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The ZnSO4 doped CeO2 nanoparticles were successfully synthesized by chemical precipitation method and then subjected to structural, optical, and antibacterial activity characterization studies. The powder XRD, scanning electron microscopy, EDAX, FTIR spectroscopy, UV–Visible and Photoluminescence (PL) studies were carried out for the synthesized nano-powders. The XRD analysis reveals the face centered cubic (FCC) structure of the nanoparticles. The spectra of FTIR analysis clearly show seven intense bands confirming the existence of CeO2 phase. Optical activity of the grown nanoparticles was measured through UV–Visible spectrophotometer which shows strong UV absorption from 200 to 800 nm. From the optical spectrum, band value has been calculated using tauc’s plot method. The PL spectrum confirms the optical emission behavior of the synthesized nanoparticles. The samples were tested against two pathogenic bacteria of S. aureus (gram positive) and P. aeruginosa (gram negative) for antibacterial activity analysis. The ZnSO4 doped CeO2 nanoparticles show a good antibacterial activity.

The study was conducted to investigate the effects of foliar-intervention of nano-TiO2 on Cd toxicity in cowpea plants. Cowpea plants were exposed to Cd toxicity at 10 mg/kg soil for 21 days and afterwards, subjected to six episodes of foliar application of nano-TiO2 intervention. Results showed that foliar-applied nano-TiO2 significantly promoted chlorophyll b and total chlorophyll contents after Cd stress as compared to Cd-stressed plants without the intervention. Interestingly, Cd contents of roots, shoots and grains were significantly reduced (p

Oil must be transported by a network of pipelines, laid over various harsh environments. Microbial invasion is more challenging in oil and gas/biofuel pipelines and storage tanks carbon steel (CS). The surfaces of pipeline colonize with the biofilm and form the complex microbial structure which breaks down even the heavy-walled CS pipes, resulting in leaks and catastrophic pipeline failure. Among the various microorganisms, sulfate reducing bacteria (SRB) is the most abundant bacterial species that cause internal corrosion of the pipelines. In the present study, Cu, Zn single layer and Cu-Ni, Zn-Ni and Cu-Zn-Ni coatings were developed by electroless plating and studied their antibacterial effect using SRB which is isolated from diesel garage. For bacterial analysis, total viable count (TVC) and epifluorescence microscope analysis were studied.

This paper presents a method for enhancing the corrosion resistance of reinforcements through nanophase modification of fly ash concrete. A combination of natural and accelerated corrosion tests were performed to evaluate the corrosion resistance of reinforcements. The tests were conducted on four types of fly ash concrete specimens with and without nanoparticles designated as fly ash concrete with 40 wt% fly ash (FA), fly ash concrete with 2 wt% nano-CaCO3 (FAC), fly ash concrete with 2 wt% nano-TiO2 (FAT) and fly ash concrete with 1 wt% nano-CaCO3 and 1 wt% nano-TiO2 (FATC). Electrochemical measurements showed that reinforcements in nano-CaCO3 modified fly ash concrete (FAC) exhibited noble potential value, high polarization resistance and lower corrosion rate. Impressed voltage test also corroborate the enhanced corrosion resistance of FAC specimens, which was evident from the longer crack initiation time with minimum anodic current as compared to fly ash concrete without nano additives. Corrosion products of cover concrete showed a comparatively lesser amount of detrimental phases like lepidocrocite and goethite which was in agreement with the corrosion results. The least depth of chloride ion penetration indicated the effective plugging of pores by nano-CaCO3 particles that prevent diffusion and movement of chloride ions to surface of the rebar and thereby maintaining the passivity of the thin iron oxide layer around the steel rebar.

Surface coating with superior corrosion resistance properties is indispensable for biomedical implant industries to reduce the cytotoxicity related problems. In this work, microstructure, biocorrosion and biological properties of magnetron sputtered TiC and ZrC coatings on type 316L stainless steel (SS) substrates are studied for biomedical applications. Biocorrosion properties have been examined in the Artificial Blood Plasma (ABP) solution with 1% and 10% of H2O2 to study the corrosion behavior of carbides coated 316L SS. The formation of strong oxide passive layers on ceramic carbide coated substrates could enhance the corrosion resistance properties than uncoated SS substrates. The whole blood protein adsorption behavior of carbides coated and uncoated SS substrates are studied and the bacterial adhesion behavior is measured with Pseudomonas aeruginosa (P.aeruginosa) pathogen. The results revealed that the coatings possess higher protein adsorption and lower bacterial adhesion than that of bare steel substrates. In addition, Alizarin red based assay is done to confirm the biomineralization (calcium precipitation) of osteoblast like cells onto test samples and the results showed that TiC and ZrC coatings could enhance the biomineralization process.

