Evaluation of the effects of injection velocity and different gel concentrations on nanoparticles in hyperthermia therapy

BACKGROUND AND OBJECTIVE

In magnetic fluid hyperthermia therapy, controlling temperature elevation and optimizing heat generation is an immense challenge in practice. The resultant heating configuration by magnetic fluid in the tumor is closely related to the dispersion of particles, frequency and intensity of magnetic field, and biological tissue properties.

METHODS

In this study, to solve heat transfer equation, we used COMSOL Multiphysics and to verify the model, an experimental setup has been used.  To show the accuracy of the model, simulations have been compared with experimental results. In the second part, by using experimental results of nanoparticles distribution inside Agarose gel according to various gel concentration, 0.5%, 1%, 2%, and 4%, as well as the injection velocity, 4 µL/min, 10 µL/min, 20 µL/min, and 40 µL/min, for 0.3 cc magnetite fluid, power dissipation inside gel has been calculated and used for temperature prediction inside of the gel.

RESULTS

The Outcomes demonstrated that by increasing the flow rate injection at determined concentrations, mean temperature drops. In addition, 2% concentration has a higher mean temperature than semi spherical nanoparticles distribution.

CONCLUSION

The results may have implications for treatment of the tumor and any kind of cancer diseases.

Effect of different concentrations of ginger root powder and its essential oil on growth performance, serum metabolites and antioxidant status in broiler chicks under heat stress

1. This study was carried out to evaluate the impact of ginger (Zingiber officinale) feed supplementation on growth performance, antioxidant status, carcass characteristics and blood parameters in broiler chicks under conditions of heat stress (32 ± 2ºC for 8 h per d). 2. A total of 336 d-old male broiler chicks (Cobb-500) were randomly assigned to one of 6 dietary groups representing: basal diet with no supplement as control, basal diet containing 100 mg/kg vitamin E as positive control, basal diets containing either 7.5 or 15 g/kg of ginger root powder, and diets containing 75 or 150 mg/kg of ginger essential oil. 3. The results indicated that at 22 d of age, the group receiving 7.5 g/kg of ginger root powder experienced significantly increased body weight (BW) and body weight gain (BWG) compared to the control group. There were no significant difference among the diet groups regarding BW, BWG, feed intake (FI) or feed conversion ratio (FCR) at 42 and 49 d of age. 4. The inclusion of powder and essential oil of ginger in broiler diets did not affect carcass characteristics and blood parameters of the chickens. However, in the group receiving 150 mg/kg ginger essential oil, the total superoxide dismutase (TSOD) activity in liver increased compared to the control group. Malondialdehyde (MDA) concentrations in liver also decreased in the groups receiving ginger powder and essential oil compared to that in the control group. There were no significant difference between experimental groups regarding glutathione peroxidise (Gpx), TSOD and catalase (CAT) enzymes in red blood cells. All dietary groups increased total antioxidant capacity (TAC) and decreased MDA concentration in serum compared to the control group. 5. The results of this study suggest that ginger powder and essential oils may be a suitable replacement for synthetic antioxidants in broiler diets. Results also suggest that ginger powder might be better than extracted essential oil for improving antioxidant status in broilers.

Experimental and numerical study on the mechanical behavior of rat brain tissue

Brain tissue is a very soft tissue in which the mechanical properties depend on the loading direction. While few studies have characterized these biomechanical properties, it is worth knowing that accurate characterization of the mechanical properties of brain tissue at different loading directions is a key asset for neuronavigation and surgery simulation through haptic devices. In this study, the hyperelastic mechanical properties of rat brain tissue were measured experimentally and computationally. Prepared cylindrical samples were excised from the parietal lobes of rats' brains and experimentally tested by a tensile testing machine. The effects of loading direction on the mechanical properties of brain tissue were measured by applying load on both longitudinal and circumferential directions. The general prediction ability of the proposed hyperelastic model was verified using finite element (FE) simulations of brain tissue tension experiments. The uniaxial experimental results compared well with those predicted by the FE models. The results revealed the influence of loading direction on the mechanical properties of brain tissue. The Ogden hyperelastic material model was suitably represented by the non-linear behavior of the brain tissue, which can be used in future biomechanical simulations. The hyperelastic properties of brain tissue provided here have interest to the medical research community as there are several applications where accurate characterization of these properties are crucial for an accurate outcome, such as neurosurgery, robotic surgery, haptic device design or car manufacturing to evaluate possible trauma due to an impact.

RETRACTED: Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications

The following article has been included in a multiple retraction:

Karimi A, Navidbakhsh M and Faghihi S. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications. Perfusion 2014;29:231–237, DOI: 10.1177/0267659113513823.

In 2015 SAGE became aware of author misconduct concerning the suspected fabrication of identities, as well as the impersonation of legitimate individuals, to manipulate the peer review process across three separate journal publications. SAGE and the journal Editors immediately launched an investigation and have decided to retract the following articles for reasons of author misconduct.

