Naphthalenediimide-based nanoarchitectonics for a fluorescent chemosensor with highly selective and sensitive detection of cyanide ions.

A naphthalenediimide (NDI)-based highly potential chemosensor for the detection of cyanide has been synthesized successfully in several steps. The NDI-based probe displayed high selectivity and sensitivity towards cyanide ions in fluorescence 'turn-off' mode over other ions used in this study. The naked-eye, UV-vis absorbance and fluorescence methods are employed to investigate the sensing performance of probe 1 toward CN- ion detection. The limit of detection for CN- ions was calculated to be 4.11 × 10-7 M. Moreover, the Stern-Volmer quenching constant and fluorescence quenching efficiency of CN- ions were estimated to be 1.1 × 105 M and 88.81%, respectively. Job's plot showed a 1 : 1 stoichiometric complexation reaction between probe 1 and CN- ions. For practical applications, probe 1 was efficiently applied for the detection of CN- ions using a paper strip method.

Determination of Acephate, Dinotefuran, and Emamectin Benzoate in a Pesticide Formulation: A Single-Laboratory Validation.

BACKGROUND: The advantage of simultaneous separation and quantification is the reduction of analysis time and consumption of solvents and reagents. OBJECTIVE: The objective of the present investigation was to optimize and validate a novel, rapid, and simple reverse-phase high-performance liquid chromatographic method for the simultaneous determination of acephate, dinotefuran, and emamectin benzoate in a pesticide formulation. METHOD: The chromatographic separation and quantification were accomplished by using Kromasil CN column (250 mm × 4.6 mm; 5 µm) with a mobile phase consisting of acetonitrile and water [0.1% (v/v) triethylamine, pH 2.7 with 10% (v/v) orthophosphoric acid] in the ratio of 50:50 (v/v) with a flow rate of 1.0 mL/min and diode array detection at the wavelength of (215 nm and 245 nm). RESULTS: The HPLC method was able to separate and quantify all the actives in the formulation by isocratic elution within 10 min. The method was fully validated in accordance with the SANCO and Collaborative International Pesticide Analytical Council guidelines concerning system suitability, specificity, linearity, precision, accuracy, and robustness. All the analytical parameters are within the range of acceptable limits in the guidelines. CONCLUSIONS: The validated method was successfully applied to a pesticide formulation. HIGHLIGHTS: The novelty of the current research work lies in the development of the simple and rapid HPLC method for simultaneous determination of acephate, dinotefuran, and emamectin benzoate in wettable granular formulation.

Mimicking the Natural World with Nanoarchitectonics for Self-Assembled Superstructures.

Scientists are often inspired by nature, where naturally occurring morphologies, such as those that resemble animals and plants, can be created in the lab. In this review, we have provided an overview on complex superstructures of animals, plants and some similar shapes from the natural world. We begin this review with a discussion about the formation of various animal-like shapes from small organic molecules and polymers, and then move onto plants and other selected shapes. Literature surveys reveal that most of the polymers studied tend to form micellar structures, with some exceptions. Nevertheless, small organic molecules tend to form not only micellar structures but also other animal shapes such as worms and caterpillars. These superstructures tend to have high surface areas and variable surface morphology, making them very useful material for applications in various field such as catalysis, solar cells, and biomedicine, amongst others.

A New 'Off-On' System Based on Core-Substituted Naphthalene Diimide with Dimethylamine for Reversible Acid-Base Sensing.

A new 'Off-On' system designed and synthesised by functionalisation of a naphthalene diimide (NDI) core with dimethylamine produces 4,9-bis(dimethylamino)-2,7-dioctylbenzo[lmn][3,8]-phenanthroline-1,3,6,8-(2H,7H)-tetraone, abbreviated as DDPT (1). DDPT 1 was synthesised using a simple strategy, namely aromatic nucleophilic substitution using Br2 -NDI with dimethylamine at 110 °C. DDPT was characterized by 1 H and 13 C NMR spectroscopy, ESI mass spectrometry and elemental analysis. DDPT 1 was then used for optical studies through protonation of its dimethylamine core with trifluoroacetic acid (TFA), blue-shifting the absorption band from 600 nm to 545 nm in solution. Interestingly, the fluorescence of DDPT 1 is weak in solution with a quantum yield Φ=0.09, which is significantly enhanced to Φ=0.78 upon addition of TFA. The limit of detection (LOD) was determined to 2.77 nm. Furthermore, DDPT 1 can be used for naked eyed detection not only under UV light (365 nm) but also using visible light, as clear changes can be clearly seen upon addition of TFA. The binding constant of DDPT was calculated to 2.1×10-3  m-1 . Importantly, DDPT 1 showed reversible switching by alternative addition of acid (TFA) and base (triethylamine) without loss of activity. Immobilised on paper, DDPT 1 can be used for strip-test sensing in which the colour changes from blue to reddish when expose to TFA vapours and reverse in the presence of triethylamine vapours.

