Transmission Electron Microscopy Examination Research Articles

Effects of Zr addition on the deformation behavior, microstructure and mechanical properties of dental Ti alloys

Aiming to obtain a martensite-free microstructure of Ti–Zr alloys with a combination of enhanced deformability and improved mechanical properties for dental application, two high Zr-containing Ti-based alloys were prepared with commercially pure titanium as a control. The effects of Zr addition on the deformation mechanism, microstructure and mechanical properties were investigated. After thermo-mechanical processing and cold deformation, samples were characterized using Vickers microhardness, tensile tests, X-ray diffraction (XRD) scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD and TEM examinations revealed that the increasing Zr addition suppressed the deformation twining and favored the deformation-induced face-centered cubic (FCC) phase, the corresponding reason was discussed. There is a competition between the deformation twin and FCC phase. The two types of FCC phase were simultaneously found with orientation relationships (ORs) of Basal-type: <11–20>HCP//<110>FCC and {0001}HCP//{111}FCC and Prismatic-type: <0001>HCP//<001>FCC and {10-10}HCP//{110}FCC. This phase transformation enhanced the deformability during processing. As the Zr addition increased, the microhardness, mechanical strength and plasticity are increased concurrently. The interactions of twins were found to cause brittle fracture of Ti20Zr alloy. Based on the texture analysis, the activated slip systems of FCC phase were determined via calculating the Schmid factor. The FCC phase not only provided additional slip systems but also impeded dislocation slip effectively, improving the strength-plasticity of Ti30Zr alloy. The findings will provide a novel approach associated with the strengthening-toughening mechanism of metallic materials.

An experimental study on stress relaxation behaviour of high strength steel wire: Microstructural evolution and degradation of mechanical properties

In this study, a series of experiments including stress relaxation, nanoindentation, tension loading experiments, and transmission electron microscope (TEM) examination were performed to investigate microstructural evolution, the stress relaxation behavior, and the influences of stress relaxation on mechanical properties of high strength steel wire. The stress relaxation experiments were performed on a single steel wire for 1000 h at three initial stress levels to characterize the stress relaxation behavior of the tested material. Microstructural evolution of the specimens deformed by stress relaxation was observed and analyzed using TEM examination. Long-term relaxation behavior was then calculated and investigated. Finally, the influences of stress relaxation on material properties were studied by performing nanoindentation and tension loading experiments on the deformed relaxation specimens. The degradation of mechanical properties under stress relaxation was interpreted through a micro-mechanism regarding the microstructural evolution and the grain boundary strengthening. The results from the present study can be used for practical designs as well as for assessing the stress relaxation behavior of high strength steel wire.

Large elastic strains and ductile necking of W nanowires embedded in TiNi matrix

The deformation behaviors of W nanowires embedded in a TiNi matrix were investigated by means of in-situ synchrotron high energy X-ray diffraction (HEXRD) and in-situ transmission electron microscopy (TEM) analysis during tensile deformation. The HEXRD measurement indicated that the W nanowires exhibited an average lattice strain of about 1.50 %, whereas the TEM examination revealed a local elastic strain of about 4.59 % in areas adjacent to the TiNi matrix where stress-induced martensitic transformation occurred. This strain corresponds to a stress of ∼15 GPa for the W nanowires. In addition, in areas adjacent to the TiNi matrix where plastic deformation and cracking were generated, the W nanowire showed significant ductile necking with ∼80 % reduction in cross-section area. The ductile necking of W nanowire is attributed to the lack of protection from the stress-induced martensitic transformation of the TiNi matrix.

Detection of Lipase Activity in Cells by a Fluorescent Probe Based on Formation of Self-Assembled Micelles.

