1,466 research outputs found
Charge Delocalization in Self-Assembled Mixed-Valence Aromatic Cation Radicals
The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation of dimer cation radicals is deliberated with the aid of a series of cyclophane-like bichromophoric donors with drastically varied interplanar angles between the cofacially arranged aryl moieties. X-ray crystallography of a number of mixed-valence cation radicals derived from monochromophoric benzenoid donors established that they generally assemble in 1D stacks in the solid state. However, the use of polychromophoric intervalence cation radicals, where a single charge is effectively delocalized among all of the chromophores, can lead to higher-order assemblies with potential applications in long-range charge transport. As a proof of concept, we show that a single charge in the cation radical of a triptycene derivative is evenly distributed on all three benzenoid rings and this triptycene cation radical forms a 2D electronically coupled assembly, as established by X-ray crystallography
Cohesion, Elastic Constants and Vibrational Mechanics of Fcc Platinum
A model in real space has been developed by extending the generalized form of the exponential potential known as extended generalized exponential potential (EGEP) to account for (a) the correct nature of repulsive and attractive components of forces for all the separations in general and that of small separations in particular, (b) the three-body forces such as volume forces in an indirect way in the framework of EGEP through the parameter n, (c) the dielectric screening functions in an alternative and simpler form through the parameter m. The model is employed to compute the cohesive energy, second-order elastic constants and phenon spectra for fcc platinum. The predictions show promising agreement with experimental findings.Author Affiliation: Divesh Verma
A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India
M L Verma* and A Verma
Department of Physics, GGDSD College, Palwal-121 102, Haryana, India
and
R P S Rathore
Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, India1.A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India 2.Department of Physics, GGDSD College, Palwal-121 102, Haryana, India 3.Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, Indi
Evaluation for early seedling vigour of hybrids and varieties of pigeonpea [Cajanus cajan (L.) Millsp.]
The research was conducted at Parbhani, Maharashtra, India during kharif 2011and 2012 to evaluate hybrid and varieties of pigeonpea for early seedling vigour and its related traits under greenhouse condition. The experimental material consists of three medium duration hybrids (ICPH 2671, ICPH 2740, and ICPH 3762) and three medium maturing varieties (BDN 711, BSMR 736, and Asha). Results revealed that hybrids recorded significantly higher rate of germination (97.58%), longer radicle length (16.75 2cm), wider leaf area (177.70 cm ), more chlorophyll content (37.35), higher seedling dry weight (4.6 g) and greater seedling vigour 2index (4139.08) as compared to varieties (91.9%, 11.85 cm, 106.27 cm , 32.81, 3.67 g and 3937.28, respectively). Genotype × environment (G × E) interaction found highly significant for all the traits except leaf area and seedling vigour index. Among G × E 2combinations, G E (ICPH 3762 in 2012) noted longer radicle (21.78 cm), wider leaf area (189.9 cm ), more chlorophyll content 3 2 (38.64) and highest seedling dry weight (5.84 g). These findings proved that hybrids had better germination percentage, uniform plant stand, longer radicle, and better seedling vigour index, an indication of producing higher seed yield over the varieties
Physico-chemical, microbial and phytotoxicity evaluation of composts from sorghum, finger millet and soybean straws
Purpose
Composting is an environmentally sustainable alternative for bioconversion of agricultural residues into a nutrient-rich product that can enhance soil fertility/microbial diversity and thereby improve agricultural productivity. The goal of the current study was to evaluate the decomposition pattern of the agro-residues and assess the maturity and phytotoxicity of the composts obtained using physico-chemical, microbial and statistical analyses. The study also attempted to determine a threshold germination index (GI) to serve as a maturity index for the composts by conducting seed germination assays with tomato, chickpea and soybean seeds.
Methods
Three agricultural residues/straws of Eleusine coracana (finger millet), Sorghum bicolor (sorghum) and Glycine max (soybean) were subjected to aerobic composting for a period of 60 days to study the impact of saw dust on the decomposition pattern and the ultimate compost quality/characteristics.
Results
The results showed efficient decomposition pattern of the agricultural residues characterized by high temperature profiles (up to 70 °C), high microbial activity, a sharp decrease in C/N ratio of the composting materials, i.e., from an initial 41–61 to final 10–17.
