Effects of Mesua ferrea Leaf and Fruit Extracts on Growth and Morphology of Staphylococcus aureus

2013 ◽  
Vol 19 (1) ◽  
pp. 254-260 ◽  
Author(s):  
Claira Arul Aruldass ◽  
Mani Maran Marimuthu ◽  
Surash Ramanathan ◽  
Sharif Mahsufi Mansor ◽  
Vikneswaran Murugaiyah
Keyword(s):  
Staphylococcus Aureus ◽  
Detrimental Effect ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Renal Diseases ◽  
Fruit Extracts ◽  
Good Antibacterial Activity ◽  
Inhibition Concentration ◽  
The Matrix ◽  
Time Kill

AbstractMesua ferrea is traditionally used for treating bleeding piles, fever, and renal diseases. It has been reported to have antimircobial activity. In the present study, antibacterial efficacy of leaf and fruit extracts on the growth and morphology of Staphylococcus aureus is evaluated. Both extracts display good antibacterial activity against S. aureus with a minimum inhibition concentration of 0.048 mg/mL. Both extracts are bacteriostatic at a minimum bacteriostatic concentration of 0.39 mg/mL. The bacteriostatic activity lasts for 24 h, and then cells start to grow as normal as shown in time-kill analysis. Scanning electron microscopy study indicated potential detrimental effect of the extracts of leaf and fruits of M. ferrea on the morphology of S. aureus. The treatment with the extracts caused extensive lysis of the cells, leakage of intracellular constituents, and aggregation of cytoplasmic contents forming an open meshwork of the matrix.

Newly formed phyllosilicates in rock matrices and fractures from CRP-3 core (Antarctica): an electron microscopy study

Clay Minerals ◽  
2007 ◽  
Vol 42 (1) ◽  
pp. 21-43 ◽  
Author(s):  
G. Giorgetti ◽  
F. S. Aghib ◽  
K. J. T. Livi ◽  
A.-C. Gaillot ◽  
T. J. Wilson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Marine Sediments ◽  
Ross Sea ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Secondary Phases ◽  
Transmission Electron Microscopy Study ◽  
Transmission Electron ◽  
The Matrix

AbstractA scanning and transmission electron microscopy study has been performed on Oligocene glacio-marine sediments, Devonian sandstones, and Jurassic dolerites recovered during CRP-3 drilling in the Ross Sea (Antarctica). Newly formed clay minerals occur in the rock matrices and as fillings in veins and faults which crosscut the whole sequence. Authigenic clays in sediments consist of beidellite-montmorillonite, berthierine/chlorite intergrowths and illite. Al,K-rich smectites and kaolinite occur in the Devonian sandstones. Saponite, berthierine/chlorite intergrowths, and Fe-hydroxides develop in the altered dolerites. Hence, the composition of the secondary phases depends also on the geochemistry of the rock they grow in. Within each sample, the same authigenic minerals form in the matrix and in the vein/fault. Clays precipitated from fluids, with variable fO2 values, which circulated in the system during the contemporaneous diagenetic and faulting events.

scholarly journals Size-Controlled Transformation of Cu2O into Zero Valent Copper within the Matrix of Anion Exchangers via Green Chemical Reduction

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2629
Author(s):  
Irena Jacukowicz-Sobala ◽  
Ewa Stanisławska ◽  
Agnieszka Baszczuk ◽  
Marek Jasiorski ◽  
Elżbieta Kociołek-Balawejder
Keyword(s):  
Chemical Reduction ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Mechanical Resistance ◽  
Anion Exchangers ◽  
Design And Synthesis ◽  
The Matrix ◽  
Potential Applications ◽  
Great Possibility ◽  
Basic Anion