SummaryReliable and sensitive detection of lipase activity is essential for the early diagnosis and monitoring of acute pancreatitis or progression of digestive diseases. However, the available fluorescent probes for detection of lipase activity are only implemented in a hexane-water two-phase system due to the nature of heterogeneous catalysis of lipase, thus limiting their applications in direct imaging of lipase activity in living cells and tissues. Here we designed and synthesized a “turn on” fluorescent probe CPP based on self-assembled micelles for hydrolysis of lipase. The CPP probe exhibits high selectivity and excellent sensitivity for the detection of lipase in such a homogeneous system and is successfully applied for monitoring lipase activity in pancreatic AR42J cells, tissues, and serums. Taken together, the fluorescent CPP probe not only provides a tool for diagnostic potential in pancreatic disease but also demonstrates an application potential for micelle self-assembly-based development of biological probes.

The formation and accumulation of radiation-induced defects and the role of lamellar interfaces in radiation damage of titanium aluminum alloy irradiated with Kr-ions at room temperature

A transmission electron microscopy (TEM) specimen of a titanium aluminide (TiAl) alloy was irradiated in-situ, at the IVEM-TANDEM facility, with 1 MeV Kr ions to a maximum fluence of 1.25 × 1019 ions m−2 at room temperature. The irradiated microstructure was then investigated ex-situ using advanced analytical TEM in combination with TEM image simulations and molecular dynamics (MD) simulations. The TEM examination showed that dot-like defects first formed in both the α2-Ti3Al and γ-TiAl phases of the irradiated microstructure. With increasing irradiation dose planar defects formed and propagated within the γ phase, and most of the planar defects were accompanied by the dot-like defects. The TEM image simulations and MD irradiation simulations revealed that the origins of the dot-like and planar defects were interstitial clusters and stacking faults, respectively, and large interstitial clusters were surrounded by dislocation loops. The interstitial clusters formed and grew in the irradiated microstructure due to much faster diffusion of interstitials than that of vacancies at room temperature. Local stress concentrations increased near large interstitial clusters and lamellar interfaces, which resulted in the nucleation and propagation of stacking faults. Moreover, the configurations of the lamellar interfaces in the start microstructure were found to play an important role in the formation and accumulation of the radiation-induced interstitial clusters and stacking faults at room temperature.

High Strength Nano Silica Based Concrete

There is a substantial curiosity in academia, the investment community and among manufacturers about the exhilarating opportunities offered by nano materials. Although a lot of applications for nanotechnology remain hypothetical, construction is one area where numerous ‘here and now’ applications have already emerged. While existing use is restricted, the market is likely to approach more than 500 million dollars within ten years. Concrete is most likely exceptional in the construction field, that it is the distinct material exclusive to business and hence, is the recipient of a reasonable quantity of research and development capital from the construction industry. SiO2 (Silica) usually is an integral part of concrete in the normal mix. On the other hand, one of the innovations made by the study of concrete at nano scale level is that particle stuffing in concrete can be enhanced by means of adding nano silica (NS), which results in the densification of the micro and nano structure of cementitious composite resulting in enhanced mechanical properties. In this research paper, the result of a thorough investigational analysis on the utilization of NS in addition to cement so that the strength and quality of concrete can improve has been achieved. The effect of various proportions of NS in concrete has been premeditated to evaluate the properties of NS based hardened concrete according to the standard concrete. The obtained outcomes after testing indicate that the addition of NS together with concrete has improved the mechanical behavior of concrete. The NS blended high strength concrete (HSC) shows a better compressive strength (CS) of 66.00 N/mm2 (MPa) after standard twenty eight days, which is an exceptional development over standard concrete. Each and every mixture containing NS in various proportions gave enhanced outcomes in comparison with the standard predictable concrete. RH (Rebound Hammer), UPV (Ultrasonic Pulse Velocity), SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope) examinations further authenticate the above results.

