Publications by authors named "Avijit Ghosh"

58 Publications

Digging out the keys in the heap of seized pangolin scales: up scaling pangolin conservation using wildlife forensics.

Forensic Sci Int 2021 Apr 20;323:110780. Epub 2021 Apr 20.

Zoological Survey of India, New Alipore, Kolkata 700053, West Bengal, India. Electronic address:

Pangolins, despite banned through legislative measures, are threatened by heavy illegal poaching for the demand of meat and scales in the making of Traditional East Asian Medicines (TEAM), resulting in severe decline of the population sizes across the distribution range. Species assignment from the confiscated scales is pre-requisite to enforce the appropriate national and international law and legislations in the successful prosecution of the cases in the court of law. In the present study, we characterised the morphological features in voucher specimens of the Indian pangolin (Manis crassicaudata) and Chinese pangolin (Manis pentadactyla) and used the identified keys to establish the species identity from the confiscated scales. We investigated intra and inter genetic variations by sequencing 624 scales of pangolin for cytb gene and obtained unique haplotypes to Indian and Chinese pangolins by comparing sequences with all eight pangolin species. Scales from the voucher specimens, which varied in the size, shape and weight, were measured for morphological features to establish species signature of Indian and Chinese pangolins. The cumulative success of species assignment using morphological features from the confiscated scales was 98.33% and 100% from the large and caudal scales, respectively. The present study has generated reference signature of Indian and Chinese pangolins from the scales and facilitates the law enforcements for taking spot decision by ascertaining species identity from the seized scales.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.forsciint.2021.110780DOI Listing
April 2021

60 years of fertilization and liming impacts on soil organic carbon stabilization in a sub-tropical Alfisol.

Environ Sci Pollut Res Int 2021 Apr 21. Epub 2021 Apr 21.

Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, New Delhi, 110012, India.

Limited information is available on the C stabilization mechanism of tropical soils under different management practices including long-term organic manuring, mineral fertilization alone, or in combination with lime. Hence, to understand the effect of continuous application (for 60 years) of organic manure, fertilizer, and lime alone or in combination on an acidic Alfisol, stabilization of soil organic carbon (SOC) was evaluated under maize (Zea mays L.) wheat (Triticum aestivum L.) cropping. There were eight treatments that included farmyard manure (FYM) and nitrogen (N) applied in terms of FYM, additional dose of phosphorus (P) and potassium (K) applied in terms of inorganic fertilizer (FYM + P'K'), FYM + P'K' with liming (FYM + P'K' + L) and NPK alone. These treatments were laid in a randomized block design with three replications. Results indicated that FYM + P'K' plots had maximum amount of SOC inside large macroaggregates. The value was 33 and 92% greater than only minerally fertilized (NPK) and unfertilized control plots, respectively, whereas microaggregate-associated C was highest in plots with FYM + P'K' and lime (FYM + P'K' + L), which was 48 and 183% more than unfertilized control and NPK plots, respectively. Inside soil microaggregates, plots under FYM + P'K' had highest labile C, while NPK + L plots had highest recalcitrant C. Plots with organic amendments contained higher glomalin in large macroaggregates. Plots treated with FYM + P'K' had maximum intra-aggregate particulate organic matter within microaggregates inside macroaggregates (iPOM_mM), which was 28 and 74% higher than NPK and unfertilized control plots, respectively. Total C stock inside the protected microaggregates within macroaggregates was maximum for FYM + P'K' plots. It had 38, 67, and 171% higher C stock than NPK, FYM, and unfertilized control plots, respectively. Interestingly, despite estimated C input in FYM-treated plots was much higher than NPK plots, FYM-treated plots had less C stabilization within microaggregates and within microaggregates inside macroaggregates. Microaggregates within macroaggregates accounted for ~54% of the recalcitrant C content. Thus, macroaggregates stabilization through occlusion of microaggregates was accountable for sequestration of SOC and only FYM application did not promote that mechanism compared to NPK. Carbon stabilization within macroaggregates under FYM plots was mainly governed by amorphous iron oxide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-021-14019-wDOI Listing
April 2021

Species identification from seized animal oil: a case study of suspected Gangetic dolphin (Platanista gangetica).

Int J Legal Med 2021 Apr 6. Epub 2021 Apr 6.

Centre for Forensic Science, Zoological Survey of India, New Alipore, Kolkata, 700 053, West Bengal, India.

Poaching of South Asian river dolphins is considered one of the main reasons for the rapid decline of their natural populations. To curb the escalated rate of poaching, high numbers of oil and meat seizures are recovered with subsequent convictions by the law enforcement agencies. In this connection, we report a case where suspected animal oil was confiscated by the forest official of West Bengal. We extracted DNA and successfully amplified partial fragments of Cytb and 16S rRNA mitochondrial genes. The generated sequences identified that the seized oil belonged to the Ganges river dolphin (Platanista gangetica) which is protected as Schedule I under the Wildlife (Protection) Act, 1972 of India and listed as "Endangered" under IUCN and APPENDIX I in CITES. In routine case work analysis, oil samples are not preferred for forensic DNA investigation due to low DNA yield and presence of inhibitors or contaminants leading to high failure rate. However, the present study generates hope for identifying species from seized animal oil and supports law enforcement in successful prosecution of the case.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00414-021-02574-3DOI Listing
April 2021

Solvent-Regulated Fluorimetric Differentiation of Al and Zn Using an AIE-Active Single Sensor.

J Phys Chem A 2021 Feb 10;125(7):1490-1504. Epub 2021 Feb 10.

Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, South Korea.

