187 research outputs found
Recommended from our members
A Multi-instrument Investigation of Pigments, Binders and Varnishes from Egyptian Paintings (AD 1300-1900): Molecular and Elemental Analysis Using Raman, GC-MS and SEM-EDX Techniques
The focus of this study was analytical investigations of Egyptian paintings, mainly
Coptic icons and Islamic wooden ceilings, dating from 1300-1900 using multiinstrumental
techniques. Twenty three Coptic icons and three wooden ceilings dated
from different periods and painted by different painters in case of icons were examined.
The materials used including pigments, media, varnishes, ground layers and gold layers.
The surface stratigraphy of paint samples, their layered structured and the composition
of materials used in each layer were analysed. Variations in painting techniques,
pigments palettes, paint media and varnishes applied in Egyptian paintings according to
painters, time and type of paintings were revealed.
A total of twenty-eight organic and inorganic pigments were identified in this study, of
which nine have never been previously included as a part of the Egyptian pigment
palettes, namely; smalt, lapis lazuli, indigo, pararealgar, Prussian blue, chrome yellow,
barium yellow, barium white and hydromagnesite. The identification of
hydromagnesite, which has never been to date considered as a pigment either in Egypt
or elsewhere and the identification of smalt from the mid-14th century, whose reported
earliest large scale use was in the 16th century. Two types of resins were identified as a
constituent of the oil/resin varnish applied on Coptic icons of which Venice turpentine
has been identified for the first time as an ingredient of Egyptian varnishes. The
identification of mosaic gold in an 18th C. icon, a novel usage of dammar resin and the
multilayered structure of the white ground layers were revealed.Egyptian Ministry of Higher Education
CHEMICAL AND BIOLOGICAL ANALYSIS OF THE BIOCTIVE FRACTIONS OF THE LEAVES OF SCAEVOLA TACCADA (GAERTN.) ROXB
Objective: Scaevola taccada. (Gaertn.) Roxb. is widely dispersed all along the coasts of Africa. It is used in folk medicine for diversity of ailments. This study aims to investigate the major phytoconstituents and biological activities of the leaves of S. taccada (Gaertn.) Roxb.
Methods: In vitro biological examination viz. antimicrobial, cytotoxic and antioxidant activities of the ethanol extract of the leaves (EE) and its fractions; (petroleum ether (PE), methylene chloride (MC), ethyl acetate (EA) and n-butanol(BuOH)) were carried out. Estimation of the phytochemicals of biologically active fractions was done.
Results: n-butanol fraction displayed remarkable antimycobacterium activity. Petroleum ether as well as n-butanol fractions evidenced a cytotoxic effect on breast carcinoma cell line (MCF7) and colon carcinoma cell line (HCT) with IC50 11.7 and 15.04 µg/ml respectively. Moreover, ethyl acetate fraction exhibits an antioxidant effect with EC50 476.7±0.57 µg/ml. n-tetradecane 1, α-amyrin palmitate 2, α-amyrin acetate 3, α-amyrin 4, stigmasterol 5, luteolin-7-O-β-glucoside 6, rutin 7 and alidyjosioside 8 were identified in S. taccada (Gaertn.) Roxb. leaves.
Conclusion: Petroleum ether fraction is a cytotoxic candidate, especially against (MCF-7). It exhibited a moderate antifungal and antibacterial against certain Gram-positive bacteria. Ethyl acetate showed an antioxidant effect along with moderate antifungal activity. n-butanol fraction exerted potential antimycobacterial, significant cytotoxic activity against (HCT), good antifungal and antibacterial against Gram-positive and Gram-negative bacteria. Stigmasterol, luteolin-7-O-β-glucoside, rutin and alidyjosioside were isolated for the first time from S. taccada (Gaertn.) Roxb. Leaves
Study of the Electrical Properties and Swelling Mechanism in Compressed Butyl Rubber Loaded with Carbon Black
The dependence of both electrical conductivity "σ" and dielectric constant "ε" for samples containing different carbon black concentrations were studied at different loads. It was found that, "σ" and "ε" are nearly load independent at low concentration, however, they change at higher concentration of carbon black. Swelling of the samples in both benzene and kerosene was measured, and found to be dependent on both carbon black concentration and the type of solvent used. The diffusion coefficient, penetration rate and the molecular mass were calculated
Effect of humic acids and the amount of mineral fertilizer on some characteristics of saline soil, growth and yield of broccoli plant under salt stress conditions
Saabunud / Received 09.04.2022 ; Aktsepteeritud / Accepted 19.06.2022 ; Avaldatud veebis / Published online 19.06.2022 ; Vastutav autor / Corresponding author: Duraid K. A. Al-Taey ; [email protected] (A pots experiment was undertaken to determine the
combined effect of humic acids and mineral fertilizer on some
characteristics of saline soil, growth, and yield components of broccoli.
