2,203 research outputs found
Multi-band optical-NIR variability of blazars on diverse timescales
To search for optical variability on a wide range of timescales, we have
carried out photometric monitoring of two flat spectrum radio quasars, 3C 454.3
and 3C 279, plus one BL Lac, S5 0716+714, all of which have been exhibiting
remarkably high activity and pronounced variability at all wavelengths. CCD
magnitudes in B, V, R and I pass-bands were determined for 7000 new
optical observations from 114 nights made during 2011 - 2014, with an average
length of 4 h each, at seven optical telescopes: four in Bulgaria, one
in Greece, and two in India. We measured multiband optical flux and colour
variations on diverse timescales. Discrete correlation functions were computed
among B, V, R, and I observations, to search for any time delays. We found weak
correlations in some cases with no significant time lags. The structure
function method was used to estimate any characteristic time-scales of
variability. We also investigated the spectral energy distribution of the three
blazars using B, V, R, I, J and K pass-band data. We found that the sources
almost always follows a bluer-when-brighter trend. We discuss possible physical
causes of the observed spectral variability.Comment: Accepted for publication in MNRAS, 16 pages, 11 figures, 5 tables,
plus supplementary material containing additional figures and tables (please
contact authors for it
Genetic Resistance in Desi and Kabuli Chickpea Lines to Fusarium Wilt Caused by Fusarium oxysporum f. sp. ciceris
Twenty five lines each of desi and of kabuli chickpea (Cicer arietinum L.) were evaluated for Fusarium wilt resistance during 2008–09 season in the field (wilt sick plot) and greenhouse at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India. Fifteen desi and nine kabuli lines were found resistant (d"10% mortality) to Fusarium wilt. Significant positive correlation was found between greenhouse and field screening techniques (r = > 0.84, P < 0.0001). Additionally, phenological traits and yield were also recorded for all the lines in the disease free field at ICRISAT, Patancheru. Six wilt resistant desi lines (ICCV 09118, ICCV 09113, ICCV 09115, ICCX-030042-F4-P12-BP-BP, ICCX-030037-F4-P9-BP-BP, ICCX-030042-F4-P1-BP-BP) and two kabuli lines (ICCV 09308, ICCV 09314) matured early between 99–107 days and yielded more than the control cultivars JG 11 for desi (2208 kg/ha yield) and JGK 1 for kabuli (2243 kg/ha). These early maturing, high maturng, high yielding and wilt resistant desi and kabuli chickpea lines can be useful sources for breeding wilt resistant varietie
Changing Plant Architecture and Density can Increase Chickpea Productivity and Facilitate for Mechanical Harvesting
Tall and erect chickpea cultivar HC 5 (Haryana Chana 5) was primarily bred for inter-cropping with autumn planted sugarcane. Cultivar HC 5 is distinctly different in morphology from traditional bushy or semi-spreading chickpea cultivars and it is found suitable for machine harvesting. However, a general recommended planting density (30 cm × 10 cm) is being followed for cv. HC 5 as well. In this study, we hypothesized that high-density planting can improve crop productivity and also improve the plant architecture for mechanical harvesting. To test this hypothesis, four plant spacing treatments (30 cm × 10 cm, 30 cm × 7.5 cm, 22.5 cm × 10 cm, and 22.5 cm × 7.5 cm) were evaluated in two chickpea cultivars (HC 5 and JAKI 9218) for crop growth, grain yield and the desirable plant traits for mechanical harvesting. The highest grain yield of cv. HC 5 was observed with 22.5 cm × 10 cm spacing that increased the grain yield by 9% (p < 0.05) over plant spacing of 30 cm × 10 cm (conventional); this indicates that high-density planting could increase the productivity of the cv. HC 5. Where grain yield of cv. JAKI 9218 was reduced (p < 0.05) with the increase in planting density over 30 cm × 10 cm. Increased grain yield of cv. HC 5 with 22.5 cm × 10 cm spacing over 30 cm × 10 cm was mainly attributed to increase in plant density (33%); however, all the plant attributes (primary branch, secondary branch, pod plant−1) were reduced as compared to plant spacing of 30 cm × 10 cm. The decrease in intra-row spacing of cv. HC 5 resulted in a strong adverse effect on plant growth and yield parameters as compared to inter-row spacing and thus not recommended. High-density planting increased the plant height (erectness) and ground clearance of cv. HC 5 (height of first pod) (~ 30 cm), an essential prerequisite for mechanical harvesting, but not in cv. JAKI 9218. Hence, cv. HC 5 requires a dense planting for higher yield and appropriate plant structure for mechanical harvesting. Therefore, it is recommended to work out the optimum planting geometry/plant population to realize the potential yield of cultivars bred for mechanical harvesting
Primary and malignant cholangiocytes undergo CD40 mediated Fas dependent Apoptosis, but are insensitive to direct activation with exogenous fas ligand
Introduction
Cholangiocarcinoma is a rare malignancy of the biliary tract, the incidence of which is rising, but the pathogenesis of which remains uncertain. No common genetic defects have been described but it is accepted that chronic inflammation is an important contributing factor. We have shown that primary human cholangiocyte and hepatocyte survival is tightly regulated via co-operative interactions between two tumour necrosis family (TNF) receptor family members; CD40 and Fas (CD95). Functional deficiency of CD154, the ligand for CD40, leads to a failure of clearance of biliary tract infections and a predisposition to cholangiocarcinoma implying a direct link between TNF receptor-mediated apoptosis and the development of cholangiocarcinoma.
