Liquid-Liquid Successive Fractionation of Stem Bark Alcoholic Extract from Acacia polyacantha: GC-MS Analysis and Antibacterial Activities.

Antimicrobial resistance is considered as one of the top problematic issues facing world health system. Fortunately, medicinal plants, considered as ongoing source of antimicrobial agents can resolve this health problem Acacia polyacantha tree (AL-Kakamout) is widely available in Sudan. It is one of the main sources of Gum Arabic and used traditionally for treating many bacterial diseases. This study aimed to analyze the fractions of hydro-ethanol extract of A. polyacantha stem bark obtained by liquid-liquid successive fractionation by GC-MS method and to determine the antibacterial activity of these fractions against two standard bacterial strains of Gram-positive bacteria Staphylococcus aureus (ATCC 25923) and Gram-negative bacteria Pseudomonas aeroginosa (ATCC 27853) by well diffusion technique. The powdered A. polyacantha stem bark was extracted by cold maceration using 70% Ethanol and successively fractionated to produce petroleum ether, butanol and aqueous fraction. The butanol fraction in which Cyclolanostanol acetate (28.29%), Dopamine, N,N-dimethyl-, dimethyl ether (21.94%), were dominating, was the most active against both bacterial strains. Petroleum ether fraction which is rich in Lupeol, trifluoroacetate (37.64%) and stigmasterol (13.05%) triterpenoids was found to be more active against P. aeroginosa and with less activity against S.aureus. While the remaining aqueous fraction where hordenine alkaloid (47.21%) and 3-O-Methyl-d-glucose (%30.46) were dominant components showed no activity against S.aureus and with low activity against P. aeroginosa. In conclusion, A.polyacantha bark extract fractions are rich in phytochemical compounds having antibacterial activity and highly recommended to be further investigated as potential antibacterial agents

Modelling bidirectional radiance measurements collected by the advanced solid-state array spectroradiometer over Oregon transect conifer forests

Thesis (M.A.)--Boston UniversityThe primary objective of this research is to test and validate a geometric-optical bidirectional reflectance canopy model developed by Li and Strahler, with respect to actual forest canopy reflectance measurments. This model treats forest canopies as scenes of discrete, three dimensional objects that are illuminated and viewed from different positions in the hemisphere. The shapes of the objects, their count densities and patterns of placement are the driving variables, and they condition the mixture of sunlit and shaded objects and background that is observed from a particular viewing direction, given a direction of illumination. This mixture, in turn, controls the brightness apparent to an observer or a radiometric instrument. The Advanced Solid-State Array Spectroradiometer (ASAS) is chosen to be the sensor having the ability of collecting measurements at various look angles and its imaged reflectance was used to validate the model. The modelled BRF's were compared to actual ASAS measured BRF's in sites with different canopy structures and densities. The comparision revealed execellent match between the modelled and measured reflectance, and great ability of the model in predicting the shape and magnitude of the BRDF, in almost all the sites investigated. It is concluded that the geometric optics approach provided a good way to model the bidirectional reflectance distribution function of natural vegetation canopies, that captures the most important features exhibited by bidirectional measurements of such canopies. Further modifications have been suggested that will improve the predicted BRF's, and yield better results. [TRUNCATED

The applications of neural network in mapping, modeling and change detection using remotely sensed data

Thesis (Ph.D.)--Boston UniversityAdvances in remote sensing and associated capabilities are expected to proceed in a number of ways in the era of the Earth Observing System (EOS). More complex multitemporal, multi-source data sets will become available, requiring more sophisticated analysis methods. This research explores the applications of artificial neural networks in land-cover mapping, forward and inverse canopy modeling and change detection. For land-cover mapping a multi-layer feed-forward neural network produced 89% classification accuracy using a single band of multi-angle data from the Advanced Solidstate Array Spectroradiometer (ASAS). The principal results include the following: directional radiance measurements contain much useful information for discrimination among land-cover classes; the combination of multi-angle and multi-spectral data improves the overall classification accuracy compared with a single multi-angle band; and neural networks can successfully learn class discrimination from directional data or multi-domain data. Forward canopy modeling shows that a multi-layer feed-forward neural network is able to predict the bidirectional reflectance distribution function (BRDF) of different canopy sites with 90% accuracy. Analysis of the signal captured by the network indicates that the canopy structural parameters, and illumination and viewing geometry, are essential for predicting the BRDF of vegetated surfaces. The inverse neural network model shows that the R2 between the network-predicted canopy parameters and the actual canopy parameters is 0.85 for canopy density and 0.75 for both the crown shape and the height parameters. [TRUNCATED

Insights into organisational capabilities that influence innovation and organisational competitiveness in SMEs (small and medium enterprises).

This thesis seeks to develop insights into the nature of organisational capabilities that influence organisational competitiveness and innovation amongst a selection of SMEs. An interpretivist approach was followed to understand the phenomena from the participants point perspective. Participants in the study were the key players in the selected organisations, and had the experience and knowledge base to help the author develop deep insights into the research subject. The emerging analysis shaped the theory which the study set out to generate. This thesis generates an understanding and insights into the role of leadership, organisational structure and culture and a company's relationships with stakeholders in making an SME company innovative and competitively sustainable.The influence of the role of leadership, the influence of organisational culture on performance and their relationships and collaborations within companies and with others towards competitiveness and innovation is explored in this study. However, the author felt that whilst previous research were interesting, they did not fully explain the nature of innovation and its relationship to the ability of a company to achieve a sustainable competitive advantage. It is for this reason the author wished to put extant literature to one side and take a fresh look at innovation from the perspective of companies that had a successful innovative culture and had achieved sustainable growth through a strong track record of innovation.This research treats the innovation phenomena holistically and draws on the stories and views of company managers to develop insights into the true nature of a strong innovative culture and it relationships with sustainable competitive advantage from the perspective of the managers building the strategy and the culture of the company. The findings of this research are explained in the formulated theory which highlights the importance of creating innovative leadership, innovative structure and culture and innovative relationships and collaboration capabilities. These elements are linked by an open organisational mindset, effective internal and external relationships and proactive and supportive knowledge systems and resourcing to create a culture of innovation

