Polymeric micro-and nanogels are defined by their water-swollen hydrophilic networks that can often impart outstanding biocompatibility and highcolloidal stability. Unfortunately, this highly hydrophilic nature limits their potential in areas where hydrophobic or amphiphilic interactions are required, for example, the delivery of hydrophobic cargoes or tailored interactions with amphipathic (bio-)surfaces. To overcome this limitation, amphiphilic microÀ/nanogels are emerging as new colloidal materials that combine properties from hydrogel networks with hydrophobic segments, known from solid hydrophobic polymer particles or micellar cores. The ability to accurately adjust the balance of hydrophobic and hydrophilic components in such amphiphilic colloidal systems enables new tailored properties. This opens up new applications ranging from the
Delivery systems that can encapsulate a precise amount of drug and offer a spatiotemporally controlled drug release are being actively sought for safe yet effective cancer therapy. Compared to polymer nanoparticle (NP)-based delivery systems that rely on physical drug encapsulation, NPs derived from stimuli-sensitive covalent polymer−drug conjugates (PDCs) have emerged as promising alternatives offering precise control over drug dosage and spatiotemporal drug release. Herein, we report a reduction-sensitive PDC "Dex-SS-PTXL" synthesized by conjugating dextran and paclitaxel (PTXL) through a disulfide bondbearing linker. The synthesized Dex-SS-PTXL PDC with a precise degree of substitution in terms of the percentage of repeat units of dextran covalently conjugated to PTXL (27 ± 0.6%) and the amount of drug carried by the PDC (39 ± 1.4 wt %) was found to self-assemble into spherical NPs with an average size of 110 ± 34 nm and a ζ-potential of −14.09 ± 8 mV. The reduction-sensitive Dex-SS-PTXL NPs were found to release PTXL exclusively in response to the reducing agent concentration reflective of the intracellular reducing environment of the tumor cells. Challenging BT-549 and MCF-7 cells with Dex-SS-PTXL NPs revealed significant cytotoxicity, while the IC 50 values and the mode of action (mitotic arrest) of Dex-SS-PTXL NPs were found to be comparable to those of free PTXL, highlighting the active nature of the intracellularly released drug. The developed PDC with its unique ability to self-assemble into NPs and stimuli-responsive drug release can enhance the success of the NP-based drug delivery systems during clinical translation.
In the current work, pure ZnO and Mn-doped ZnO nanoparticles were synthesized by the sol–gel autocombustion method. Structural analysis and phase determination were done by X-ray diffraction, and a hexagonal wurtzite structure was exhibited with disparate microstructures for all samples. Mn2+ ions were well composed, as evidenced by the fluctuation of lattice parameters, dislocation density, and lattice strain. Crystallite size decreases from 38.42 to 27.54 nm by increasing the doping concentration. Field emission scanning electron microscopy results shows the combination of evenly distributed spherical-like and hexagon-like structures. Fourier transform infrared spectra revealed that when Mn content increased, the absorption bands red-shifted. The drop in the energy band gap from 3.25 eV for ZnO to 2.99 eV for Zn0.96Mn0.04O was predicted by ultraviolet–visible absorption spectra. This red shift in the energy band gap can be explained by the sp–d exchange interaction between the band electrons of ZnO and localized d electrons of Mn. A study of magnetic properties revealed the change of the diamagnetic attribute for pure ZnO to the room-temperature ferromagnetic attribute of doped samples. In the current study, room-temperature ferromagnetism was achieved for Mn-doped ZnO nanoparticles, which can serve as a desirable option for practical applications in the future.
