1,603 research outputs found
Study of the Optical Properties of Zno Nano-structure at Different Ti Content
Zinc oxide (ZnO) and TZO samples having different Ti content were synthesized from doping to composite by Citrate sol-gel method (dissolving and react with citric acid) characterized according to their optical properties. The UV - vis characterization exhibiting good optical properties. The results show there are one absorption edge at pure and low Ti doping but at higher Ti% another edge appeared and slightly shifted around 400 nm. The maximum absorption nearly at 350 nm, and the band gap energy of Ti-doped ZnO increase from 3.16 to 3.20 eV achieving a blue-shift. A red shift from 3.07 to 3.19 eV in the visible range which has a very important application, this improves the optical properties of ZnO and gives an indication how to tune its band gap (increase or decrease by doping or composition)
A meta-analysis of fMRI studies of semantic cognition in children
Our capacity to derive meaning from things that we see and words that we hear is unparalleled in other animal species and current AI systems. Despite a wealth of functional magnetic resonance imaging (fMRI) studies on where different semantic features are processed in the adult brain, the development of these systems in children is poorly understood. Here we conducted an extensive database search and identified 50 fMRI experiments investigating semantic world knowledge, semantic relatedness judgments, and the differentiation of visual semantic object categories in children (total N = 1,018, mean age = 10.1 years, range 4–15 years). Synthesizing the results of these experiments, we found consistent activation in the bilateral inferior frontal gyri (IFG), fusiform gyri (FG), and supplementary motor areas (SMA), as well as in the left middle and superior temporal gyri (MTG/STG). Within this system, we found little evidence for age-related changes across childhood and high overlap with the adult semantic system. In sum, the identification of these cortical areas provides the starting point for further research on the mechanisms by which the developing brain learns to make sense of its environment
Synthesis of fluorinated 3-hydrazino-1,2,4-triazino[5,6-b] indoles as novel herbicidal systems
A few fluorinated 3-hydrazino-1,2,4-triazino[5,6-b] indoles (5-8) have been synthesized and screened for their herbicidal effect. Treatment of 3-hydrazino-8H/8-fluoro-1,2,4-triazino[5,6-b] indoles (3 and 4) with fluorinated acyl derivatives (A and B) yielded the rich fluorine 1,2,4-triazino indole. Structure of the products have been established by elemental analysis and spectral measurements. The presence and position of fluorine atoms have been deduced from 19FÂ NMR. The novel fluorinated hydrazino-1,2,4-triazino[5,6-b] indoles have been tested for post-emergent herbicidal activity against grass weed species and broadleaf weed species
Synthesis of fluorinated 3-hydrazino-1,2,4-triazino[5,6-b] indoles as novel herbicidal systems
1703-1706A few fluorinated 3-hydrazino-1,2,4-triazino[5,6-b] indoles (5-8) have been synthesized and screened for their herbicidal effect. Treatment of 3-hydrazino-8H/8-fluoro-1,2,4-triazino[5,6-b] indoles (3 and 4) with fluorinated acyl derivatives (A and B) yielded the rich fluorine 1,2,4-triazino indole. Structure of the products have been established by elemental analysis and spectral measurements. The presence and position of fluorine atoms have been deduced from 19F NMR. The novel fluorinated hydrazino-1,2,4-triazino[5,6-b] indoles have been tested for post-emergent herbicidal activity against grass weed species and broadleaf weed species
Cytotoxicity of Nubein6.8 peptide isolated from the snake venom of Naja nubiae on melanoma and ovarian carcinoma cell lines
This study was conducted to examine the cytotoxic effects of Nubein6.8 isolated from the venom of the Egyptian Spitting Cobra Naja nubiae on melanoma (A375) and ovarian carcinoma cell lines and to reveal its mode of action. The size of Nubein6.8 (6801.8 Da) and its N-terminal sequence are similar to cytotoxins purified from the venom of other spitting cobras. Nubein6.8 showed a high significant cytotoxic effect on A375 cell line and moderate effect on A2780. A clonogenic assay showed that Nubein6.8 has a significant long-term potency on A375 cell survival when compared to A2780. The molecular intracellular signaling pathways of Nubein6.8 have been investigated using Western blotting analysis, flow cytometry, and microscale protein labeling. This data revealed that Nubein6.8 has DNA damaging effects and the ability to activate apoptosis in both tumor cell lines. Cellular uptake recordings revealed that the labeled-Nubein6.8 was intracellularly present in A375 cells while A2780 displayed resistance against it. SEM examination showed that Nubein6.8 was found to have high accessibility to malignant melanoma cells. The apoptotic effect of Nubein6.8 was confirmed by TEM examination that revealed many evident characteristics for Nubein6.8 apoptotic efficacy on A375 cell sections. Also, TEM reflected many resistant characteristics that faced Nubein6.8 acquisition through ovarian carcinoma cell sections. Accordingly, the snake venom peptide of Nubein6.8 is a promising template for developing potential cytotoxic agents targeting human melanoma and ovarian carcinoma
Fate of the Universe, Age of the Universe, Dark Matter, and the Decaying Vacuum Energy
It is shown that in the cosmological models based on a vacuum energy decaying
as a^{-2}, where a is the scale factor of the universe, the fate of the
universe in regard to whether it will collapse in future or expand forever is
determined not by the curvature constant k but by an effective curvature
constant k_{eff}. It is argued that a closed universe with k=1 may expand
forever, in other words simulate the expansion dynamics of a flat or an open
universe because of the possibility that k_{eff}=0 or -1, respectively. Two
such models, in one of which the vacuum does not interact with matter and in
another of which it does, are studied. It is shown that the vacuum equation of
state p_{vac}= -\rho_{vac} may be realized in a decaying vacuum cosmology
provided the vacuum interacts wuth matter. The optical depths for gravitational
lensing as a function of the matter density and other parameters in the models
are calculated at a source redshift of 2. The age of the universe is discussed
and shown to be compatible with the new Hipparcos lower limit of 11Gyr. The
possibility that a time-varying vacuum energy may serve as dark matter is
suggested.Comment: AAS LaTex, 29 pages, published in the Astrophysical Journal, 520, 45,
199
IMPACT OF PLANT GROWTH-PROMOTING RHIZOBACTERIA ON COWPEA GROWTH PERFORMANCE AND ROOT DISEASES CONTROLLING UNDER GREENHOUSE CONDITIONS
This study was executed during two successive seasons 2014 and 2015 for evaluating the effect of inoculation with Bradyrhizobium sp, Bacillus megaterium, Bacillus circulans, Glomus macrocarpum and Pseudomonas fluorescens on infection percentage, enzymatic activity, growth characteristics, total phenol, peroxidase and polyphenol oxidase activity in presence or absence of Fusarium oxysporum in sterilized or non- sterilized soil under greenhouse condition. The obtained results observed that the tested strains showed suppression for F. oxysporum in vitro. Similar results were obtained under greenhouse experiment where the inoculation of soil with biofertilizers strains in presence of P. fluorescens showed the lowest records of infection percentage as well as the higher values of enzymatic activity, growth characteristics, total phenol, peroxidase and polyphenol oxidase activity compared to full dose of chemical fertilizers treatment. This study provides evidence for diminishing the adverse evolved from the continues application of chemical fertilizers in high doses and replacing it (at least partially) through biofertilizers and biocontrol application
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