Search

In this research, a novel nanocarrier is synthesized based on tragacanth as a natural polysaccharide. For this purpose, carboxymethyl tragacanth (CMT) is first synthesized from tragacanth and then it is functionalized with isocyanate (IS) groups. In another parallel synthesis, magnetite nanoparticles (MNPs) are prepared by the co‐precipitation method and coated with SiO2 to form MNPs coated SiO2 (MNPs@SiO2). Then MNPs@SiO2 is reacted with CMT‐IS to form Fe3O4@SiO2/CMT. In the second step, the MNPs@SiO2/CMT surface is aminated by reaction with 3‐amino propyl triethoxy silane (APTES) and then it is reacted with folic acid (FA) as a targeting agent to form MNPs@SiO2/CMT/FA nanocarrier. The synthesized nanocarrier is characterized by FT‐IR, SEM, EDX, TEM, XRD, VSM, TGA, and zeta potential analysis and then it is loaded with doxorubicin (DOX) as a typical anti‐cancer drug. The in vitro drug release studies are carried out from the DOX‐loaded nanocarrier. The pH sensitivity of the DOX‐loaded nanocarrier is examined attwo different pHs. The effect of DOX‐loaded nanocarrier is investigated on MCF7 human breast cancer cells and the rate of cancer cell death is determined by MTT assay and drug IC50. The changes in the morphology of the tumor cell nuclei are observed using fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Polymer‐supported PdCu alloy nanoparticles with a palladium to copper atom ratio of 1 have been synthesized upon: (i) Coordination of palladium/copper acetate to 2,2'‐bipyridine‐end functionalized poly(lactic acid) (PLA); (ii) Stereocomplexation of PLA‐based macrocomplexes of opposite stereochemistry, and (iii) metal reduction with hydrogen. The obtained supported PdCu nanoparticles were successfully applied in the semi‐hydrogenation of industrially important alkynols, such as 3‐hexyn‐1‐ol and 2‐butyne‐1,4‐diol leading to the corresponding cis‐alkenol in high selectivity (98 %) under mild reaction conditions (i. e. ethanol, T (25 °C), p(H2)=3 bar) in the absence of any further additive. From a comparison of the catalytic performance of supported PdCu nanoparticles with those of Pd and Cu, located in the same chemical environment, emerged a clear alloy effect (i. e. high chemoselectivity for the alkene at high alkyne conversion). Recycling experiments conducted with the PdCu‐based catalyst proved the stability of the catalyst with time, even by its recovering in air atmosphere. [ABSTRACT FROM AUTHOR]

In the present research, a new nanocarrier for targeted drug delivery to tumor cells based on nanocrystalline cellulose (NCC) was synthesized. For this purpose, firstly, the NCC was prepared from microcrystalline cellulose by acidic hydrolysis and then it was modified by aminopropyl trimethoxy silane (APTMS) as a linker. The L‐cysteine was oxidized to form a disulfide bond and conjugated to modify NCC. Afterwards, the disulfide NCC was reacted with carboxymethyl‐β‐cyclodextrin (CM‐β‐CD) and finally, folic acid (FA) as a targeting agent was embedded into the CD cavity via host‐guest interactions for the synthesis of the NCC targeted nanocarrier. Doxorubicin (DOX) was loaded into nanocarrier spheres and the total release of the NCC targeted nanocarrier is about 71% at pH = 5, and about 48% at pH = 7.4 in 45 hours at 37 °C. In the presence of 10 mM DTT, most of the disulfide bonds are broken and the complex nanocarrier is destroyed, thus drug release increases and reaches 83%. The effect of the drugloaded nanocarrier was investigated on breast cancer cells (MCF7 cells). Characterization was performed using Fourier‐transform infrared spectroscopy (FT‐IR), Thermogravimetric analysis (TGA), Proton nuclear magnetic resonance (1H‐NMR), Scanning electron microscope (SEM), Energy dispersive X‐ray (EDX), and Ultraviolet‐visible spectrophotometry (UV‐Vis) analyses. [ABSTRACT FROM AUTHOR]