The absence of d-orbital electrons or presence of full-filled d-orbital electrons in metal ions is a well-known Achilles' heel problem for the detection of these metal ions by a simple UV-visible study. For this reason, detection of metal ions such as Al with no d-orbital electrons or Zn with filled d-orbital electrons is a challenging task. Herein, we report a 2-naphthol-based fluorescent probe [1-(()-(()-(5-bromo-2-hydroxybenzylidene)hydrazono)methyl)naphthalen-2-ol] () that has been used to sense and discriminate Al and Zn via solvent regulation. The probe exhibits excellent selectivity and swift sensitivity toward Al in MeOH-water (9:1, v/v) and toward Zn in dimethyl sulfoxide (DMSO)-water (9:1, v/v) among various metal ions. The respective detection limit is found to be 9.78 and 3.65 μM. The sensing mechanism is attributed to multiple processes, viz., the inhibition of photo-induced electron transfer (PET) along with the introduction of chelation-enhanced emission (CHEF) and excited-state intramolecular proton transfer (ESIPT) inhibition, which are experimentally well verified by UV-vis absorption spectroscopy, emission spectroscopy, and NMR spectroscopy. The probe shows aggregation-induced emissive (AIE) response in ≥70% aqueous media as well as in the solid state. The experimental results are well corroborated by time-resolved photoluminescence (TRPL) and density functional theory (DFT) calculations. An advanced-level OR-AND-NOT logic gate has been constructed from a different chemical combinational input and emission output. The reversible recognition of both Al in MeOH-water (9:1, v/v) and Zn in DMSO-water (9:1, v/v) is also ascertained in the presence of NaEDTA, enabling the construction of a molecular memory device. The probe also detects intracellular Al/Zn ions in Hela cells. Altogether, our fundamental findings will pave the way for designing and synthesis of unique chemosensors that could be used for cell imaging studies as well as constructing molecular logic gates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpca.0c10518DOI Listing
February 2021

Geological and Pleistocene glaciations explain the demography and disjunct distribution of red panda (A. fulgens) in eastern Himalayas.

Sci Rep 2021 Jan 8;11(1):65. Epub 2021 Jan 8.

Zoological Survey of India, New Alipore, Kolkata, West Bengal, 700053, India.

Pleistocene glaciations facilitated climatic oscillations that caused for enormous heterogeneity in landscapes, and consequently affected demography and distribution patterns of the mountain endemic species. In this context, we investigated demographic history and population genetic structure of red panda, distributed along the geographical proximity in the southern edge of the Qinghai-Tibetan Plateau. Bayesian based phylogeny demonstrated that red panda diverged about 0.30 million years ago (CI 0.23-0.39) into two phylogenetic (sub) species, that correspond to the middle-late Pleistocene transition. The observed intraspecific clades with respect to Himalayan and Chinese red panda indicated restricted gene flow resulting from the Pleistocene glaciations in the eastern and southern Tibetan Plateau. We found Himalayan red panda population at least in KL-India declined abruptly in last 5-10 thousand years after being under demographic equilibrium. We suggest revisiting the ongoing conservation activities through cross border collaboration by developing multi-nationals, and multi-lateral species-oriented conservation action plans to support the red panda populations in transboundary landscapes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-80586-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794540PMC
January 2021

Hyaluronic acid engrafted metformin loaded graphene oxide nanoparticle as CD44 targeted anti-cancer therapy for triple negative breast cancer.

Biochim Biophys Acta Gen Subj 2021 03 5;1865(3):129841. Epub 2021 Jan 5.

Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Sector III, Salt lake, Kolkata 700098, India. Electronic address:

Background: Triple negative breast cancer (TNBC) is the most aggressive form of breast cancer with limited treatment modalities. It is associated with high propensity of cancer recurrence.

Methods: UV Spectroscopy, FTIR, DLS, Zeta potential, TEM and SEM were employed to characterize nanoparticles. MTT assay, Wound healing assay, SEM, Immunocytochemistry analysis, Western blot, RT-PCR, mammosphere formation assay were employed to study apoptosis, cell migration and stemness. Tumor regression was studied in chick embryo xenograft and BALB/c mice model.

Results: Hylaluronic acid engrafted metformin loaded graphene oxide (HA-GO-Met) nanoparticles exhibited an anti-cancer efficacy at much lower dosage as compared to metformin alone. HA-GO-Met nanoparticles induced apoptosis and inhibited cell migration of TNBC cells by targeting miR-10b/PTEN axis via NFkB-p65. Upregulation of PTEN affected pAKT(473) expression that induced apoptosis. Cell migration was inhibited by reduction of pFAK/integrinβ1 expressions. Treatment inhibited epithelial mesenchymal transition (EMT) and reduced stemness as evident from the increase in E-cadherin expression, inhibition of mammosphere formation and low expression levels of stemness markers including nanog, oct4 and sox2 as compared to control. Moreover, tumor regression was studied in chick embryo xenograft and BALB/c mice model. HA-GO-Met nanoparticle treatment reduced tumor load and nullified toxicity in peripheral organs imparted by tumor.

Conclusions: HA-GO-Met nanoparticles exhibited an enormous anti-cancer efficacy in TNBC in vitro and in vivo.

General Significance: HA-GO-Met nanoparticles induced apoptosis and attenuated cell migration in TNBC. It nullified overall toxicity imparted by tumor load. It inhibited EMT and reduced stemness and thereby addressed the issue of cancer recurrence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbagen.2020.129841DOI Listing
March 2021

Time-lapse sentinel surveillance of SARS-CoV-2 spread in India.

PLoS One 2020 22;15(10):e0241172. Epub 2020 Oct 22.

Zoological Survey of India, New Alipore, Kolkata, West Bengal, India.

The novel coronavirus 2019 (COVID-19) global pandemic has drastically affected the world economy, raised public anxiety, and placed a substantial psychological burden on the governments and healthcare professionals by affecting over 4.7 million people worldwide. As a preventive measure to minimise the risk of community transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in India, a nationwide lockdown was imposed initially for 21 days to limit the movement of 1.3 billion people. These restrictions continue in most areas, with a conditional relaxation occurring in a few Indian states. In an attempt to assess the emerging mutants of SARS-CoV-2 and determine their spread in India, we analysed 112 complete genomes of SARS-CoV-2 in a time-lapse manner. We found 72 distinct SARS-CoV-2 haplotypes, defined by 143 polymorphic sites and high haplotype diversity, suggesting that this virus possesses a high evolutionary potential. We also demonstrated that early introduction of SARS-CoV-2 into India was from China, Italy and Iran and observed signs of community spread of the virus following its rapid demographic expansion since its first outbreak in the country. Additionally, we identified 18 mutations in the SARS-CoV-2 spike glycoprotein and a few selected mutations showed to increase stability, binding affinity, and molecular flexibility in the overall tertiary structure of the protein that may facilitate interaction between the receptor binding domain (RBD) of spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor. The study provides a pragmatic view of haplotype-dependent spread of SARS-CoV-2 in India which could be important in tailoring the pharmacologic treatments to be more effective for those infected with the most common haplotypes. The findings based on the time-lapse sentinel surveillance of SARS-CoV-2 will aid in the development of a real-time practical framework to tackle the ongoing, fast-evolving epidemic challenges in the country.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0241172PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7580942PMC
November 2020

Fine-scale landscape genetics unveiling contemporary asymmetric movement of red panda (Ailurus fulgens) in Kangchenjunga landscape, India.