Microstructure-strength relationship of ultrafine-grained titanium manufactured by unconventional severe plastic deformation process

Abstract With regard to medical applications, the need for producing high-strength titanium-based materials continues to rise due to the fact that pure titanium is characterized by low mechanical properties, yet remarkable corrosion resistance and biocompatibility. Microstructure-strength relationship for pure titanium (grade 2) fabricated by hydrostatic extrusion, an unconventional severe plastic deformation technique, has been quantified within the present study. X-ray powder diffraction, transmission electron microscopy and electron backscatter diffraction examinations were carried out as well as mechanical behavior was tested in order to find out which of the strengthening mechanisms contribute the most to the overall yield strength of the obtained material. Special emphasis has been put on grain refinement, grain boundary character and a few intragranular characteristics, indicating grain fragmentation. Applying multi-stage hydrostatic extrusion process to pure titanium resulted in fabricating the material that exhibits strong, fiber texture and non-homogeneous, ultrafine-grained microstructure with a host of structural defects in the form of dislocations and low-angle grain boundaries. The material tends to demonstrate remarkable mechanical properties, exceeding those of Ti-6Al-4V, yet its ductility is substantially lower. Based on the microstructure-property analysis it was found that the contribution of grain refinement and substructure evolution to the strength of the hydrostatically extruded titanium was of the highest significance.

Light Microscopic and Ultrastructural Characteristics of Heterophil Toxicity and Left-shifting in Green Sea Turtles (Chelonia mydas) from Taiwan.

Heterophil toxic change (TC) and left-shifting (LS) are widely used as indicators of accelerated granulopoiesis. However, the ultrastructure of heterophil TC and LS in sea turtles remain poorly understood. This study aimed to describe the ultrastructural characteristics of sea turtle TC and LS heterophils, compare the staining quality of accessible staining methods, and provide a better understanding of the clinical applications and limitations of heterophil TC and LS examinations. Blood samples were collected from 21 rescued sea turtles from January 2017 to September 2018. Morphologic (n = 22) and ultrastructural (n = 15) examination of TC and LS heterophils were performed, and the qualities of three staining methods (Wright-Giemsa stain, Diff-Quik stain and Liu's stain) were analyzed to diagnose TC and LS heterophils. In addition, the diagnostic values of TC and LS heterophils were examined. Diff-Quik stain was significantly inferior in the assessment of heterophil TC and/or LS comparing to the Wright-Giemsa stain and Liu's stain (Mann-Whitney test, P < 0.001). Microscopic examinations of heterophil TC and/or LS were comparable to transmission electron microscopy examinations (Cohen's kappa coefficient, κ = 1). The correlation between the presence of heterophil TC and/or LS and clinical inflammatory state was weak (Spearman's rank correlation coefficient, rs = 0.171, p = 0.445). In conclusion, this is the first study to describe the ultrastructural characteristics of reptile TC and LS heterophils. Wright-Giemsa stain and Liu's stain were suitable staining methods for the microscopic observations of TC and LS heterophil in sea turtles. Given the poor correlation between TC and/or LS and clinical findings, TC and LS are not a suitable diagnostic indicator of green sea turtles' inflammation status.

Single-phase Cr2O3 nanoparticles for biomedical applications

Bio-nanotechnology plays an essential role in the application of nanotechnology in today's fascinating world due to the rapid development of science and technology. Here, we report an environmentally friendly Cr2O3 synthesis using the extract of rambutan (Nephelium lappaceum L.) fruit peels as an efficient reducing and capping agent. The structural, optical, elemental composition and morphological analyses of the synthesized products were conducted using X-ray diffractometer, photoluminescence measurements, X-ray photoelectron spectroscopy, and transmission electron microscopy examinations. Rhombohedral polycrystalline nature of Cr2O3 powder was confirmed by X-ray diffraction. Different normal modes of vibrations were analyzed by Fourier-transform infrared and Raman studies. The spherical shapes of the nanoparticles were observed for all the 1-, 4-, and 7-day incubated reaction products. Cells were exposed to different concentrations in the range of 10–500 μg/ml (i.e. 10, 50, 100, and 500 μg/ml) for 24 h and the values observed were 83.33, 80, 59.33, and 48.66%, respectively. The cell viability and cytotoxicity analyses were carried out using MTT assay of human breast cancer cell line.

