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Abstract: In this paper we propose a specific sandwich immunoassay method for human-immunoglobulin G (HIgG). This immunoassay protocol takes advantage of sandwich binding of primary and secondary antibodies for increased specificity. Polystyrene microspheres (PS) serve as immobilizing support, site for sandwich immunoassay and then subsequently used for chemiluminescence (CL) detections. In this sandwich immunoassay, PS microspheres were modified with the primary anti-HIgG (Ab1) via electrostatic interaction, while CdTe nanoparticles (CdTeNPs) were modified with horseradish peroxidase labeled anti-HIgG (Ab2) via covalent binding. Antigen HIgG (Ag) was specifically captured by the first and secondary antibody and form sandwich immunoassay format. Combination of the remarkable sensitivity of CL method and the use of CdTe NPs as anti-HIgG–HRP carrier for the enzymatic signal amplification, provide a linear response range of HIgG from 0.01 to 300ngmL−1 with an extremely low detection limit of 0.3pgmL−1. This immunoassay system has many desirable merits including sensitivity, accuracy, and little required instrumentation. The assay results were compared with enzyme-linked immunosorbent assay (ELISA), and showed relatively good reliability. Significantly the new protocol may become quite promising technique for protein immune-detection as well as DNA analysis and other biological analyses. [Copyright &y& Elsevier]

Land is a pricy and scarce resource, particularly in urban areas. If it is utilized effectively, suitable sites can be allocated for urban wastewater safe disposal through effluents treatment and reuse. This study used multicriteria decision-making approach known as weighted linear combination to map the suitability of an on-site natural wastewater treatment system in the urban and industrial environments—selecting Faisalabad City in Pakistan as the study area. Location of the study region in a water-scarce zone increases the scope of the untreated wastewater disposal into land and water bodies as well as its reuse for irrigation. Data on climate parameters (i.e., temperature, rainfall, and evapotranspiration), geophysical parameters, (i.e., including soil, topography, depth to groundwater table, and groundwater electrical conductivity), and socioeconomic parameters (i.e., land cover maps and proximity from roads/railways and rivers/canals) are used for the development of weighted linear combination based suitability index maps. Analytical hierarchical process-based heuristic approach is adapted to estimate the relative importance of all the parameters. Weights with less than 0.10 consistency ratio are used in the preparation of the final suitability map. The land area required for the proposed on-site wastewater treatment system is estimated as a function of climatic factors and wastewater characteristics. Adoption of the proposed multicriteria framework helped identifying four potentially environment-friendly and economically viable sites. The results show that geospatial multicriteria framework could efficiently help urban planners in sustainable wastewater management, particularly in developing countries where climate-change-induced water scarcity and associated health issues are critical. • Better wastewater management in cities is critical for socio-ecological well-being. • A spatial framework for siting an on-site wastewater treatment plant is proposed. • The framework identifies potential ergonomic sites in a decentralized manner. • The framework acts as a decision-support-system for urban planning/design. • The application of the spatial framework is equally useful for other urban regions. [ABSTRACT FROM AUTHOR]

A green approach was employed for the synthesis of heterostructures of g-C 3 N 4 @MoO 3 and characterized by XRD, UV–vis, SEM and FTIR techniques to evaluate the structural, morphological, and optical features of the heterostructures. The XRD analysis revealed the high crystallinity and intensity of g-C 3 N 4 /MoO 3 higher than the g-C 3 N 4 and MoO 3. The g-C 3 N 4 shows a crumpled layered arrangement and a MoO 3 rod-like structure. The refractive index (n), bandgap energy (E g) and extinction coefficient (k) (optical properties) are determined by UV–vis spectroscopy. The g-C 3 N 4 /MoO 3 optical properties like k (2.15), n (2.37), dielectric coefficient (0.43), electronegativity (0.739) and bandgap energy (2.75 eV) were enhanced significantly. In visible region, the g-C 3 N 4 /MoO 3 demonstrated excellent performance for the degradation of RhB dye. The mobility and detachment of electron-hole pairs in type-II heterojunction semiconductors are responsible for the enhancement of photocatalytic activity (PCA) in visible region, which can be utilized for the dyes remediation in effluents under natural sunlight irradiation. [Display omitted] • A green route was employed for graphatic-C 3 N 4 @MoO 3 heterostructure synthesis. • Characterization was done by XRD, UV–vis, SEM and FTIR techniques. • The optical properties enhanced of g-C 3 N 4 @MoO 3 versus g-C 3 N 4 and MoO 3. • g-C 3 N 4 @MoO 3 showed promising catalytic activity under visible light irradiation. [ABSTRACT FROM AUTHOR]