Conclusions
Statistical evaluation of seed germination assays showed that only the compost obtained from sorghum straw + saw dust was mature and free from any phytotoxicity as all the tested seeds showed higher and statistically significant GIs. It was difficult to attribute a single threshold GI value to indicate maturity of compost and could not further be applied to different types of composts as different seeds responded differently to the same compost
Physico-chemical, microbial and phytotoxicity evaluation of composts from sorghum, finger millet and soybean straws
Purpose
Composting is an environmentally sustainable alternative for bioconversion of agricultural residues into a nutrient-rich product that can enhance soil fertility/microbial diversity and thereby improve agricultural productivity. The goal of the current study was to evaluate the decomposition pattern of the agro-residues and assess the maturity and phytotoxicity of the composts obtained using physico-chemical, microbial and statistical analyses. The study also attempted to determine a threshold germination index (GI) to serve as a maturity index for the composts by conducting seed germination assays with tomato, chickpea and soybean seeds.
Methods
Three agricultural residues/straws of Eleusine coracana (finger millet), Sorghum bicolor (sorghum) and Glycine max (soybean) were subjected to aerobic composting for a period of 60 days to study the impact of saw dust on the decomposition pattern and the ultimate compost quality/characteristics.
Results
The results showed efficient decomposition pattern of the agricultural residues characterized by high temperature profiles (up to 70 °C), high microbial activity, a sharp decrease in C/N ratio of the composting materials, i.e., from an initial 41–61 to final 10–17.
Conclusions
Statistical evaluation of seed germination assays showed that only the compost obtained from sorghum straw + saw dust was mature and free from any phytotoxicity as all the tested seeds showed higher and statistically significant GIs. It was difficult to attribute a single threshold GI value to indicate maturity of compost and could not further be applied to different types of composts as different seeds responded differently to the same compost
Genetic variability, genotype × environment interaction and correlation analysis for grain iron and zinc contents in recombinant inbred line population of pearl millet [Pennisetum glaucum (L). R.
Micronutrient malnutrition is one of the major health
problems, especially iron (Fe) and zinc (Zn) deficiencies
that are widespread coupled with inadequate food supply
in the developing world. Pearl millet grains are a good source
of Fe and Zn elements making it a potential staple crop for
overcoming hidden-hunger and micronutrient deficiencies.
Breeding pearl millet with high levels of grain Zn and Fe
contents represents a major opportunity to enhance the
intake of these minerals for poor and malnourished people.
A precise understanding of the genetic variability,
correlation of mineral nutrients, genotype × environment
(G × E) interaction is important for developing improved
lines with high Fe and Zn content. To get fair estimates, we
used a bi-parental recombinant inbred lines (RIL) mapping
population representing F2 phenotypic variance. A total of
317 RILs were evaluated for grain iron and zinc content in
two seasons, Summer 2016 (E1) and Summer 2017 (E2).
The result from the analysis of variance exhibited a large
variability for grain Fe and Zn content across the two
environments. The G × E for high grain Fe were significant
at P < 0.01. The mean performance across the two
environments data for grain Fe ranged from 22.9 to 154.5
mg kg-1 (ppm) and Zn content ranged from 19.3 to 121 mg
kg-1. The correlation coefficient for grain Fe and Zn was 0.9,
and 0.8 and across the two (E1 and E2) environments. The
value of correlation coefficient (0.9) was found to be highly
significant at P < 0.01 level, that indicated good
opportunities for simultaneous genetic improvement of
both iron and zinc contents in pearl millet
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Measures of multiple deprivation and visual field loss in glaucoma clinics in England: lessons from big data
Background/Objectives
To examine the association between multiple deprivation with late diagnosis and rapid worsening of glaucoma in patients in English hospital eye services (HES).
Methods
602,439 visual fields (VFs) were extracted from five regionally different glaucoma clinics in England. Mean Deviation (MD) worse than −12 dB was used as a surrogate definition for advanced VF loss at diagnosis in patients with ≥2 reliable VF records. MD loss worse than -1 dB per year was used to define rapid VF progression in patients with ≥6 VFs. Patient data were stratified into deciles of the Index of Multiple Deprivation (IMD) from residential postcodes.
Results
There was an association between IMD and advanced VF loss at diagnosis in 44,956 patients with 18% (293/1608) and 11% (771/6929) in the most and least deprived IMD decile, respectively. Age-corrected odds ratio (OR) for having advanced VF loss at entry into HES was 1.42 (95% confidence interval [CI] 1.21–1.67) and 0.75 (95% CI: 0.66–0.85) in the most and least deprived IMD decile respectively (reference = fifth decile). In 15,094 patients with follow up data (median [interquartile range] of 6.9 [4.5, 10.0] years), the proportion having rapid VF progression did not differ across the IMD spectrum.
Conclusion
Large-scale VF data from clinics indicates that glaucoma severity at presentation to English HES is associated with levels of multiple deprivation. We found no evidence to suggest likelihood of having rapid VF progression during follow-up is associated with IMD; this hints at equity of glaucoma care and outcomes once patients are in English HES
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