Batul Nasrabadi, Mohammad Ismail Zibaii, Seyedeh Mahshad Hosseini,
Volume 16, Issue 1 (1-2022)
Abstract
ta charset="UTF-8" >Optogenetics is an advanced optical tool in neuroscience research. However, light stimulation in optogenetic experiments may also affect neural function by generating heat. In this paper, the effect of increasing the temperature of the brain tissue was studied during light stimulation. The Hodgkin-Huxley model and the hippocampal pyramidal cell model have been used to investigate the effect of temperature on spike neurons. The modeling results show that irradiation of brain tissue by pulsed laser with a frequency of 40 Hz, the duty cycle of 90% and wavelength of 593 nm at a distance of 10 μm from the tip of the fiber, for 60 seconds with a power of 1 and 40 mW leads to the temperature change from 37 °C to 39 °C. The obtained results show that the laser intensity decreases to zero at a distance of 1 mm from the tip of a fiber, which is absorbed by the tissue and causes a temperature rise of 2 °C that can increase the spike rate of neurons by 16.6%.
Zoha Ameri, Fazel Jahangiri,
Volume 16, Issue 2 (7-2022)
Abstract
Using terahertz waves for intra-body communications between nanomachines is associated with dissipation during propagation, of which scattering is one of the most important effects. In this paper, scattering path loss with two different assumptions of air-enclosed and tissue-enclosed in subcutaneous fat is calculated and compared. The results show that for TM polarization, air-enclosed assumption gives smaller and greater scattering loss for frequencies less and bigger than 0.26 THz. The greatest difference between air-enclosed and tissue-enclosed results is observed for TE polarization at the approximate frequency of 0.4 THz.
Nasrin Vahedi. G, Asghar Asgari, Gholamreza Dehghan,
Volume 16, Issue 2 (7-2022)
Abstract
Efforts to understand genetic diseases and mutations in biological systems are the most important driver of research development in medical and biomolecular sciences. Rapid, sensitive, accurate, and cost-effective biomolecule analysis is particularly important in diagnosis and treatment. The discovery of graphene as a new nanomaterial with a carbon structure with a single atom thickness due to its unique electronic, mechanical, thermal, and optical properties has opened a new topic in research in various biomedical sciences and the production of biosensors for biomolecule analysis. In this research, a biosensor based on a graphene field-effect transistor (GFET) is used to detect DNA with optimal accuracy and sensitivity, which can be a basis for making DNA detection tools. In the studied structure, using non-equilibrium Green function equations and Poisson equation, we study the electron transfer in graphene field-effect transistors. Then, by examining the interaction between nucleotide bases (C, G, A, T) and O6-carboxymethylguanine related to the colorectal cancer DNA sequence to detection of mutation will be identified by GFET, and their binding energy determined.
Tarek Al-Saeed,
Volume 17, Issue 1 (1-2023)
Abstract
In this work we applied a Bessel beam (BB) to a layer of turbid medium. We applied the Monte Carlo simulation. This work emulates a tissue under surgery by a Bessel beam. Actually, the BB introduces less divergence. Thus it will be good for surgery. On the other part this is done by Monte Carlo simulation. Upon simulation we got family of curves to characterize absorption, reflection and scattering of this layer. Where we got numerical values of absorption, transmission and reflection of this layer. The curves are for layer thickness that varies along with varying scattering coefficient, absorption coefficient and anisotropy factor.
Maliheh Ranjbaran, Maryam Rezaei, Sattar Jalali, Mobina Sadat Maroufi,
Volume 17, Issue 2 (6-2023)
Abstract
Cataracts, along with presbyopia, is a common age-related vision problem that can indeed make it challenging to achieve clear vision. Multifocal intraocular lenses (IOLs) have emerged as a promising treatment option to improve vision in individuals with cataracts and presbyopia. With their unique design, these lenses provide adequate vision at multiple distances and reduce the dependency on glasses. In this study, we utilized the Liou-Brennan model in Zemax software to simulate a healthy eye and then introduced cataracts with presbyopia to the model. Subsequently, we applied treatment in the form of multifocal intraocular lenses. The improvements in the patient's vision were indicated using spot diagrams and modulation transfer function for three different viewing distances: far, intermediate, and near at three different entrance pupil diameters.
Nastaran Kahrarian, Atoosa Sadat Arabanian, Zinab Moradi Alvand, Hasan Rafati, Reza Massudi,
Volume 18, Issue 1 (10-2024)
Abstract
The modification of cell surface structures has become a focal point in cell biology, with methods like drugs, chemicals, and non-destructive techniques such as laser light exposure being utilized. In particular, exposure to femtosecond laser pulses has been found to increase cell permeability to formulations without causing thermal damage. This study aimed to observe and document the changes in the structure of Staphylococcus aureus bacteria when they were optically trapped and subjected to femtosecond laser pulses, along with the application of a medicinal substance, over 20 minutes. The research successfully determined the optimal power and exposure time of the laser light on the bacterial surface and demonstrated the ability of femtosecond laser pulses to enhance the efficacy of the medicinal substance.
