•In-situ synthesis of NiCoFe2O4 nanoparticles along with reduced graphene oxide.•The synthesis process results in the formation of RGO layers decorated with ferrite nanoparticles.•The composite shows ...shielding effectiveness value of 36.3 dB (~ 99.98% attenuation) dominated by absorption.•Shielding properties depends upon the concentration of RGO and synergy between the RGO and ferrite nanoparticles.
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With the rapid evolution of wireless communication technology, microwave absorbing materials having broad frequency bandwidth has been at center stage. Present article reports the direct facile method for synthesis of Ni0.5Co0.5Fe2O4 nanoparticles decorated reduced graphene oxide (RGO) nanocomposites (NG) by insitu genesis of Ni0.5Co0.5Fe2O4 nanoparticles in graphene oxide heterogeneous mixture, preceded by hydrazine reduction and calcination. Because of magnetic Ni0.5Co0.5Fe2O4 and dielectric reduced graphene oxide, the intercalated microstructure of NG nanocomposites shows increased shielding effectiveness due to absorption with major contribution from strong conduction loss, polarization effects, enhanced attenuation ability, eddy current losses and multiple scattering. Consequently, the shielding effectiveness of 36.3 dB (~99.98% attenuation of the electromagnetic wave) has been attained in 12.4–18 GHz for a corresponding thickness of 2 mm. The results indicates that the interface linkages and synergy among Ni0.5Co0.5Fe2O4 and RGO plays an important role in improvement of microwave absorbing properties and hence in designing of lightweight microwave absorbers.
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•Highly corrosion resistant conducting polymer composite coatings are fabricated.•Properties of conducting copolymers, chitosan and SiO2 nano particles are combined.•Prolong corrosion ...protection in presence of chloride containing electrolyte.•The film forming tendency of chitosan promotes the formation of a uniform coating.•The redox properties of conducting copolymer repassivate the porosities in coating.
Present study focuses on the development of composite coating for corrosion protection of mild steel in marine environment. In the present work, in-situ chemical oxidative polymerization process is employed to synthesize poly(aniline-anisidine)/chitosan/SiO2 composite in aqueous medium of chitosan. The synthesized copolymer composites were characterized by FTIR, XRD, TGA, and SEM. Corrosion resistant coatings were developed by loading of the copolymer composites in the epoxy resin. Electrochemical behavior of coatings was studied in 3.5% NaCl for a span of 20 days. The electrochemical measurements have clearly demonstrated excellent improvement in the corrosion resistant properties of the substrate after application of coatings. Salt spray test (as per ASTM B117 standards) revealed that the composite coatings can withstand under accelerated corrosion conditions of high salt content and humidity for prolong periods. The improved corrosion resistance of the composite coatings is attributed to the effective combination of fillers (SiO2 nanoparticles), biopolymer (chitosan) in conducting matrix (poly(aniline-anisidine)).
Polyaniline-graphite composites were prepared via in situ emulsion pathway, using different weight ratios of aniline to graphite. These composites were characterized for thermal, electrical, and ...spectral attributes. The thermal stability (~ 230°C) and electrical conductivity (67.9 S/cm) were improved significantly as compared with polyaniline doped with conventional inorganic dopants such as HCl (140°C and 10 S/cm). Scanning electron micrographs indicated a systematic change in morphology from globular to flaky with increasing amounts of graphite. The relative shifting of UV-visible bands indicates that some interactions exist between doped polyaniline and graphite. Absorption-dominated total electromagnetic interference shielding effectiveness of the order of -33.6 dB suggests that these materials can be used as futuristic microwave shielding materials. The good electrical conductivity and thermal stability make them ideal candidates for preparing conducting composites by melt blending with conventional thermoplastics such as polyethylene, polypropylene, and polystyrene, etc.
