A Brief Overview on Ferrite (Fe3O4) Based Polymeric Nanocomposites: Recent Developments and Challenges

In this article, we have mainly discussed about ferrite (Fe3O4) and its polymer based nanocomposites. Ferrite particles have become an important research material because of their vast applications in the field of biotechnology, magnetic resonance imaging (MRI), and data storage. It has been observed that ferrite Fe3O4 particles show best performance for size less than 10-30 nm. This happens due to the super paramagnetic nature of such particles. In super paramagnetic range these particles exhibit zero remanence or coercivity. Therefore, various properties of ferrite (Fe3O4) nanoparticles and its polymer nanocomposites are very much dependent on the size, and distribution of the particles in the polymeric matrix. Moreover, it has been also observed that the shape of the nanocrystals plays important role in the determination of their fundamental properties. These particles show instability over longer times due to the formation of agglomerates generated by high surface energies. Therefore, protection strategies such as grafting and coatings with silica/carbon or polymers have been developed to stabilize them chemically. Recently, silylation technique is mainly used for the modification of nanoparticles. Experimentally, it has been observed that nanocomposites composed of polymer matrices and ferrite showed substantial improvements in stiffness, fracture toughness, sensing ability (magnetic as well as electric), impact energy absorption, and electro-catalytic activities to bio-species

Butyl Rubber-Nylon Composites with Improved Flame Retardancy & Gas Impermeability

Butyl rubber, because of its high packing density and chemical structure is inherently impermeable to air and gases. However, the elastomer is highly flammable owing to its neat carbon-hydrogen backbone structure. The particular rubber is extensively being used as coating materials for nylon, cotton, polyester etc., for development of clothing outfits for service personnel working in hazardous chemical environments . It is, therefore , essential to evolve flame retardant butyl rubber compositions which could make such clothings impermeable to chemical agents having adequate flame retardancy.The present paper describes an attempt towards using various chemical additives viz. brominated phenyl ethers, chlorinated paraffin, various inorganic oxides and halogenated elastomer, either singly or in combinations as potential flame retardants in bromo-butyl rubber compositions. The cements were then prepared by adding toluene to these compositions (20 to 30% solid content). The homogenised cements were then applied on both sides of nylon fabric with varying add -on concentrations in a laboratory coating machine with doctors blade specially designed for this purpose. The coated fabrics were cured at different temperatures in step curing between 70-150°C, tested for impermeability against hazardous warfare agents and found to offer enhanced protection against these chemicals . Standard test methods e.g. (a) exposure of the fabric to direct flame as per BS method 3119 (b) limited oxygen index as per ASTM specification D-2663 were followed in the evaluation of flame retardancy. The fabrics showed no after glow- low after flame (2.5 sec. against 6 sec. specified)and 7.2 cm char length against 12 cm max. permissible value. The hysicomechanical' properties e.g., breaking and tensile strengths were determined . Morphology and rubber fabric adhesion were studied using Scanning Electron Microscopy

Lignin Reinforced Rubber Composites

Lignin is the country's second most abundant renewable biomass resource next to cellulose. The pulp and paper industries produce very large quantities of lignin, most of those are burned to recover energy, pulping chemicals, enzymatic or acid hydrolysis to sugars followed by fermentation to alcohols. Another emerging technology where the lignin being used is in the adhesives and asphalts. For the former, lignin partly replaces phenol in phenol-formaldehyde formulations, for the latter lignin is used as an extender. Lignin in polyurethanes is for good mechanical properties and reactions of lignin such as grafting and crosslinking agent are also well known. Novolak-hexamine based phenolic resins are commonly used as reinforcing and processing aids in nitrile rubber (NBR) compounds. Not only the oil and petrol resistances increase significantly , resin loading is also found to offer better heat resistant properties than carbon blacks. For seals, valves and gasket applications addition of phenolic resins provides superior abrasion resistance, ageing and negligible hardening effects at elevated temperatures. Poor tackiness of NBR compounds can easily be eliminated by using phenolic resin in place of carbon black. The study presented here is to explore the possibility of employing lignin into some value -added rubber based composites . Lignin, gymnosperms, angiosperms and glass varieties, contain alcohol and phenolic groups and also double bonds in their structural moiety and therefore, could resinify into prepolymer in presence of hexamine.Varied proportions of lignin upto 50 parts with respect to total rubber plus hexamine,have been incorporated in medium acrylonitrile (37%) NBR and studied for their processing characteristics and physico-mechanical properties e.g. reinforcement, oil and fuel resistances, ageing and thermal stability. Efficacy of lignin has been found to be superior to either phenolic resin-hexamine or carbon black filled compounds. Finally, attempt has also been made to modify the surface chemistry incorporating CO,> C=O etc. groups by additions of dicumyl peroxide and this modified lignin was found to offer improved rubber-filler adhesion, tackiness and physical properties

