Magnetic Fe3O4@ polydopamine biopolymer: Synthesis,characterization and fabrication of promising nanocomposite

In this work, Functional Fe₃O₄@ polydopamine nanocomposite (Fe₃O₄@PDA) with magnetic response and special surface area were successfully assembled utilizing the strong coordination interactions between these two versatile materials. The morphology and size, crystal structure, specific saturation magnetization, chemical structure, and thermal properties were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD), vibration magnetometer (VSM), point of zero charge (pH_pzc), Fourier infrared (FT‐IR) and thermogravimetric analysis (TGA). The self‐polymerization of dopamine could be completed within 3 days, and Fe₃O₄ nanoparticles were embedded into PDA polymer. TGA results showed that PDA content of nanocomposite can be up to 51.7 wt% and also showed a significant decrease in the decomposition temperature of PDA from 530 to 270°C in the presence of the Fe₃O₄ nanoparticles. Through TGA analysis the coating thickness was estimated to be about 0.86 nm that it is well coincident with the measured values using TEM images and XRD analysis. At room temperature by vibrating sample magnetometer (VSM), Fe₃O₄ and Fe₃O₄@PDA exhibit superparamagnetic behavior with a saturation moment of 57.87 and 44.7 emu/g, respectively. Furthermore, PZC value reduced for Fe₃O₄@PDA compared with Fe₃O₄ nanoparticles and fell from 6.7 to 3.04. J. VINYL ADDIT. TECHNOL., 25:41–47, 2019. © 2018 Society of Plastics Engineers     

Taxonomic study of subfamily Nepetoideae (Lamiaceae) by polynomorphological approach

The present study is insight into pollen morphology for characterizing species and their utility in the taxonomic separation of certain taxa of subfamily Nepetoideae (Lamiaceae) from Pakistan. The pollen micromorphology of 11 species of the Nepetoideae was analyzed and documented using light microscopy and scanning electron microscopy (SEM) for both qualitative and quantitative characteristics. Most species have hexazonocolpate pollen grains but trizonocolpate and tetrazonocolpate pollen with circular and oval amb were also rarely observed in Mentha spicata. The basic pollen shape in most of the studied species was subspheroidal but prolate grains were also observed in M. spicata, S. coccinea, and S. plebeia. The exine sculpturing of Nepetoideae pollen was taxonomically very informative particularly at subfamily level. Observations of exine sculpturing with SEM revealed various types of pollen grains: reticulate, bireticulate, microreticulate, perforate, aerolate, and gammate. The bireticulate type further subdivided into three subtypes based on the number of secondary lumina in each primary lumen and is characterized by varying characteristics of the secondary reticulum and primary muri. A significant variation was observed in colpus surface ornamentation. The maximum polar diameter was found in O. americanum (58 ± 5.8 μm) and the maximum equatorial diameter observed in O. basilicum (50.25 ± 1.37 μm). Pollen features of the studied species were discussed and compared based on the current taxonomical concepts. The results showed that pollen traits of the subfamily Nepetoideae was found significant to classify the taxa. Furthermore, pollen features provide additional evidence to distinguish macromorphologically similar taxa from each other.     

Systematic approach to the correct identification of Asplenium dalhousiae (Aspleniaceae) with their medicinal uses

In present study, multiple microscope techniques were used for the systematics identification of the species Asplenium dalhousiae. The plant was collected from different phytogeographical and its natural habitat of Pakistan, where it shows higher diversity. Morphology, foliar epidermal anatomy, and spore morphological characters of the species were studied in detailed using multiple microscopic techniques through light microscopy (LM) and scanning electron microscopy (SEM). LM and SEM were used for the systematics identification of the species. Traditionally, the species is used in the ailment of many diseases, so the spore morphology, anatomical features, and morphological characters are relevant to describe the species taxonomy. The importance of multiple methods of taxonomic study (e.g., documentation and morphological characteristics) for characterizing herbs are important step in systematic certification to maintain the efficacy of herbal medicines. The aim of the present study is to examine the morphological, anatomical, and spore morphology of the species A. dalhousiae in more detailed for the correct taxonomic identification and their medicinal validation from Pakistan.     