Sci Rep 2020 09 22;10(1):15446. Epub 2020 Sep 22.

Zoological Survey of India, New Alipore, Kolkata, West Bengal, 700053, India.

Wildlife management in rapid changing landscapes requires critical planning through cross cutting networks, and understanding of landscape features, often affected by the anthropogenic activities. The present study demonstrates fine-scale spatial patterns of genetic variation and contemporary gene flow of red panda (Ailurus fulgens) populations with respect to landscape connectivity in Kangchenjunga Landscape (KL), India. The study found about 1,309.54 km area suitable for red panda in KL-India, of which 62.21% area fell under the Protected Area network. We identified 24 unique individuals from 234 feces collected at nine microsatellite loci. The spatially explicit and non-explicit Bayesian clustering algorithms evident to exhibit population structuring and supported red panda populations to exist in meta-population frame work. In concurrence to the habitat suitability and landscape connectivity models, gene flow results supported a contemporary asymmetric movement of red panda by connecting KL-India in a crescent arc. We demonstrate the structural-operational connectivity of corridors in KL-India that facilitated red panda movement in the past. We also seek for cooperation in Nepal, Bhutan and China to aid in preparing for a comprehensive monitoring plan for the long-term conservation and management of red panda in trans-boundary landscapes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-72427-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508845PMC
September 2020

Combinatorial therapy of Thymoquinone and Emodin synergistically enhances apoptosis, attenuates cell migration and reduces stemness efficiently in breast cancer.

Biochim Biophys Acta Gen Subj 2020 11 29;1864(11):129695. Epub 2020 Jul 29.

Center for Research in Nanoscience and Nanotechnology, Technology Campus, University of Calcutta, JD-2, Sector III, Salt Lake City, Kolkata, 700106, India. Electronic address:

Background: Breast cancer intimidates the contemporary medical advances, attempting to revolutionize cancer therapeutics. While patients suffering an advanced breast cancer are dependent on mono drugs, yet the build out of resistance leading to treatment fails has become inevitable.

Methods: Cell viability Assay with MTT revealed the "IC50" concentrations of the drugs in both cancer as well as PBMC. Cell cycle arrest, flow cytometric ROS analysis & apoptosis evaluation pointed out the efficacy of the dual drug. Wound Healing, Transwell Migration & Immunocytochemistry indicated anti-migratory potential of TQ-Emo while expression patterns of Cl-Cas3, p53, Bax, Bcl2 & the stemness markers further vouched the potential of the combinatorial drug. Furthermore, validation of tumor inhibitory effect was earned by an ex-ovo xenograft model.

Results: Dual dosage enhanced apoptosis through ROS generation, anti- migratory effect by targeting FAK &Integrins, displaying effective stemness control by assessing regulatory proteins- Oct4, Sox2, Nanog, ALDH1/2. Ex-ovo xenograft model validated tumor regression. Our study thereby deals with devastating effects of cancer drug resistance while trying to abate enhanced migratory potential & stemness, utilizing the synergism of the combinable therapy.

Conclusion: TQ/Emo inhibited breast cancer proliferation synergistically while enhancing cytotoxicity, inducing apoptosis on MCF-7 cells while curbing migration & stemness.

General Significance: Employment of the combinatorial phytochemicals, Thymoquinone & Emodin attempted to achieve deliverables like reduced cellular toxicity, drug resistance, anti-migratory potency & stemness. Besides, decreased p-FAK expression or regression in Mammosphere & tumor size in ex-ovo xenograft model is indicative of the better anti-tumorigenic potential of the dual formulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbagen.2020.129695DOI Listing
November 2020

Delivery of dual miRNA through CD44-targeted mesoporous silica nanoparticles for enhanced and effective triple-negative breast cancer therapy.

Biomater Sci 2020 May 22;8(10):2939-2954. Epub 2020 Apr 22.

Center for Research in Nanoscience and Nanotechnology, Technology Campus, University of Calcutta, JD-2, Sector-III, Salt Lake City, Kolkata 700106, India.

The development of new therapeutic strategies to target triple-negative breast cancer (TNBC) is in much demand to overcome the roadblocks associated with the existing treatment procedures. In this regard, therapies targeting the CD44 receptor have drawn attention for more than a decade. MicroRNAs (miRNAs) modulate post-transcriptional gene regulation and thus, the correction of specific miRNA alterations using miRNA mimics or antagomiRs is an emerging strategy to normalize the genetic regulation in the tumor microenvironment. It has been acknowledged that miR-34a is downregulated and miR-10b is upregulated in TNBC, which promotes tumorigenesis and metastatic dissemination. However, there are a few barriers related to miRNA delivery. Herein, we have introduced tailored mesoporous silica nanoparticles (MSNs) for the co-delivery of miR-34a-mimic and antisense-miR-10b. MSN was functionalized with a cationic basic side chain and then loaded with the dual combination to overexpress miR-34a and downregulate miR-10b simultaneously. Finally, the loaded MSNs were coated with an hyaluronic acid-appended PEG-PLGA polymer for specific targeting. The cellular uptake, release profile, and subsequent effect in TNBC cells were evaluated. In vitro and in vivo studies demonstrated high specificity in TNBC tumor targeting, leading to efficient tumor growth inhibition as well as the retardation of metastasis, which affirmed the clinical application potential of the system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0bm00015aDOI Listing
May 2020

Delivery of thymoquinone through hyaluronic acid-decorated mixed Pluronic® nanoparticles to attenuate angiogenesis and metastasis of triple-negative breast cancer.

J Control Release 2020 06 31;322:357-374. Epub 2020 Mar 31.