Therapeutic efficacy of a novel βIII/βIV-tubulin inhibitor (VERU-111) in pancreatic cancer

Background: The management of pancreatic cancer (PanCa) is exceptionally difficult due to poor response to available therapeutic modalities. Tubulins play a major role in cell dynamics, thus are important molecular targets for cancer therapy. Among various tubulins, βIII and βIV-tubulin isoforms have been primarily implicated in PanCa progression, metastasis and chemo-resistance. However, specific inhibitors of these isoforms that have potent anti-cancer activity with low toxicity are not readily available. Methods: We determined anti-cancer molecular mechanisms and therapeutic efficacy of a novel small molecule inhibitor (VERU-111) using in vitro (MTS, wound healing, Boyden chamber and real-time xCELLigence assays) and in vivo (xenograft studies) models of PanCa. The effects of VERU-111 treatment on the expression of β-tubulin isoforms, apoptosis, cancer markers and microRNAs were determined by Western blot, immunohistochemistry (IHC), confocal microscopy, qRT-PCR and in situ hybridization (ISH) analyses. Results: We have identified a novel small molecule inhibitor (VERU-111), which preferentially represses clinically important, βIII and βIV tubulin isoforms via restoring the expression of miR-200c. As a result, VERU-111 efficiently inhibited tumorigenic and metastatic characteristics of PanCa cells. VERU-111 arrested the cell cycle in the G2/M phase and induced apoptosis in PanCa cell lines via modulation of cell cycle regulatory (Cdc2, Cdc25c, and Cyclin B1) and apoptosis - associated (Bax, Bad, Bcl-2, and Bcl-xl) proteins. VERU-111 treatment also inhibited tumor growth (P \u3c 0.01) in a PanCa xenograft mouse model. Conclusions: This study has identified an inhibitor of βIII/βIV tubulins, which appears to have excellent potential as monotherapy or in combination with conventional therapeutic regimens for PanCa treatment

VERU-111 suppresses tumor growth and metastatic phenotypes of cervical cancer cells through the activation of p53 signaling pathway

In this study, we investigated the therapeutic efficacy of VERU-111 in vitro and in vivo model systems of cervical cancer. VERU-111 treatment inhibited cell proliferation and, clonogenic potential, induce accumulation of p53 and down regulated the expression of HPV E6/E7 expression in cervical cancer cells. In addition, VERU-111 treatment also decreased the expression of phosphorylation of Jak2 (TyR1007/1008) and STAT3 at Tyr705 and Ser727. VERU-111 treatment arrested cell cycle in the G2/M phase and modulated cell cycle regulatory proteins (cyclin B1, p21 p34cdc2 and pcdk1). Moreover, VERU-111 treatment induced apoptosis and modulated the expression of Bid, Bcl-xl, Survivin, Bax, Bcl2 and cleavage in PARP. In functional assays, VERU-111 markedly reduced the tumorigenic, migratory, and invasive potential of cervical cancer cells via modulations of MMPs. VERU-111 treatment also showed significant (P\u3c0.05) inhibition of orthotopic xenograft tumor growth in athymic nude mice. Taken together, our results demonstrate the potential anti-cancer efficacy of VERU-111 in in vitro and in vivo. VERU-111 can be explored as a potent therapeutic agent for the treatment of cervical cancer