We propose a novel, canopy density estimation solution using a three‐dimensional (3D) ray cloud representation for perennial horticultural crops at the field scale. To attain high spatial and temporal fidelity in field conditions, we propose the application of continuous‐time 3D SLAM (simultaneous localization and mapping) to a spinning lidar payload (AgScan3D) mounted on a moving farm vehicle. The AgScan3D data are processed through a Continuous‐Time SLAM algorithm into a globally registered 3D ray cloud. The global ray cloud is a canonical data format (a digital twin) from which we can compare vineyard snapshots over multiple times within a season and across seasons. Then, the vineyard rows are automatically extracted from the ray cloud and a novel density calculation is performed to estimate the maximum likelihood canopy densities of the vineyard. This combination of digital twinning, together with the accurate extraction of canopy structure information, allows entire vineyards to be analyzed and compared, across the growing season and from year to year. The proposed method is evaluated both in simulation and field experiments. Field experiments were performed at four sites, which varied in vineyard structure and vine management, over two growing seasons and 64 data collection campaigns, resulting in a total traversal of 160 km, 42.4 scanned hectares of vines with a combined total of approximately 93,000 scanned vines. Our experiments show canopy density repeatability of 3.8% (relative root mean square error) per vineyard panel, for acquisition speeds of 5–6 km/h, and under half the standard deviation in estimated densities when compared with an industry standard gap‐fraction based solution. The code and field data sets are available at https://github.com/csiro-robotics/agscan3d. [ABSTRACT FROM AUTHOR]

New pyrazolo[4′,3′:5,6]pyrido[2,3‐d]pyrimidines, with an associated spiro‐3,3′‐oxindole attachment, were prepared by three‐component combinations of 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione with a pair of reactants chosen from a pyrazol‐5‐one, a pyrazole‐5‐amine, a barbituric acid, or a 6‐aminouracil. [ABSTRACT FROM AUTHOR]

In this study, a new nanocomposite was synthesized based on graphene‐oxide (GO) for the selective removal of Pb2+ ions from aqueous solutions. In the first step, the GO was synthesized from graphite. Then amino‐telechelic poly (hexamethylenediisocyanate‐co‐propylene glycol) (THMDI‐PG) was synthesized. Finally, The GO was reacted with the THMDI‐PG to obtain the final nanocomposite. The prepared nanocomposite was then used as the heavy metal ions adsorbent in Pb2+ and binary ionic metal media and showed a selective behavior toward the Pb2+ ions. The abundant oxygen‐containing groups on the surfaces of nanocomposite played an important role in Pb2+ ion adsorption on GO and the adsorption was dependent on pH values and independent of ionic strength. Different analysis such as Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy were carried out to characterize the prepared nanocomposite. Moreover, the effect of various adsorption parameters such as pH, adsorbent dose, adsorption time, temperature, agitation speed, and initial concentration of the ions were investigated and optimized. The obtained results showed an efficient performance of the prepared nanocomposite for the removal of the Pb2+ ions. POLYM. COMPOS., 40:730–737, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: The metal–organic frameworks (MOFs) M(BPZNO2) (M=Co, Cu, Zn; H2BPZNO2=3‐nitro‐4,4′‐bipyrazole) were prepared through solvothermal routes and were fully investigated in the solid state. They showed good thermal stability both under a N2 atmosphere and in air, with decomposition temperatures peaking up to 663 K for Zn(BPZNO2). Their crystal structure is characterized by 3D networks with square (M=Co, Zn) or rhombic (M=Cu) channels decorated by polar NO2 groups. As revealed by N2 adsorption at 77 K, they are micro‐mesoporous materials with BET specific surface areas ranging from 400 to 900 m2 g−1. Remarkably, under the mild conditions of 298 K and 1.2 bar, Zn(BPZNO2) adsorbs 21.8 wt % CO2 (4.95 mmol g−1). It shows a Henry CO2/N2 selectivity of 15 and an ideal adsorbed solution theory (IAST) selectivity of 12 at p=1 bar. As a CO2 adsorbent, this compound is the best‐performing MOF to date among those bearing a nitro group as a unique chemical tag. High‐resolution powder X‐ray diffraction at 298 K and different CO2 loadings revealed, for the first time in a NO2‐functionalized MOF, the insurgence of primary host–guest interactions involving the C(3)–NO2 moiety of the framework and the oxygen atoms of carbon dioxide, as confirmed by Grand Canonical Monte Carlo simulations. This interaction mode is markedly different from that observed in NH2‐functionalized MOFs, for which the carbon atom of CO2 is involved. [ABSTRACT FROM AUTHOR]