Structural Characterization and Physical Properties of Syzygium cumini Flowering Plant

ABSTRACT: In this study, the flowering plant of syzygium cumini was used. X-ray fluorescence (XRF) and X-ray diffraction (XRD) were used to investigate the structure of the leaves and barks of syzygium cumini. The XRD results were indicated that the structures of both leaves and bark were amorphous. The XRF results indicated that both leaves and barks contained Potassium (K), Calcium (Ca), (Ti), and Magnesium (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Zernike (As), Lead (Pb), Barium (Br), Strontium (Sr). The optical properties of syzygium cumini were carried out using Fourier Transformation infrared spectroscopy (FTIR) and Ultra violet spectroscopy (UV). The FTIR spectra showed a broad and strong absorption band in the range (685-1638) cm -1 , and these absorptions were assigned to the different stretching vibrations. The absorption for bark and leave was found to be 2.45 and 2.52 a u, while the wave length was found to be 277.4 and 277.5 nm, respectively. The energy band gap is calculated and found to be 5.017 and 4.67 eV, for bark and leave, respectively

In vitro Antimicrobial Assessment of Lepidium sativum L. Seeds Extracts

Abstract: The antimicrobial activity of the petroleum ether, methanol and water extracts of Lepidium sativum seed extracts against six opportunistic pathogens namely Staphylococcus aureus, Escherichia coli, Klebsiella pneumonae, Proteus vulgaris, Pseudomonas aeruginosa and one fungus Candida albicans was assessed using the concentrations of 2.5, 5 and 10%. The antimicrobial activity of plant seeds extracts were compared with that of Gentamicin or Ketoconzol, as reference antibiotics. The petroleum ether extract of Lepidium sativum seeds in different concentrations (2.5-5-10%) were found to be active antimicrobials against all the test microorganisms with a strong antifungal activity at the concentration 2.5 and 10%. At the concentration of 5%, the methanolic extract of this plant had no activity against Candida albicans. Staphylococcus aureus and Candida albicans were resistant to 2.5 and 5% water extracts, whereas the latter was also resistant to 5% methanolic extract. The antimicrobial activity of Gentamicin and Ketoconzol against the same test microorganisms was compared with that of the extracts of L. sativum seeds

Phloretin attenuates STAT-3 activity and overcomes sorafenib resistance targeting SHP-1-mediated inhibition of STAT3 and Akt/VEGFR2 pathway in hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Phloretin (PH) possesses anticancer, antitumor, and hepatoprotective effects, however, the effects and potential mechanisms of phloretin remain elusive. Methods: Five HCC cells were tested in vitro for sensitivity to PH, Sorafenib (Sor) or both and the apoptosis, signal transduction and phosphatase activity were analyzed. To validate the role of SHP-1, we used PTP inhibitor III and SHP-1 siRNA. Further, we used purified SHP-1 proteins or HCC cells expressing deletion N-SH2 domain or D61A point mutants to study the PH efficacy on SHP-1. The 'in vivo studies were conducted using HepG2 and SK-Hep1 and Sor resistant HepG2SR and Huh7SR xenografts. Molecular docking was done with Swiss dock and Auto Dock Vina. Results: PH inhibited cell growth and induced apoptosis in all HCC cells by upregulating SHP-1 expression and downregulating STAT3 expression and further inhibited pAKT/pERK signaling. PH activated SHP-1 by disruption of autoinhibition of SHP-1, leading to reduced p-STAT3Tyr705 level. PH induced apoptosis in two Sor-resistant cell lines and overcome STAT3, AKT, MAPK and VEGFR2 dependent Sor resistance in HCCs. PH potently inhibited tumor growth in both Sor-sensitive and Sor-resistant xenografts in vivo by impairing angiogenesis, cell proliferation and inducing apoptosis via targeting the SHP-1/STAT3 signaling pathway. Conclusion: Our data suggest that PH inhibits STAT3 activity in Sor-sensitive and -resistant HCCs via SHP-1-mediated inhibition of STAT3 and AKT/mTOR/JAK2/VEGFR2 pathway. Our results clearly indicate that PH may be a potent reagent for hepatocellular carcinoma and a noveltargeted therapy for further clinical investigations. Graphical abstract: [Figure not available: see fulltext]. - 2019 The Author(s).The publication of this article was funded by the Qatar National Library, Qatar. The graphical abstract was created with BioRender.comScopu

Modeling Short-Term Deflection of Reinforced Concrete Slabs using the Layered Approach

This paper examines the short-term deflection of reinforced concrete slabs taking the tension-stiffening phenomenon into account. The main goal of this study is to develop a model that predicts the deflection of one-way slabs made of reinforced concrete. The model takes into account concrete contribution in carrying tension between cracks thoroughly considering the stress-strain relationship material model. The model has been developed using MATLAB Program incorporating a numerical technique known as the layered approach. The developed layered approach model was validated using experimental deflection results reported in a previous study. Based on the experimental validation, the model showed its tendency in predicting the real-case deflection of one-way concrete reinforced slabs. It was concluded that different types of tension stiffening models can be added to the program to model deflection and crack propagation