Lithium Carbonate as a Corrosion Inhibitor for Mg Alloy Sheet Metal Product

Reducing the overall mass of transportation vehicles by the use of strong lightweight materials is arguably the best enabling means to improve fuels efficiency and, thus reduce harmful emissions. Wrought Mg alloys with high specific strength, stiffness and warm formability (ZE alloys) provide enabling opportunities as an integral part of lightweight multi-material structural assemblies to achieve this goal. One key technical issue preventing widespread implementation of Mg alloy components is the high rate of dissolution (corrosion) in aqueous environments. This is driven in large part by the inherent reactivity of Mg (lowest standard reduction potential among industrial engineering metals), the high rate of the hydrogen evolution reaction that dominates the cathodic process and the tendency of the native oxide surface film to breakdown and be replaced with a significantly thicker and much less protective corrosion product film. Dissolved Li2CO3 (aq) is being evaluated as an effective corrosion inhibitor for bare Mg alloy sheet metal product (AZ31B and ZEK100) when immersed in 0.1 M NaCl (aq) as a precursor to the development of a conversion coating technology. The extent of corrosion protection is being determined at various Li2CO3 levels (mM) by making volumetric H2 gas evolution and mass loss measurements as a function of immersion time. Complementary potentiodynamic polarization measurements are being conducted to determine the manner in which dissolved Li2CO3 (aq) affects the global anodic and/or cathodic processes that control corrosion. SVP measurements are being made to resolve and track changes in the localized filament corrosion and associated cathodic activation resulting from effective inhibition of dissolved Li2CO3 (aq). Both surface analysis by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) examination of FIB-prepared cross-sections are being utilized to determine the film chemistry and local fine-scale structure involved in the filament corrosion and associated cathodic activation if and when it develops with time. A similar set of measurements is being made with Li(OH)2 (aq) additions (at equivalent pHs) to determine the specific role of Li+ (aq) and CO3 2− (aq) ions in providing improved corrosion control. This paper presents and discusses the results within the context of developing a self-healing conversion coating layer for inclusion in automotive paint schemes.

Characterization of strain amplitude-dependent behavior of hardness and indentation size effect of SS400 structural steel

In this paper, the continuous stiffness measurement (CSM) indentation is employed to investigate fatigue mechanical properties of structural steel under cyclic loading. For this purpose, several representative analytical approaches were introduced to estimate the basic mechanical properties including Young’s modulus and indentation hardness from the characteristics of the loading/unloading curves. Several experiments including CSM nanoindentation, low-cycle fatigue experiment for four strain amplitude levels, optical microscope (OM), and transmission electron microscopy (TEM) examinations were conducted to observe the variation characteristics of mechanical properties at the microscale and their micro-mechanisms. The microstructural evolution of the specimens deformed by the low-cycle fatigue was observed using the OM and TEM examinations. The standard nanoindentation experiments were then performed at different strain rate levels to characterize the influences of strain rate indentation on hardness of the material. The micro-mechanisms established based on the microstructural evolution and strain gradient plasticity theory were introduced to be responsible for the variation of indentation hardness under cyclic loading. Finally, the indentation size effect (ISE) phenomenon in SS400 structural steel was investigated and explained through the strain gradient plasticity theory regarding geometrically necessary dislocations underneath the indenter tip. The experimental results can be used for practical designs as well as for understanding the fatigue behavior of SS400 structural steel.&#x0D; Keywords:&#x0D; cyclic loading; fatigue; nanoindentation; indentation size effect; strain rate sensitivity; structural steel.

Curative and Suppressive Activities of Essential Tea Tree Oil against Fungal Plant Pathogens

Timorex Gold based on the essential tea tree oil (TTO) derived from the Australian tea tree oil (Melaleuca alternifolia) plant has demonstrated high efficacy and a strong curative activity against black Sigatoka in banana and controlled it in stages 1, 2, 3, and 4 of disease development. Transmission electron microscope (TEM) examination of infected leaf sections treated with Timorex Gold revealed disruption of the fungal cell membrane and destruction of the fungal cell wall in disease development stages 4 and 5. Mineral oil and the fungicide difenoconazole, when applied alone, had no curative effect and did not disrupt the fungal cell wall or membrane, similar to the untreated control tissue. A single spray of Timorex Gold effectively controlled and suppressed powdery mildew in cucumber by causing the disappearance of 99% of established colonies recorded 1 or 2 days after the application and was effective for up to 8 days after application. Scanning electron microscope (SEM) examination of infected and Timorex Gold-treated leaves indicated strong shrinkage and disruption of fungal hyphae and conidial cells. The curative and suppressive modes of action of the Timorex Gold may explain its success in controlling both diseases.