The experiment was conducted in a randomized complete block design
with three replications. The first factor consists of two levels of humic
acids, namely without humic acid (H0 = 0.00 g L–1
) and humic acid
application (H1 = 0.35 g L–1
), while the second factor included nine
fertilizer (92 kg N ha
–1
, 200 kg P2O5 ha–1
, 150 kg K2O ha–1
) application
rates that were (100, 100, 100%), (120, 120, 120%), (120, 120, 100%),
(80, 120, 120%), (100, 100, 120%), (80.100, 100%), (120, 80, 80%), (100,
80, 80%), (80, 80, 80%) which added as a percentage of original fertilizer
recommendation taking the symbols of R1 to R9 respectively. The
treatment R1 was designated as a control treatment. The results indicated
that humic acid application (H1) and increasing the amount of applied
mineral fertilizer (R2) reduced the hydraulic conductivity of the soil for
different soil depths. Humic acid addition (H1) increased concentrations
of calcium and magnesium while reducing sodium concentration
compared to control (H0). Contrary to humic acid, increasing the supplied
mineral fertilizer led to a reduction in concentrations of calcium and
magnesium while increasing sodium concentration in the soil. The sodium
adsorption in soil particles in the ground was decreased due to humic acid
application while improving the mineral fertilizer. Humic acid (H1)
combined with increasing the amount of chemical fertilizer (R2) gave the
desirable results in decreasing the sulphate, chloride and bicarbonate in the
soil profile. The addition of humic acid (H1) and increasing mineral
fertilizer application (R2) led to a significant increase in plant height, leaf
area and head weight of broccoli per plant. Similarly, the interaction
between humic acids and chemical fertilizers (H1R2) led to a significant
increase in plant height, leaf area and head weight of broccoli per plant
Genome-wide association mapping in a diverse spring barley collection reveals the presence of QTL hotspots and candidate genes for root and shoot architecture traits at seedling stage
Figure S1. Examples of scanned root images from individual plants. Figure S2. Concatenated split network tree for the collection of 233 accessions based on 6019 SNP markers. Figure S3. LD pattern along the individual chromosomes of barley. Figure S4. Schematic representation of the eight re-sequenced candidate genes models. (DOCX 3427 kb
Development of Non-Natural Flavanones as Antimicrobial Agents
With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often with these added compounds enabling the transport of a toxic molecule into the infecting species. Flavonoids are among the most abundant plant secondary metabolites and have been shown to have natural abilities as microbial deterrents and anti-infection agents in plants. Combining these ideas we first sought to investigate the potency of natural flavonoids in the presence of efflux pump inhibitors to limit Escherichia coli growth. Then we used the natural flavonoid scaffold to synthesize non-natural flavanone molecules and further evaluate their antimicrobial efficacy on Escherichia coli, Bacillus subtilis and the fungal pathogens Cryptococcus neoformans and Aspergillus fumigatus. Of those screened, we identified the synthetic molecule 4-chloro-flavanone as the most potent antimicrobial compound with a MIC value of 70 µg/mL in E. coli when combined with the inhibitor Phe-Arg-ß-naphthylamide, and MICs of 30 µg/mL in S. cerevesiae and 30 µg/mL in C. neoformans when used alone. Through this study we have demonstrated that combinatorial synthesis of non-natural flavonones can identify novel antimicrobial agents with activity against bacteria and fungi but with minimal toxicity to human cells
Local-Scale Patterns of Genetic Variability, Outcrossing, and Spatial Structure in Natural Stands of Arabidopsis thaliana
As Arabidopsis thaliana is increasingly employed in evolutionary and ecological studies, it is essential to understand patterns of natural genetic variation and the forces that shape them. Previous work focusing mostly on global and regional scales has demonstrated the importance of historical events such as long-distance migration and colonization. Far less is known about the role of contemporary factors or environmental heterogeneity in generating diversity patterns at local scales. We sampled 1,005 individuals from 77 closely spaced stands in diverse settings around Tübingen, Germany. A set of 436 SNP markers was used to characterize genome-wide patterns of relatedness and recombination. Neighboring genotypes often shared mosaic blocks of alternating marker identity and divergence. We detected recent outcrossing as well as stretches of residual heterozygosity in largely homozygous recombinants. As has been observed for several other selfing species, there was considerable heterogeneity among sites in diversity and outcrossing, with rural stands exhibiting greater diversity and heterozygosity than urban stands. Fine-scale spatial structure was evident as well. Within stands, spatial structure correlated negatively with observed heterozygosity, suggesting that the high homozygosity of natural A. thaliana may be partially attributable to nearest-neighbor mating of related individuals. The large number of markers and extensive local sampling employed here afforded unusual power to characterize local genetic patterns. Contemporary processes such as ongoing outcrossing play an important role in determining distribution of genetic diversity at this scale. Local “outcrossing hotspots” appear to reshuffle genetic information at surprising rates, while other stands contribute comparatively little. Our findings have important implications for sampling and interpreting diversity among A. thaliana accessions
- …