ABSTRACT In the present study, a new, green, and biodegradable molecularly imprinted polymer (MIP) based on modified cellulose is introduced for the drug furosemide. First, microcrystalline cellulose was converted into cellulose acrylate (CA). Then the prepared CA underwent self-crosslinking in the drug preassembly solution. The preassembly solution of the drug was also prepared using furosemide as the template molecule and acrylamide as the functional monomer in an aqueous medium. The results obtained from the binding and selectivity studies indicate the successful preparation of the CA-based MIP (CA-MIP) in aqueous solution. In the final step, an in vitro release study of furosemide from the synthesized polymers was carried out in a pH = 7.41 phosphate-buffered saline solution at 37 °C. The drug release profiles showed that the release rate of the CA-MIP is more controlled than that of the corresponding nonimprinted polymer, especially at the early stages of release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45581. [ABSTRACT FROM AUTHOR]

In the present study, a green and biodegradable molecularly imprinted polymer (MIP) based on cellulose is introduced for Furosemide drug for the first time. Firstly sodium carboxymethyl cellulose (CMC) was synthesized from microcrystalline cellulose. Then the prepared CMC underwent cross-linking in the drug pre-assembly solution using 2-hydroxyethyl methacrylate as the comonomer and ammonium peroxydisulfate as the CMC activating agent. The pre-assembly solution of the drug was also prepared using Furosemide as the template molecule and acrylamide as the functional monomer in aqueous medium. The obtained results from binding and selectivity studies indicated the successful preparation of the CMC-based MIP (CMC-MIP) in aqueous solution. Besides, structural, thermal, and morphological characterization of the prepared system was investigated. In the final step, the in vitro release study of Furosemide from the synthesized polymers was carried out in pH = 7.41 phosphate buffered saline solution at 37°C. According to the results, the CMC-MIP had a larger drug loading capacity and a higher amount of drug release at its equilibrium state compared to the corresponding non-imprinted polymer (CMC-NIP). Moreover, the drug release profiles showed that the drug release rate of the CMC-MIP is more controlled than that of the CMC-NIP, especially at the early stages of release. [ABSTRACT FROM AUTHOR]

Methoxy poly (ethylene glycol)/starch grafted copolymers (MPEG-g-S) were synthesized through bromoacetylation of potato starch followed by substitution of methoxy poly (ethylene glycol) (MPEG)with various MWs (MPEG-500, MPEG-2000, and MPEG-5000). Grafting was performed at 50°C. The structure of the copolymers was characterized by FTIR, DSC, Thermal Gravimetric Analysis (TGA), XRD, and AFM. Loading of ceftizoxime antibiotic was carried out on the prepared copolymers and in vitro drug released behavior was investigated in three different media (HCl solution: pH = 3 and buffer solutions: pH = 6 and pH = 8). [ABSTRACT FROM AUTHOR]

ABSTRACT In the present study, we synthesized a low-cost biodegradable hydrogel based on cellulose in order to perform controlled release of fertilizer. For this purpose, the cellulose was modified and crosslinked with urea. Then the prepared hydrogel underwent loading with the fertilizer in order to study the controlled release. Characterization of the samples was carried out by Fourier Transform Infrared (FT-IR) spectroscopy, elemental analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The hydrogel showed a good swelling behavior in distilled water, tap water, and 0.9% NaCl solution. Besides, water holding and water retention behavior of the hydrogel was investigated. Finally, the release of fertilizer from the loaded hydrogel was studied and showed excellent controlled release. According to the results, this hydrogel can be employed as a suitable moisture-holding additive in the soil for agricultural purposes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42935. [ABSTRACT FROM AUTHOR]