A novel validated simple derivatization liquid chromatographic method with diode array detection for the simultaneous determination of mancozeb, azoxystrobin and difenoconazole in pesticide dosage form.

A novel, rapid and simple reverse-phase high performance liquid chromatography (RP-HPLC) method for the simultaneous determination of three pesticides - mancozeb, azoxystrobin and difenoconazole by derivatization with ethyl iodide is presented. Analysis was performed on a C18 column (Agilent Eclipse plus, 150 mm × 4.6 mm; 5 µ) with the mobile phase consisting of acetonitrile + methanol (90 + 10 v/v) - water (0.1% v/v trifluoroacetic acid) (60 : 40, v/v) pumped isocratically at a flow rate of 1.0 mL min-1 and detection wavelength of 205 nm and 272 nm. The factors affecting the derivatization reaction and separation conditions were carefully evaluated and optimized. The method was linear over the concentration range of 3.50 mg L-1 to 31.48 mg L-1 for mancozeb, 0.32 mg L-1 to 2.85 mg L-1 for azoxystrobin and 0.32 mg L-1 to 2.89 mg L-1 for difenoconazole. The new method was successfully applied for the analysis of mancozeb, azoxystrobin and difenoconazole in the pesticide formulation with range recoveries of 99.46% to 100.76%, 99.07% to 101.09% and 98.59% to 101.59%, respectively. The present method is suitable and favorable for the simultaneous separation and analysis of tertiary mixture analytes on account of its sensitivity, rapidity and cost-effectiveness. In addition, it could have excellent application prospects for the simultaneous determination of all three pesticides in other formulated products.

A simple derivatization RP-HPLC method for the simultaneous determination of zineb and hexaconazole in pesticide formulation using a PDA detector.

A simple derivatization reverse-phase high performance liquid chromatographic method for the simultaneous analysis (separation and quantification) of zineb and hexaconazole has been optimized and validated. The method was carried out on an Agilent Eclipse plus C18 column (150 × 4.6 mm; 5 µm), with a mobile phase comprising acetonitrile + methanol (80 + 20 v/v): water (0.1% v/v trifluoroacetic acid) (60 : 40 v/v) at a flow rate of 1.0 mL minute-1, and the quantification was achieved at 272 nm and 205 nm. The retention times of zineb and hexaconazole were found to be 6.4 min and 7.6 min, respectively. The performance of the method was validated according to the SANCO, CIPAC and ICH guidelines for specificity, selectivity, linearity, precision, accuracy, limit of detection, limit of quantification and robustness. The developed method was successfully applied for the estimation of zineb and hexaconazole in a pesticide dosage form.

Aggregation Induced Emissive Luminogens for Sensing of Toxic Elements.

The major findings in the growing field of aggregation induced emissive (AIE) active materials for the detection of environmental toxic pollutants have been summarized and discussed in this Review article. Owing to the underlying photophysical phenomenon, fluorescent AIE active molecules show more impact on sensing applications. The major focus in current research efforts is on the development of AIE active materials such as TPE based organic fluorescent molecules, metal organic framework, and polymers that can be employed for the detection of toxic pollutants such as CN- , NO2- , Hg2+ , Cd2+ , As3+ , As5+ , F- , Pb2+ , Sb3+ ions.

Engineered nano-foam of tri-metallic (FeCuCo) oxide catalyst for enhanced hydrogen generation via NaBH4 hydrolysis.

Catalytic hydrolysis of sodium borohydride can potentially be considered as a convenient and safe method to generate hydrogen, an environmentally clean and sustainable fuel for the future. The present effort establishes the development of FeCuCo tri-metallic oxide catalyst by a simple, single-step solution combustion synthesis (SCS) method for hydrogen generation from NaBH4 hydrolysis. Amongst series of FeCuCo tri-metallic oxide catalyst synthesized, FeCuCo with 50:37.5:12.5 wt% respective precursor loading displayed remarkable activity by generating hydrogen at the rate of 1380 mL min-1 g-1 (1242 mL in 18 min) with turnover frequency (TOF) of 62.02 mol g-1 min-1. The catalyst was characterized by using various techniques to understand their physiochemical and morphological properties. The results revealed that the catalyst synthesized by combustion method led to the formation of FeCuCo with appreciable surface area, porous foam-like morphology and high surface acidity. Major factors affecting the hydrolysis of NaBH4 such as catalyst loading, NaOH concentration and temperature variation were studied in detail. Additionally, the FeCuCo catalyst also displayed substantial recyclability performance up to eight cycles without considerable loss in its catalytic activity. Therefore, FeCuCo oxide can be demonstrated as one of the most efficient, cost effective tri-metallic catalyst so far for application in the hydrogen generation.

SAR, pharmacokinetics, safety, and efficacy of glucokinase activating 2-(4-sulfonylphenyl)-N-thiazol-2-ylacetamides: discovery of PSN-GK1.