Surface tailoring of titanium (Ti) implant is an effective way to prevent the initial bacterial adhesion and to improve the biocompatibility of the implants. In view of that, single layered silver (Ag)-ceria stabilized zirconia (CeSZ) nanocomposite coatings were developed on titanium substrates by co-evaporation method using electron beam physical vapor deposition (EBPVD) technique. The concentration of silver was varied from 0, 5 and 10 weight percentage and their microstructure, morphology, bacterial adhesion and corrosion properties were analyzed. Silver-ceria stabilized zirconia nanocomposite coatings have shown superior corrosion resistance than uncoated Ti substrate. Antibacterial efficiency of the coated and uncoated Ti substrates were evaluated using E. coli bacterial strain. Cytotoxic behavior of silver doped and undoped CeSZ coating was carried out in 3T3 mouse fibroblast cells. Electrochemical impedance spectroscopy (EIS) analysis indicated that higher corrosion resistance was observed in 5 wt% Ag added CeSZ nanocomposite coating system than other coated and uncoated substrates.

Numerous metallic implant materials have been used to replace various damaged or missed part of the body due to its strength, wear resistance and moderate corrosion resistant properties. However, the ideal implant characteristics such as bioactivity, hemocompatibility, corrosion resistance, mechanical strength, antimicrobial activity, etc are not usually achieved in single metallic implant materials. Hence, the surface tailored ceramics coating onto metallic materials will be a suitable choice to obtain the above ideal biomaterials characteristic properties in a single system. Different phases of zirconia ( m -ZrO 2 , t -ZrO 2 and c -ZrO 2 ) were deposited onto 316L SS substrate by electron beam physical vapor deposition (EBPVD) method. The microstructure and surface topography was analyzed by X-ray diffraction and atomic force microscopy (AFM) respectively. Further, bacterial invasion analysis by total viable count (TVC) and the results showed that different ZrO 2 coating effectively protected the bacterial invasion. Hemolysis behavior was studies and it did not express any hemolytic nature against the test samples. Furthermore, electrochemical behavior of the samples was examined in presence of goat whole blood as electrolyte solution. The EIS results divulged that the coated materials ( m -ZrO 2 , t -ZrO 2 and c -ZrO 2 ) showed higher corrosion resistance nature than that of bare 316L SS substrate. Hence, the overall result\s reveal that ZrO2 coating with three different phases can be used for potential biomedical applications.

Concrete structures in proximity of water environment whether exposed directly or indirectly undergo physical and chemical changes. The water can be seeping into the porous concrete and this triggers the need to modify the exposed concrete with suitable add-ons. Cow dung ash is having pozzolanic qualities which can produce quality concrete structures. This study is focused on M30 grade concrete mix namely normal concrete and concrete modified with CDA. Concrete modified with CDA was prepared by 15% partial replacement of OPC with CDA. After 28 days of curing, specimens were exposed in fresh water for 56, 90, 180 and 365 days. Result showed that pH, compressive and split tensile strength and better durability was significant. X-ray diffraction studies were done to find out the crystalline structures whereas Field Emission Scanning Electron Microscope studies were performed to analyze the structural morphology of concrete specimens. Both studies showed the presence of more calcium silicate hydrate and more cementitious products in concrete modified with CDA. Lesser bacterial density was observed on concrete modified with CDA compared to NC.

