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Polycrystalline (1-x)SnO2-xCeO2 nanocomposites, where x = 0, 0.05, and 0.10, were synthesized using conventional co-precipitation method without any traces of impurities. Structural characterization revealed that the composition with x = 0 exhibited single-phase tetragonal rutile symmetry, whereas for x = 0.05 and 0.10 compositions showed both tetragonal and cubic phase coexistence as confirmed by Rietveld refinement studies. HRTEM micrographs showed nanoscale formation of nanocomposites and also displayed fringes depicting d spacing (110) = 0.34 nm belonging to SnO2 crystal matrix and d spacing (111) = 0.31 nm for cubic CeO2 crystal lattice. Dielectric properties of host SnO2 nanoparticles were improved by CeO2 addition in the SnO2. The increment in the real part of dielectric permittivity was observed for CeO2 modification of SnO2 matrix.

Fingerprints are of core importance to the forensic science for the case investigations. The latent fingerprints are the invisible fingerprints which needs different methods to be visualized. Many methods have been developed for the visualiztion of the latent fingerprints through which the unique ridge pattern of the individual can be identified, but there is a strong requirement for the detection of sweat residues present in the latent fingerprint ridges. The latent fingerprints opens a wide scope of unexplored area in research that is beyond the scope of forensics in detecting various illicit drugs or metabolites of clinical importance. These prints generally show surface-based phonemenon and the nanomaterials provides new opportunities in surface-based sciences. Therefore, the nanoparticles can play a vital role in the detection of molecules in the latent fingerprint ridges. The synthesis of nanoparticles from natural products like green plants provides non-toxic, eco-friendly, biodegradable materials which can be easily utilized in the environment.

The present study depicts physicochemical characteristics of Gd3+ modified Fe3O4 nanoparticles synthesized via the sol-gel combustion method. Structural, microstructural, optical, electrical, and magnetic characteristics were investigated. X-ray diffraction studies demonstrated that all the compositions exhibit cubic crystallinity and phase pure crystal structure with space group $$Fd\bar{3}m$$ . FESEM micrographs depicted that the average crystallite size increases from 15.35 nm [x = 0] to 23.74 nm [x = 0.10] with increasing Gd3+ content. FTIR spectra of the compositions show bend at 522 cm− 1 belonging to Fe–O stretching, which confirms the formation of ferrite nanoparticles. Photocatalytic activity of Fe(3−x)GdxO4 nanoparticles with x = 0 and 0.10 was carried out using methylene blue (MB) dye under UV light. Dielectric studies revealed that the dielectric constant decreases due to the incorporation of Gd3+ ion in the Fe3O4 crystal lattice. Negligible coercivity and remnant magnetization revealed the superparamagnetic behavior for all the compositions and it was observed that saturation magnetization decreases with increasing Gd3+ concentration. Magnetic recyclability illustrated the reusability of Gd3+ modified Fe3O4 nanoparticles.

Purpose: Contribution of radiation doses from medical X-ray examination to collective dose is significant. Unusually, high doses may increase the risk of stochastic effects of radiations. Therefore, radiation dose assessment was performed in 241 digital X-ray examinations in the study and was compared with published dose reference levels (DRLs). Methods: Entrance surface air kerma (ESAK) was calculated in chest PA, cervical AP/Lat, abdomen AP, lumbar AP/Lat and pelvis AP digital radiographic examinations (119 male and 122 female) following the International Atomic Energy Agency recommended protocol. Initially, 270 digital examinations were selected, reject analysis was performed and final 241 examinations were enrolled in the study for dose calculations. The exposure parameters and X-ray tube output were used for dose calculations. Effective doses were estimated with the help of conversion coefficients from ICRP 103. Results: Median ESAK (mGy) and associated effective doses obtained were cervical spine AP (1.30 mGy, 0.045 mSv), cervical spine Lat (0.25 mGy, 0.005 mSv), chest PA (0.11 mGy, 0.014 mSv), abdomen AP (0.90 mGy, 0.118 mSv), lumbar spine AP (1.52 mGy, 0.177 mSv), lumbar spine Lat (7.76 mGy, 0.209 mSv) and pelvis AP (0.82 mGy, 0.081 mSv). Results were compared with the studies of UK, Oman, India and Canada. Conclusion: The calculated ESAK and effective dose values were less than or close to previously published literature except for cervical spine AP and lumbar spine Lat. The results reinforce the need for radiation protection optimization, improving examination techniques and appropriate use of automatic exposure control in digital radiography. ESAK values reported in this study could further contribute to establishing local DRLs, regional DRLs and national DRLs.

