Synthesis of polyester urethane urea and fabrication of elastomeric nanofibrous scaffolds for myocardial regeneration

Fabrication of bioactive scaffolds is one of the most promising strategies to reconstruct the infarcted myocardium. In this study, we synthesized polyester urethane urea (PEUU), further blended it with gelatin and fabricated PEUU/G nanofibrous scaffolds. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and X-ray diffraction were used for the characterization of the synthesized PEUU and properties of nanofibrous scaffolds were evaluated using scanning electron microscopy (SEM), ATR-FTIR, contact angle measurement, biodegradation test, tensile strength analysis and dynamic mechanical analysis (DMA). In vitro biocompatibility studies were performed using cardiomyocytes. DMA analysis showed that the scaffolds could be reshaped with cyclic deformations and might remain stable in the frequencies of the physiological activity of the heart. On the whole, our study suggests that aligned PEUU/G 70:30 nanofibrous scaffolds meet the required specifications for cardiac tissue engineering and could be used as a promising construct for myocardial regeneration.

Modeling the Electrohydrodynamic (EHD) Drying of Banana Slices

Electrohydrodynamic (EHD) drying of banana slices was modeled both numerically and empirically. The drying process was conducted using the EHD technique at 6, 8, and 10 kV cm−1 with banana slices 3 mm thick. Based on the maximum coefficient of determination (R2) and minimum value of root mean square of error (RMSE) observed in the experimental and predicted values of moisture ratio, the diffusion model was identified as the best prediction model. The values for effective moisture diffusivity were calculated to be in the range of 3.12 × 10−10 to 4.23 × 10−10 m2 s−1. In addition, a theoretical model was developed using the numerical (implicit) solution of the second Fick’s equation based on low variation in the external resistance by applying EHD. Moisture ratio versus time showed a falling rate period indicating that the internal moisture transfer is dominant at EHD. Results of numerical solution showed adequate consistency with experimental data, having the maximum difference of less than 0.16 g g−1 in moisture content.

Synthesis, characterization and gas separation properties of novel copolyimide membranes based on flexible etheric–aliphatic moieties

The structural properties and gas permeation of a group of copolyimide membranes were investigated.

Olefin–paraffin separation performance of polyimide Matrimid®/silica nanocomposite membranes

In this study, the performance of polyimide Matrimid® membranes in the separation of ethylene/ethane and propylene/propane was improved by silica nanoparticles.

Investigation of LiF, Mg and Ti (TLD-100) Reproducibility

LiF, Mg and Ti cubical TLD chips (known as TLD-100) are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy) with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC) were obtained 4 times by irradiating them to doses of 81 mGy (two times), 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

Static standing, dynamic standing and spasticity in individuals with spinal cord injury

STUDY DESIGN

This was a cross-over efficacy study design.

OBJECTIVE

To determine spasticity differences between static and dynamic standing training in individuals with spinal cord injury (SCI).

SETTING

Vancouver, Canada.

METHODS

Ten individuals with SCI who could stand with or without bracing or supports participated in both dynamic and static standing training (one session each, 2 days apart) using a Segway. The primary outcome was spasticity as measured by Visual Analog Scale (VAS), Modified Ashworth Scale (MAS) and electromyography (EMG) of the quadriceps, hamstrings, adductors and gastrocnemius.

RESULTS

There was no statistically detectable difference in spasticity between dynamic and static standing training in individuals with SCI as measured by VAS, MAS or EMG, although there was a trend towards decreased spasticity after the dynamic training.

CONCLUSION

There is no significant difference in spasticity outcomes between static and dynamic standing training on a Segway for individuals with SCI.

SPONSORSHIP

This research was funded by Natural Sciences and Engineering Research Council of Canada and International Collaboration on Repair Discoveries.

