Synthesis and Characterization of Novel Polyvinylether Polymers Produced Using Carbocationic Polymerization

Using carbocationic polymerization, a series of novel polyvinylether polymers and copolymers were synthesized and characterized. A series of polysiloxane copolymers containing polymer grafts possessing Triclosan moieties (PTVE) were synthesized using living carbocationic polymerization followed by hydrosilylation and investigated for potential application as environmental friendly coatings to control biofouling on marine vessels and biomedical devices. Copolymers possessing a relatively low molecular weight polysiloxane backbone and relatively high PTVE content exhibited very high reductions in biofilm retention for S. epidermidis and moderate reductions for C. lytica and C. albicans. In the second example, a novel monoallyl-functional initiator that was capable of producing very fast initiation of the living carbocationic polymerization of chloroethyl vinyl ether was synthesized and characterized. The monoallyl-functional polymers were used to produce a series of block copolymers containing blocks of polyquaternary ammonium compounds and polydimethylsiloxane (PDMS-b-PCVE-b-PQ) using hydrosilylation followed by quaternization with an n-alkyldimethyl amine. The PDMS-bPCVE-b-PQ copolymers in solution showed very high antimicrobial activity toward E. coli and S. aureus when the n-alkyl chains attached to the nitrogens of the quaternary ammonium compounds are consisted of 12 - 14 carbons and 14 - 16 carbons, respectively. In the third example, a novel, highly brominated polymer was synthesized from pentabromo-6-ethoxybenzene vinyl ether (BrVE) using cationic polymerization. The thermal and rheological properties of the polyBrVE (PBrVE) were compared to a commercially available oligomeric brominated flame retardant, poly(pentabromobenzyl acrylate) (PBrBA). In addition, polymer blends based on polybutylene terephthalate (PBT) were prepared with the two brominated polymers and the thermal stability, mechanical, and rheological properties compared. The use of PBrVE resulted in lower melt viscosity and better compatibility in blends with PBT which would be expected to provide enhanced processability with regard to creating injection molded parts with relatively thin walls, such as those encountered in the electronics industry. Finally, a process was developed to obtain vinyl ether-functional monomers containing fatty acid pendent groups directly from soybean oil (SBO) using base-catalyzed transesterification. Moreover, a carbocationic polymerization process was developed for the vinyl ether monomers that allowed for high molecular weight polymers to be produced. Compared to SBO, which possesses on average 4.5 vinyl groups per molecule, the polyvinylethers based on the soybean oil-derived vinyl ether monomers (polyVESFA) can possess tens to hundredss of vinyl groups per molecule depending on the polymer molecular weight produced. As a result of this difference, coatings based on polyVESF A were shown to possess much higher crosslink density at a given degree of functional group conversion compared to analogs based on conventional SBO. In addition, the dramatically higher number of functional groups per molecule associated with polyVESF A results in gel-points being reached at much lower functional group conversion, which was shown to dramatically reduce cure-time compared to SBO based analogs

Quantification of rutin in rats brain by UHPLC/ESI-Q-TOF-MS/MS after intranasal administration of rutin loaded chitosan nanoparticles

Rutin (RT), an antioxidant drug, has been utilized to treat cerebral ischemia hence a sensitive quantification method for estimation of RT in brain homogenate is necessary to develop. This study aims to prepare RT loaded Chitosan Nanoparticles (RT-CS-NPs) develop and validate ultra-high performance liquid chromatography-electrospray ionization-synapt mass spectrometric method Synapt Mass Spectrometry (Synapt MS) (UHPLC/ESI-QTOF-MS/MS) for quantification of RT in brain homogenate from Wistar rat. The process of chromatographic separation was carried out on Waters ACQUITY UPLC™ with the components of separation in detail as; column: BEH C-18 with dimension as 2.1 mm×100 mm and particle size 1.7 µm, mobile phase: acetonitrile (85 % v/v/v): 2 mM ammonium formate (15 % v/v/v): formic acid (0.1 % v/v/v) and flow rate: 0.25 mL/min. Liquid-liquid extraction method (LLE), in mixture, i.e. ethyl acetate:acetonitrile, was considered to optimize the recovery of analyte from the brain homogenate of Wistar rat. Over a total run time of 5 minutes, the elution time for RT and internal standard (IS), i.e. Tolbutamide, observed was 2.67 and 2.82 min respectively whereas the transition observed for RT and IS was at m/z 611.1023/303.1071 and 271.1263/155.1073, respectively. Results, regarding various processes and parameters studied for RT as summarized, established a linear dynamic range over a concentration range of 1.00 ng/mL - 1000.0 ng/mL with r2; 0.9991±0.0010. Accuracy for intra and inter-assay in terms of % CV revealed a range of 0.45- 2.11 whereas lower limit of detection (LOD) and quantitation (LOQ) observed was 0.09 ng/mL and 0.142 ng/mL, respectively. The analyte stability as well as method specificity and accuracy, i.e. recovery > 86 %, supports the idea for application of current developed method in order to quantify and evaluate the RT-loaded-CS-NPs for RT determination in brain homogenate after intranasal drug delivery

Neuroprotective Effect of Fisetin Through Suppression of IL-1R/TLR Axis and Apoptosis in Pentylenetetrazole-Induced Kindling in Mice