Synthesis,characterization and use of iron oxide nano particles for antibacterial activity

In this decade, the use of nano particles (NPs) against bacterial growth is increasing day by day due to remarkable alternative properties compared to molecular antibiotics. Thus, the use of iron oxide nanoparticles (IONPs) has proven one of the most important transition metals oxide‐based remedy in nanotechnological advances and biological applications due to enriched biocompatibility of iron. In this study synthesis of IONPs was carried out via co‐precipitation method. The crystallographic morphology of the synthesized particles was studied via X‐ray diffraction which revealed cubic structure of the particles, whereas, the spinal shaped morphology of the prepared NPs was confirmed from scanning electron microscopy. Likewise, the presence of the major elements in the sample was determined through energy dispersive X‐ray analysis characterization. Bactericidal effect of the NPs was assessed at pre‐defined concentrations (50 and 100 μg/ml) against Gram +ve bacteria Staphylococcus aureus, Gram ?ve bacteria Shigella dysentry and Escherichia coli . Bacterial strains, which demonstrate the potential of NPs. The purpose of this study was assessing the structure of the synthesized NPs for protective effect against harmful bacterial activity.     

Finite element modelling the mechanical performance of pressure garments produced from elastic weft knitted fabrics

Compression garments mainly produced from elastic knitted fabrics have attracted many attentions due to their medical care performances. Components’ characteristics of the pressure garments such as yarn and fabric structure affect significantly the pressure applied on the human body. In this paper, it is aimed to simulate the effect of yarn’s mechanical properties as well as fabric structure on mechanical performance of the compression garment. For this purpose, a precise geometrical model for fabric structure is needed by which the pressure applied to the body could be predicted. Accordingly, double jersey knitted fabrics containing elastane weft yarns were produced on an electronic flat knitting machine and the fabric tensile properties were measured in course direction. Using equations governing the fabric structural unit-cell, a real geometric model was created in a finite element software environment. Considering the linear visco-elastic properties for elastane weft yarn, stress-strain curve was extracted. The results obtained from numerical simulation were compared with the experimental data in order to validate the proposed geometrical model. The findings demonstrate a good agreement between experimental and simulation results.     

Investigation of charge transport mechanism in semiconducting La<Subscript>0.5</Subscript>Ca<Subscript>0.5</Subscript>Mn<Subscript>0.5</Subscript>Fe<Subscript>0.5</Subscript>O<Subscript>3</Subscript> manganite prepared by sol–gel method

Here in, we report the charge transport mechanism in semiconducting La_0.5Ca_0.5Mn_0.5Fe_0.5O₃ (LCMFO) polycrystalline material synthesized via sol–gel auto combustion route. X-ray diffraction (XRD) analysis confirmed the orthorhombic phase of the prepared material. Temperature dependent resistivity and impedance spectroscopy measurements have been carried out to probe the dielectric and electrical conduction mechanism which revealed a change of Mott variable range to the small polaronic hopping conduction mechanism around 303 K. The complex impedance and modulus spectra undoubtedly showed the contribution of both grain and grain boundary effect on the conduction properties of LCMFO. An equivalent circuit [(R_gbQ_gb) (R_gQ_g)] model has been used to address the electrical parameters associated with the different phases (grains and grain boundaries) having different relaxation times. The values of resistances of two phases obtained after fitting the equivalent circuit in the nyquist plot have been analyzed which confirmed the change of conduction mechanism around 303 K. The resultant change in conduction mechanism is also supported by the conductivity plots.     

The Tunable Porous Structure of Gelatin–Bioglass Nanocomposite Scaffolds for Bone Tissue Engineering Applications: Physicochemical,Mechanical, and In Vitro Properties

Unidirectional freeze‐casting method is used to fabricate gelatin–bioglass nanoparticles (BGNPs) scaffolds. Transmission electron microscopy (TEM) images show that sol–gel prepared BGNPs are distributed throughout the scaffold with diameters of less than 10 nm. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetric are used to evaluate the physicochemical properties of BGNPs. Scanning electron microscopy (SEM) micrographs present an oriented porous structure and a homogeneous distribution of BGNPs in the gelatin matrix. The lamellar‐type structure indicates an improvement of mechanical strength and absorption capacity of the scaffolds. Increasing the concentration of BGNPs from 0 to 50 wt% have no noticeable effect on pore orientation, but decreases porosity and pore size distribution. Increase in BGNPs content improves the compressive strength. The absorption and biodegradation rate reduces with augmentation in BGNPs concentration. Bioactivity is evaluated through apatite formation after immersion of the nanocomposites in simulated body fluid and is verified by SEM–energy‐dispersive X‐ray spectroscopy (EDS), an element map analysis, X‐ray powder diffractometer, and FTIR spectrum. SEM images and methyl thiazolyl tetrazolium assay confirm the biocompatibility of scaffolds and the supportive behavior of nanocomposites in cellular spreading. The results show that gelatin–(30 wt%)bioglass nanocomposites have incipient physicochemical and biological properties.