Allelopathic potential of a noxious weed on mung bean

Eupatorium odoratum have invaded the waste lands of South West Bengal, India. A field study indicated a gradual and also significant increase in Eupatorium odoratum accompanied with significant decrease in other coexisting species. Considering the above in mind, a study was undertaken to evaluate the existence of inhibitory effect of leaf extracts and leaf leachates noxious weed Eupatorium odoratum using fully viable seeds of mung bean (Vigna radiata) as the bioassay material. The study showed the reduced the percentage germination and TTC stainability along with extended T50 values of mung bean seeds. The levels of protein, DNA and RNA, activities of dehydrogenase and catalase enzymes were significantly retarded in pretreated seed samples. Amino acid and sugar levels were increased in the leachates of seeds pretreated with leaf extracts and leaf leachates. Thus, from the overall results it can be concluded that various inhibitors present in E. odoratum can impart strong inhibitory effect on mung bean. The study suggests that the leaves of E. odoratum possess phytotoxic or allelopathic chemicals which potentially rendered the inhibitory action on mung bean seeds

Alkali and Alkaline Earth Metal Complexes as Versatile Catalysts for Ring‐Opening Polymerization of Cyclic Esters

Biodegradable polyesters such as poly(ϵ-caprolactone) (PCL) and poly(lactic acid) (PLA) have been considered for use in several areas, such as drug delivery devices, sutures, tissue engineering, and GBR membranes, due to its bio-renewability, biodegradability, and biocompatibility. Several synthetic techniques for the preparation of polyesters have been reported in the literature, amongst which the ring-opening polymerization (ROP) of cyclic esters is the most efficient. A convenient approach to access iso-selective PLAs is polymerization of racemic lactide (rac-LA), which shows excellent stereoregularity without the need for costly chiral auxiliaries or ligands. In this personal account, we review a series of methods that have been practiced to the synthesis of biodegradable polyesters from various cyclic monomers using alkali and alkaline earth metal complexes as efficient catalysts

Recent development of alkali metal complex promoted iso-selective ring opening polymerization of rac-Lactide

Polyesters especially polylactide (PLA) are one of the most important and extensively studied biodegradable polymers for their use in medicine, agriculture, packaging, and drug delivery. Importantly, these polymers can be formed by the ring opening polymerization (ROP) of lactide by carefully designed metal complexes that can act as catalysts for such reactions have emerged as useful tools to achieve this goal. In recent years, alkali metal-based organometallic complexes have appeared as an alternative to transition metal and rare earth metals catalysts for the ROP of rac-LA systems. This strategy is advantageous because it obviates the need for pre-generated toxic metal precursors. This review highlights the progress of alkali metal-based catalysis for the ROP of rac-LA that come out with a critical assessment of the futuristic research, spotlight the major developments achieved in the past few years, and provides an overview of the challenges and opportunities

Alkali Metal Complex–Mediated Ring-opening Polymerization of rac-LA, ε-Caprolactone, and δ-Valerolactone

A series of alkali metal complexes formed by N-(2-fluoro/2-nitro phenyl)-P,P-diphenylphosphinoselenoic amide [(Ph2P(Se)NH(2-RC4H4)] [R = F (1-H); NO2 (2-H)] ligands with molecular formulas [M(THF)2(Ph2P(Se)N(2-RC4H4)] [M = Li, R = F (3a), NO2 (3b)] and [M(THF)2(Ph2P(Se)N(2-RC4H4)] [M = Na, R = F (4a), NO2 (4b); M = K, R = F (5a), NO2 (5b)] have been synthesized in great yield and fully characterized. The molecular structures of protic-ligands 1-H and 2-H, and alkali metal complexes 3b, 4a, and 4b were analyzed using single-crystal X-ray diffraction analysis. Sodium and potassium complexes 4a,b and 5a,b were proved to be active catalysts for the ring-opening polymerization (ROP) of rac-LA (rac-LA), ε-caprolactone, and δ-valerolactone at room temperature only. The best isoselectivity of poly(lactide) (PLA) was achieved to a high value of Pi = 0.78 using sodium complex 4b. One exceedingly dynamic potassium complex (5a,5b) even can catalyze the polymerization of 1,000 counterparts of rac-LA and yield polylactide with a high molecular weight and narrow polydispersity record (PDI). Experimental outcomes also showed steric hindrance, and electronic impacts have noteworthy consequences for this catalysis in the ROP of rac-LA

Ring Opening Polymerization and Copolymerization of Cyclic Esters Catalyzed by Group 2 Metal Complexes Supported by Functionalized P–N Ligands