Fly ash is used in concrete industry to reduce the amount of cement and to enhance the durability of concrete. Nuclear industry recently adopted fly ash concrete as a government initiative to reduce carbon footprint and also to provide an impermeable skin for the several structures in the cooling water system exposed to marine environment for enhanced durability. Earlier detailed studies on fly ash concrete has shown that despite its superiority over conventional concrete with respect to strength and durability, some concerns such as delayed setting and hydration, low early-age strength, and higher carbonation may pose a problem for its wider application. The present work is an attempt to overcome these deficiencies by nanophase modification of concrete with the incorporation of nano-titania and nano-calcium carbonate at 2% by weight of cement. Four different types of concrete mix were arrived and specimens of different sizes were cast in order to explore the various properties of concrete. After 28 days of curing in potable water, the samples were exposed to seawater at Nuclear Desalination Demonstration Plant (NDDP) sump at Kalpakkam and were withdrawn for testing at different ages like 56, 90, 180 and 365 days. Nanophase modification increased the pozzolanic activity resulting in faster hydration, early-age strength and long-term compressive and split tensile strength, permissible electrical resistivity for corrosion, lower chloride ion penetration, carbonation depth biofilm formation and higher internal pH. Among the different mixes, the synergy of 1% NC and 1% NT emerged superior with excellent concrete properties related to mechanical properties, pore structure, durability and optimum antibacterial activity.

Surface modification is an established technology in biomedical industries to improve the performance of implant materials. In the present study, monoclinic (m-ZrO2) and tetragonal (t-ZrO2) phases of zirconia were deposited on stainless steel (316L SS) by electron beam physical vapor deposition (EBPVD) to enhance several properties of substrate material. m-ZrO2 and t-ZrO2 coatings effectively protected bacterial invasion against pathogenic Pseudomonas aeruginosa (P. aeruginosa) and subsequent biofilm formation. Superior fibroblast cell viability with improved cells spreading was observed in m-ZrO2 and t-ZrO2 coatings. Furthermore, electrochemical impedance spectroscopy (EIS) results exhibited enhanced charge transfer resistance (Rct) and thus, strongly improved corrosion protection by m-ZrO2 and t-ZrO2 coatings compared to bare 316L SS substrate in artificial blood plasma (ABP).

Transparent semiconducting nitrides are important materials for many modern technologies. Here, optical transparent semiconducting zinc nitride (Zn3N2) thin films have been developed by reactive RF magnetron sputtering at different nitrogen (N2) contents. The deposited films are found to be cubic with preferred orientation of (3 2 1) plane. High optical transmittance (∼96%) and refractive index (1.32) at the wavelength of 500 nm and optical band gap of 3.1 eV have been observed for the films deposited at 45% nitrogen content. The investigation on other optical constants such as extinction coefficient and dielectric constant as a function of wavelength shows enhanced optical behavior. The Zn3N2 thin films show n-type conductivity with carrier concentration of ∼1020–1021 cm−3, mobility in the range of 4 to 56 cm2/Vs (which is 1–2 times higher than the values of TCOs) and resistivity around 10−4 Ωcm as a function of nitrogen content. These results suggested that Zn3N2 thin films could perform as potential transparent semiconductors for thin film solar cells.

The process of manufacturing of ordinary Portland cement (OPC) is energy intensive and creates various environmental problems such as pollution and emission of CO2. There is a need for the an alternative eco-friendly Green Concrete. The waste materials from agriculture, industries, bio-waste, marine waste and e-waste can be recycled and used as a supplementary Green Concrete materials. This will reduce environmental impact of the production of OPC and reduces energy consumption. The application of nanotechnology for a Green building in the current and future is very much significant. The production and implementation of Green Concrete is still in its infancy stage. Academicians and R & D need to step in by promoting application at the industry level. The focus of this review paper is to create awareness to utilize the discarded materials as well as to highlight the new technology to manufacture Green Concrete.

In the present study, zirconia (ZrO2) film was deposited onto 316L SS substrate by electron beam physical vapour deposition (EBPVD) technique. The microstructure of the ZrO2 film was studied using X-ray diffraction (XRD) and atomic force microscopy (AFM) and scanning electron microscopy (SEM). Hydrophilic nature was observed on ZrO2 coated film and least hydrophilic behaviour was found on bare 316L SS substrate. The bacterial adhesion test was performed against Streptococcus mutans (S. mutans) and revealed that ZrO2 film protects the bacterial adhesion on its surface. In-vitro cytotoxicity and biocompatibility behaviour of ZrO2 film were investigated using fibroblast cell line, which exhibited high degree of cell viability and proliferation rate rather than bare 316L SS substrate. Electrochemical studies were performed in acidulated artificial saliva (AS) solution containing 0.2% and 2% of sodium fluoride (NaF). The results revealed that ZrO2 coated 316L SS showed excellent corrosion resistant behaviour and can be considered as a potential bioimplant for dental applications.