Aims
To determine whether malignant cholangiocytes display defects in CD40 mediated apoptosis. By comparing CD40 and Fas-mediated apoptosis and intracellular signalling in primary human cholangiocytes and three cholangiocyte cell lines.
Results
Primary cholangiocytes and cholangiocyte cell lines were relatively insensitive to direct Fas-mediated killing with exogenous FasL when compared with Jurkat cells, which readily underwent Fas-mediated apoptosis, but were extremely sensitive to CD154 stimulation. The sensitivity of cells to CD40 activation was similar in magnitude in both primary and malignant cells and was STAT-3 and AP-1 dependent in both.
Conclusions
1) Both primary and malignant cholangiocytes are relatively resistant to Fas–mediated killing but show exquisite sensitivity to CD154, suggesting that the CD40 pathway is intact and fully functional in both primary and malignant cholangiocytes 2) The relative insensitivity of cholangiocytes to Fas activation demonstrates the importance of CD40 augmentation of Fas dependent death in these cells. Agonistic therapies which target CD40 and associated intracellular signalling pathways may be effective in promoting apoptosis of malignant cholangiocytes
Impact of heat and drought stresses on grain nutrient content in chickpea: Genome-wide marker-trait associations for protein, Fe and Zn
Chickpea is a cheap source of protein and micronutrients to the poor and vegetarian population living in south-
Asia and sub-Saharan Africa. Due to changes in climatic conditions and cropping systems, the crop is being
exposed to severe drought and heat stress during its reproductive period, which leads to significant yield losses
and fluctuations in grain nutrient accumulation. The study was conducted with 140 diverse genotypes under nonstress,
drought, and heat stress conditions to estimate their effects on grain nutrient (protein, Fe and Zn) contents
and identify the marker-trait associations. Analysis of variance revealed highly significant differences among
genotypes for nutrient content under respective planting conditions. The seed yield was negatively associated
with the grain Fe (r
MAGIC lines in chickpea: development and exploitation of genetic diversity
In chickpea a multi-parent advanced generation intercross (MAGIC) population was developed using eight parents that are improved varieties and widely adaptable breeding lines. The main objective was to enhance the genetic diversity and bring novel alleles for developing superior chickpea varieties. The development scheme involved a sequence of 28 two-way, 14 four-way and 7 eight-way crosses, followed by bulking of final F1 plants. From F2 generation onwards single plants were grown as progenies and advanced to F8 by single seed descent method. The finally developed 1136 MAGIC lines were phenotyped under rainfed (RF) and irrigated (IR) conditions for 2 years (2013 and 2014) under normal season, and one year under heat stress (HS) condition (summer-2014) in field to estimate the genetic diversity created among these lines. Under RF-2014, RF-2013, IR-2014, IR-2013 and S-2014 seasons 46, 62, 83, 50 and 61 lines showed significantly higher grain yield than the best parent, respectively. Similarly, 23 and 19 common lines were identified under RF and IR conditions over two years and no common line was identified between RF/IR and HS conditions. Preliminary evaluation showed a large variation among MAGIC lines for flowering time (34–69 days), maturity (80–120 days), plant height (23.3–65 cm), grain yield (179–4554 kg/ha), harvest index (0.10–0.77) and 100 seed weight (10–45 g) under RF and IR conditions. Several genotypes with higher grain yield than the best check under heat stress were identified. These MAGIC lines provide a useful germplasm source with diverse allelic combinations to global chickpea community
Malnutrition Has No Effect on the Timing of Human Tooth Formation
The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females) consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off) were used to identify the malnourished group (N = 474) while the normal was defined by Z-scores of ≥0 (N = 799). Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05). This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems
A novel method for spectrophotometric determination of pregabalin in pure form and in capsules
<p>Abstract</p> <p>Background</p> <p>Pregabalin, a γ-amino-n-butyric acid derivative, is an antiepileptic drug not yet official in any pharmacopeia and development of analytical procedures for this drug in bulk/formulation forms is a necessity. We herein, report a new, simple, extraction free, cost effective, sensitive and reproducible spectrophotometric method for the determination of the pregabalin.</p> <p>Results</p> <p>Pregabalin, as a primary amine was reacted with ninhydrin in phosphate buffer pH 7.4 to form blue violet colored chromogen which could be measured spectrophotometrically at λ<sub>max </sub>402.6 nm. The method was validated with respect to linearity, accuracy, precision and robustness. The method showed linearity in a wide concentration range of 50-1000 μg mL<sup>-1 </sup>with good correlation coefficient (0.992). The limits of assays detection was found to be 6.0 μg mL<sup>-1 </sup>and quantitation limit was 20.0 μg mL<sup>-1</sup>. The suggested method was applied to the determination of the drug in capsules. No interference could be observed from the additives in the capsules. The percentage recovery was found to be 100.43 ± 1.24.</p> <p>Conclusion</p> <p>The developed method was successfully validated and applied to the determination of pregabalin in bulk and pharmaceutical formulations without any interference from common excipients. Hence, this method can be potentially useful for routine laboratory analysis of pregabalin.</p
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