Center for Research in Nanoscience and Nanotechnology, University of Calcutta, Technology Campus, JD-2, Sector-III, Salt Lake, Kolkata 700106, West Bengal, India. Electronic address:

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic subtype of breast cancer showing non-responsiveness to most available therapeutic options. Therefore, smart therapeutic approaches to selectively transport and target TNBCs are required. Herein, we developed thymoquinone (TQ)-loaded, hyaluronic acid (HA)-conjugated Pluronic® P123 and F127 copolymer nanoparticles (HA-TQ-Nps) as a selective drug-carrying vehicle to deliver anticancer phytochemical TQ to TNBC cells. The mean size of nanoparticles was around 19.3 ± 3.2 nm. and they were stable at room temperature up to 4 months. HA-TQ-Nps were immensely cytotoxic towards TNBC cells but did not show the toxic effect on normal cells. Detailed investigations also demonstrated its pro-apoptotic, anti-metastatic and anti-angiogenic activity. In-depth mechanistic studies highlighted that HA-TQ-Nps retarded cell migration of TNBC cells through up-regulation of microRNA-361 which in turn down-regulated Rac1 and RhoA mediated cell migration and also perturbed the cancer cell migration under the influence of the autocrine effect of VEGF-A. Moreover, HA-TQ-Np-treatment also perturbed tumor-induced vascularization by reducing the secretion of VEGF-A. The anti-metastatic and anti-angiogenic activity of HA-TQ-Nps was found to be evident in both MDA-MB-231 xenograft chick embryos and 4T1-mammary solid tumor model in syngeneic mice. Thus, an innovative targeted nano-therapeutic approach is being established to reduce the tumor burden and inhibit metastasis and angiogenesis simultaneously for better management of TNBC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jconrel.2020.03.033DOI Listing
June 2020

A Promising Proton Conducting Electrolyte BaZrHoO (0.05 ≤ x ≤ 0.20) Ceramics for Intermediate Temperature Solid Oxide Fuel Cells.

Sci Rep 2020 Feb 26;10(1):3461. Epub 2020 Feb 26.

Materials Science Centre, Indian Institute of Technology, Kharagpur, 721302, India.

In this study, the Ho-substituted BaZrO electrolyte ceramics (BaZrHoO, 0.05 ≤ x ≤ 0.20) were synthesized through a low-cost flash pyrolysis process followed by conventional sintering. The effects of Ho-substitution in BaZrO studied in terms of the structural phase relationship, microstructure and electrical conductivity to substantiate augmented total electrical conductivity for intermediate temperature solid oxide fuel cells (IT-SOFCs). The Rietveld refined X-ray diffraction (XRD) patterns revealed that pure phase with [Formula: see text] space group symmetry of cubic crystal system as originated in all samples sintered at 1600 °C for 8 h. The Raman spectroscopic investigations also approved that Ho incorporation in BaZrO ceramics. Field Emission Scanning Microscopic (FESEM) study informed a mixture of fine and coarse grains in the fracture surface of Ho-substituted BaZrO sintered samples. The relative density and average grain size of samples were observed to decrease as per the addition of Ho-substitution in BaZrO ceramics. The electrical conductivity study was accomplished by Electrical Impedance Spectroscopy (EIS) under 3% humidified O atmosphere from 300 to 800 °C. Furthermore, the total electrical conductivity of BaZrHoO ceramic was found to be 5.8 × 10 S-cm at 600 °C under 3% humidified atmosphere, which may be a promising electrolyte for IT-SOFCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-60174-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7044191PMC
February 2020

Agriculture, dairy and fishery farming practices and greenhouse gas emission footprint: a strategic appraisal for mitigation.

Environ Sci Pollut Res Int 2020 Apr 14;27(10):10160-10184. Epub 2020 Feb 14.

ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan, Almora, Uttarakhand, 263601, India.

Rising global population would force farmers to amplify food production substantially in upcoming 3-4 decades. The easiest way to increase grain production is through expanding cropping area by clearing uncultivated land. This is attained by permitting deadly loss of carbon (C) stocks, jeopardizing ecosystem biodiversity and deteriorating environmental quality. We aim to propose key agronomical tactics, livestock management strategy and advance approaches for aquaculture to increase productivity and simultaneously reduce the environmental impacts of farming sector. For this, we considered three major sectors of farming, i.e. agriculture, fishery and dairy. We collected literatures stating approaches or technologies that could reduce GHG emission from these sectors. Thereafter, we synthesized strategies or options that are more feasible and accessible for inclusion in farm sector to reduce GHG emission. Having comprehensively reviewed several publications, we propose potential strategies to reduce GHG emission. Agronomic practices like crop diversification, reducing summer fallow, soil organic carbon sequestration, tillage and crop residue management and inclusion of N-fixing pulses in crop rotations are some of those. Livestock management through changing animals' diets, optimal use of the gas produced from manures, frequent and complete manure removal from animal housing and aquaculture management strategies to improve fish health and improve feed conversion efficiency could reduce their GHG emission footprint too. Adapting of effective and economic practices GHG emission footprint reduction potential of farming sector could make farming sector a C neutral enterprise. To overcome the ecological, technological and institutional barriers, policy on trade, tax, grazing practice and GHG pricing should be implemented properly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-020-07949-4DOI Listing
April 2020

Soft chromophore featured liquid porphyrins and their utilization toward liquid electret applications.

Nat Commun 2019 09 30;10(1):4210. Epub 2019 Sep 30.

International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044, Japan.

Optoelectronically active viscous liquids are ideal for fabricating foldable/stretchable electronics owing to their excellent deformability and predictable π-unit-based optoelectronic functions, which are independent of the device shape and geometry. Here we show, unprecedented 'liquid electret' devices that exhibit mechanoelectrical and electroacoustic functions, as well as stretchability, have been prepared using solvent-free liquid porphyrins. The fluidic nature of the free-base alkylated-tetraphenylporphyrins was controlled by attaching flexible and bulky branched alkyl chains at different positions. Furthermore, a subtle porphyrin ring distortion that originated from the bulkiness of alkyl chains was observed. Its consequences on the electronic perturbation of the porphyrin-unit were precisely elucidated by spectroscopic techniques and theoretical modelling. This molecular design allows shielding of the porphyrin unit by insulating alkyl chains, which facilitates its corona-charged state for a long period under ambient conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-019-12249-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768991PMC
September 2019

Sequential Fluorescence Recognition of Molybdenum(VI), Arsenite, and Phosphate Ions in a Ratiometric Manner: A Facile Approach for Discrimination of AsO and HPO.

ACS Omega 2019 Jun 21;4(6):10877-10890. Epub 2019 Jun 21.

Department of Chemistry, The University of Burdwan, Burdwan 713104, West Bengal, India.

