Publications by authors named "Toktam Jalayer"

3 Publications

  • Page 1 of 1

Fabrication and characterization of collagen-hydroxyapatite-based composite scaffolds containing doxycycline via freeze-casting method for bone tissue engineering.

J Biomater Appl 2018 10;33(4):501-513

1 Faculty of dentistry, Shahed University, Tehran, Iran.

In this study, hydroxyapatite nanoparticles containing 10% doxycycline, a structural isomer of tetracycline, was prepared by the co-precipitation method. It was added to collagen solution for the preparation of the scaffold with freeze-casting method in order to develop a composite scaffold with both antibacterial and osteoinductive properties for repairing bone defects. The scaffolds were evaluated regarding their morphology, porosity, degradation and cellular response. The scaffolds for further investigation were added in a rat calvaria defect model. The study showed that after eight weeks, the bone formation was relatively higher in the collagen/nano-hydroxyapatite/doxycycline group with completely filled defect when compared with other groups. Histopathological evaluation showed that the defect in the collagen/nano-hydroxyapatite/doxycycline group was fully replaced by the new bone and connective tissue. Our results provide evidence supporting the possible applicability of doxycycline-containing scaffolds for successful bone regeneration.
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http://dx.doi.org/10.1177/0885328218805229DOI Listing
October 2018

Intrarater and interrater reliability of sagittal head posture: a novel technique performed by a physiotherapist and a speech and language pathologist.

J Voice 2014 Nov 18;28(6):842.e11-6. Epub 2014 Jun 18.

Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Introduction: Different professionals such as speech and language pathologists and voice scientists are involved in the evaluation of head and neck posture. Therefore, a reliable, time-efficient, and precise method of posture assessment is essential for use in clinical and research settings. Photogrammetry is one of the most commonly used methods to assess head and neck posture. The objectives of this study were to evaluate the intrarater reliability of the method with a large sample size and the interrater reliability by two different specialists (a physiotherapist and a speech and language pathologist).

Method: A total of three hundred four subjects (144 males and 160 females) aged between 18 and 28 years participated in the study. During the test session, a photograph was taken of the left-side profile of each subject in their ordinary and comfortable position. The head posture angle of each picture was calculated by two raters. The whole procedure was repeated in a retest session, 24 hours later. A total number of eight analyses were performed for each subject. The reliability was evaluated at several stages hierarchically and after confirming the reliability in each step, the next step was investigated. Paired t tests on the differences of scores obtained at all the aforementioned stages were used to ensure the absence of any systematic bias. To assess the reliability, intraclass correlation coefficients (ICCs) and the standard error of measurements (SEMs) were calculated.

Results: There was no significant difference between the mean values of the test and the retest angles at any stage of calculating the head posture angle in both pictures by both examiners (P > 0.05). The ICC and SEM values calculated for all stages were between 0.86-0.97 and 0.52-1.53, respectively.

Conclusion: Systematic bias has not occurred at any stage. The ICC and SEM values calculated have demonstrated that there were appropriate relative and absolute reliabilities in all stages. This method is suggested to be used simply in research and clinical areas by different specialists.
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http://dx.doi.org/10.1016/j.jvoice.2014.02.014DOI Listing
November 2014

Long-term average spectra of adult Iranian speakers' voice.

J Voice 2014 May 13;28(3):305-10. Epub 2013 Nov 13.

Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Introduction: Long-term average spectrum (LTAS) allows quantifying the voice quality and provides an overview of the mean spectral characteristics of a voice. The aims of this study were to survey normal spectral characteristics of Persian and investigate sex-related changes in the source characteristics of dynamic speech using LTAS.

Method: Speech samples obtained from 30 male and 30 female Persian-speaking participants reading a text in habitual pitch and loudness level. At the LTAS window and using Praat software, the amplitude values were obtained at equal intervals of 160 Hz, ranging from 0 to 8 kHz.

Results: The main features of the average spectrum were as follows: peak in the region of 480 Hz with a reduction at higher frequencies, a 20 dB decline from 480 to 960 Hz, a flat region from 960 to 1920 Hz, a further decline from 1920 to 3040 Hz, and a further flat region from 3040 to 8000 Hz. In comparison to men, women revealed significant lower levels of amplitude at frequencies of 160 and 320 Hz and higher levels of amplitude at frequencies of 960, 3360, 3520, 3680, 3840, and 5920 Hz.

Conclusion: The overall shape and gender-related energy distribution pattern of the LTAS of Persian were more similar to those of English than to those of Korean. The more phonetic differences between Persian and Korean compared with Persian and English might contribute to different spectral characteristics. The present study tried to clarify the spectral characteristics of Iranian male and female voices and focused on more breathy voice quality for women than men.
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http://dx.doi.org/10.1016/j.jvoice.2013.09.002DOI Listing
May 2014