The hyperactivated Wnt/β-catenin signaling acts as a switch to induce epithelial to mesenchymal transition and promote colorectal cancer. However, due to its essential role in gut homeostasis, ...therapeutic targeting of this pathway has proven challenging. Additionally, IL-6/Stat-3 signaling, activated by microbial translocation through the dysregulated mucosal barrier in colon adenomas, facilitates the adenoma to adenocarcinomas transition. However, inter-dependence between these signaling pathways and key mucosal barrier components in regulating colon tumorigenesis and cancer progression remains unclear. In current study, we have discovered, using a comprehensive investigative regimen, a novel and tissue-specific role of claudin-3, a tight junction integral protein, in inhibiting colon cancer progression by serving as the common rheostat of Stat-3 and Wnt-signaling activation. Loss of claudin-3 also predicted poor patient survival. These findings however contrasted an upregulated claudin-3 expression in other cancer types and implicated role of the epigenetic regulation. Claudin-3-/- mice revealed dedifferentiated and leaky colonic epithelium, and developed invasive adenocarcinoma when subjected to colon cancer. Wnt-signaling hyperactivation, albeit in GSK-3β independent manner, differentiated colon cancer in claudin-3-/- mice versus WT-mice. Claudin-3 loss also upregulated the gp130/IL6/Stat3 signaling in colonic epithelium potentially assisted by infiltrating immune components. Genetic and pharmacological studies confirmed that claudin-3 loss induces Wnt/β-catenin activation, which is further exacerbated by Stat-3-activation and help promote colon cancer. Overall, these novel findings identify claudin-3 as a therapeutic target for inhibiting overactivation of Wnt-signaling to prevent CRC malignancy.
Herein, we developed a strategy for fabrication of iron oxide infiltrated vertically aligned multiwalled carbon nanotubes (MWCNT forest) sandwiched with reduced graphene oxide (rGO) sheets network ...for high performance electromagnetic interference (EMI) shielding application which offers a new avenue in this area. Such engineered sandwiched network exhibits enhanced shielding effectiveness compared to conventional EMI shielding materials. This network of exotic carbons demonstrates the shielding effectiveness value more than 37dB (>99.98% attenuation) in Ku-band (12.4–18GHz), which is greater than the recommended limit (∼30dB) for techno-commercial applications.
Inflammatory bowel disease (IBD) is a multifactorial disease. A breach in the mucosal barrier, otherwise known as "leaky gut," is alleged to promote mucosal inflammation by intensifying immune ...activation. However, interaction between the luminal antigen and mucosal immune system is necessary to maintain mucosal homeostasis. Furthermore, manipulations leading to deregulated gut permeability have resulted in susceptibility in mice to colitis as well as to creating adaptive immunity. These findings implicate a complex but dynamic association between mucosal permeability and immune homeostasis; however, they also emphasize that compromised gut permeability alone may not be sufficient to induce colitis. Emerging evidence further supports the role(s) of proteins associated with the mucosal barrier in epithelial injury and repair: manipulations of associated proteins also modified epithelial differentiation, proliferation, and apoptosis. Taken together, the role of gut permeability and proteins associated in regulating mucosal inflammatory diseases appears to be more complex than previously thought. Herein, we review outcomes from recent mouse models where gut permeability was altered by direct and indirect effects of manipulating mucosal barrier-associated proteins, to highlight the significance of mucosal permeability and the non-barrier-related roles of these proteins in regulating chronic mucosal inflammatory conditions.
Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Early diagnosis through effective screening programs is likely to improve vision outcomes. The ETDRS ...seven-standard-field 35-mm stereoscopic color retinal imaging (ETDRS) of the dilated eye is elaborate and requires mydriasis, and is unsuitable for screening. We evaluated an image analysis application for the automated diagnosis of DR from non-mydriatic single-field images. Patients suffering from diabetes for at least 5 years were included if they were 18 years or older. Patients already diagnosed with DR were excluded. Physiologic mydriasis was achieved by placing the subjects in a dark room. Images were captured using a Bosch Mobile Eye Care fundus camera. The images were analyzed by the Retinal Imaging Bosch DR Algorithm for the diagnosis of DR. All subjects also subsequently underwent pharmacological mydriasis and ETDRS imaging. Non-mydriatic and mydriatic images were read by ophthalmologists. The ETDRS readings were used as the gold standard for calculating the sensitivity and specificity for the software. 564 consecutive subjects (1128 eyes) were recruited from six centers in India. Each subject was evaluated at a single outpatient visit. Forty-four of 1128 images (3.9%) could not be read by the algorithm, and were categorized as inconclusive. In four subjects, neither eye provided an acceptable image: these four subjects were excluded from the analysis. This left 560 subjects for analysis (1084 eyes). The algorithm correctly diagnosed 531 of 560 cases. The sensitivity, specificity, and positive and negative predictive values were 91%, 97%, 94%, and 95% respectively. The Bosch DR Algorithm shows favorable sensitivity and specificity in diagnosing DR from non-mydriatic images, and can greatly simplify screening for DR. This also has major implications for telemedicine in the use of screening for retinopathy in patients with diabetes mellitus.
An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon fibers/ferrofluid (Fe
3
O
4
particles) composite sheets using novolac resin via compression molding for ...electromagnetic shielding applications. The optimized formulation has been achieved to get an excellent combination of thermal, mechanical, and electrical properties of the composite sheet. Structural and morphological studies were carried out by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Polypyrrole/carbon fibers composite sheets shows maximum flexural strength and a flexural modulus of 62.4 ± 1 MPa and 0.60 ± 0.02 GPa, respectively, with total shielding effectiveness of 22.8 dB in the Ku-band (12.4–18 GHz) but when ferrofluid is added to the polypyrrole/carbon fibers composite system, flexural strength increases to 92.3 ± 1 MPa and the same trend has been observed for flexural modulus with a value of 0.65 ± 0.04 GPa. This multiphase lightweight polypyrrole composite sheet having 34 vol.% of carbon fibers and 4 vol.% of Fe
3
O
4
nanoparticles offers total shielding effectiveness of 31.9 dB (>99.99% attenuation) in the Ku-band (12.4–18 GHz) frequency range with a thickness of ∼1.25 mm. This is accredited to high dielectric losses and magnetic losses in conducting composite sheets. The observed results suggest that lightweight compression molded polypyrrole composite sheets could be a potential commercial alternative for electromagnetic shielding applications.
Nanocomposite materials, based on commercial thermoplastic polyurethane filled with graphene, are new alternative candidates for electrostatic charge dissipation and electromagnetic interference ...shielding applications due to their light weight, ease of processing and tunable electrical conductivities. The solution blending approach was used to fabricate a series of polyurethane/graphene (PUG) nanocomposites with graphene loading ranging from 0–5.5 vol%. For the preparation of polymer nanocomposites, graphene was prepared by the successful oxidation of pristine graphite, followed by thermal exfoliation and reduction. The effect of graphene on the electrical properties of PUG nanocomposites was investigated to evaluate the potential of these nanocomposites as an effective and light weight electrostatic charge dissipative (ESD) and electromagnetic interference (EMI) shielding material in the frequency range of 8.2–12.4 GHz (X band). The suitability of the nanocomposites for ESD was examined by displaying the decay of the voltage as a function of time. The experimental results indicate that a static decay time of 0.49 s at 1.6 vol% graphene and an EMI shielding effectiveness of ∼−21 dB in the X-band for 3 mm thickness was achieved at 5.5 vol% graphene loading. In addition, the electromagnetic attributes, such as the real and imaginary permittivity of the composites as a function of frequency, were also investigated. Therefore, such polyurethane nanocomposites shall not only be useful for antistatic coatings but also have great potential as an effective and light weight shielding material for protection from electromagnetic radiation, in electromagnetic shielding bags for packaging of electronic circuits and in a variety of applications.
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