Retinal image analysis is one of the crucial topics in medical image processing. During the last three decades, people are trying to extract the different features (like blood vessels, optic disk, ...macula, fovea etc.) automatically from retinal image. Fovea is one of the important feature of a fundus retinal image. This paper present a simple and fast algorithm using Mathematical Morphology to find the fovea region. Proposed algorithm is based on the structure of the blood vessels and little bit information of the optic disk. We have tested our result on a publicly available DRIVE database and got a comparable results with a state of the art in this area.
Triphenylamine-based donor-acceptor conjugated microporous polymers, namely PTPA-AQ and PTPA-AM, were synthesized for the first time
Suzuki-Miyaura coupling of ...tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-amine as a donor with 2,6-dibromoanthracene-9,10-dione and 2,2'-(2,6-dibromoanthracene-9,10-diylidene)dimalononitrile acceptors for efficient visible-light driven oxidative hydroxylation of various phenylboronic acids. The dimalononitrile derivative having greater acceptor ability showed tunable photophysical properties of PTPA-AM (lower band gap of 1.47 eV and better exciton separation efficiency) as well as porosity (lower Brunauer-Emmett-Teller (BET) surface area of 43 m
g
). PTPA-AQ having higher BET surface area (400 m
g
), suitable HOMO-LUMO positions and an optimal band gap (1.94 eV) showed better photocatalytic activity for the hydroxylation with yields up to 96%.
Drought is one of the major limiting factors for productivity of crops including rice (Oryza sativa L.). Understanding the role of allelic variations of key regulatory genes involved in ...stress-tolerance is essential for developing an effective strategy to combat drought. The bZIP transcription factors play a crucial role in abiotic-stress adaptation in plants via abscisic acid (ABA) signaling pathway. The present study aimed to search for allelic polymorphism in the OsbZIP23 gene across selected drought-tolerant and drought-sensitive rice genotypes, and to characterize the new allele through overexpression (OE) and gene-silencing (RNAi). Analyses of the coding DNA sequence (CDS) of the cloned OsbZIP23 gene revealed single nucleotide polymorphism at four places and a 15-nucleotide deletion at one place. The single-copy OsbZIP23 gene is expressed at relatively higher level in leaf tissues of drought-tolerant genotypes, and its abundance is more in reproductive stage. Cloning and sequence analyses of the OsbZIP23-promoter from drought-tolerant O. rufipogon and drought-sensitive IR20 cultivar showed variation in the number of stress-responsive cis-elements and a 35-nucleotide deletion at 5'-UTR in IR20. Analysis of the GFP reporter gene function revealed that the promoter activity of O. rufipogon is comparatively higher than that of IR20. The overexpression of any of the two polymorphic forms (1083 bp and 1068 bp CDS) of OsbZIP23 improved drought tolerance and yield-related traits significantly by retaining higher content of cellular water, soluble sugar and proline; and exhibited decrease in membrane lipid peroxidation in comparison to RNAi lines and non-transgenic plants. The OE lines showed higher expression of target genes-OsRab16B, OsRab21 and OsLEA3-1 and increased ABA sensitivity; indicating that OsbZIP23 is a positive transcriptional-regulator of the ABA-signaling pathway. Taken together, the present study concludes that the enhanced gene expression rather than natural polymorphism in coding sequence of OsbZIP23 is accountable for improved drought tolerance and yield performance in rice genotypes.
A new metal-, oxidant-, and solvent-free ecofriendly domino method has been established for modular synthesis of a diverse range of medicinally promising hydroxyarylated unsymmetrical pyridines in ...good to high chemical yields with an excellent regioselectivity. This domino process involves a range of N-sulfonyl ketimines as C,N-binucleophiles, enolizable ketones, and aromatic/heteroaromatic aldehydes using ammonium acetate as an ideal promoter under neat conditions, which creates two new C–C bonds and one C–N bond. Notably, the neutral reaction conditions are mild enough to tolerate a range of functionalities and cover a variety of substrates, thus bestowing a powerful avenue to access tri- and tetrasubstituted pyridines including carbo- and heterocyclic fused ones. Interestingly, a practical, scalable, and high-yielding synthesis of pyridylphenol derivatives was successfully accomplished by our unique method.