Epilepsy is a complex neurological disorder, characterized by frequent electrical activity in brain regions. Inflammation and apoptosis cascade activation are serious neurological sequelae during seizures. Fisetin (3, 3′,4′,7-tetrahydroxyflavone), a flavonoid molecule, is considered for its effective anti-inflammatory and anti-apoptotic properties. This study investigated the neuroprotective effect of fisetin on experimental epilepsy. For acute studies, increasing current electroshock (ICES) and pentylenetetrazole (PTZ)-induced seizure tests were performed to evaluate the antiseizure activity of fisetin. For the chronic study, the kindling model was established by the administration of PTZ in subconvulsive dose (25 mg/kg, i.p.). Mice were treated with fisetin (5, 10, and 20 mg/kg, p.o.) to study its probable antiseizure mechanism. The kindled mice were evaluated for seizure scores. Their hippocampus and cortex were assessed for neuronal damage, inflammation, and apoptosis. Histological alterations were observed in the hippocampus of the experimental mice. Levels of high mobility group box 1 (HMGB1), Toll-like receptor-4 (TLR-4), interleukin-1 receptor 1 (IL-1R1), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were assessed in the hippocampus and cortex by ELISA. The immunoreactivity and mRNA expressions of nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), cytochrome C, and caspase-3 were quantified by immunohistochemical analysis and real-time PCR. Phosphorylation ELISA was performed to evaluate AkT/mTOR (mammalian target of rapamycin) activation in the hippocampus and cortex of the kindled mice. The results showed that fisetin administration increased the seizure threshold current (STC) in the ICES test. In PTZ-induced seizures, fisetin administration increased the latency for myoclonic jerks (MJs) and generalized seizures (GSs). In the PTZ-induced kindling model, fisetin administration dose-dependently suppressed the development of kindling and the associated neuronal damage in the experimental mice. Further, fisetin administration ameliorated kindling-induced neuroinflammation as evident from decreased levels of HMGB1, TLR-4, IL-1R1, IL-1β, IL-6, and TNF-α in the hippocampus and cortex of the kindled mice. Also, the immunoreactivity and mRNA expressions of inflammatory molecules, NF-κB, and COX-2 were decreased with fisetin administration in the kindled animals. Decreased phosphorylation of the AkT/mTOR pathway was reported with fisetin administration in the hippocampus and cortex of the kindled mice. The immunoreactivity and mRNA expressions of apoptotic molecules, cytochrome C, and caspase-3 were attenuated upon fisetin administration. The findings suggest that fisetin shows a neuroprotective effect by suppressing the release of inflammatory and apoptosis molecules and attenuating histological alterations during experimental epilepsy.</jats:p

Preliminary Evaluation of Morphological and Pomological Characters to Illustrate Genetic Diversity of Apricots (Prunus armeniaca L.) in Afghanistan

Afghanistan assumed to be a part of the diversity center of Central Asian group of apricots but due to lack of proper collection, precise detection and documentation of distinct variability, the apricot diversity in the country is under unknown and unprecedented threat. This study, therefore, was run in Badam-Bagh research station for two consecutive seasons (2016-2017) to assess 28 various characters of 20 native Afghan apricot accessions. Results showed a high variability among studied genotypes. Leaf and fruit characteristics such as leaf blade length, leaf blade width, fruit weight, kernel weight, mesocarp percentage, kernel bitterness and fruit quality like total soluble solids, pH, and titratable acidity, skin color and fruit shape which subsequently determines customer appeal and marketability, displayed huge variation. Based on fruit weight, there were two groups of apricot genotypes; small fruits (&lt;37 g) and large fruits (&gt;37 g). Accessions with large fruits embrace: “Amiri”, “Bid-Mushk”, “Hassan-Khili”, “Jibraelli”, “Koorpa”, “Qandak”, “Pir-Naqshi”, “Seyed-Abadi”, “Salari-Sorkh”, and “Saqi”. Most genotypes were early flowering and intermediately ripening in nature. Kernels of only “Walayati” accession had strong bitterness and remained were sweet-kernelled. The mesocarps of most accessions were very weakly adhered to stones. PCA showed 86.15% of total variance among genotypes to be due to first seven components. UPGMA cluster analysis separated 20 accessions into 2 main groups (13 accessions in the first and 7 accessions in the second groups). The results exhibited that morphological characters of leaf and fruit and pomological characters are of immense importance in fast and easy description of apricot genotypes. This is per se the first study on genetic diversity of apricot accessions performed in Afghanistan. The results would provide opportunity for apricot breeders to select accessions with elite and premium characters in terms of marketability and adaptability for particular growing sites.</jats:p

Effect of IBA, NAA and their Combination on Rooting and Biochemical Parameters of Stem Cuttings in Barbados Cherry

An investigation was to assess the influence of growth regulators IBA, NAA and their combination on rooting and biochemical parameters of stem cuttings in Barbados cherry. It was observed that, the least number of days (21.33) taken for root initiation, maximum percentage of rooting (80.00) was observed in cutting treated with IBA 5000 ppm followed by IBA 4500 ppm over other treatments. Significantly highest Chlorophyll-a (1.26), Chlorophyll –b (0.55) and total chlorophyll content (1.82 mg/g of fresh weight) of leaves and C : N ratio (8.74) was observed in cuttings treated with IBA 5000 ppm followed by IBA 4500 ppm over all other treatments.</jats:p