78 research outputs found
Effect of hydraulic conductivity and permeability on drug distribution, an investigation based on a part of a real tissue
In this study, a computational simulation is employed to place two essential
parameters, the permeability of vessels and hydraulic conductivity, under
assessment. These parameters impact the movement of drug particles through
vessels, and normal and tumoral tissue to examine the concentration of
nanoparticles, interstitial pressure, and velocity. To provide a geometric
model detailing the capillary network under normal and tumoral tissue
conditions, the geometry is extracted via real image processing. Subsequently,
the real conditions were considered to solve the equations pertaining to drug
transport and intravascular and interstitial flows in the tissue. The results
showed that an increase in permeability and hydraulic conductivity leads to an
increase in drug concentration in the tumor. Finally, Methotrexate drug has the
most effect in the treatment of tumors. Overall, the computational model for
anti-cancer delivery provides a powerful tool for understanding and optimizing
drug delivery strategies for the treatment of cancer.Comment: 15 page
A study on the association of diabetic dermopathy with nephropathy and retinopathy in patients with type 2 diabetes mellitus
Background: Diabetic dermopathy is one of the most prevalent skin complications in diabetes patients. Some studies have pointed to association of diabetic dermopathy with retinopathy and nephropathy in patients with type 2 diabetes as microangiopathy presentations, but no rigorous study has been conducted to confirm this association. Objectives: This study investigated association of diabetic dermopathy with nephropathy and retinopathy in patients with type 2 diabetes referring specialty clinic of Shahrekord. Patients and Methods: This descriptive, cross-sectional study was conducted on 102 type 2 diabetes patients with dermopathy referring clinic constantly or as outpatient. Dermatological and ophthalmological examinations and examination for nephropathy were done for all patients. Demographic data and results of examinations and patients history, and biochemical tests were gathered and recorded by researcher developed checklists. Results: Mean age of patients was 83.8 2.60 years, of whom 64 (63.7%) were female and 37.3% were male. Prevalence of retinopathy in patients was 4.31% and nephropathy 3.33%. In this study, significant associations of diabetic dermopathy with diabetic nephropathy (P = 0.001), with retinopathy (P 0.05). Conclusions: Results of this study confirm the association of diabetic dermopathy with retinopathy and nephropathy in patients with type 2 diabetes. Since dermopathy is usually developed before retinopathy and nephropathy, dermopathy could be used as a clinical finding in early diagnosis and prevention of retinopathy and nephropathy in diabetes patients. © 2016 The Author(s)
Modeling the propagation of optical beams in three-dimensional photonic crystals
© 2008 Optical Society of AmericaThe definitive version of this paper is available at: http://dx.doi.org/10.1364/JOSAB.25.000785DOI: 10.1364/JOSAB.25.000785We show that the propagation effects of optical beams in three-dimensional photonic crystal structures can be modeled using a direction-dependent effective diffractive index model. The parameters of the model (i.e., the effective diffractive indices) can be calculated using the curvatures of the band structure of the photonic crystal at the operation point. After finding these indices, the wave propagation inside the photonic crystal can be analyzed using simple geometrical optics formulas. We show that the model has good accuracy for most practical applications of photonic crystals. As an example, the application of the model for diffraction compensation in a tetragonal woodpile photonic crystal is demonstrate
Investigation of physical mechanisms in coupling photonic crystal waveguiding structures
We explain the fundamental physical mechanisms involved in
coupling triangular lattice photonic crystal waveguides to conventional dielectric slab waveguides. We show that the two waveguides can be efficiently coupled outside the mode gap frequencies. We especially focus on the coupling of the
two structures within the mode gap frequencies and show for the first time that the diffraction from the main photonic crystal structure plays an important role on the reflection of power back into the slab waveguide. The practical importance of this effect and possible strategies to modify it are also discussed
Induced Myopia Secondary to Blunt Trauma