In this report, an environment friendly and cost effective green synthesis method of magnetite nanoparticles (Fe3O4 NPs) was introduced. Fe3O4 NPs were successfully synthesized by green route using Ocimum basilicum leaf extract. The structural investigation of Fe3O4 NPs using X-Ray diffraction technique revealed the cubic crystallinity with Fd3m space group, which was confirmed with an aid of Rietveld refinement. No secondary phases (such as Fe2O3 and FeO) were observed, which confirmed the high purity of synthesized Fe3O4 NPs. The characteristics peak at 3320 cm−1 displayed the phenolic constituents of Ocimum basilicum leaf extract and peak at 665 cm−1 illustrated the Fe–O bending, which confirmed the formation of Fe3O4 NPs. Ocimum basilicum leaf extract mediated Fe3O4 NPs possess spherical morphology with an average particle size ~ 15 nm as depicted by transmission electron microscopy (TEM). The magnetic potential of Ocimum basilicum leaf extract mediated Fe3O4 NPs was also carried out by using a vibration sample magnetometer (VSM), which revealed the superparamagnetic behavior of Fe3O4 NPs. Cytotoxicity of the as-synthesized Fe3O4 NPs nanoparticles was also examined on the human breast cancer cell line, which illustrated the efficacy of the synthesized nanoparticles with a low value of IC50 (~ 17.75 µg/ml). The results displayed the potent anticancerous effect of Ocimum basilicum leaf extract capped Fe3O4 NPs, which made these nanoparticles suitable for a drug-loaded vehicle for the drug delivery system for biomedical applications.

In this report, we adopted an auto-combustion method to synthesize polycrystalline magnetite (Fe3O4) and magnesium ferrites (MgFe2O4) nanoparticles. The synthesized nanoparticles were characterized using techniques such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), Vibration sample magnetometer (VSM) and photoluminescence (PL) spectroscopy. X-ray diffraction profiles of all the synthesized nanoparticles [Fe3O4 (500 °C): FO NPs, MgFe2O4 (500 °C): MFO1 NPs and MgFe2O4 (700 °C): MFO2 NPs] confirmed phase pure crystallinity without any secondary phases such as FeO and Fe2O3, etc. The implementation of Rietveld refinement determined the cubic crystal symmetry with space group $$Fd\stackrel{-}{3}m$$ for all the synthesized nanoparticles. FE-SEM micrographs depicted the pseudo-spherical morphology with an average grain size of 26.18 nm, 51.6 nm, and 69.68 nm for FO NPs, MFO1 NPs, and MFO2 NPs, respectively. FTIR spectra illustrated the appearance of peaks at 1645 cm−1 and 1345 cm−1 which attributes to metal ions (Fe3+/Mg2+). Photoluminescence spectra of synthesized nanoparticles displayed the emission wavelength in a range of 508–521 nm. The values of saturation magnetization for FO NPs, MFO1 NPs, and MFO2 NPs were found to be 34.2 emu/g, 15.3 emu/g, and 28.8 emu/g, respectively. The magnetization of MgFe2O4 nanoparticles increased with increasing calcination temperature (500–700 °C) so as the grain size. It indicated that Mg substitution at A-site of AB2O4-type (MgFe2O4) spinel ferrite not only gave the phase pure crystal structure but also compete with the magnetic properties of Fe3O4 with increasing calcination temperature. MgFe2O4 nanoparticles (calcined at 700 °C) depicted superparamagnetic behavior and can be utilized as a drug delivery agent for biomedical applications.

In the present era the demand for fossil fuels is increasing at an alarming rate and to meet the need of time, it is required to switch to renewable sources for our energy needs. Hydrogen is reportedly considered as a future fuel as it can store three times more energy as compared to conventional fuel and emit zero emission [1]. However, it’s safe and efficient storage is quite a challenge. Out of the three modes of storage, solid storage of hydrogen is proved to be the safest [2]. The common materials used for the electrochemical hydrogen storage are reported collectively in this paper. These include complex hydrides, activated carbon (aC), metal hydrides, metal organic frameworks, capillary arrays, clathrate hydrates, metal nitrides, doped polymer and zeolites. This paper presents a comparative study of selective materials used so far for electrochemical hydrogen storage with broader prospects in the field of hydrogen fuel technology. The literature review in this paper provides an insight of the materials that have already been used for storing hydrogen in solid-state. The study also highlights the limitations of using these materials