An amide-based smart probe (L) is explored for nanomolar detection of Mo(VI) ion in a ratiometric manner, involving hydrogen-bond-assisted chelation-enhanced fluorescence process through inhibition of photoinduced electron transfer process. The recognition of Mo(VI) is associated with a 17-fold fluorescence enhancement and confirmed by single-crystal X-ray diffraction of the resulting Mo(VI) complex (M1). Further, M1 selectively recognizes arsenite through green emission of their adduct (C1) with an 81-fold fluorescence enhancement. Interestingly, dihydrogen phosphate causes dissociation of C1 back to free L having weak fluorescence. The methods are fast, highly selective, and allow their bare eye visualization at physiological pH. All of the interactions have been substantiated by time-dependent density functional theory calculations to rationalize their spectroscopic properties. The corresponding lowest detection limits are 1.5 × 10 M for Mo(VI), 1.2 × 10 M for AsO, and 3.2 × 10 M for HPO, whereas the respective association constants are 4.21 × 10 M for Mo(VI), 6.49 × 10 M for AsO, and 2.11 × 10 M for HPO. The L is useful for efficient enrichment of Mo(VI) from aqueous solution, while M1 efficiently removes AsO from environmental samples by solid-phase extraction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.9b00377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648501PMC
June 2019

Transferrin-decorated thymoquinone-loaded PEG-PLGA nanoparticles exhibit anticarcinogenic effect in non-small cell lung carcinoma via the modulation of miR-34a and miR-16.

Biomater Sci 2019 Oct 14;7(10):4325-4344. Epub 2019 Aug 14.

Center for Research in Nanoscience and Nanotechnology, Technology Campus, University of Calcutta, JD-2, Sector III, Salt Lake City, Kolkata-700106, West Bengal, India.

Non-small cell lung carcinoma (NSCLC) is a highly lethal type of cancer with limited therapeutic avenues available to date. In the present study, we formulated PEGylated PLGA thymoquinone nanoparticles (TQ-Np) for improved TQ delivery to NSCLC cells. Transferrin (TF), a biodegradable, non-immunogenic and non-toxic protein, is well known to bind to TFR (transferrin receptor) over-expressed in non-small cell lung carcinoma A549 cells. Thus, the further decoration of the PEGylated PLGA thymoquinone nanoparticles with transferrin (TF-TQ-Np) enhanced the internalization of the nanoparticles within the A549 cells and the activity of TQ. We established TF-TQ-Np as a potent anti-tumorigenic agent through the involvement of p53 and the ROS feedback loop in regulating the microRNA (miRNA) circuitry to control apoptosis and migration of NSCLC cells. TF-TQ-Np-mediated p53 up-regulation favored the potential simultaneous activation of miR-34a and miR-16 targeting Bcl2 to induce apoptosis in the A549 cells. Additionally, TF-TQ-Np also restricted the migration through actin de-polymerization via activation of the p53/miR-34a axis. Further studies in chick CAM xenograft models confirmed the anti-cancer activity of TF-TQ-Np by controlling the p53/miR-34a/miR-16 axis. Furthermore, in vivo experiments conducted in a xenograft model in immunosuppressed Balb/c mice also proved the efficacy of the nanoparticles as an antitumor agent against NSCLC. Thus, our findings cumulatively suggest that the transferrin-adorned TQ-Np successfully coupled two distinct miRNA pathways to potentiate the apoptotic death cascade in the very lethal NSCLC cells and also restricts the migration of these cells without imparting any significant toxicity, which occurs in the widely used chemotherapeutic combinations. Thereby, our findings rekindle new hopes for the development of improved targeted therapeutic options with specified molecular objectives for combating the deadly NSCLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9bm00912dDOI Listing
October 2019

Long-term in situ moisture conservation in horti-pasture system improves biological health of degraded land.

J Environ Manage 2019 Oct 5;248:109339. Epub 2019 Aug 5.

ICAR- Indian Grassland and Fodder Research Institute, Jhansi, Uttar Pradesh, 284 003, India.

In situ moisture conservation practices can conserve fertile topsoil and enhance available water in soil profile. We hypothesised that reclaiming degraded land ecologically through tree + pasture + in situ moisture conservation practices would significantly improve soil organic carbon (SOC) and health. Hence, the objectives were a) to identify changes in nutrient cycling enzymes and SOC status due to different in situ soil moisture conservation options in surface and subsurface soil layers, and b) to test the potentiality of soil enzymes to determine long-term nutrient availability. We conducted a long-term experiment involving aonla (Emblica officinalis) trees + pasture (Cenchrus ciliaris + Stylosanthes seabrana) + in situ soil moisture conservation measures viz. staggered contour trenches (T1), continuous contour trenches (T2), stone mulch (T3), vegetative barriers (T4), control (T5) and fallow land (T6) since 2007. Recommended dose of nitrogen (N), phosphorus (P) and potassium (K) were added to all treatments, except T6. SOC concentration increased by ~51 and 31% in T1 and T2, respectively, over T5 in surface (0-15 cm) soil. Culturable bacterial and fungal populations increased by ~20 and 95% in T1 over T5 in surface soil. Activities of all soil enzymes increased in T1 and T2 (ranging from 42 to 289%) over T5 and T6 in both surface and sub-surface (15-30 cm) layers. However, specific activity of phenol oxidase was ~25% lower for T1 than T6, suggesting more efficient SOC sequestration in T1. Moreover, geometric mean enzyme activity of T1 was ~65 and 33% higher than T5 and T3, respectively, in surface soil. Treated soil quality index (T-SQI) of T1 was ~184% higher than T5. Soil functional diversity was also ~1.24 and 1.22 times higher in T1 and T2 than T5, respectively. Peroxidase was the major C degrading enzyme in this ecosystem. Protease, urease and phosphatase significantly influenced N and P availability along with fruit and pasture yields. Importantly, ~96, 62 and 82% variability of SOC, N and P concentrations, respectively, could be attributed to their corresponding enzyme activities. Principal components analysis (PCA) revealed one-way operational role of soil enzymes. Thus, enzymes are potentially important for recycling nutrients from litters, root biomass of fruit trees and grasses to boost their availability in the long run. Adoption of horti-pasture system combined with moisture conservation practices and staggered contour trenches or continuous contour trenches ensured higher above ground biomass yield, SOC, nutrient availability and soil quality. Thus, long-term use of these practices could be recommended for reclamation and improving soil health and crop productivity of degraded lands of central India.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jenvman.2019.109339DOI Listing
October 2019

Modeling Exposure to Understand and Predict Kidney Injury.

Semin Nephrol 2019 Mar;39(2):176-189

Medicine Design Modeling and Simulation, Pfizer, Inc, Cambridge, MA.