A 28-year-old young man presented with sudden and severe visual loss in the left eye, starting three days ago following blunt head trauma from a closed fist. Vision was not improved to better than 0.4 in the left eye. Slit lamp examinations revealed asymmetric anterior chamber depth (ACD) with shallow ACD in the left eye. The key learning in this report is the use of anterior segment optical coherence tomography (AS-OCT) to better document the anterior segment changes following the blunt trauma. AS-OCT was used to visualize the forward displacement of the iris-crystalline lens diaphragm secondary to ciliary body anterior rotation and ciliochoroidal effusion. There was a temporary myopic shift about 7.00D which resolved after 15 days
Evaluation of the results of chromen drug derivatives and their effect on colon cancer
Cancer is a huge phenomenon in human society that it observe in developing countries and even more developed countries in terms of economic as well. Colon cancer is created by increasing cancer cells that its main reason is the uncontrollable growth of cells in Colon. In this research, two groups of stable chromene compounds which was calculated in the previous study using bioinformatics software selected and their toxicity effect and the kind of cell death that they cause investigated on HT-29 cancer cell line, which is related to colon cancer. Also, toxicity of 2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano [2,3-c] chromene -2-carbonitrile (S1), 2-amino-4-(4-bromophenyl)-5-oxo-4H,5H-pyrano [2,3-c] chromene -2-carbonitrile (S2) which had an appropriate stable determined. At concentrations of 1, 2, 3, 5, 10 and 20 μg / ml, a control group was performed on HT-29 cancer cell lines in comparison with the chemotherapeutic drug Campusar with similar concentrations of the chemotherapy drug using MTT assay. Analysis of data was done by statistical software Graphpad Prism 8 and ANOVA test and ultimately, the type of cell death which created by Flow cytometry technique was examined. The results showed that chromium derivatives by causing apoptosis in HT-29 cancer cells could be further studied as a suitable candidate for the effect on colon cancer
Galilei Corneal Tomography for Screening of Refractive Surgery Candidates: A Review of the Literature, Part II
Corneal topography is the most widely used technology for examining the anterior corneal surface. Scheimpflug imaging is a newer technique that allows for measurement of both the anterior and posterior corneal surface, which allows for three-dimensional reconstruction of the cornea. This is of particular interest and value in the field of cataract and refractive surgery. The Galilei camera is a commercially available dual Scheimpflug system that combines curvature data from Placido disc-based corneal topography with elevation data from Scheimpflug technology. The addition of Placido disc topography makes the Galilei unique from its more popular counterpart, the Pentacam, which was discussed in Part I. Compared to the Pentacam, and however, the Galilei analyzer is a newer system that has emerged as a valuable screening tool given its dual Scheimpflug capability. In the first article of this series, the authors summarized the refractive indices available on the Pentacam system with the purpose of identifying the best diagnostic parameters for keratoconus. Similarly, the purpose of this article is to summarize corneal surface indices available on the Galilei system and evaluate their use in screening of the refractive surgery candidate. Since post-operative keratectasia is still prevalent, this paper aims to identify the most clinically relevant indices that may be used in pre-operative evaluation
Advances in Biomechanical Parameters for Screening of Refractive Surgery Candidates: A Review of the Literature, Part III
Corneal biomechanical properties have garnered significant interest in their relation to the development of ectatic corneal disease. Alongside the advent of corneal tomography and Scheimpflug imaging such as Pentacam and Galilei, there have been advances in assessing the cornea based on its biomechanical characteristics. Though the aforementioned imaging systems are highly capable of identifying morphologic abnormalities, they cannot assess mechanical stability of the cornea. This article, in contrast to Parts I and II of this article series, will focus on in vivo corneal biomechanical imaging systems. The two most readily available commercial systems include the Corvis ST and the Ocular Response Analyzer. Both of these systems aimed to characterize corneal biomechanics via distinct measurements. While in Parts I and II of this article series the authors focused on elevation, pachymetric, and keratometric data, the purpose of this article was to summarize biomechanical parameters and their clinical use in screening refractive surgery candidates. Moreover, this article explores biomechanical decompensation and its role in the development of corneal ectasia and keratoconus. There is a focus on the diagnostic accuracy of biomechanical indices in the identification of diseases such as keratoconus that may preclude a patient from undergoing refractive surgery
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