Abstract: Polymers either serve as shielding or capping agents to restrict the nanoparticle size. This study demonstrates the polymer depositions and their effects in synthesis and sharp stabilization of gold nanoparticles (AuNPs) and to develop gold/silver nanoalloys (Au/Ag nanoalloys). Effects of different polymers are tested to justify their role in synthesis and stability of phloroglucinol (PG) coated AuNPs and Au/Ag nanoalloys. Cationic and anionic i.e. [Polydiallyldimethylammonium]+ (PDDA), [Polyethyleneimine]+ (PEI), [Polystyrene sulfonate]2− (PSS) and neutral polymer Polychlorotriflouroethylene (PCTFE) produce praiseworthy stable AuNPs and Au/Ag nanoalloy. To prove polymer effects characterization protocols including UV–vis, Fluorescence (PL), IR and AFM imaging are performed to fully investigate the mechanism and size characteristics of these nanoparticles/nanoalloys. In this study sharp size controlling/sheilding effects were observed particularly with cationic polymers simply through the favorable electrostatic interactions with the terminal ends of PG Potent/significant detection of doxorubicin (DOX, an antileukemic agent) via fluorescence resonance energy transfer (FRET) between PEI shielded AuNPs (AuNPEI) and DOX was achieved upto 10pM level, while PDDA protected AuNPs facilitated the detection of ascorbic acid based on fluorescence enhancement effects in wide range (10–200nM) and with detection limit of 200pM. Similarly sensing performance of PEI stabilized Au/Ag nanoalloys on addition of halides (Cl−, Br-, I−) is evaluated through red shifted SPR along with continuous increase in absorbance and also through AFM. Moreover the addition of halide ions also helped the regeneration of AuNPs by taking away silver from the Au/Ag nanoalloys enabling their detections upto subnanomolar levels. [Copyright &y& Elsevier]

Abstract: Conventional synthesis of silver nanoparticles employs a reducing agent and a capping agent. In this report water-soluble silver nanoparticles (AgNPs) were prepared facilely by chemical reduction of Ag(I) ions. 4-Amino-3-(d-gluco-pentitol-1-yl)-4,5-dihydro-1,2,4-triazole-5-thione (AGTT) was used both as reducing and stabilizing agent. Direct heating methodology was found to be more suitable for achieving particles with a hydrodynamic diameter of ∼20nm. AGTT exists as tautomer in solution form and our studies indicate that –NH2 group is involved in the reduction and stabilization of Ag+ and thione (Δ=S) group of AGTT is possibly involved in stabilizing the nanoparticles via coordinate covalent linkage. Characterization of synthesized silver nanoparticles was performed by UV–vis, FT-IR and by FESEM. Based on the absorption properties of synthesized AgNPs, we used AgNPs to detect bovine serum albumin (BSA) and AgNPs-BSA composite nanoprobe was further applied to detect Cu2+ based on absorbance recovery. The proposed method has advantages over existing methods in terms of rapid synthesis and stability of AgNPs and their applications. Analysis is reproducible, cost effective and highly sensitive. The lowest detectable concentration of BSA in this approach is 3nM, and for Cu2+ it can detect upto 200pM. [Copyright &y& Elsevier]