Surface tailoring of bioimplants is a prerequisite for reducing inflammation and improving durability. In this work, novel calcia stabilized zirconia (CaSZ) and silver-CaSZ nanocomposite coatings were developed on medical grade stainless steel (316L SS). We analyzed their microstructure, mechanical, biological and corrosion resistance performance. Ag-CaSZ nanocomposite coating effectively arrested Pseudomonas aeruginosa bacterial growth without compromising its biocompatibility. Hemolytic behavior was studied and the results confirmed that the samples expressed hemocompatible nature. Further, CaSZ and Ag-CaSZ nanocomposite coatings enhanced osteoblast-like cells (MG-63) adhesion with improved calcite precipitation (biomineralization) using Alizarin red-based assay (ARS). Finally, electrochemical bio-corrosion was performed with Artificial Blood Plasma (ABP) solution. The chemical inertness of ceramics and the formation of the passive layer could enhance corrosion resistance.

Yttria stabilized zirconia (YSZ) was deposited onto titanium (Ti) substrates using electron beam physical vapor deposition (EB-PVD) method. The crystalline nature of as-deposited YSZ coating was evaluated using X-ray diffraction (XRD) technique and cubic phase was noticed. Smooth and uniform surface topography was observed by atomic force microscopy (AFM) analysis. The hardness and scratch resistance of the coating was determined by nanoindentation and scratch test analysis respectively. Wettability studies exhibited more hydrophilic nature on YSZ coating and least hydrophilic on uncoated Ti substrate. Anti-adhesion and antibacterial efficiency were performed against gram (-)ve ( E.coli ) and gram (+)ve ( S. aureus ) bacterial strains and revealed that YSZ coating effectively protected bacterial invasion. Hemocompatibility was evaluated by platelets adhesion and their activation behavior was studied onto uncoated and YSZ coated Ti substrates. YSZ coating exhibited less activated platelets; whereas, platelets activation (large number of pseudopods) were seen on uncoated Ti substrates. Furthermore, superior in vitro biomineralization behavior with increased weight gain, higher protein adsorption and superior biocompatible nature with NIH 3T3 fibroblast cells were observed on YSZ coating. Overall results indicated that surface modification by YSZ coating could become a promising material for biomedical applications.

β-lactamase inhibitors are potent synergistic drugs to deteriorate the multidrug-resistant bacteria. Here, we report the β-lactamase inhibitory ability of kalafungin isolated from a marine sponge derived Streptomyces sp. SBRK1. The IC50 value of the kalafungin was calculated as 225.37 ± 1.95 μM against β-lactamase. The enzyme kinetic analysis showed the Km value of 3.448 ± 0.7 μM and Vmax value of 215.356 ± 8 μM/min and the inhibition mechanism was identified as uncompetitive type. Along with the antibacterial activity, the cell surface analysis of kalafungin treated Staphylococcus aureus cells revealed destruction of cell membrane in response to β-lactamase inhibition. Molecular docking studies have confirmed the binding property of kalafungin against β-lactamase with two hydrogen bonds. In vivo efficacy studies in the zebrafish model by green fluorescent protein expressing S. aureus infection, survival, safety and behavioral profile were reported. The toxicity and anti-infection revealed that the compound was evidently active and safe to all organs. In conclusion, this is the first report on kalafungin with β- lactamase inhibition and suggests that kalafungin may useful for synergic antibacterial therapy with β-lactam drugs to overcome β-lactamase-based resistance of any bacterial pathogens.