In the present work, photocatalytic degradation of indigo dye by synthesized graphene oxide (GO) nanomaterials using conventional and improved Hummers method has been reported. In the present research, the emphasis is to explore the photocatalytic degradation of GO, using NaNO3 (N-GO) and without using NaNO3 (WN-GO) under the exposure of UV light. WN-GO possesses eco-friendly behaviour as it eliminates the generation of toxic gases (NO2/N2O2) in the atmosphere. Synthesized nanomaterials were characterized using SEM–EDS, XRD, Raman spectroscopy, UV–Vis and FTIR. Indigo dye (C16H10N2O2) was identified as a model to investigate the photocatalytic degradation of GO nanoparticles under UV exposure. The absorbance peak of indigo dye with N-GO and WN-GO has been plotted as a function of irradiation time. The progress of the decolourization reaction of dye with catalysts was measured by a change in colour from blue to transparent. Compared to N-GO, WN-GO possesses organic and eco-friendly degradation of indigo dye under UV irradiation. The versatile photocatalytic characteristics of WN-GO possess higher-order degradation rate constant (k) makes it a potential candidate for bioremediation of wastewater treatment. Therefore, the degradation of indigo dye with GO exhibits encouraging solution for treating contaminated water and provides a facile route towards environmental cleanness.

The present study reports photocatalytic behaviors of stand-alone graphene oxide (GO) and reduced graphene oxide (rGO) nanostructures synthesized by improved Hummer’s method. The synthesized materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, ultra-violet visible (UV–Vis) and Fourier-transform infrared (FTIR) spectrometry. The photocatalytic activities of the synthesized nanostructures were evaluated from monitoring the degradation of methylene blue (MB) dye solution under UV/sunlight exposure. The experimental results showed that stand-alone GO/rGO nanostructures have significant intrinsic photocatalytic character to replace other toxic semiconductor photocatalysts. The photocatalytic character of bare GO/rGO nanomaterials are attributed to existence of finite band gap tuned by oxygen containing functionalities on their aromatic rings.

A systematic investigation is performed to analyze the synergetic effect of Gd3+ substitution and annealing temperature on the fundamental properties of BiFeO3 nanoparticles. Both pure and Gd3+ substituted BiFeO3 nanoparticles were prepared by simple sol-gel method and annealed in two different temperatures (450 °C and 650 °C). The structural transformation of BiFeO3 from rhombohedral to orthorhombic was observed in the X-ray diffraction (XRD) analysis. FE-SEM images were evident enough in showing the decrease in the agglomeration due to effect of substitution, on the other hand increase in annealing temperature resulted in the growth of particle size. The Gd3+ substituted BiFeO3 prepared at 450 °C possesses higher saturation magnetization value as compared to that of pure BiFeO3 and Gd3+ substituted sample prepared at 650 °C which were analyzed in vibrating sample magnetometer (VSM). Increased value of dielectric constant was observed in Gd3+ substituted samples prepared at both 450 °C and 650 °C.

Energy production from renewable sources is increasing at a quite high rate in order to have a refined phase of energy consumption. Hydrogen has emerged as a clean and efficient energy carrier since 1839. The storage of hydrogen is one of the essential requirements for the development of renewable-based energy system but, it still remains a great challenge for technologists. Many researchers have reported about the numerous materials being used for hydrogen storage. Nanostructure oxide and activated carbon (aC) material seem to be more suitable for storing the hydrogen efficiently. In the present review, numerous hydrogen storage materials those are being used for electrochemical hydrogen storage have been discussed. The relative comparison of different hydrogen storage materials may be very useful for future experiments as electrochemical hydrogen storage.

Reduced graphene oxide (RGO) is a potential material for new era nano devices due to its novel property and morphology. The numerous synthesis methods for this material have been explored by various researchers. The chemical method named modified hummer method used to oxidate the graphite to form graphene oxide (GO). Afterward, it is exfoliated and reduced to form reduced graphene oxide is the most relevant method. Hence, in the present paper, Reduced Graphene oxide (RGO) has been obtained by this method. In this paper, Sodium borohydride (NaBH4) is used as a reducing agent in chemical reduction of exfoliated GO. X-Ray diffraction (XRD) peaks are observed at 25.5° with interspacing distance 4.038 Ao and at 26.2° with an interspacing distance of 1.657 Ao, for the GO and RGO respectively. The scanning electron microscopy images GO and RGO predicts multi-layers morphology. The view of RGO reveals the exfoliated multi-layer confirms the appearance of transparent wrinkles and due to the reduction of the oxygen-containing functional group. The Raman spectroscopy of graphene oxide displays strong G and D peak at 1592 cm−1 and 1358 cm−1 respectively which attributes to local defects and disorders. Whereas for RGO has been shifted back to 1585 cm−1 and 1340 cm−1 for G and D peak respectively. There is a rise in intensities ratio from 0.770 – 0.902 associated with decreased in average size of sp2 domains. So, RGO is considered as a smart material for different nano electronics applications like sensors, solar cells, optoelectronics devices, energy storage capacitors, lithium-ion batteries etc.