An intriguing DABCO-catalyzed and DBU-promoted one-pot synthesis of an important class of (2-hydroxyaryl)pyridine derivatives bearing a carboxylate or a nitrile group suitably placed at C3 position ...of the aza-ring has been achieved in acceptable chemical yields with a broad functional group tolerance. This sequential C-C/C-N bond making process proceeds through a regioselective allylic alkylation/aza-Michael reaction between MBH carbonates derived from an acrylate/acrylonitrile and
-sulfonyl ketimines as C,N-binucleophiles catalyzed by DABCO, followed by elimination of SO
under the influence of base and subsequent aromatization in an open atmosphere.
Triphenylamine (TPA)–anthracene (AN)-based conjugated microporous polymers (CMPs), namely PTPA-AN-9,10 and PTPA-AN-2,6, were synthesized by the Suzuki–Miyaura cross-coupling reaction of ...tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-amine with 9,10-dibromoanthracene and 2,6-dibromoanthracene, respectively. The as-synthesized polymers exhibited cauliflower-like nanoscale morphology , high Brunauer–Emmett–Teller surface area of 362 m2/g, and thermal stability up to 458 °C in the case of PTPA-AN-2,6. Interestingly, PTPA-AN-9,10 showed bright cyan fluorescence in tetrahydrofuran dispersion and exhibited fluorescence-based sensing of various nitroaromatics, where 2,4,6-trinitrophenol exhibited the lowest limit of detection of 34 μM and the highest Stern–Volmer constant (K SV) of 5.8 × 103 L mol–1. On the other hand, PTPA-AN-2,6 showed efficient photocatalytic reduction of various nitroaromatic micropollutants such as p-nitrophenol (p-NP) (k = 0.164 min–1 and turnover frequency (TOF) = 0.769 h–1) and degradation of Congo red from water with ultrafast kinetics (k = 0.047 min–1 and TOF = 0.024 h–1) which are much better than most of the previously reported CMPs. These polymers were recovered using simple filtration and were recycled four to five times without losing their catalytic efficiency significantly for p-NP reduction as well as dye degradation. In general, TPA-based CMPs have been used as efficient multitasking materials for the sensing of nitroaromatic micropollutants and photocatalytic degradation of Congo red dye as well as p-NP to its value-added product p-aminophenol.
An efficient, solvent-free, and eco-friendly domino reaction of 5/6-membered cyclic sulfamidate imines with a variety of β,γ-unsaturated α-ketocarbonyls in neat conditions under MW irradiation ...promoted by DABCO as a solid organobase has been developed for the rapid construction of a novel class of densely functionalized picolinates. This interesting metal–solvent-free tactic allows a wide range of useful functionalities on the aryl rings and delivers good to excellent yields of the aforesaid aza-heterocycles within short time spans (20–40 min). A biologically promising imidazo1,2-apyridine was successfully synthesized through our unique procedure.
Presence of multiple heteroatoms in porous polymers enable Lewis acid-base type host-guest interactions for the excellent uptake of iodine in vapor phase.
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•A set of phosphate-based ...porous polymers were made via nucleophilic substitution of various aromatic alcohols with POCl3.•Among them, AZO-POP-P showed excellent iodine uptake capacity of 356 wt% in vapour phase with reusability for five times.•The DFT based complexation energy was maximum for AZO-POP-P (501.6 kcal/mol) agreeing well with the experimental trend.•The possibility of facile host-guest charge transfer was evident from the XPS, EPR and Raman spectra.
Radioactive iodine pollution from nuclear waste poses significant threat to both the environment and human health. As a result, the utmost importance lies in the capture and safe storage of radioactive iodine. To address this concern, a set of porous organic polymers with phosphate linkages, namely AZO-POP-P, OPN-3, OPN-4, and OPN-5, were synthesized for the uptake of iodine in vapor phase. Additionally, a triazine-based porous organic polymer, AZO-POP-T was also synthesized to compare the iodine uptake capacity. Syntheses of these phosphate-linked and triazine-based polymers involved a nucleophilic substitution reaction of various aromatic alcohols with POCl3 or cyanuric chloride, respectively. This study represents an inaugural investigation into the iodine uptake capability by phosphate-based porous organic polymers. They exhibited efficient iodine capture from vapor phase, demonstrating uptake capacities of 3.56, 1.30, 2.70, and 0.63 g.g−1 for AZO-POP-P, OPN-3, OPN-4, and OPN-5 respectively, at 75 °C. Meanwhile, the triazine-based AZO-POP-T exhibited an uptake capacity of 1.83 g.g−1 at 75 °C. These porous organic polymers demonstrated easy and scalable synthesis, high thermal stability, and recyclability for at least five cycles without significant decrease in the uptake capacity towards volatile iodine from vapour phase.
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