospects as scaffolds for bone and tooth tissue engineering.