In current work, pure ZnO and Zn 0.96– x Cu 0.04 Co x O (0 ≤ x ≤ 0.05) nanoparticles were synthesized by the co-precipitation method. Structural analysis and phase determination of the formed nanoparticles was carried out using X-ray diffraction (XRD) and Williamson–Hall plots. The hexagonal wurtzite structure was manifested by all the samples with divergent microstructures. The change in lattice parameters, bond length, dislocation density, and lattice strain indicates that Cu and Co were successfully incorporated. Average crystallite size was found to be in the range of 32.16–45.42 nm for various doping concentrations. Field emission scanning electron microscopy results exhibited that the surface morphology is an amalgam of spherical-like and hexagon-like structures. Spherical-shaped grains were homogeneous and evenly distributed all over the structure. Fourier transform infrared spectra indicated that the absorption bands were blue-shifted with increasing Co concentration. The UV–visible absorption spectra showed high absorption in the UV region and weak absorption in the visible region. An increase in the energy band gap for the maximum absorption peak was observed from 3.49 eV for ZnO to 3.88 eV for Zn 0.91 Cu 0.04 Co 0.05 O. The Burstein–Moss effect explained the noticed blue shift in absorption spectra and energy band gaps. The vibrating sample magnetometer study revealed the change in the diamagnetic behavior of pure ZnO to the ferromagnetic behavior of the prepared nanoparticles at room temperature for different doping concentrations. In the current study, we have developed the room-temperature ferromagnetism (RTFM) for Cu and Co co-doped ZnO nanoparticles. Since RTFM is the key objective for dilute magnetic semiconductors, therefore it can be served as the desirable expectant for spintronics applications with improved functionalities and device concepts.
The impact of fish oil concentration on the oxidative stability of microcapsules through the spray drying process using chitosan and maltodextrin as wall material was studied. Emulsions were prepared with different Tuna fish oil (TFO) content (TFO-10%, TFO20%, TF030% TF0-40%) while wall material concentration was kept constant. Microencapsulated powder resulting from emulsion prepared with high fish oil load have high moisture content, wettability, total oil and low encapsulation efficiency, hygroscopicity and bulk tapped density. Oxidative stability was evaluated periodically by placing microcapsules at room temperature. Microcapsules prepared with TFO-10% presented high oxidative stability in terms of peroxide value (2.94±0.04) and anisidine value (1.54±0.02) after 30 days of storage. It was concluded that optimal amounts of fish oil for microencapsulation are 10% and 20% using chitosan and maltodextrin that extended its shelf life during study period.
Motile Aeromonas septicemia (MAS) is a common freshwater fish disease and major threat to the aquaculture in Pakistan. The present study was carried out on suspected fish samples to isolate and characterize local strains of Aeromonas hydrophila, a key pathogen responsible for the said disease in aquacultured fishes. A total of ninety suspected fish specimens were collected from fish farms in Kasur, Okara and Gujranwala districts of Punjab, Pakistan from June 2018 to April 2019. The specimens were processed and A. hydrophila strains were isolated. The primary identification of sixty seven isolates were verified by colony morphology, microscopy and phenotypic characterization with ten biochemical reactions. The A. hydrophila strains of test samples were molecularly characterized by polymerase chain reaction (PCR) using 16S rRNA at desired size of 356bp. The PCR amplified product was subjected to DNA sequencing and phylogenetic analysis showed homology with related strains of Aeromonas spp. By antibiotic sensitivity test, the isolates were checked for nine antibiotics in which the pathogen was sensitive to four and resistant to five drugs. Results of genetic analysis confirmed strains as A. hydrophila which are useful to take preventive measures against the said disease.
This research focuses on Timed-Arc Petri-netsbased agent communication in real-time multi-agent systems. The Agent Communication Language is a standard language for the agents to communicate. The objective is to combine Timed-Arc Petri-nets and FIPA Performatives in real-time multi-agent systems. FIPA standards provide a richer framework for the interaction of agents and makes it easier to develop a well-defined system. It also ensures the management by precisely specifying the agent's interaction. Though FIPA protocol has already been described with the help of Petri-nets but this specification lacks the timing aspect that is a dire need for real-time multi-agent systems. The main objective of this research is to provide a method of modeling existing FIPA performatives by combining Timed-Arc Petri-nets in real-time multi-agent systems. We have used properties, such as liveness, deadlock and reachability for the formal verification of the proposed modeling technique.
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