Alireza Karimi was the submitting author on 12 of the articles. SAGE regrets the academic record was compromised by manipulation of the peer review process and apologises to readers.

OnlineFirst articles (these articles will not be published in an issue)

International Journal of Damage Mechanics

Karimi A, Navidbakhsh M and Razaghi R. Dynamic finite element simulation of the human head damage mechanics protected by polyvinyl alcohol sponge. Int J Damage Mech, first published on 15 May 2014, DOI: 10.1177/1056789514535945.

Journal of Thermoplastic Composite Materials

Karimi A, Navidbakhsh M and Haghpanahi M. Constitutive model for numerical analysis of polyvinyl alcohol sponge under different strain rates. J Thermoplast Compos Mater, first published on 15 January 2014, DOI: 10.1177/0892705713520176.

Karimi A, Navidbakhsh M, Yousefi H et al. An experimental study on the elastic modulus of gelatin hydrogels using different stress–strain definitions. J Thermoplast Compos Mater, first published on 29 April 2014, DOI: 10.1177/0892705714533377.

Elhamian MM, Alizadeh M, Shokrieh MM, et al. An innovative three-dimensional biphasic-laminated composite model for articular cartilage tissue. J Thermoplast Compos Mater, first published on 1 February 2015, DOI: 10.1177/0892705715569821.

Perfusion

Karimi A, Navidbakhsh M, Yamada H, et al. A comparative study on the quasilinear viscoelastic mechanical properties of the umbilical artery and the umbilical vein. Perfusion, first published on 22 May 2014, DOI: 10.1177/0267659114536761.

Tehrani P, Rahmani S, Karimi A, et al. A novel cardiac assist device (AVICENA): a numerical study to compute the generated power. Perfusion, first published on 19 August 2014, DOI: 10.1177/ 0267659114547943.

Elhamian SMM, Alizadeh M, Shokrieh MM, et al. The effect of collagen fiber volume fraction on the mechanical properties of articular cartilage by micromechanics models. Perfusion, first published on 20 August 2014, DOI: 10.1177/0267659114547942.

Razaghi R, Karimi A, Navidbakhsh M, et al. Determination of the vulnerable plaque in a stenotic human coronary artery – finite element modelling. Perfusion, first published on 28 October 2014, DOI: 10.1177/0267659114557720.

Articles published in an issue

International Journal of Damage Mechanics

Karimi A, Navidbakhsh M, Beigzadeh B, et al. Hyperelastic mechanical behavior of rat brain infected by Plasmodium berghei ANKA – experimental testing and constitutive modelling. Int J Damage Mech 2014;23:857–871, DOI: 10.1177/1056789513514072.

Perfusion

Karimi A, Navidbakhsh M and Faghihi S. A comparative study on plaque vulnerability using constitutive equations. Perfusion, 2014;29:178–183, DOI: 10.1177/0267659113502835.

Abdi M, Karimi A, Navidbakhsh M, et al. Modeling of cerebral aneurysm using equivalent electrical circuit (Lumped Model). Perfusion 2014;29:142–152, DOI: 10.1177/0267659113498617.

Karimi A, Navidbakhsh M and Faghihi S. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications. Perfusion 2014;29:231–237, DOI: 10.1177/ 0267659113513823.

Karimi A, Navidbakhsh M, Yousefi H, et al. Experimental and numerical study on the mechanical behavior of rat brain tissue. Perfusion 2014;29:307–314, DOI: 10.1177/0267659114522088.

A comparative study on plaque vulnerability using constitutive equations

Atherosclerosis is the most serious and common form of cardiovascular disease in which plaque builds up inside the arteries. Peak plaque stress is considered as the main reason for plaque rupture, which results in heart attack and stroke. In the current research, the finite element method is used to anticipate plaque vulnerability, using human samples. A total of 23 healthy and atherosclerotic human coronary arteries (14 healthy and 9 atherosclerotic) were removed within 5 h postmortem. The samples were mounted on a uniaxial tensile test machine and the obtained mechanical properties were used in finite element models. The peak plaque stresses for the Ogden hyperelastic model were compared to the Mooney-Rivlin and Neo-Hookean outcomes. The results indicated that hypocellular plaque in all three models has the highest stress values compared to the cellular and calcified ones and, as a result, is quite prone to rupture. The calcified plaque type, in contrast, has the lowest stress values and remains stable. The results can be used in plaque vulnerability prediction and have clinical implications for interventions and surgeries such as balloon-angioplasty, cardiopulmonary bypass and stenting.