In this study, cellulose, a biodegradable polymer, was successfully aminated. For this purpose the cellulose was converted to a bromoacetylated derivative by reaction with bromoacetyl bromide. The resulting bromide derivative was then substituted with azido groups by reaction with sodium azide. Then the azido group was reduced to amines via the formation of the triphenylphosphinimine intermediate followed by hydrolysis using aqueous hydrazine. This sequence produced amino-cellulose. To gain a tumor-targeting doxorubicin (DOX) delivery system, we conjugated an active tumor-targeting ligand, folic acid, to the end of the resulting copolymer (FA-Amino-Cell). The structure of this copolymer was confirmed by FT-IR, UV-Vis, TGA, SEM, and 1H NMR spectroscopy. The SEM images showed that the hydrodynamic dimension of the resulted product is about 40 nm. Moreover, the Release profiles of DOX from the FA-Amino-Cell and its loading capacity were determined by UV-Vis absorption measurement at λmax 483 nm. The results showed that the DOX loaded copolymer had good control on the release period of DOX. So, it seems that the FA-Amino-Cell is a potential candidate for the targeted delivery of DOX for cancer treatment. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, we investigated some hydrogels based on natural, biodegradable, and biocompatible polysaccharides and cellulose, as sustained release carriers and evaluated their controlled drug release. The crosslinking of bromoacetylated cellulose with various aliphatic and aromatic diamines, such as ethylene diamine, hexamethylene diamine, and paraphenylene diamine, were carried out in N,N-dimethylformamide in the presence of triethylamine as a base. On the other hand, the synthesized hydrogels were characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and CHN elemental analysis. Also, the equilibrium swelling behavior of the hydrogels in water was calculated, and this indicated their sustained expansion. The loading of ceftizoxime antibiotic was carried out on the prepared hydrogels, and the in vitro and drug-release behaviors were investigated in three different media (HCl solution at pH 3 and bicarbonate buffer solutions at pH 6 and 8). Finally, the release profiles of ceftizoxime from the hydrogels and their loading capacities were determined by ultraviolet-visible absorption measurements at λmax 295 nm. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42568. [ABSTRACT FROM AUTHOR]

Synthesis and characterization of polyaniline-grafted poly(styrene- alt-maleic anhydride) (PANI- g-PSMA) was carried out to obtain conductive comb copolymers with highly improved processability. First, polyaniline (PANI) was prepared in nano-scale by chemical synthesis under ultrasonic irradiation. Then the poly(styrene- alt-maleic anhydride) (PSMA) was synthesized by free radical polymerization. Moreover, the PANI was grafted on the PSMA backbone to prepare a comb-like conductive copolymer for improving its processability as a new method. The products were characterized by Fourier transform infrared, ultraviolet-visible spectroscopy and X-ray diffraction patterns. Morphology of the samples was also investigated by scanning electron microscopy images. Finally, the solubility and conductivity of the products were studied, and it resulted in high solubility of the products in water and other common organic solvents in comparison to the pure PANI. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Novel polypyrrole/modified poly(styrene- alt-maleic anhydride) conducting nanocomposites were prepared via emulsion polymerization using sodium dodecyl sulfate as an emulsifier and ammonium persulfate as an oxidant. Modified poly(styrene- alt-maleic anhydride) was used as an external dopant for conductivity enhancement of polypyrrole. The conductivity of nanocomposites was measured with a four-probe method. The maximum electrical conductivity of the nanocomposite was 1.40 S/cm. The data from this research showed that the novel nanocomposite presents good tendency for the removal of heavy metal ions from aqueous solutions. Also the prepared nanocomposites were analyzed for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay. The results showed that the antioxidant activity of the nanocomposite was 60%. The nanocomposites were characterized by Fourier transform infrared, ultraviolet-visible, X -ray diffraction, field emission scanning electron microscopy, and differential scanning calorimetry measurements. POLYM. COMPOS., 36:138-144, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT Three-dimensional polymeric networks, which quickly swell by imbibing a large amount of water or deswell in response to changes in their external environment, are called hydrogels. These types of polymeric materials are good potential candidates for drug-delivery systems. In this study, we first synthesized poly(vinyl acetate- co-maleic anhydride) by free-radical copolymerization. Then, they were modified with different molar ratios of melamine to prepare hydrogels that could be used in drug-delivery systems. The hydrogels were characterized by Fourier transform infrared spectroscopy, 1H-NMR, differential scanning calorimetry, and scanning electron microscopy. In the second step, Ceftazidime antibiotic was loaded on selected hydrogels. The in vitro drug release was investigated and compared in three different media (HCl solution at pH = 3 and buffer solutions at pH 6.1and pH 8). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40389. [ABSTRACT FROM AUTHOR]

