Reuse-focused selection of appropriate technologies for municipal wastewater treatment: a multi-criteria approach.

Wastewater treatment technologies (WWTTs) are employed across the world, and the selection is mainly based on 'past experiences' aimed at 'pollution prevention' in the receiving water bodies. This paper aims to develop a methodology for the selection of an appropriate wastewater treatment chain that produces effluent suitable for the defined reuse. Adopting the least weighted cost approach, four decision criteria: Capital cost, Operation and Maintenance cost, Land requirement, and Energy requirement, have been used and the Full Consistency Method (FUCOM) has been employed for obtaining weights. Quality expectations for 14 reuses have been enlisted, and 25 WWTTs have been evaluated in a total of 360 combinations. In Kanpur city, for water reuse in industrial cooling under restricted land and challenging influent quality conditions, a combination of Membrane Bioreactor (MBR) with Wuhrmann process (WP) is obtained as the most preferred suggestion. For non-potable domestic reuse, Anaerobic Anoxic Oxic (A2O) with Ultrafiltration (UF) and Reverse Osmosis (RO) is the most preferred combination. In Varanasi city, for vehicular washing operations and for flow augmentation (inland surface water), under energy-constraint scenario, high-rate activated sludge-based biological filtration and oxygenated reactor (BIOFOR-F) is suggested. For technology supplementation to existing ASP-based STPs in the city to obtain effluent for inland surface water augmentation, WP in combination with microfiltration (MF) and reverse osmosis (RO) is suggested. Thus, the developed model may be used as a decision-making tool for planning a reuse-focused water reclamation program or for upgradation of existing STPs as per resource availability and target reuse objectives.

Anticarcinogenic activity of blue fluorescent hexagonal boron nitride quantum dots: as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin.

Blue fluorescent hexagonal boron nitride quantum dots (h-BNQDs) of ∼10 nm size as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin (DOX) were synthesized using simple one-step hydrothermal disintegration of exfoliated hexagonal boron nitride at very low temperature âˆ¼ 120 °C. Boron nitride quantum dots (BNQDs) at a concentration of 25 µg/ml enhanced DNA cleavage activity of DOX up to 70% as checked by converting supercoiled fragment into nicked circular PBR322 DNA. The interaction of BNQDs with DOX is proportional to the concentration of BNQDs, with binding constant K b ∼0.07338 µg/ml. In addition, ab initio theoretical results indicate that DOX is absorbed on BNQDs at the N-terminated edge with binding energy -1.075 eV and prevented the normal replication mechanisms in DNA. BNQDs have been shown to kill the breast cancer cell MCF-7 extensively as compared with the normal human keratinocyte cell HaCaT. The cytotoxicity of BNQDs may be correlated with reduced reactive oxygen species level and increased apoptosis in MCF-7 cells, which may be liable to enhance the anticancerous activity of DOX. The results provide a base to develop BNQD-DOX as a more effective anticancer drug.

Synthesis and radioiodination of a nido-1,2-carboranyl derivative of 2-nitroimidazole.

The synthesis of a nido-carboranyl congener of misonidazole, 1-(3'-nido-carboranyl-2'-hydroxy)propyl-2-nitroimidazole, has been carried out. Alternative methods of preparations were conducted to optimize the chemical yield, with a five step synthesis giving an overall yield (from 1,2-carborane) of 36%. A diastereomeric pair of nido-carboranyl compounds was obtained. The diastereomeric nido-carboranyl misonidazole congeners were (radio)iodinated to yield (> 90%) a mixture of diastereomeric compounds in which the iodine had bonded to a boron atom on the nido-carborane moiety. These compounds will be investigated for their application to boron neutron capture therapy (BNCT) and hypoxia imaging of cancer.

Synthesis and radioiodination of N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine tetrafluorophenyl ester: preparation of a radiolabeled phenylalanine derivative for peptide synthesis.

An investigation to prepare a phenylalanine derivative which could be radioiodinated and used directly in peptide synthesis was conducted. N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine tetrafluorophenyl ester was targeted and synthesized from N-Boc-p-iodo-L-phenylalanine. The requisite aryl stannylation reaction was found to be best conducted using the phenylalanine methyl ester. Thus, N-Boc-p-iodo-L-phenylalanine methyl ester was prepared and stannylated using bis(tributyltin) and tetrakis-(triphenylphosphine)palladium(0) in refluxing toluene to prepare N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine methyl ester. Demethylation with aqueous base was accomplished without racemization to yield N-Boc-p-(tri-n-butylstannyl)-L-phenylalanine. Preparation of the targeted stannylphenylalanine tetrafluorophenyl ester was then accomplished using 2,3,5,6-tetrafluorophenol and 1,3-dicyclohexyl-carbodiimide in anhydrous THF. Iodination and radioiodination reactions of the targeted compound were conducted in MeOH/1% HOAc to yield 83-95% of the desired N-Boc-p-[*I]iodo-L-phenylalanine tetrafluorophenyl ester.