The present work reports study on antimicrobial activity of pure and doped ZnO nanocomposites. Polyvinyl pyrrolidone capped Mn- and Fe-doped ZnO nanocomposites were synthesised using simple chemical co-precipitation technique. The synthesised materials were characterised using transmission electron microscope (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared (FTIR) spectroscopy and ultraviolet (UV) visible spectroscopy. The XRD and TEM studies reveal that the synthesised ZnO nanocrystals have a hexagonal wurtzite structure with average crystalline size ∼7–14 nm. EDXRF and FTIR study confirmed the doping and the incorporation of impurity in ZnO nanostructure. The antimicrobial activities of nanoparticles (NPs) were studied against fungi, gram-positive and gram-negative bacteria using the standard disc diffusion method. The photocatalytic activities of prepared NPs were evaluated by degradation of methylene blue dye in aqueous solution under UV l...

Polyvinyl pyrrolidone (PVP) capped Zn1−xCrxO (0.000001≤x≤0.1) nanocomposites were successfully synthesized using a simple chemical co-precipitation technique. The synthesized nanostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray fluorescence (EDXRF), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements. The structural characterization by XRD, TEM, FTIR and EDXRF confirmed the formation of wurtzite structure and incorporation of Cr in the ZnO lattice. The photocatalytic activities of as prepared nanocomposites were evaluated by degradation of methylene blue (MB) dye in aqueous solution under UV/sunlight light irradiation. The results demonstrated that Zn1−xCrxO (x=0.0001) nanocomposite effectively bleached out MB, showing as impressive photocatalytic enhancement over pure ZnO and ZnS nanoparticles. This enhanced photocatalytic activity at optimum concentration was attributed to increased absorption ability of light and high separation rate of photoinduced charge carriers on the nanocomposite photocatalyst surface. The VSM measurements showed significant ferromagnetism in Cr-doped ZnO nanostructures and the value of saturated magnetism was found to decrease with increase in Cr content.

The aim of the present invention was to develop a novel energy bar which is nutritious and healthy for all age groups. The ingredients used for the newly developed energy bar are cocoa butter, stevia in combination with banana, orange, peanuts, raisins and oats. Standardization of the novel energy bar by sensory evaluation, chemical analysis, carbohydrate content, protein content and shelf life were evaluated. The developed novel energy bar was found to contain 63.50% total solid contents, 27.50% moisture contents, The total solid content holds 1.55% ash value, 17.46% crude fat, 5.65% protein, 17% carbohydrates capable of expending total 166 K.cal of energy per bar. Stevia rebaudiana has antimicrobial and antibacterial properties and is also a natural sweetening agent. The energy bar also contains no preservatives. The bar is full of natural goodness with no additives of flour or any other binding agents and the taste is enhanced by using natural acids from oranges. The energy bar was highly accepted by all consumers for desirable sensory qualities.

Presence of trace amount of foreign impurities (both metallic and non-metallic) in standard salts used for sample preparation and during the synthesis process can alter the physical and chemical behavior of the pure and doped nano-materials. Therefore, it becomes important to determine concentration of various elements present in synthesized nano-material sample. In present work, the elemental and compositional analysis of nano-materials synthesized using various methods has been performed using photon-atom interaction based energy dispersive x-ray fluorescence (EDXRF) technique. This technique due to its multielement analytical capability, lower detection limit, capability to analyze metals and non-metals alike and almost no sample preparation requirements can be utilized for analysis of nano-materials. The EDXRF spectrometer involves a 2.4 kW Mo anode x-ray tube (Pananalytic, Netherland) equipped with selective absorbers as an excitation source and an LEGe detector (FWHM = 150 eV at 5.895 keV, Canberra, US) coupled with PC based multichannel analyzer used to collect the fluorescent x-ray spectra. The analytical results showed good agreements with the expected values calculated on the basis of the precursor used in preparation of nano-materials.