Modeling of cerebral aneurysm using equivalent electrical circuit (Lumped Model)

The circle of Willis (CoW) is a key asset in brain performance as it supports adequate blood supply to the brain. The lumped method (electrical equivalent circuits) is a useful model to simulate the process of the human cardiovascular system. In this study, the whole cardiovascular system is modeled, using an equivalent electrical circuit to investigate an aneurysm in an artery. The cerebrovascular system consists of 29 compartments, which includes the CoW. Each vessel is modeled by a resistor, a capacitor and an inductor. Using MATLAB Simulink, the left and right ventricles are modeled by controlled voltage sources and diodes. The effects of the left internal carotid artery aneurysm (Fusiform) on the pressure of the efferent arteries in the circle of Willis are studied. The modeling results are entirely in agreement with the available clinical observations. The results of the present study may have clinical implications for modeling different cardiovascular diseases, such as arterial stiffness and atherosclerosis.

First- and second-generation drug-eluting balloons for femoro-popliteal arterial obstructions: update of technique and results

The use of drug-eluting balloons for treatment of long-segment femoropopliteal artery obstructions has become widespread in recent years. The possibility to deliver a drug into the arterial wall with sustained antiproliferative effects, without leaving behind metal scaffolding, seems very promising. The current generation of drug-eluting balloons differs in the formulation of the drug (usually paclitaxel), technique of coating, and the elution excipients. Results of published randomized trials are reviewed in this report. A new innovative coating technique has been introduced recently. The PRIMUS® coronary drug-eluting balloon and the Legflow® peripheral drug-eluting balloon consist of paclitaxel nanoparticles that are embedded underneath the surface of the balloon as well as inside a new shellolic acid drug-release matrix. Risk for dislodgement of the paclitaxel particles is minimized in the newest generation of drug-eluting balloons. Short-term in vitro and in vivo results of this stable, coated balloon are promising, and large randomized trials have been started recently to gather more long-term and robust clinical data.

Bioconvection in spatially extended domains

We numerically explore gyrotactic bioconvection in large spatially extended domains of finite depth using parameter values from available experiments with the unicellular alga Chlamydomonas nivalis. We numerically integrate the three-dimensional, time-dependent continuum model of Pedley et al. [J. Fluid Mech. 195, 223 (1988)] using a high-order, parallel, spectral-element approach. We explore the long-time nonlinear patterns and dynamics found for layers with an aspect ratio of 10 over a range of Rayleigh numbers. Our results yield the pattern wavelength and pattern dynamics which we compare with available theory and experimental measurement. There is good agreement for the pattern wavelength at short times between numerics, experiment, and a linear stability analysis. At long times we find that the general sequence of patterns given by the nonlinear evolution of the governing equations correspond qualitatively to what has been described experimentally. However, at long times the patterns in numerics grow to larger wavelengths, in contrast to what is observed in experiment where the wavelength is found to decrease with time.

Hydrodynamic mechanisms of cell and particle trapping in microfluidics

Focusing and sorting cells and particles utilizing microfluidic phenomena have been flourishing areas of development in recent years. These processes are largely beneficial in biomedical applications and fundamental studies of cell biology as they provide cost-effective and point-of-care miniaturized diagnostic devices and rare cell enrichment techniques. Due to inherent problems of isolation methods based on the biomarkers and antigens, separation approaches exploiting physical characteristics of cells of interest, such as size, deformability, and electric and magnetic properties, have gained currency in many medical assays. Here, we present an overview of the cell/particle sorting techniques by harnessing intrinsic hydrodynamic effects in microchannels. Our emphasis is on the underlying fluid dynamical mechanisms causing cross stream migration of objects in shear and vortical flows. We also highlight the advantages and drawbacks of each method in terms of throughput, separation efficiency, and cell viability. Finally, we discuss the future research areas for extending the scope of hydrodynamic mechanisms and exploring new physical directions for microfluidic applications.

Length scale of a chaotic element in Rayleigh-Bénard convection

We describe an approach to quantify the length scale of a chaotic element of a Rayleigh-Bénard convection layer exhibiting spatiotemporal chaos. The length scale of a chaotic element is determined by simultaneously evolving the dynamics of two convection layers with a unidirectional coupling that involves only the time-varying values of the fluid velocity and temperature on the lateral boundaries of the domain. In our results we numerically simulate the full Boussinesq equations for the precise conditions of experiment. By varying the size of the boundary used for the coupling we identify a length scale that describes the size of a chaotic element. The length scale of the chaotic element is of the same order of magnitude, and exhibits similar trends, as the natural chaotic length scale that is based upon the fractal dimension.

Infectious diseases in Iran: a bird's eye view

Thanks to improved health standards in Iran over the past three decades, we have witnessed a shift in the causes of death in Iran from infectious causes to non-communicable diseases-mainly cardiovascular disorders, cancers, and road traffic injuries. The incidence and prevalence of many infectious diseases, such as many parasitic infections, have fallen significantly; there have been no reported cases of dracunculiasis in Iran since the mid-1970s. Great strides have also been made towards the elimination of schistosomiasis in Iran. However, we still have some problems with cutaneous leishmaniasis, hepatitis C, human immunodeficiency virus, tuberculosis, infections among immunocompromised hosts, hospital-acquired infections, and antibiotic-resistant bacterial strains. We need to emphasize improvements in sanitation, good clinical practice, and education about the rational administration of antibiotics.