Composite materials containing zero valent copper (ZVC) dispersed in the matrix of two commercially available strongly basic anion exchangers with a macroreticular (Amberlite IRA 900Cl) and gel-like (Amberlite IRA 402OH) structure were obtained. Cu0 particles appeared in the resin phase as the product of the reduction of the precursor, i.e., copper oxide(I) particles previously deposited in the two supporting materials. As a result of a one-step transformation of preformed Cu2O particles as templates conducted using green reductant ascorbic acid and under mild conditions, macroporous and gel-type hybrid products containing ZVC were obtained with a total copper content of 7.7 and 5.3 wt%, respectively. X-ray diffraction and FTIR spectroscopy confirmed the successful transformation of the starting oxide particles into a metallic deposit. A scanning electron microscopy study showed that the morphology of the deposit is mainly influenced by the type of matrix exchanger. In turn, the drying steps were crucial to its porosity and mechanical resistance. Because both the shape and size of copper particles and the internal structure of the supporting solid materials can have a decisive impact on the potential applications of the obtained materials, the results presented here reveal a great possibility for the design and synthesis of functional nanocrystalline solids.

An In-situ Electron Microscopy Study of Microstructural Evolution in a Co-NbCo2 Binary Alloy

2008 ◽  
Vol 1128 ◽  
Author(s):  
Sharvan Kumar ◽  
Padam Jain ◽  
Seong Woong Kim ◽  
Frank Stein ◽  
Martin Palm
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Laves Phase ◽  
Face Centered Cubic ◽  
The Matrix ◽  
The Individual ◽  
Individual Grains

AbstractThe microstructure in a Co-rich, Co-15 at.% Nb alloy was characterized in the as-cast condition. A predominantly lamellar eutectic morphology composed of a Co-Nb solid solution and the C15 Laves phase NbCo2 was confirmed by transmission electron microscopy. The C15 phase was heavily twinned, with only one variant of twins being present in the individual lamella, while the Co solid solution had the face centered cubic structure. In-situ heating to 600°C in the microscope confirmed the decomposition of the metastable Laves phase into a fine equiaxed, ˜10-20 nm grain size microstructure, and the product phase is the monoclinic Nb2Co7. The individual grains appear faulted. The matrix solid solution retained the fcc structure and no change in structure was observed on cooling to room temperature. Heating to temperatures as high as 1130°C leads to rapid grain growth in the Nb2Co7 phase, and the nucleation and growth of a few new grains within the original grains; however, the reverse peritectoid transformation previously reported, was not observed.

Electron microscopy of a Gd–Ba–Cu–O superconductor

1989 ◽  
Vol 4 (3) ◽  
pp. 515-520 ◽  
Author(s):  
R. Ramesh ◽  
G. Thomas ◽  
R. L. Meng ◽  
P. H. Hor ◽  
C. W. Chu
Keyword(s):  
Electron Microscopy ◽  
Microscopy Study ◽  
Annealed Sample ◽  
Electron Microscopy Study ◽  
Zone Axis ◽  
Matrix Phase ◽  
The Matrix ◽  
Tetragonal Form ◽  
Convergent Beam ◽  
Beam Patterns

An electron microscopy study has been carried out to characterize the microstructure of a sintered Gd–Ba–Cu–O superconductor alloy. The GdBa2Cu3O7−x phase in the oxygen annealed sample is orthorhombic while in the vacuum annealed sample it is tetragonal. It is shown that the details of the fine structure in the [001] zone axis convergent beam patterns can be used to distinguish between the orthorhombic form and the tetragonal form. In addition to this matrix phase, an amorphous phase is frequently observed at the triple grain junctions. Gd-rich inclusions have been observed inside the matrix phase.

Resistivity and Electron Microscopy Study of Precipitates in Fe-Ni-Co-Mo

1970 ◽  
Vol 28 ◽  
pp. 448-449
Author(s):  
A. Christou ◽  
R.W. Lowry
Keyword(s):  
Electron Microscopy ◽  
Precipitation Hardening ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Density Of Dislocations ◽  
Nucleation Sites ◽  
The Matrix ◽  
Hardening Mechanisms ◽  
Kinetics Of ◽  
Short Times

The details of the precipitation hardening mechanisms have been studied previously. Peters and Cupp have measured the kinetics of precipitation in an 18 pet Ni-Co-Mo steel. Hardy and Heal have studied the reversion processes caused by annealing for short times at temperatures above the aging temperature. This paper reports studies of the pre-precipitation and reversion stages in an 18 pct. Ni-Co-Mo steel (maraging with .46 pct Ti).The annealed microstructure of the parent steel consists of BCC martensitic grains. Within the matrix lies a fairly high density of dislocations whose configurations appear irregular. These dislocations are nucleation sites and are shown in Figure 1.

