28 research outputs found
The Presentation of Financial Crisis Forecast Pattern (Evidence from Tehran Stock Exchange)
Abstract The purpose of this study is presenting a model for forecasting financial crisis in Tehran Stock Exchange listed companies. To do this, productive firms that had accepted in Tehran Stock Exchange between 2002 and 2009, were selected as the study sample. First the independent variables were obtained based on financial ratios and then based on Article 141 of the Co mme rce Law, the insolvent and solvent firms were separated. Next , based on these two groups of firms, the presence or absence of meaningful d ifference between independent variables (financial ratios) of this two groups samples were tested. The results obtained fro m this test contributed to the ext raction of a proper model of forecast using logistic regression. The results indicated that the variables of debt to the equity ratio, net profit to net sales ratio & working capital to assets ratio were identified as independent variables in the final model. In addition, the results indicated that using the test data, the forecast strength of the model is 81.49%, its degree of sensitivity is 96.12% and its degree of identification is 67.48%
Biodegradable elastic nanofibrous platforms with integrated flexible heaters for on-demand drug delivery
Delivery of drugs with controlled temporal profiles is essential for wound treatment and regenerative medicine applications. For example, bacterial infection is a key challenge in the treatment of chronic and deep wounds. Current treatment strategies are based on systemic administration of high doses of antibiotics, which result in side effects and drug resistance. On-demand delivery of drugs with controlled temporal profile is highly desirable. Here, we have developed thermally controllable, antibiotic-releasing nanofibrous sheets. Poly(glycerol sebacate)- poly(caprolactone) (PGS-PCL) blends were electrospun to form elastic polymeric sheets with fiber diameters ranging from 350 to 1100 nm and substrates with a tensile modulus of approximately 4-8 MPa. A bioresorbable metallic heater was patterned directly on the nanofibrous substrate for applying thermal stimulation to release antibiotics on-demand. In vitro studies confirmed the platform’s biocompatibility and biodegradability. The released antibiotics were potent against tested bacterial strains. These results may pave the path toward developing electronically controllable wound dressings that can deliver drugs with desired temporal patterns
Boron-Based Cluster Modeling and Simulations: Application Point of View
Among sub-nanometer clusters, boron-based clusters and their atom-doped counterparts have attracted great attention due to their mechanical, physical, and chemical properties as well as their applications. Molecular dynamics (MDs) simulations and ab initio methods, including density functional theory (DFT) calculations, have been used to understand the physical and chemical properties of different materials. Much research has recently been conducted by using various methods to determine the different properties of boron clusters. In this chapter, we briefly introduce the relevant modeling and simulation methods, then review very recent theoretical researches on the application of small boron clusters, such as gas sensors, electrodes, H2 storage, drug delivery, and catalytic applications
Chlorinated phosphorene for energy application
Abstract: The influence of decoration with impurities and the composition dependent band gap in 2D materials has been the subject of debate for a long time. Here, by using Density Functional Theory (DFT) calculations, we systematically disclose physical properties of chlorinated phosphorene having the stoichiometry of PmCln. By analyzing the adsorption energy, charge density, migration energy barrier, structural, vibrational, and electronic properties of chlorinated phosphorene, we found that (I) the Cl-P bonds are strong with binding energy Eb =-1.61 eV, decreases with increasing n. (II) Cl atoms on phosphorene have anionic feature, (III) the migration path of Cl on phosphorene is anisotropic with an energy barrier of 0.38 eV, (IV) the phonon band dispersion reveal that chlorinated phosphorenes are stable when r <= 0.25 where r = m/n, (V) chlorinated phosphorenes is found to be a photonic crystal in the frequency range of 280 cm-1 to 325 cm-1, (VI) electronic band structure of chlorinated phosphorenes exhibits quasi-flat bands emerging around the Fermi level with widths in the range of 22 meV to 580 meV, and (VII) Cl adsorption causes a semiconducting to metallic/semi-metallic transition which makes it suitable for application as an electroactive material. To elucidate this application, we investigated the change in binding energy (Eb), specific capacity, and open-circuit voltage as a function of the density of adsorbed Cl. The theoretical storage capacity of the chlorinated phosphorene is found to be 168.19 mA h g-1with a large average voltage (similar to 2.08 V) which is ideal number as a cathode in chloride-ion batteries