Surface engineered materials are presently used in dental, orthopedic and cardiovascular applications made of titanium, cobalt-chromium, stainless steel alloys, etc. In this perspective, different phases of zirconia (ZrO2; henceforth ZrO2 allotropes) coatings (m-ZrO2, t-ZrO2 and c-ZrO2) were developed by electron beam physical vapor deposition (EBPVD) technique. ZrO2 allotropes obtained a smooth surface with a drastic reduction of human pathogenic bacterial adhesion. t-ZrO2 coating evolved higher surface hardness followed by c-ZrO2 and m-ZrO2 coatings. ZrO2 allotropes showed higher blood plasma protein adherence using a whole blood test. Whilst, the role of proteins in the degradation of ZrO2 allotrope coatings was examined in detail by electrochemical impedance spectroscopy (EIS) in the presence and absence of bovine serum albumin (BSA) in artificial blood plasma (ABP) solution.

The usage of waste materials which are having cementitious properties such as fly ash, silica fume, slag cement, rice hush ash and cow dung ash etc., has been increased in the construction industries due to its pozzolanic activities. These materials are used as a partial replacement with cement which would reduce the carbon dioxide emission from the cement industry and environmental pollution. In this study, agricultural waste such as Rice Husk Ash (RHA) was used as a partial replacement of Ordinary Portland Cement (OPC) which was obtained by combustion of rice husk at controlled temperature. The size of the RHA was analyzed and observed as nanoparticles which were confirmed as ∼50-70 nm. Two different types of M30 grade concrete such as, concrete with partially replaced by Fly ash (FA) and concrete with partially replaced by RHA were prepared. The 20% and 3% replacement of cement by flyash and RHA was maintained respectively. The compressive, split tensile and flexural strength was measured to know the mechanical properties of the two types of concrete after the curing period of 7 days, 28 days and 56 days. The microstructural properties such as X-ray diffraction (XRD) and field scanning electron microscopy (FESEM) showed the presence of amorphous silica and scanning electron microscope showed the fineness of the RHA which increases the strength of the concrete.

Fly ash is used in concrete industry to reduce the amount of cement and to enhance durability of concrete. Some early-age performance issues of fly ash concrete are, delayed setting time, low early-age strength, and a more stringent curing conditions. To overcome this deficiency, nano modifications are adopted. This study is attempted to understand the effect of nano TiO2 (NT), nano CaCO3 (NC) particles and a combination of NT and NC particles (NTC) on various properties like compressive strength, workability and durability of fly ash concrete by partial replacement of cement. NT and NC particles with average diameter of 50-70 nm were used with six different contents ranging from 0.5 to 3% by weight of cement, with an increment of 0.5%. The results showed that addition of NT particles up to a maximum replacement level of 3.0% produced concrete with improved strength, whereas addition of NC and NTC particles in the mix showed higher strength up to 2% and thereafter it decreased. Workability of fresh concrete increased at 0.5% addition of all the three nano particles and thereafter, though it decreased for given water to powder content, the mixes were workable. This was confirmed with consistency tests. The fresh and hardened properties along with low rapid chloride penetration values and high pH values highlight the advantages of nano modification of flyash concrete.

Three different types of nanophase modified fly ash mortar specimens were prepared to evaluate the antimicrobial properties in seawater. Two percentage of OPC was replaced by 50-80nm and 50-70nm sized TiO 2 (FAT) and CaCO 3 (FAC) nanoparticles respectively. In the third type of mortar specimens a 2% of the OPC was replaced by mixture of both nanoparticles in same ratio (FATC). All the nanophase modified specimens along with FA specimens were cured in water for 28 days and exposed in seawater for a month. Specimens were withdrawn at different intervals for post-exposure analysis. Detailed microbiological characterization involving density of total heterotrophic aerobic bacteria, slime formers, anaerobic bacteria, manganese-oxidizing bacteria, fungus, sulfur oxidizing bacteria and biofilm imaging using epifluorescence microscopy, total dissolved and suspended solids in biofilm were carried out. pH reduction of the surface of the specimens were measured by flat surface electrode. Results demonstrated lesser pH reduction and enhanced antibacterial activity on the surface of FAT and FATC mortar specimens under the influence of TiO 2 nanoparticles.