Exposure is a critically important aspect to consider in the study and management of drug-induced kidney injury. Although blood concentrations of kidney toxicants often may provide a valid surrogate measure of kidney exposure, the kidney has several unique physiological and biochemical properties that lend themselves to accumulation or exclusion of some drugs at sites of toxicity. In such cases, an understanding of these pharmacokinetic mechanisms can be as important as understanding the underlying mechanisms of toxicity. Physiologically based pharmacokinetic models, which mathematically codify such mechanisms in a biologically plausible form, increasingly are being used for developing an understanding of pharmacokinetics across patient populations, drug-drug interactions, and pharmacokinetic-pharmacodynamic relationships. This perspective provides a review of the physiological and biochemical mechanisms as well as the physiochemical properties that theoretically could drive drug accumulation or exclusion within the kidney, along with examples in which these mechanisms have proven important in driving the manifestation of toxicity in vivo. In addition, an overview of the structure, applications, and limitations of existing kidney physiologically based pharmacokinetic models is provided. Finally, a perspective on gaps and associated challenges to such models in the field of toxicology is discussed briefly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semnephrol.2018.12.006DOI Listing
March 2019

Municipal solid waste (MSW): Strategies to improve salt affected soil sustainability: A review.

Waste Manag 2019 Feb 19;84:38-53. Epub 2018 Nov 19.

NBSS and LUP, Regional Centre, University Campus, Bhora Ganeshji Road, Udaipur 313001, Rajasthan, India.

Salt-induced soil degradation is a serious threat to global agriculture which is responsible for diminished productivity of agro-ecosystems. Irrigation with poor quality water and indiscriminate use of chemical fertilizers to increase crop productivity creates salt accumulation in soil profile thereby reducing crop sustainability. High concentration of salts in soil inhibits plant growth due to low osmotic potential of the soil solution, ion toxicity and imbalance reduces nutrient uptake, crop yields. Low productivity of saline soils is not only due to salt toxicity or excess amounts of soluble salts but also lack of available mineral nutrients especially nitrogen, phosphorus, potassium and soil organic matter. Hence, sustainable management of salt-affected soils are paramount importance to meet the demands of food grain production for an ever-rising population in the world. Recently, municipal solid waste has gained importance as an organic amendment for restoring soil fertility and finally contributing to productivity of salt-affected soils. This paper compares extant waste generation, their properties and standards pertinent to municipal solid waste in different countries and explores the unique recent history in some countries that shows high environmental regard and rapid changes and also suggests policy experiencing from high environmental regard and rapid changes from other countries, so that policy makers can propose new or revise current municipal solid waste standards for salt affected soils. Municipal solid waste compost improves soil biological, physical and chemical properties because of high soil organic matter and lower concentration of pollutants. Therefore, the use of municipal solid waste in salt-affected soils could be an alternative to costly chemical amendments as well as reduce the reliance on chemical fertilizers for increasing productivity of salt-affected soil. The municipal solid wastes significantly improve crop yields. However, further long-term experimental investigations are needed to re-validate the application of municipal solid waste compost in improving physical, chemical and biological properties and to step up organic fertilization use in a wide range of both saline and sodic soils. In future, research should be directed to address these issues globally to minimise ecological disturbances and to set environmental standards, and evaluate the feasibility of the policies in different countries and their impact on socio-economic conditions of local people.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.wasman.2018.11.020DOI Listing
February 2019

Folic-Acid-Adorned PEGylated Graphene Oxide Interferes with the Cell Migration of Triple Negative Breast Cancer Cell Line, MDAMB-231 by Targeting miR-21/PTEN Axis through NFκB.

ACS Biomater Sci Eng 2019 Jan 4;5(1):373-389. Epub 2018 Dec 4.

Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Sector III, Salt Lake, Kolkata 700106, India.

Triple negative breast cancer (TNBC), characterized by its aggressive and highly metastatic nature, is difficult to cure by the currently available therapies. In our investigation, folic-acid-adorned PEGylated graphene oxide (FA-PEG-GO) was synthesized by modifying graphene oxide (GO) with folic acid-PEG conjugate (FA-PEG-NH) by EDC/NHS coupling reaction. FA-PEG-GO exhibited an exceptional potential to attenuate cell migration of TNBC cell line ,MDAMB-231 as compared to GO because of the adorned folic acid moiety, which rendered better targeting. FA-PEG-GO inhibited cell migration by actin depolymerization and perturbing lamellipodia formation. The immunocytochemistry and western blot data unraveled the fact that FA-PEG-GO inhibited cell migration by targeting miR-21 by restricting the nuclear translocation of NFκB. The downregulation of miR-21 resulted in the elevation of PTEN expression which sequentially downregulated pFAK resulting in inhibition of cell migration. Moreover, upregulation of PTEN in FA-PEG-GO treated cells led to the decrease in expression of the downstream regulators including pAkt(Ser473) and pERK1/2, which contributed to the retardation of cell migration. Interestingly, the overexpression of NFκB-p65 by the transfection of NFκB-p65 expression plasmid in TNBC cells reversed the inhibitory effect of FA-PEG-GO on the nuclear translocation of NFκB-p65 which stabilized miR-21 expression and successively downregulated PTEN expression in FA-PEG-GO treated cells. Furthermore, miR-21 overexpression by transfection of miR-21 mimic in turn downregulated PTEN expression and sequentially restored the expression of pFAK even upon FA-PEG-GO treatment. miR-21 overexpression also compensated the inhibitory effect of FA-PEG-GO on pAkt(Ser473) and pERK1/2 which was evident from their significant expression in FA-PEG-GO-treated cells. The studies on chick embryo model ratified the antimigratory efficacy of FA-PEG-GO. Altogether, our study unveiled the enormous potential of FA-PEG-GO to attenuate migration of TNBC cell line, MDAMB-231 by targeting the miR-21/PTEN axis through NFκB and thereby providing insights on cancer treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsbiomaterials.8b01088DOI Listing
January 2019

Reuse of fly ash and bottom ash in mortars with improved thermal conductivity performance for buildings.

Heliyon 2018 Nov 16;4(11):e00934. Epub 2018 Nov 16.

School of Energy Studies, Jadavpur University, Kolkata-32, West Bengal, India.