Novel composites containing very small quantities of functionalized multiwalled carbon nanotubes (MWCNTs-COOH; 0.025, 0.050, and 0.075 g), and furan were synthesized via in situ chemical oxidative polymerization. The polymerization was carried out in nitromethane at room temperature using anhydrous iron (III) chloride (FeCl3) as an oxidant. The nanocomposites were characterized by Fourier transform infrared, ultraviolet-visible, X-ray diffraction, differential scanning calorimetry, and field emission scanning electron microscopy. All synthesized composites were crystalline and showed good solubility in dimethyl sulfoxide and N-methyl 2-pyrrolidone. The conductivity of composites was measured with a four-probe method, and it was found that the electrical conductivity increased by increasing the amount of MWCNTs-COOH. The maximum electrical conductivity value (6.68 × 10−4 S cm−1) was obtained for polyfuran/MWCNTs-COOH (1:0.075, v/w). The resulting composites were analyzed for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay. The results showed that the antioxidant activity of the composites increased by increasing the amount of MWCNTs-COOH in nanocomposite. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Chelating resins have been considered to be suitable materials for the recovery of heavy metals in water treatments. A chelating resin based on modified poly(styrene- alt-maleic anhydride) with 2-aminopyridine was synthesized. This modified resin was further reacted with 1,2-diaminoethan or 1,3-diaminopropane in the presence of ultrasonic irradiation for the preparation of a tridimensional chelating resin on the nanoscale for the recovery of heavy metals from aqueous solutions. The adsorption behavior of Fe2+, Cu2+, Zn2+, and Pb2+ ions were investigated by the synthesis of chelating resins at various pH's. The prepared resins showed a good tendency for removing the selected metal ions from aqueous solution, even at acidic pH. Also, the prepared resins were examined for the removal of metal ions from industrial wastewater and were shown to be very efficient at adsorption in the cases of Cu2+, Fe2+, and Pb2+. However; the adsorption of Zn2+ was lower than those of the others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry analysis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

A chelating resin based on modified poly (styrene-alt-maleic anhydride) with 3-aminobenzoic acid was synthesized. This modified resin was further reacted by 1,2-diaminoethane or 1,3-diaminopropane in the presence of ultrasonic irradiation to prepare tridimensional chelating resin for the removal of heavy metal ions from aqueous solutions. The adsorption behavior of Fe(II), Cu(II), Zn(II) and Pb(II) ions was investigated by synthesized chelating resins in various pH. Among the synthesized resins, CSMA-AB1 and CSMA-AB2 demonstrated a high affinity for the selected metal ions compared to SMA-AB, and the order of removal percentage changes as follow: Fe(II) > Cu(II) > Zn(II) > Pb(II). The adsorption of all metal ions in acidic medium was moderate, and it was favored at the pH value of 6 and 7. Also, the prepared resins were examined for removal of metal ions from industrial wastewater and were shown to have a very efficient adsorption in the case of Cu(II), Fe(II) and Pb(II); however, the adsorption of Zn(II) was lower than others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis and thermogravimetric analysis/derivative thermogravimetry. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this article, we describe electrically conductive nanoblends containing poly(aniline- co-3- aminobenzoic acid) (PANABA), poly(styrene- alt-maleic acid) (PSMAC), and polystyrene. PANABA copolymers on a nanoscale were prepared under ultrasonic irradiation by the oxidative copolymerization of aniline and 3-aminobenzoic acid at different molar ratios. PSMAC was also prepared in our laboratory. The obtained conductive nanoblends formed films with good homogeneity and flexibility. The conductivity of the obtained nanoblends was measured with a four-probe method. The maximum electrical conductivity obtained was 0.60 S/cm. The characterization of the obtained copolymers and nanoblends was carried out by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and X-ray diffraction. Scanning electron microscopic images were taken from the obtained nanoblends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

A series of graft copolymers were synthesized based on ethylene-co-m,p-methylstyrene (EMS) (backbone copolymer), ethylene-1-hexene-m,p-methylstyrene (EHMS) (backbone terpolymer), and polyethylene glycol monomethyl ethers (PEGM) (grafts) in this study. The PEGMs with molecular weights of 750 and 2000 were used. The chemical composition of the graft copolymers was analyzed by NMR and DSC measurements. The graft copolymers exhibited a phase-separated morphology with the backbone and the methoxy polyethylene glycol (MPEG) grafts forming separate crystalline phases. The MPEG phase had a melting temperature lower than the corresponding MPEG homopolymer, as determined by DSC. The melting point of the crystalline phase formed by the EMS and EHMS main chains was lower than that of pure polymer backbone. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]