We report the preparation of alkali and alkaline earth (Ae) metal complexes supported by 2-picolylamino-diphenylphosphane chalcogenide [(Ph2P(=E)NHCH2(C5H4N)] [E = S (1-H); Se (2-H)] ligands. The treatment of the protic ligand, 1-H or 2-H, with alkali metal hexamethyldisilazides at room temperature afforded the corresponding alkali metal salts [M(THF)2(Ph2P(=E)NCH2(C5H4N)] [M = Li, E = S (3a), Se (3b)] and [{M(THF)n(Ph2P(=E)NCH2(C5H4N)}2] [M = Na, E = S (4a), Se (4b); M = K, E = Se (5b)] in good yield. The homoleptic Ae metal complexes [κ2-(Ph2P(=Se)NCH2(C5H4N)Mg(THF)] (6b) and [κ3-{(Ph2P(=Se)NCH2(C5H4N)}2M(THF)n] (M = Ca (7b), Sr (8b), Ba (9b)] were synthesized by the one-pot reaction of 2-H with [KN(SiMe3)2] and MI2 in a 2:2:1 molar ratio at room temperature. The molecular structures of the protic-ligands 1-H and 2-H, as well as complexes 3a,b–5a,b and 6b–9b were established using single-crystal X-ray analysis. The Ae metal complexes 6b–9b were tested for ring-opening polymerization (ROP) of racemic lactide (rac-LA) and copolymerization of rac-LA and ε-caprolactone (ε-CL) at room temperature. In the ROP of rac-LA, the calcium complex 7b exhibited high isoselectivity, with Pi = 0.89, whereas both the barium and strontium complexes showed lower isoselectivity with Pi = 0.78–0.62. In the copolymerization of rac-LA and ε-CL, both barium and strontium complexes proved to be efficient precatalysts for the formation of the block copolymer rac-LA-CL, but the reactivity of 9b was found to be better than that of 8b. All the polymers were fully characterized using differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography analyses. Kinetic studies on the ROP reaction of LA confirmed that the rate of polymerization followed the order Ba ≫ Sr ≈ Ca

Thermal synthesis of Hematite nanoparticles : structural, magnetic and morphological characterizations

Hematite (α-Fe2O3) nanoparticle was synthesized using organometallic compound - ferrocene carboxaldehyde through solventless solid state thermal decomposition technique. The crystal structure, magnetic and morphological properties of the decomposed material were studied using powder X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry, 57Fe Mössbauer spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. Structural study confirmed that the synthesized material is hematite with hexagonal phase and good crystallinity. The temperature-dependent magnetization measurement exhibited the Morin transition - the yardstick for hematite formation. Mössbauer spectroscopic study confirmed the purity of phase of the synthesized material. The SEM study observed mostly the agglomerated tiny particles along with some ring-shaped surface structures. The TEM study of the synthesized material showed that the highest distribution of the particles with ~5 nm size. The observed EDX spectra confirmed the existence of Fe and O in the synthesized material. The solid state reaction process leading to hematite on decomposition of ferrocene carboxaldehyde has also been proposed. Present study describes a simple process for the preparation of pure hematite nanoparticle by solventless method

Ring Opening Polymerization and Copolymerization of Cyclic Esters Catalyzed by Group 2 Metal Complexes Supported by Functionalized P–N Ligands