An approach towards effective utilization of fly ash and bottom ash in the construction of energy efficient buildings has been presented in this paper. Two masonry mortar grades MM3 and MM5 were considered for trial mix. Portland pozzolana cement with substitution of sand by fly ash and bottom ash separately in different substitution ratios (SR) were adopted for preparation of test samples. Fly ash and bottom ash with lime dust and marble dust combinations were also tested as sand free mortars. 28 days compressive strength, apparent porosity, bulk density and thermal conductivity parameters were evaluated for all such samples. By analysing the test results, it was observed that all the SR combinations satisfied the minimum masonry mortar grade MM0.7, as per IS 2250. Both the MM3 and MM5 grade mortars could be produced at 60% SR by fly ash, and corresponding reductions in thermal conductivity values were 69%, and 54% respectively, while compared with conventional mortar. Sand less mortar for both the grades resulted around 57% reductions in corresponding thermal conductivity values. Overall heat transfer co-efficient (U-value) for both side plastered and rendered brick masonry wall panel was found to be reduced by 15.58%, while comparison made between conventional mix of MM5 grade and corresponding 50% fly ash substituted mix. Thus such ash blended mortar mix appears to be advantageous in building envelop application for lowering the overall cooling/heating demand of building, besides utilizing the coal ash up to largest extent and saving natural mineral sand from depletion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.heliyon.2018.e00934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6240810PMC
November 2018

Nitrogen-Free Bifunctional Bianthryl Leads to Stable White-Light Emission in Bilayer and Multilayer OLED Devices.

ACS Omega 2018 Feb 2;3(2):1416-1424. Epub 2018 Feb 2.

Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India.

White organic light-emitting diodes (WOLEDs) are at the center stage of OLED research today because of their advantages in replacing the high energy-consuming lighting technologies in vogue for a long time. New materials that emit white light in simple devices are much sought after. We have developed two novel electroluminescent materials, referred to as and , based on a twisted bianthryl core, which are brilliantly fluorescent, thermally highly stable with high and , and exhibit reversible redox property. Although inherently blue emissive, leads to white-light emission (CIE ≈ 0.28, 0.33) with a moderate power efficiency of 2.24 lm/W and a very high luminance of 15 600 cd/m in the fabricated multilayer nondoped OLED device. This device exhibited excellent color stability over a range of applied potential. Remarkably, similar white-light emission was captured even from a double-layer device, attesting to the innate hole-transporting ability of despite it being non-nitrogenous, that is, lacking any traditional hole-transporting di-/triarylamino group(s). Similar studies with led to inferior device performance results, thereby underscoring the importance of dibenzofuryl groups in . Experimental as well as theoretical studies suggest the possibility of emission from multiple species involving and its exciplex and electroplex in the devices. The serendipitously observed white-light emission from a double-layer device fabricated with an unconventional hole-transporting material (HTM) opens up new avenues to create new non-nitrogenous HTMs that may lead to more efficient white-light emission in simple double-layer devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.7b01712DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641470PMC
February 2018

Industry Perspective on Contemporary Protein-Binding Methodologies: Considerations for Regulatory Drug-Drug Interaction and Related Guidelines on Highly Bound Drugs.

J Pharm Sci 2017 12 18;106(12):3442-3452. Epub 2017 Sep 18.

GlaxoSmithKline, King of Prussia, Pennsylvania 19406.

Regulatory agencies have recently issued drug-drug interaction guidelines, which require determination of plasma protein binding (PPB). To err on the conservative side, the agencies recommend that a 0.01 lower limit of fraction unbound (f) be used for highly bound compounds (>99%), irrespective of the actual measured values. While this may avoid false negatives, the recommendation would likely result in a high rate of false positive predictions, resulting in unnecessary clinical studies and more stringent inclusion/exclusion criteria, which may add cost and time in delivery of new medicines to patients. In this perspective, we provide a review of current approaches to measure PPB, and important determinants in enabling the accuracy and precision in these measurements. The ability to measure f is further illustrated by a cross-company data comparison of PPB for warfarin and itraconazole, demonstrating good concordance of the measured f values. The data indicate that f values of ≤0.01 may be determined accurately across laboratories when appropriate methods are used. These data, along with numerous other examples presented in the literature, support the use of experimentally measured f values for drug-drug interaction predictions, rather than using the arbitrary cutoff value of 0.01 as recommended in current regulatory guidelines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.xphs.2017.09.005DOI Listing
December 2017

Frontiers of solvent-free functional molecular liquids.

Chem Commun (Camb) 2017 Sep;53(75):10344-10357

International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.

The chemistry of functional molecular liquids (FMLs) is a recently developed research area that describes the unique properties of the liquid physical state of the materials under solvent-free conditions. FMLs are generally composed of uncharged molecular units and exist in free-flowing as well as amorphous states in nature under ambient conditions. Attachment of flexible and bulky alkyl chains to a π-conjugated chromophore is the most common method for producing such molecular liquids. FMLs exhibit many uncommon phenomena, including inherent molecular properties which have rarely been observed for conventional organic condensed materials. In the last decade, these optoelectronically active alkylated-π liquids have attracted significant attention because of their applicability to flexible/foldable electronic devices with high stability towards photo-oxidation and thermal decomposition, as well as facile processability into devices. Besides these π-conjugated chromophore-based liquids, a few other types of fluidic materials such as liquid biomaterials and liquid metals also exhibit many attractive functions in their solvent-free state. The breakthrough of FMLs in cutting-edge research and their fundamental liquid features on the basis of intermolecular architectures are highlighted in this Feature Article. It is expected that this Feature Article will encourage the understanding of liquid properties as a consequence of intermolecular interactions and inspire the development of molecular architectures that could be useful for designing more attractive FMLs with specific functions in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c7cc05883gDOI Listing
September 2017

Development of a Novel Simplified PBPK Absorption Model to Explain the Higher Relative Bioavailability of the OROS® Formulation of Oxybutynin.

AAPS J 2016 11 8;18(6):1532-1549. Epub 2016 Sep 8.

Centre for Applied Pharmacokinetic Research, Manchester Pharmacy School, The University of Manchester, Manchester, UK.