Spermidine Suppresses Development of Experimental Abdominal Aortic Aneurysms.

BackgroundThe protective effects of polyamines on cardiovascular disease have been demonstrated in many studies. However, the roles of spermidine, a natural polyamine, in abdominal aortic aneurysm (AAA) disease have not been studied. In this study, we investigated the influence and potential mechanisms of spermidine treatment on experimental AAA disease.Methods and ResultsExperimental AAAs were induced in 8‐ to 10‐week‐old male C57BL/6J mice by transient intra‐aortic infusion of porcine pancreatic elastase. Spermidine was administered via drinking water at a concentration of 3 mmol/L. Spermidine treatment prevented experimental AAA formation with preservation of medial elastin and smooth muscle cells. In immunostaining, macrophages, T cells, neutrophils, and neovessels were significantly reduced in aorta of spermidine‐treated, as compared with vehicle‐treated elastase‐infused mice. Additionally, flow cytometric analysis showed that spermidine treatment reduced aortic leukocyte infiltration and circulating inflammatory cells. Furthermore, we demonstrated that spermidine treatment promoted autophagy‐related proteins in experimental AAAs using Western blot analysis, immunostaining, and transmission electron microscopic examination. Autophagic function was evaluated for human abdominal aneurysmal and nonaneurysmal adjacent aortae from AAA patients using Western blot analysis and immunohistochemistry. Dysregulated autophagic function, as evidenced by increased SQSTM1/p62 protein and phosphorylated mTOR, was found in aneurysmal, as compared with nonaneurysmal, aortic segments.ConclusionsOur results suggest that spermidine supplementation limits experimental AAA formation associated with preserved aortic structural integrity, attenuated aortic inflammatory infiltration, reduced circulating inflammatory monocytes, and increased autophagy‐related proteins. These findings suggest that spermidine may be a promising treatment for AAA disease.

Variant selection of α precipitation in a beta titanium alloy during selective laser melting and its influence on mechanical properties

A β titanium alloy was fabricated horizontally and vertically at two different energy densities by selective laser melting. The microstructures of the as-fabricated samples were examined using a range of characterization techniques and the properties evaluated by tensile testing. It was found that the samples that were horizontally built at the lower energy density were dominated by both β and athermal ω phases while the vertically built samples consist of not only β and ω but also nano-sized α laths. Increased energy density led to a significant increase of α in horizontally built samples which tended to constitute a grid-like structure in the β matrix. All the α-bearing samples showed preferential α variant selection and pronounced α micro-texture. The α-free samples all showed high 0.2% yield strengths (922-934 MPa), high ultimate tensile strengths (935-939 MPa) and good ductility (10.2%–13.8% elongation) whereas the α-bearing samples all exhibited poor ductility (elongation < 1.2%). A significant anisotropy in plasticity was observed in the samples made with the lower energy density. Transmission electron microscopy examination revealed that the α-free samples experienced global plastic deformation via both long-range dislocation slipping and twinning whereas the α-bearing samples underwent localised plastic deformation where slipping was either interrupted by the nano-sized α laths or contained within the α-grid demarcated β matrix, which may account for their poor ductility.

Mechanistic Study of Triazole Based Aminodiol Derivatives in Leukemic Cells-Crosstalk between Mitochondrial Stress-Involved Apoptosis and Autophagy.