We report the preparation of alkali and alkaline earth (Ae) metal complexes supported by 2-picolylamino-diphenylphosphane chalcogenide [(Ph₂P­(=E)­NHCH₂­(C₅H₄N)] [E = S (<b>1-H</b>); Se (<b>2-H</b>)] ligands. The treatment of the protic ligand, <b>1-H</b> or <b>2-H</b>, with alkali metal hexamethyldisilazides at room temperature afforded the corresponding alkali metal salts [M­(THF)₂­(Ph₂P­(=E)­NCH₂­(C₅H₄N)] [M = Li, E = S (<b>3a</b>), Se (<b>3b</b>)] and [{M­(THF)_<i>n</i>­(Ph₂P­(=E)­NCH₂­(C₅H₄N)}₂] [M = Na, E = S (<b>4a</b>), Se (<b>4b</b>); M = K, E = Se (<b>5b</b>)] in good yield. The homoleptic Ae metal complexes [κ²-(Ph₂P­(=Se)­NCH₂­(C₅H₄N)­Mg­(THF)] (<b>6b</b>) and [κ³-{(Ph₂P­(=Se)­NCH₂­(C₅H₄N)}₂­M­(THF)_<i>n</i>] (M = Ca (<b>7b</b>), Sr (<b>8b</b>), Ba (<b>9b</b>)] were synthesized by the one-pot reaction of <b>2-H</b> with [KN­(SiMe₃)₂] and MI₂ in a 2:2:1 molar ratio at room temperature. The molecular structures of the protic-ligands <b>1-H</b> and <b>2-H</b>, as well as complexes <b>3a</b>,<b>b</b>–<b>5a</b>,<b>b</b> and <b>6b</b>–<b>9b</b> were established using single-crystal X-ray analysis. The Ae metal complexes <b>6b</b>–<b>9b</b> were tested for ring-opening polymerization (ROP) of racemic lactide (<i>rac</i>-LA) and copolymerization of <i>rac</i>-LA and ε-caprolactone (ε-CL) at room temperature. In the ROP of <i>rac</i>-LA, the calcium complex <b>7b</b> exhibited high isoselectivity, with <i>P</i>_i = 0.89, whereas both the barium and strontium complexes showed lower isoselectivity with <i>P</i>_i = 0.78–0.62. In the copolymerization of <i>rac</i>-LA and ε-CL, both barium and strontium complexes proved to be efficient precatalysts for the formation of the block copolymer <i>rac</i>-LA-CL, but the reactivity of <b>9b</b> was found to be better than that of <b>8b</b>. All the polymers were fully characterized using differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography analyses. Kinetic studies on the ROP reaction of LA confirmed that the rate of polymerization followed the order Ba ≫ Sr ≈ Ca

Angioplasty of unprotected left main coronary stenosis: Real world experience of a single-operator group from eastern India

AbstractBackgroundCoronary artery bypass graft surgery is the standard treatment of unprotected left main coronary stenosis (ULMCA). However, in the real world scenario, many of these patients are unfit for CABG or prefer angioplasty as an alternative when offered the choice.MethodsA total of 86 clinically stable patients with ULMCA stenosis who were unfit or unwilling for CABG underwent PCI with DES at two tertiary care centers in Kolkata. Patients were followed up prospectively for a median of 34.6 months for major adverse cardiovascular events. Angiographic follow-up was done after 1 year of index procedure or earlier, if indicated.ResultsFifty-five patients (64%) had distal left main stenosis. Two-stent technique was used in 19 patients (22%) and single-stent technique in 36 patients (42%) with distal left main lesion. Thirteen patients (15.1%) had left ventricular ejection fraction (LVEF) of ≤45%. There was no in-hospital death, MI, or stent thrombosis. During follow-up, major adverse cardiac event (MACE) occurred in 9 patients (10.5%). Our study revealed significantly greater MACE in patients with distal left main lesion with LVEF ≤45% (50% vs 6.38%, p=0.0002), high SYNTAX score (36.36% vs 6.82%, p=0.008), and diabetes (17.95% vs 0.00%, p=0.07). Overall, also patients with Diabetes, LVEF ≤ 45%, and SYNTAX score >32 had significantly higher MACE. Use of IC Stent, IVUS, or procedural strategy in distal lesion did not affect MACE.ConclusionIn selective patients with low-intermediate SYNTAX score and without diabetes and LV dysfunction, ULMCA PCI with DES is feasible

Emerging extraction and diagnostic tools for detection of plant pathogens: Recent trends, challenges, and future scope

Plant pathogens are a serious threat to agriculture for long-term viability and cost loss of billions of dollars yearly. Many pathogens have been documented in the literature that infect a variety of crops. Nevertheless, new pathogens emerge and often result in disease outbreaks, leading to million-dollar losses. Currently, several diagnostic approaches with enhanced sensitivity and specificity for the identification of widespread and/or unknown plant pathogens are constantly being developed. Whereas the extensively used approaches for plant pathogen diagnostics are mostly serological and nucleic acid-based assays, many different nucleic acid-based approaches for amplifying target DNA/RNA have also emerged over time. However, these approaches lack precision, specificity, and rapidity, making them unsuitable for on-field analysis. As a result, there is a lot of interest arising in field-deployable point of care (POC) devices and artificial intelligence (AI)-assisted pathogens' detection accurately at an early stage within a minute. Similarly, development of a cell-lysis and purification-free DNA/RNA extraction process is also crucial for quick sample preparation for molecular diagnosis of plant pathogens at field level. In this review, we have discussed advanced tools that are trending not only to extract nucleic acids but also detect plant pathogens. We have also discussed critical challenges and future perspectives of disease diagnostic tools for plant pathogens' detection. In summary, advanced plant disease diagnostic tools can be helpful for routine monitoring of plant pathogens toward improving crop productivity and yield that can be used for improving the financial status of farmers.Web of Science2588185