A new minimal Segmented Transit and Absorption model (mSAT) model has been recently proposed and combined with intrinsic intestinal effective permeability (P ) to predict the regional gastrointestinal (GI) absorption (f ) of several drugs. Herein, this model was extended and applied for the prediction of oral bioavailability and pharmacokinetics of oxybutynin and its enantiomers to provide a mechanistic explanation of the higher relative bioavailability observed for oxybutynin's modified-release OROS® formulation compared to its immediate-release (IR) counterpart. The expansion of the model involved the incorporation of mechanistic equations for the prediction of release, transit, dissolution, permeation and first-pass metabolism. The predicted pharmacokinetics of oxybutynin enantiomers after oral administration for both the IR and OROS® formulations were in close agreement with the observed data. The predicted absolute bioavailability for the IR formulation was within 5% of the observed value, and the model adequately predicted the higher relative bioavailability observed for the OROS® formulation vs. the IR counterpart. From the model predictions, it can be noticed that the higher bioavailability observed for the OROS® formulation was mainly attributable to differences in the intestinal availability (F ) rather than due to a higher colonic f , thus confirming previous hypotheses. The predicted f was almost 70% lower for the OROS® formulation compared to the IR formulation, whereas the F was almost eightfold higher than in the IR formulation. These results provide further support to the hypothesis of an increased F as the main factor responsible for the higher bioavailability of oxybutynin's OROS® formulation vs. the IR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1208/s12248-016-9965-3DOI Listing
November 2016

Colorimetric and fluorescence probe for the detection of nano-molar lysine in aqueous medium.

Org Biomol Chem 2016 Dec 1;14(45):10688-10694. Epub 2016 Nov 1.

Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, West Bengal, India.

A single crystal X-ray structurally characterized BODIPY based probe, THBPY, derived from 4-hydroxy-5-isopropyl-2 methyl-isophthalaldehyde, detects nano-molar lysine in aqueous medium. In the presence of lysine, THBPY visibly changes its color and fluorescence profile due to the formation of a stable imine bond. A distinctive color change allows for facile discrimination over other amino acids in a wide range of concentrations of lysine. The detection limit for lysine is 0.001 μM by a fluorescence method and 0.01 μM by a colorimetric method. The probe shows good reversibility for multiple uses and cleanly discriminates between lysine and other amino acids. Density functional theoretical studies closely resemble experimental results.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c6ob01704eDOI Listing
December 2016

Ring Opening of a meso-Triaryl 25-Oxasmaragdyrin Macrocycle by m-Chloroperoxybenzoic Acid.

Chemistry 2016 Feb 8;22(6):2153-2157. Epub 2016 Jan 8.

Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, 400076, India.

Smaragdyrin, a class of expanded porphyrin macrocycles, upon treatment with meta-chloroperoxybenzoic acid (mCPBA) underwent oxidative ring opening to form an unprecedented linear pentaheterocyclic compound. The linear pentaheterocyclic compound was freely soluble in common organic solvents and characterized in detail by HRMS, 1D and 2D NMR spectroscopy, and X-ray crystallography. Our preliminary studies indicated that the linear pentaheterocyclic compound can specifically sense anions such as H PO and CN ions, which was corroborated by absorption and fluorescence studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.201503905DOI Listing
February 2016

Benzophenones as Generic Host Materials for Phosphorescent Organic Light-Emitting Diodes.

ACS Appl Mater Interfaces 2016 Jan 8;8(2):1527-35. Epub 2016 Jan 8.

Department of Chemistry, Indian Institute of Technology , Kanpur 208016, India.

Despite the fact that benzophenone has traditionally served as a prototype molecular system for establishing triplet state chemistry, materials based on molecular systems containing the benzophenone moiety as an integral part have not been exploited as generic host materials in phosphorescent organic light-emitting diodes (PhOLEDs). We have designed and synthesized three novel host materials, i.e., BP2-BP4, which contain benzophenone as the active triplet sensitizing molecular component. It is shown that their high band gap (3.91-3.93 eV) as well as triplet energies (2.95-2.97 eV) permit their applicability as universal host materials for blue, green, yellow, and red phosphors. While they serve reasonably well for all types of dopants, excellent performance characteristics observed for yellow and green devices are indeed the hallmark of benzophenone-based host materials. For example, maximum external quantum efficiencies of the order of 19.2% and 17.0% were obtained from the devices fabricated with yellow and green phosphors using BP2 as the host material. White light emission, albeit with rather poor efficiencies, has been demonstrated as a proof-of-concept by fabrication of co-doped and stacked devices with blue and yellow phosphors using BP2 as the host material.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.5b11232DOI Listing
January 2016

Tailoring Ligand Environment toward Development of Colorimetric and Fluorescence Indicator for Biological Mn(II) Imaging.

Anal Chem 2016 Jan 22;88(2):1106-10. Epub 2015 Dec 22.

Department of Chemistry, The University of Burdwan , Burdwan 713104, West Bengal, India.

Mn(2+) ion plays an essential role in all forms of life. Paramagnetic nature of Mn(2+) and its close resemblance with Ca(2+) and Mg(2+) are two key limiting factors responsible for the least development of fluorescence probes suitable for bioimaging. In literature we have found only a few Mn(2+) selective fluorescent sensor and their applications. These probes are mainly based on linear polydentate and macrocyclic ligands. Systematic tuning of ligand environment allows colorimetric and fluorescence recognition of traces Mn(2+) in real sample and fluorescence indicator in living RAW264.7 cells. Two probes, one based on fluorescein (FHDB) and the other based on rhodamine (RDDB) showed turn-on response toward Mn(2+) in DMSO and acetonitrile, respectively. Colorimetric detection of Mn(2+) ion is also possible in the presence of other metal ions. The new sensing probe RDDB shows higher sensitivity as well as faster response compared to the reported systems. The detection limit of RDDB is 5 × 10(-8) M and FHDB is 1 × 10(-7) M. DFT studies strongly support the experimental facts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.analchem.5b03551DOI Listing
January 2016

Strategically Modified Rhodamine-Quinoline Conjugate as a CHEF-Assisted FRET Probe for Au(3+): DFT and Living Cell Imaging Studies.

J Org Chem 2015 Sep 14;80(17):8530-8. Epub 2015 Aug 14.

Department of Chemistry, The University of Burdwan , Burdwan 713104, West Bengal, India.

A systematic journey from O-donor through S-donor to N-donor chelator led to the development of a highly selective Au(3+) chemosensor that operates via a CHEF-induced FRET mechanism. This sensing protocol avoids unwanted possible side reactions observed in alkyne-based gold sensors. DFT studies strongly support the experimental facts. The probe RT-2 detects Au(3+) in the presence of the masking agent KI to minimize Hg(2+) interference; however, RQ-2 selectively detects Au(3+) without any interference and shows reversibility in the sensing in the presence of tetrabutylammonium cyanide. The probe efficiently images Au(3+) in living HeLa cells under a fluorescence microscope.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.joc.5b01141DOI Listing
September 2015