Various derivatives that mimic ceramide structures by introducing a triazole to connect the aminodiol moiety and long alkyl chain have been synthesized and screened for their anti-leukemia activity. SPS8 stood out among the derivatives, showing cytotoxic selectivity between leukemic cell lines and human peripheral blood mononuclear cells (about ten times). DAPI nuclear staining and H&E staining revealed DNA fragmentation under the action of SPS8. SPS8 induced an increase in intracellular Ca2+ levels and mitochondrial stress in HL-60 cells identified by the loss of mitochondrial membrane potential, transmission electron microscopy (TEM) examination, and altered expressions of Bcl-2 family proteins. SPS8 also induced autophagy through the detection of Atg5, beclin-1, and LC3 II protein expression, as well as TEM examination. Chloroquine, an autophagy inhibitor, promoted SPS8-induced apoptosis, suggesting the cytoprotective role of autophagy in hindering SPS8 from apoptosis. Furthermore, SPS8 was shown to alter the expressions of a variety of genes using a microarray analysis and volcano plot filtering. A further cellular signaling pathways analysis suggested that SPS8 induced several cellular processes in HL-60, including the sterol biosynthesis process and cholesterol biosynthesis process, and inhibited some cellular pathways, in which STAT3 was the most critical nuclear factor. Further identification revealed that SPS8 inhibited the phosphorylation of STAT3, representing the loss of cytoprotective activity. In conclusion, the data suggest that SPS8 induces both apoptosis and autophagy in leukemic cells, in which autophagy plays a cytoprotective role in impeding apoptosis. Moreover, the inhibition of STAT3 phosphorylation may support SPS8-induced anti-leukemic activity.

THE EFFECT OF BONE MARROW MESENCHYMAL STEM CELLS ON EXPERIMENTALLY-INDUCED GASTROCNEMIUS MUSCLE INJURY IN FEMALE ALBINO RATS

Objective: Skeletal muscle injury has become an important condition to treat. With traumas increasing and poor health outcome it has become important to find a suitable treatment to enhance the regeneration of this tissue. Many treatment options are available but there is still no best technique to treat the skeletal muscles in a rapid and effective way. Bone marrow-derived mesenchymal stem cells (BM-MSCs) need to be demonstrated to be able to do this in a very well way.Aim: To evaluate the therapeutic potential of BM-MSCs in treatment of gastrocnemius muscle injury after 14 days.Material and Methods: Fifteen female rats were randomly divided into three groups:1.Group I (Control Group)2.Group II (Gastrocnemius muscle injury without BM-MSCs local injection)3.Group III (Gastrocnemius muscle injury with BM-MSCs local injection)The muscle specimens were processed for the light microscope, transmission electron microscope examination, and real time-quantitative polymerase chain reaction (RQ-PCR) assay for Y-chromosome, and CM-Dil.Results: Group II showed destruction of the muscle fibres and replacement with fibrous tissue. There was depletion of the cytoplasmic content. Group III showed regeneration of the muscle fibres with minimal amount of fibrous tissue. The nuclei of the muscle fibres regained their normal architecture and bridging between the muscle fibres remained. The BM-MSCs become part of the muscle fibres as proved by CM-Dil.Conclusion: The results confirmed that BM-MSCs are a great option for the use in skeletal muscle regeneration. They were capable of both accelerating the healing process and allowing the skeletal muscle to repair with health new muscular tissue.

A novel method for the extraction of outer membrane vesicles (OMVs) from Bordetella pertussis Tohama strain

There are many pertussis outbreaks which is mainly due to the reduction in the immunity of acellular pertussis (aP) vaccines. Therefore, there is a crucial necessity to develop a new generation of pertussis vaccine. Preceding researches have shown that Bordetella pertussis outer membrane vesicles (OMVs) have appropriate specifications, making them a suitable vaccine candidate against pertussis. The OMVs were separated by a new serial ultra centrifugation technique. Transmission electron microscopy (TEM) examination, SDS-PAGE, Western blotting and ELISA assay were used to characterize the OMVs. TEM studies showed the size of the extracted OMVs at 40-200 nm. The presence of pertussis toxin, filamentous hemagglutinin, and pertactin was verified using Western blot and ELISA assay. The presented technique is a simple and effective way to obtain OMVs from Bordetella pertussis. So it can be utilized as an appropriate procedure in the development of an OMV-based vaccine against pertussis.

Ultrastructural and Echocardiographic Assessment of Chronic Doxorubicin-Induced Cardiotoxicity in Rats.