The symbiotic association between plant roots and arbuscular mycorrhizal fungi (AMF) promotes plant growth, and reduces toxic metals accumulation in plants. In this study, the effect of inoculation with indigenous AMF (Glomus Spp.) and co-application of AMF and nano-TiO2 on Cd accumulation on activities of stress enzymes in cowpea at pre-flowering stage was examined. Soil substrates were spiked with either Cd (10 mg/kg) and inoculated with either AMF suspension (7 ml) or AMF+nTiO2 (200 mg/kg). The results showed that inoculation with AMF and AMF+nTiO2 promoted germination and chlorophyll contents by at least 12% and 45%, respectively. As envisaged, AMF+nTiO2 reduced uptake and decreased translocation of Cd to above-ground biomass better than inoculation solely with AMF. In the aspect of Cd toxicity assessed by enzymes activity, sole AMF inoculation and AMF+nTiO2 had varied effects on the stress enzymes activity. However, nTiO2 interacted synergistically with AMF to improve stress tolerance by reducing the lipid peroxidation in plants (in term of the amount of malondialdehyde) more than sole inoculation with AMF. In conclusion, the present study demonstrated that there is stimulatory effect of nano-TiO2 on the activity of AMF in alleviating Cd stress in pre-flowering cowpea.

The major cause of concrete corrosion is carbonation where atmospheric carbon dioxide (CO2 penetrates the concrete structure and deteriorates it. In this study, fly ash concrete (FA) with 40 percentage by weight (wt.) of cement, 2 wt% of TiO2 nanoparticles added to fly ash concrete (FAT), 2 wt% of CaCO3 nanoparticles added to fly ash concrete (FAC) and equal ratio (1:1) of CaCO3 and TiO2 nanoparticles was added to fly ash concrete with (FATC). After curing, these specimens were exposed in atmospheric condition, accelerated carbonation and sea water for 56 and 90 days and withdrawn for various analyses. TGA/DTA was done before exposing the specimens in different environments. The post-exposure analysis included surface pH, carbonation depth and XRD and FESEM to analyses the crystalline phases and morphology of specimens. Results showed that FA concrete modified with nanoparticles has decreased the carbonation depth. Among different types of FA concrete, FATC with an equal ratio of CaCO3 and TiO2 nanoparticles showed higher carbonation resistance in all environments.

The production of metallic nanoparticles is greatly increasing due to its wide range of applications in agricultural formulations. The present pot experiment investigated the uptake of Zn from nano-zinc oxide (n-ZnO)-amended soil at 300, 600 and 1000 mg n-ZnO/kg concentrations, and its effects on the enzymatic and non-enzymatic antioxidants in tomato tissues and fruits respectively. Results showed that root uptake of Zn increased with increasing n-ZnO concentrations. The enzyme activity showed that n-ZnO, through the generation of H 2 O2 and induction of oxidative stress, significantly reduced the activity of stress-controlling enzymes (APX and SOD) in the root. Conversely in leaves, despite alteration in chlorophylls in the early growing stage, APX activity was only significant at 1000 mg n-ZnO/kg) while SOD activity was enhanced at all treatments. CAT activity was significantly reduced, unlike in the roots where CAT activity was significantly enhanced. Contents of total phenols, flavonoids, β -carotene and lycopene in fruits were significantly reduced by at least 4.8% while ascorbic acid was promoted at low n-ZnO treatments. In conclusion, the toxic effect of n-ZnO on stress enzymes was prominent in tomato roots, and there was also inhibitory effect on induction of non-enzymatic antioxidants in the tomato fruits.

Surface tailoring is an existing technology in biomedical industries to improve the performance of implant materials. Surface tailoring with zirconia (ZrO2) was performed on medical-grade stainless steel (316L SS) by electron beam physical vapor deposition (EBPVD) to enhance their properties. Monoclinic crystal phase and uniform microstructure were found in structural analysis. Superhydrophilicity nature was found on coated and bare 316L SS substrates, in the presence of lactic acid (LA) and hydrogen peroxide (H2O2) liquids. Pseudomonas aeruginosa (P. aeruginosa) bacterial adhesion was drastically decreased on ZrO2 films even at 4th day of incubation. Further, superior protein adhesion as well as hemocompatible behavior were observed on ZrO2 films. Electrochemical impedance spectroscopy (EIS) analysis revealed higher charge transfer resistance (Rct) and corrosion protection in the presence of ZrO2 films in artificial blood plasma (ABP) containing H2O2 and LA compared to bare 316L SS substrate.