Zn1−xCo x S (0.00001 ≤ x ≤ 0.1) nanocrystals have been synthesized using facile bottom-up synthesis technique chemical co-precipitation method. Crystallographic and morphological characterizations of synthesized nanomaterials have been done using X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. XRD studies confirm the formation of zinc blende crystallites having average crystallite size about 3.0 nm, which is in close agreement with the average particle size calculated from TEM micrographs. The photo-catalytic activity potential of synthesized nanocrystals has been tested using methylene blue dye as test contaminant in aqueous media. Photo-catalytic activity dependence on dopant concentration has been described in detail. Moreover, room temperature energy resolved photoluminescence spectra have been also recorded to correlate the various charge carrier recombination and interfacial charge transfer processes.

Polyvinyl pyrrolidone capped Zn1−xCuxS (0.00001 ≤ x ≤ 0.1) nanocrystals have been synthesized using facile wet chemical co-precipitation method. Crystallographic and morphological characterizations of synthesized materials have been carried out using X-ray diffraction and transmission electron microscope. Diffraction studies reveal the zinc blende crystal structure of synthesized nanomaterials with average crystallite size ~3 nm. Average particle size calculated from electron micrographs is comparable with the average crystallite size, which confirms the formation of single nanocrystals. Photo-catalytic activity potential of synthesized nanomaterials under UV radiation exposure has been tested using methylene blue dye as test contaminant in aqueous media.

Abtract Intrinsic and extrinsic semiconductor nanostructures have attracted great attention due to their size tunable photo-physical and photo-chemical properties. In the present paper, polyvinyl pyrrolidone (PVP) capped Zn 1-x Eu x S (0.00001≤x≤0.1) nanocrystals have been synthesized by means of a facile chemical synthesis method. Crystallography and morphology of synthesized materials have been deliberated using X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. Diffraction and electron micrograph studies reveal that the synthesized materials are zinc blende nanocrystals having average particle size ~3nm. Elemental and compositional analyses of the nanocrystals have been done using energy dispersive X-ray fluorescence (EDXRF) technique. Steady state photoluminescence spectra have been recorded for optical characterization of synthesized nanomaterials. Photocatalytic activity potential of synthesized nanomaterials under UV radiation exposure has been investigated using methylene blue (MB) dye as a test contaminant in aqueous media. Photo-physical and photo-chemical behaviour dependence on doping concentration has been described in detail. Moreover, the sophistication of competition between charge carrier recombination and charge carrier trapping followed by the competition between recombination of trapped carriers and interfacial charge transfer processes have been presented in a fantastic and elaborative way by comparative study of photoluminescence and photo-catalytic activity results.

Background/Objectives: Microwave absorbing materials can be used to reduce electro- magnetic interference. M-type hexaferrites (SrFe12O19 and BaFe12O19) have attracted intensive attention on account of their important applications in microwave absorbing materials. Methods/Statistical Analysis: M-type hexaferrite nanoparticles with a composition of TbxSr1-xFe12O19 (x = 0-0.1) were amalgamted by a chemical method known as co-precipitation method. A successive solid state reaction at different calcination temperatures at fixed holding time has lead to the formation of pure and Tb substituted strontium hexaferrite. The reaction of swaping of Tb cations on the magnetic, structural, and electrical properties of nanoparticles was characterized by X-ray diffraction XRD, FTIR,TEM and VSM. Findings: Microstructure by TEM showed that grains are of extremely fine phase. Identification by XRD confers the single-phase material of nanometeric size. Evaluation on magnetic characteristics for the material showed that coercivity decreased progressively as number of Tb3+ ion increases. Although this was followed by a significant increase in total magnetization. Reflection loss and reflection coefficient and loss tangent for a range of 1-5 KHz were derived which confirms that the material can be considered for high frequency applications.

Nickel-doped barium nanohexaferrites with the chemical formula BaNixFe(12-x)O19 are prepared using the chemical co-precipitation technique. The calcination of the samples is done at 800°C for 4 h. In order to carry out the structural analysis that includes the crystallographic and the morphological investigations, X-ray diffraction and TEM are carried out to govern the phase, structure and the size of the crystal. By the use of Debye–Scherrer equation, the size of the crystallite is calculated to be in the range of 38–100 nm. TEM results reveal the magnetoplumbite structure of the hexaferrites. The M–H curve obtained using the Vibrating Sample Magnetometer computes the magnetic parameters like saturation magnetization, coercivity, remanence and verifies the behaviour of hexaferrites as hard magnetic materials. Further, the effect of variation in calcination temperature is also investigated on the values of magnetic parameters of hexaferrites. In order to carry out the investigations on the electrical properties of hexaferrites, the two-probe method and parallel plate capacitor set-up are used. The values of relative permittivity, dielectric loss and loss tangent are computed as a function of frequency. The values of DC electrical resistance for pure and nickel-doped barium nanohexaferrites are evaluated from the slope of I–V graphs.