Numerical modeling of drug delivery in a dynamic solid tumor microvasculature

The complicated capillary network induced by angiogenesis is one of the main reasons of unsuccessful cancer therapy. A multi-scale mathematical method which simulates drug transport to a solid tumor is used in this study to investigate how capillary network structure affects drug delivery. The mathematical method involves processes such as blood flow through vessels, solute and fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. The effect of heterogeneous dynamic network on interstitial fluid flow and drug delivery is investigated by this multi-scale method. The sprouting angiogenesis model is used for generating capillary network and then fluid flow governing equations are implemented to calculate blood flow through the tumor-induced capillary network and fluid flow in normal and tumor tissues. Finally, convection-diffusion equation is used to simulate drug delivery. Three approaches are used to simulate drug transport based on the developed mathematical method: without a vascular network, using a static vascular network, and a dynamic vascular network. The avascular approach predicts more uniform and higher drug concentration than vascular approaches since the simplified assumptions are implemented in this method. The dynamic network which uses more realistic assumptions predicts more irregular blood vessels, high interstitial pressure, and more heterogeneity in drug distribution than other two approaches.

Awareness of Religious Leaders' Fatwa and Willingness to Donate Organ

BACKGROUND

It is believed that religious leaders' positive attitude towards organ donation can be an effective factor in Muslims' inclination to donate organs.

OBJECTIVE

To assess the knowledge of freshmen students in Mashhad University of Medical Sciences about religious leaders' fatwa on organ donation and its effect on their willingness to donate organs.

METHODS

This cross-sectional study was conducted in 2013 on 400 freshmen of various medical disciplines, selected using a simple random sampling in Mashhad, Iran. Data were collected by a valid and reliable researcher-made questionnaire. Data were analyzed by multiple logistic regression analysis.

RESULTS

41.5% of the students were aware of religious authorities' views on organ donation and 55.6% were willing to donate organs. Participants' main reasons for lack of willingness to donate organs included the fear of organ donation before the brain death is confirmed (52%), unwillingness to disfigure their body (51%), and belief in the burial of organs (50%). The willingness to organ donation for students who were aware of religious leaders opinion was more than twice more than those who were not (OR: 2.56, 95% CI: 1.75-4.52). Also, female gender, the Shia religion and awareness of the correct definition of brain death were associated factors affecting the desire to donate organs, although their effects were not statistically significant on regression model.

CONCLUSION

A considerable proportion of students were not aware of the religious leaders' fatwa on organ donation. The most important factor for the desire to donate organs was the awareness of religious leaders' fatwa. Therefore, it seems necessary that religious leaders' fatwa be known to all by appropriate methods.

Investigation of the entrance surface dose and dose to different organs in lumbar spine imaging

BACKGROUND

Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology.

OBJECTIVE

The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views.

METHODS

To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging.

RESULTS

The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement.

CONCLUSION

According to the results, the GR200 has greater sensitivity than the TLD-100.

Association of pituitary specific transcription factor-1 (POU1F1) gene polymorphism with growth and biometric traits and blood metabolites in Iranian Zel and Lori-Bakhtiari sheep

The pituitary-specific positive transcription factor 1 (POU1F1) gene has been the subject of many recent studies because of its important roles in growth and development of mammals. In this study, we investigated the single nucleotide polymorphisms (SNPs) at the third exon of POU1F1 gene and its association with growth and biometric traits and blood metabolites in two Iranian sheep breeds, Zel and Lori-Bakhtiari. Blood samples from 90 Lori-Bakhtiari and 90 Zel sheep were collected to extract DNA and the 295-bp fragment of the POU1F1 gene was amplified and the restriction fragment length polymorphism (RFLP) technique was adopted for genotyping. A SNP was identified in both Lori-Bakhtiari and Zel sheep breeds, which represents a non-synonymous single base mutation at restriction site for endonuclease AciI. The results revealed differential frequencies of alleles between the two studied breeds, where A allele was more frequent in Lori-Bakhtiari breed, while G allele was more frequent in Zel breed. When POU1F1 genotypes were tested, the animals with AA genotype had a higher weaning weight than those with GG genotype (p < 0.05), however there were not significant association between genotypes and birth weight, biometric traits (body length, body height, heart girth, thigh girth and abdominal girth) and blood metabolites (triglyceride and cholesterol) of the studied breeds (p > 0.05). These findings imply that the POU1F1 polymorphism may affect weaning weight, thus can be used as a molecular marker for this production trait.