X Chromosome Inactivation in Opioid Addicted Women
Introduction: X chromosome inactivation (XCI) is a process during which one of the two X
chromosomes in female human is silenced leading to equal gene expression with males who
have only one X chromosome. Here we have investigated XCI ratio in females with opioid
addiction to see whether XCI skewness in women could be a risk factor for opioid addiction. Methods: 30 adult females meeting DSM IV criteria for opioid addiction and 30 control females
with no known history of addiction were included in the study. Digested and undigested DNA
samples which were extracted from blood were analyzed after amplification of the polymorphic
androgen receptor (AR) gene located on the X chromosome. XCI skewness was studied in 3
ranges: 50:50–64:36 (random inactivation), 65:35–80:20 (moderately skewed) and >80:20
(highly skewed). Results: XCI from informative females in control group was 63% (N=19) random, 27% (N=8)
moderately skewed and 10% (N=3) highly skewed. Addicted women showed 57%, 23% and
20%, respectively. The distribution and frequency of XCI status in women with opioid addiction
was not significantly different from control group (P=0.55). Discussion: Our data did not approve our hypothesis of increased XCI skewness among women
with opioid addiction or unbalanced (non-random) expression of genes associated with X
chromosome in female opioid addicted subjects
Composite Living Fibers for Creating Tissue Constructs Using Textile Techniques.
The fabrication of cell-laden structures with anisotropic mechanical properties while having a precise control over the distribution of different cell types within the constructs is important for many tissue engineering applications. Automated textile technologies for making fabrics allow simultaneous control over the color pattern and directional mechanical properties. The use of textile techniques in tissue engineering, however, demands the presence of cell-laden fibers that can withstand the mechanical stresses during the assembly process. Here, the concept of composite living fibers (CLFs) in which a core of load bearing synthetic polymer is coated by a hydrogel layer containing cells or microparticles is introduced. The core thread is drawn sequentially through reservoirs containing a cell-laden prepolymer and a crosslinking reagent. The thickness of the hydrogel layer increases linearly with to the drawing speed and the prepolymer viscosity. CLFs are fabricated and assembled using regular textile processes including weaving, knitting, braiding, winding, and embroidering, to form cell-laden structures. Cellular viability and metabolic activity are preserved during CLF fabrication and assembly, demonstrating the feasibility of using these processes for engineering functional 3D tissue constructs
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Composite Living Fibers for Creating Tissue Constructs Using Textile Techniques.
The fabrication of cell-laden structures with anisotropic mechanical properties while having a precise control over the distribution of different cell types within the constructs is important for many tissue engineering applications. Automated textile technologies for making fabrics allow simultaneous control over the color pattern and directional mechanical properties. The use of textile techniques in tissue engineering, however, demands the presence of cell-laden fibers that can withstand the mechanical stresses during the assembly process. Here, the concept of composite living fibers (CLFs) in which a core of load bearing synthetic polymer is coated by a hydrogel layer containing cells or microparticles is introduced. The core thread is drawn sequentially through reservoirs containing a cell-laden prepolymer and a crosslinking reagent. The thickness of the hydrogel layer increases linearly with to the drawing speed and the prepolymer viscosity. CLFs are fabricated and assembled using regular textile processes including weaving, knitting, braiding, winding, and embroidering, to form cell-laden structures. Cellular viability and metabolic activity are preserved during CLF fabrication and assembly, demonstrating the feasibility of using these processes for engineering functional 3D tissue constructs