Allosteric activators of the glucose-sensing enzyme glucokinase (GK) are currently attracting much interest as potential antidiabetic therapies because they can achieve powerful blood glucose lowering through actions in multiple organs. Here, the optimization of a weakly active high-throughput screening hit to (2 R)-2-(4-cyclopropanesulfonylphenyl)- N-(5-fluorothiazol-2-yl)-3-(tetrahydropyran-4-yl)propionamide (PSN-GK1), a potent GK activator with an improved pharmacokinetic and safety profile, is described. Following oral administration, this compound elicited robust glucose lowering in rats.

Glucokinase-activating ureas.

The synthesis, SAR and biological evaluation of a series of ureas that activate glucokinase, a target for diabetes therapy as a result of its critical role in the regulation of whole-body glucose homeostasis, are described. Some of the urea-containing glucokinase activators lowered blood glucose levels in vivo following oral dosing to C57BL/6J mice.

Moderate visual impairment in India: the Andhra Pradesh Eye Disease Study.

AIM: To assess the prevalence and demographic associations of moderate visual impairment in the population of the southern Indian state of Andhra Pradesh. METHODS: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 people of all ages were sampled using a stratified, random, cluster, systematic sampling strategy. The eligible people were invited for interview and detailed dilated eye examination by trained professionals. Moderate visual impairment was defined as presenting distance visual acuity less than 6/18 to 6/60 or equivalent visual field loss in the better eye. RESULTS: Of those sampled, 10,293 (87.3%) people participated in the study. In addition to the previously reported 1.84% prevalence of blindness (presenting distance visual acuity less than 6/60 or central visual field less than 20 degrees in the better eye) in this sample, 1237 people had moderate visual impairment, an adjusted prevalence of 8.09% (95% CI 6.89 to 9.30%). The majority of this moderate visual impairment was caused by refractive error (45.8%) and cataract (39.9%). Increasing age, female sex, decreasing socioeconomic status, and rural area of residence had significantly higher odds of being associated with moderate visual impairment. CONCLUSIONS: These data suggest that there is a significant burden of moderate visual impairment in this population in addition to blindness. Extrapolation of these data to the population of India suggests that there were 82 million people with moderate visual impairment in the year 2000, and this number is likely to be 139 million by the year 2020 if the current trend continues. This impending large burden of moderate visual impairment, the majority of which is due to the relatively easily treatable refractive error and cataract, would have to be taken into account while estimating the eye care needs in India, in addition to dealing with blindness. Specific strategies targeting the elderly population, people with low socioeconomic status, those living in the rural areas, and females would have to be implemented in the long term to reduce moderate visual impairment.

Blindness in the Indian state of Andhra Pradesh.

PURPOSE: To determine the current prevalence and causes of blindness in the Indian state of Andhra Pradesh to assess if blindness has decreased since the last survey of 1986-1989. METHODS: A population-based epidemiology study, using a stratified, random, cluster, systematic sampling strategy, was conducted in the state of Andhra Pradesh in India. Participants of all ages (n = 10,293), 87.3% of the 11,786 eligible, from 94 clusters in one urban and three rural areas representative of the population of Andhra Pradesh, underwent interview and a detailed dilated ocular evaluation by trained professionals. Blindness was defined as presenting distance visual acuity < 6/60 or central visual field < 20(o) in the better eye. RESULTS: Two hundred seventy-five participants were blind, a prevalence of 1.84% (95% confidence interval, 1.49%-2.19%) when adjusted for the age, sex, and urban-rural distribution of the population in 2000. The causes of this blindness were easily treatable in 60.3% (cataract, 44%; refractive error, 16.3%). Preventable corneal disease, glaucoma, complications of cataract surgery, and amblyopia caused another 19% of the blindness. Blindness was more likely with increasing age and decreasing socioeconomic status, and in female subjects and in rural areas. Among the 76 million population of Andhra Pradesh, 714,400 are estimated to have cataract-related blindness (615,600 cataract, 53,200 cataract surgery-related complications, 45,600 aphakia), and 228,000 refractive error-related blindness (159,600 myopia, 22,800 hyperopia, 45,600 refractive error-related amblyopia). If 95% of the cataract and refractive error blindness in Andhra Pradesh had been treated effectively, 3.4 and 7.4 million blind-person-years, respectively, could have been prevented. If 90% of the blindness due to preventable corneal disease and glaucoma had been prevented, another 2.7 million blind-person-years could have been prevented. CONCLUSIONS: The prevalence of blindness in this Indian state has increased from 1.5% in the late 1980s to 1.84% currently, as against the target of the National Program for Control of Blindness to reduce the prevalence to 0.3% by 2000. The number of people with cataract-related blindness has not reduced even with the eye care policy focus on cataract. Reduction of blindness in India will require strategies that are more effective than those that have been pursued so far.