Doxorubicin (DOX) is one of the secondary metabolites of Streptomyces peucetius var. caesius. It is a common and effective chemotherapeutic agent used for the treatment of different diseases, including lymphoma, leukemia, breast cancer, and solid tumors. However, this medicine causes cardiotoxic side effects, which limit its clinical application. The present study examined the cardiomyopathy induced by DOX via echocardiography and transmission electron microscopy (TEM). The main objective was to evaluate the capacity of echocardiography and TEM as diagnostic tools for DOX-induced cardiotoxicity. Moreover, the correlation between intracellular and functional changes due to cardiotoxicity was assessed in a rat model. Cardiomyopathy was induced in rats by two cumulative doses of DOX. Group I received DOX 12 [i.e., 12 mg/kg, intraperitoneal (IP)] and group II received DOX 15 (i.e., 15 mg/kg, IP) in six equal doses over two weeks. Group III as the control (Ctrl) group received normal saline as a vehicle. Mortality during the study was only observed in the DOX 15 group. The echocardiographic assessments revealed significant changes in ejection fraction, fractional shortening, and heart rate in the groups which received DOX. In addition, severe cardiac arrhythmia was evident in DOX-treated groups. Remarkable adverse effects, such as moderately degenerated cells and inflated mitochondria were observed in the TEM analysis of rat hearts in the DOX groups. The present study indicated that rat models are suitable for investigating DOX-induced cardiomyopathy, especially at the dose of 12 mg/kg. Furthermore, echocardiography and TEM examinations were found to be valuable methods for the determination of cardiotoxicity in rats due to DOX.

Preparation, Characterization and Cytotoxic Activity of New Oleuropein Microemulsion Against HCT-116 Colon Cancer Cells

The work was aimed to elucidate whether the nanoencapsulation of oleuropein would potentiate its anticancer activity against colon cancer or not. Oleuropein microemulsion was prepared using the water dilution method, in which oleic acid, tween 20, and ethanol were selected as the oily phase, surfactant, and cosurfactant, respectively. The microemulsion was characterized in terms of particle size, zeta potential, polydispersity index, morphology, in vitro drug release, stability, and anticancer activity on HCT-116 colon cancer cells. Results showed that oleuropein microemulsion was successfully prepared with a particle size of 10 nm, polydispersity index of 0.283, and a neutral charge. Moreover, it was able to sustain the release of drug for 24 h with a cumulative percentage release of 99%. Transmission electron microscopic examination of the microemulsion confirmed its small particle size and revealed spherical particle morphology. The as-prepared microemulsion was stable, with no significant changes in particle size, polydispersity or charge observed upon storage. Moreover, the oleuropein microemulsion was 106 times more cytotoxic than oleuropein alone on HCT-116 colon cancer cells. Therefore, it can be concluded that the proposed microemulsion is a promising delivery carrier for oleuropein, which is worthy of further experimentation on animals to examine the drug bioavailability.

Effect of ultrasonic shot peening duration on microstructure, corrosion behavior and cell response of cp-Ti

Surface mechanical attrition treatment (SMAT) of metallic biomaterials has gained significant importance due to its ability to develop nano structure in the surface region. In the present study, the microstructural changes and corrosion behavior of the commercially pure titanium (cp-Ti), following different durations of ultrasonic shot peening (USSP) has been investigated. cp-Ti was shot peened for different durations from 0 to 120 s and the treated samples were examined for microstructural changes in the surface region, cell viability and corrosion behavior. Cell viability was considerably increased after USSP for 60–120 s, exhibiting maximum for the 90 s of USSP. The passivation tendency was also improved with peening duration up to 90 s, however, it declined for longer duration of USSP. The beneficial effects of USSP may be attributed to nano structuring in the surface region and development of higher positive potentials at the USSP treated surface. Transmission Electron Microscope (TEM) examination of the USSPed surface revealed dislocation entanglement and substructure. Also, higher surface volta potential was observed over the USSPed sample exhibiting better cell proliferation. The present work is corollary to previous work of the group and mainly discusses the role of USSP duration, as a process parameter, on the cell viability and corrosion resistance of cp-Ti.