A facile synthesis of nontoxic luminescent carbon dots for detection of chromium and iron in real water sample and bio-imaging

In this study, we have reported the synthesis of luminescent carbon dots (CDs) from indigenous potato sources by simple heating reactions. The as-synthesized CDs exhibited an average size of ~ 5.97 nm with a quantum yield (QY) of 6.08%. Furthermore, the CDs possessed high water-solubility, possibly due to the presence of ─COOH and ─OH groups on their surfaces. The quenching of luminescence of the CDs specifically by Cr⁶⁺ and Fe³⁺ ions was used to detect chromium and iron in the water sample. The minimum limit of detection (LOD) for Cr⁶⁺ and Fe³⁺ ions was found to be 0.012 μM and 0.000549 μM, respectively, in a linear range of 0.5 μM-100 μM and 0.5 μM-5 μM for Cr⁶⁺ and Fe³⁺, respectively, which was well below the concentration specified by WHO. We used our sensing system to detect the metal ions in water from the Brahmaputra River as well as in tannery water. In addition, the MTT-based cell viability experiments showed that the CDs were nontoxic within 200 μg/mL. High quantum yield and the easy uptake of CDs enabled the quick labelling of cytoplasm of the HeLa cells, which can be further attributed to bioimaging applications.     

Antimicrobial activity of silver nanoparticles synthesised by using microbial biosurfactant produced by a newly isolated Bacillus vallismortis MDU6 strain

Microbial biosurfactants has evolved as green molecules and their chemical diversity has gained momentum in recent time not only in the field of environmental and industrial sectors but also in the pharmaceutical sector. In this study, an effort was made for the biosynthesis of silver nanoparticle (AgNPs) having antimicrobial and non‐cytotoxic activities with the help of microbial biosurfactant extracted from a novel Bacillus vallismortis strain MDU6 (Genbank accession no. {"type":"entrez-nucleotide","attrs":{"text":"MH382951","term_id":"1546647362"}}MH382951) from petroleum oil logged soil sample in Dibrugarh, Assam. The isolate shows excellent potential for the production of biosurfactant by reducing the surface tension of diesel supplemented medium up to 56.57% only within 5 days. FTIR spectra of the crude biosurfactant show the presence of ʋ _CH2 (asymmetric stretching), ʋ _CH2 (symmetric stretching), ʋ _C=C (stretch), ʋ _C−C (stretch), ʋ _C−H (bending), ʋ _C−O (stretch) and ʋ _C−H (bending) functional groups and LC‐MS/MS analysis confirms it as a cyclic lipopeptide which is a mixture of surfactin and iturin. The synthesized AgNPs showed excellent antimicrobial activities against Escherichia coli (ATCC no. 25922), Listeria monocytogenes (ATCC No. BAA‐751), Staphylococcus aureus (ATCC No. 9542) and Bacillus subtilis (ATCC no. 6051) and showed no cytotoxicity against primary mouse liver cell lines.Inspec keywords: nanoparticles, molecular biophysics, silver, liver, nanofabrication, microorganisms, petroleum, biotechnology, antibacterial activity, surfactants, cellular biophysics, toxicology, surface tension, nanomedicine, Fourier transform infrared spectraOther keywords: C−H functional groups, bending, synthesised AgNPs, excellent antimicrobial activities, ATCC no, bacillus subtilis, antimicrobial activity, silver nanoparticles, bacillus vallismortis MDU6 strain, microbial biosurfactants, green molecules, chemical diversity, environmental sectors, industrial sectors, pharmaceutical sector, noncytotoxic activities, petroleum oil, soil sample, isolate, surface tension, crude biosurfactant show, asymmetric stretching, symmetric stretching, Genbank accession no. {"type":"entrez-nucleotide","attrs":{"text":"MH382951","term_id":"1546647362"}}MH382951, time 5.0 d, Ag     

Self-assembly of neutral dinuclear and trinuclear zinc-benzoate complexes

A structurally important self-assembly of dinuclear and trinuclear zinc-benzoate complexes having formula [Zn₃(μ-OBz)₆(py)₂] · [Zn₂(OBz)₄(py)₂] (A) (where OBz is benzoate and py is pyridine ligand) is reported. The dinuclear and trinuclear complexes present in the crystal lattice of the self-assembly are held together by weak C–Hπ and C–HO interactions.     

Seven Coordinated Metal Complexes derived from (3-Carboxymethoxy-Naphthalen-2-yloxy)-Acetic Acid and Coordination Polymers

A design principle for seven coordinated metal carboxylate complexes and coordination polymers of Mn(II), Cd(II) and Na(I) derived from (3-carboxymethoxy-naphthalen-2-yloxy)-acetic acid (LH2) is presented. The complexes/coordination polymer [Mn(L)(H₂O)₃]·3H₂O (1), [{Cd(L)(H₂O)₂}·H₂O]_n (2); [Cd(L)(py)₃]·3H₂O (3) have metal ions in pentagonal bipyramid environments (py = pyridine). The coordination polymer [{Cd(L)(H₂O)₂}·H₂O]_n (2) may be considered to be the self-assembly of hexacoordinated [Cd(L)(H₂O)₂] units; it reacts with pyridine to form mono-nuclear complex 3. Depending on the reaction conditions, Ni-coordination polymers of L adopt different compositions. From the reaction carried out with NiCl₂ and NaOH in quinoline and water, a hetero bimetallic coordination polymer; namely, [[NaL(H₂O)]₂Ni(H₂O)₄]_n (4) is obtained. A similar reaction in pyridine-water solvent led to [{Ni(L)(py)₃}.py]_n (5). The coordination polymer 5 has pyridine in its interstices held by C–H···π interactions.     

GIS-Based Estimation of Soil Loss from Hilly Urban Area Incorporating Hill Cut Factor into RUSLE

Unplanned residential development in hilly areas leads to steep cuts in natural hillslopes, which in turn, results in excessive soil loss. GIS-based Revised Universal Soil Loss Equation (RUSLE), applied in such a case, underestimates soil loss since such near vertical surfaces are not completely projected in orthorectified satellite images. This paper introduces a "hill cut factor (H_f)", which is input into the cover management factor of RUSLE model. Model is validated with observed soil loss data of a mini hilly urban watershed located in Japorigog hill of Guwahati city. GIS-based soil loss estimation has been carried out for two scenarios: with and without consideration of H_f. Results reveal that consideration of H_f in GIS-based RUSLE replicates the picture of erosion more accurately and gives a similar result with observed soil loss data. Without consideration of H_f, RUSLE underestimates annual soil loss from the studied watershed by almost 28% than the observed value. Adequate design of drainage system by using more accurate soil loss information, derived in this way, can lower the urban flood problem caused due to blockage of drains and culverts with sediments brought down from the inhabited hills in a city.     

Current mode instrumentation amplifier with CDCCC

Analog Integrated Circuits and Signal Processing - In this paper, a new current-mode instrumentation amplifier is presented using a single current differencing current controlled current conveyor...     

A hexanuclear cerium(IV) cluster with mixed coordination environment

Synthesis and structure of a modified intermediate derived from ammonium cerium(IV) nitrate for oxidative reactions as a hexanuclear cerium(IV) complex that has cerium ions in two different coordination environment is reported. The complex having ability to oxidise three moles of catechol to corresponding quinone has a composition NH₄[Ce₆(µ³-O)₅(µ³-OH)₃(µ²-C₆H₅COO)₉(NO₃)₃(DMF)₃].DMF.H₂O is prepared under room temperature and is characterised by X-ray crystallography.