Intrinsic and extrinsic semiconductor nanocrystals seem to be good candidates for modern era optoelectronic and photo-catalytic applications due to their size tunable photo-physical and photo-chemical properties. In the present investigation, polyvinyl pyrrolidone (PVP) capped quencher impurity (Ni) doped ZnS nanocrystals have been synthesized using facile bottom-up synthesis technique; colloidal chemical co-precipitation method. Crystallographic and morphological characterization of synthesized nanomaterials have been carried out using X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. Photo-catalytic activity of the synthesized nanomaterials has been studied using methylene blue (MB) dye as a test contaminant. Photo-catalytic behavior dependence on dopant concentration, UV radiation curing and annealing of synthesized semiconductor nanomaterials have been studied in detail under sun light exposure.

Transdermal drug delivery is one of the most potential methods for drug application. Though the skin, in particular the stratum corneum, possesses a dreadful barrier to drug penetration thus limiting topical and transdermal bioavailability. So skin penetration enhancement techniques have been developed to improve bioavailability and to increase the range of drugs, the topical and transdermal delivery is a viable option. The technique is generally non-invasive, well accepted by patients and can be used to provide local delivery over several days. Various chemical enhancers are used to improve bioavailability of the drugs such as sulfoxides, fatty acids, azones and non ionic surfactants. This review article presents the comprehensive different aspects of drug delivery by transdermal route with various chemical penetration enhancers.

Nanolabeling is an invaluable novel technique in biology to detect and characterize different parts of biological systems including microscopic entities, viz., cells inside the living systems. Stem cells (SCs) are multipotent cells with the potential to differentiate into bone, cartilage, fat, muscle cells, and neurons and are being investigated for their utility in cell-based transplantation therapy. Yet, adequate methods to track transplanted SCs in vivo are limited, precluding functional studies. Nanoparticles (quantum dots) offer an alternative to organic dyes and fluorescent proteins to label and track cells in vitro and in vivo. These nanoparticles are resistant to chemical and metabolic degradation, demonstrating long-term photo stability. Here, we describe the technology of labeling the stem cells with silver nitrate nanoparticles in an in vitro coculture model. This is followed by defining the procedure of administering these cells in vivo and studying the distribution pattern and resultant regenerative effects of the "tagged" stem cells.

Zn 1−x TM x S [(TM: Fe or Ni); (0.00001≤×≤0.1)] nanocrystals have been synthesized using well known bottom-up synthesis technique; colloidal chemical coprecipitation method. Powder X-ray diffractometer and Transmission Electron Microscope (TEM) have been used for crystallographic and morphological characterization. Analysis of recorded broad X-ray diffraction patterns show zinc blende structured crystallites having average crystallite size ∼3nm. Average particle size calculated from the electron micrographs is in close agreement with the average crystallite size calculated from diffraction studies. Room temperature steady state luminescence spectra have been recorded for optical characterization. Detailed description about the radiative and non-radiative recombination mechanism dependence on the dopant concentration has been established from luminescence studies. Photo-catalytic properties of synthesized nanocrystals have been examined by degradation of methylene blue (MB) dye. Luminescence quantum efficiency and photo-catalytic behaviour dependence on the dopant concentration have been studied in detail.

Polyvinyl pyrrolidone capped Zn1-x Mn x S (0 ≤ x ≤ 0.1) nanocrystals have been synthesized using wet chemical co-precipitation method. Crystallographic and morphological characterization of the synthesized materials have been done using X-ray diffraction and transmission electron microscope. Crystallographic studies show the zinc blende crystals having average crystallite size approx. 3 nm, which is almost similar to the average particle size calculated from electron micrographs. Atomic absorption spectrometer has been used for qualitative and quantitative analysis of synthesized nanomaterials. Photo-catalytic activity has been studied using methylene blue dye as a test contaminant. Energy resolved luminescence spectra have been recorded for the detailed description of radiative and non-radiative recombination mechanisms. Photo-catalytic activity dependence on dopant concentration and luminescence quantum yield has been studied in detail.