Microstructural Aspects of Low Cycle Fatigue of Aged GX12CrMoVNbN9-1 Cast Steel

2013 ◽  
Vol 592-593 ◽  
pp. 708-711
Author(s):  
Stanisław Mroziński ◽  
Grzegorz Golański ◽  
Krzysztof Werner
Keyword(s):  
Low Cycle Fatigue ◽  
Cast Steel ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Fatigue Tests ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Transmission Electron Microscopy Study ◽  
Transmission Electron ◽  
The Matrix

The paper presents the results of research on the changes in microstructure of GX12CrMoVNbN9-1 cast steel subject to aging at the temperature of 600°C and holding time of 8000 hours, followed by low-cycle fatigue. The characteristics of the microstructure of the examined cast steel after ageing and low-cycle fatigue was described using transmission electron microscopy (study of the dislocation microstructure) and morphology of precipitations. It has been shown that low cycle fatigue leads to the matrix softening as a result of the processes of recovery, polygonization and repolygonization. Moreover, the processes of precipitation of Laves phase and coagulation of M23C6 carbides were observed in the microstructure. Intensity of these processes depended not only on the temperature of fatigue tests, but also on the level of total strain amplitude εac.

Matrix Damage in Iron

2000 ◽  
Vol 650 ◽  
Author(s):  
A C Nicol ◽  
M L Jenkins ◽  
M A Kirk
Keyword(s):  
Indirect Evidence ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Dislocation Loops ◽  
Image Size ◽  
Weak Beam ◽  
Transmission Electron ◽  
The Matrix ◽  
Beam Transmission ◽  
Matrix Damage

ABSTRACTWe present results of a weak-beam transmission electron microscopy study of “matrix damage” in two nearly-pure irons (designated alloys 1A and 2A) produced by neutron irradiation to a fluence of 0.06 dpa at 280°C. The matrix damage in both materials was found to consist of small (2-6 nm) dislocation loops. About 80 % have Burgers vectors b = a<100>, and the remainder have b = a/2<111>. The loops in alloy 1A have a mean image size dmean = 2.8± 0.1 nm and a mean maximum image size dmax = 4.2± 0.3 nm, while those in 2A have d mean = 3.4± 0.1 nm and d max = 4.5± 0.3 nm. The number densities are about 8.5 × 1021 m−3 in alloy 1A, and 6.6 × 1021 m−3 in 2A. It can be shown that the loops can account for the observed irradiation hardening. At least some loops are stable under thermal annealing to temperatures of at least 430°C. This and other indirect evidence suggests that their nature is interstitial.

Flow Cytometry and Electron Microscopy Study of Staphylococcus aureus and Escherichia coli Treated with Mdc-Hly

2015 ◽  
Vol 21 (2) ◽  
pp. 351-357 ◽  
Author(s):  
Xuemei Lu ◽  
Xiaobao Jin ◽  
Jiayong Zhu
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Foodborne Pathogens ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Antibacterial Mechanism ◽  
Transmission Electron ◽  
Clinical Environments

AbstractIn our previous study, a novel hybrid protein combining human lysozyme (Hly) with Musca domestica cecropin (Mdc) was successfully constructed. The broad antibacterial activity against various foodborne pathogens of Mdc-hly suggests its scope as a food preservative. The aim of the present study was to investigate the antibacterial mechanism of the recombinant Mdc-hly. The damage induced by Mdc-hly on Staphylococcus aureus and Escherichia coli was investigated using flow cytometry (FC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of FC showed that Mdc-hly causes bacterial membrane permeabilization. SEM and TEM studies revealed that Mdc-hly is capable of damaging both the membrane and the wall of bacteria, resulting in efflux of essential cytoplasmic contents. Both FC and EM revealed that the effects of Mdc-hly were greater than its parental peptides. Understanding the antibacterial mechanism of Mdc-hly is of a great interest in further utilization of its use in treatment of food and in clinical environments.

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