---

Background: The comparison between voluntary and automatic contraction of deep abdominal muscles in patients with Nonspecific Low Back Pain (nLBP) may the best treat for them. The aim of this case-controlled study was to compare changes in the thickness of the Transverses Abdomin is (TrA) and Internal Oblique (IO) muscles during the Abdominal Drawing-In Maneuver (ADIM) and the Active Straight-Leg Raise (ASLR) test. Methods: This study involved 30 women including 20 women with and 10 women without non-specific low back pain. The abdominal muscle thickness in the supine crook-lying, ASLR, and ADIM exercises were measured. Two-way repeated-measures ANOVA was used to compare the thickness ratio results between the two groups. Results: There were significant differences between the TrA (p < 0.05) and IO (p < 0.05) muscle thickness ratios during the ADIM compared to the ASLR in the neutral lumbar posture in supine lying in the healthy group; However, in the subjects with nLBP, only the TrA (p < 0.005) muscle thickness ratio was significantly higher in the ADIM rather than in the ASLR. Conclusion: These findings suggest that in both groups the deep abdominal muscles (the TrA and the IO) responded differently according to the variable type of activities such as voluntary or automatic, therefore, in training programs, in addition to a voluntary workout, automatic type of exercises should also be taught.  

---

Objective: This study presents an efficient, cost-effective method to improve proliferation and colonization of spermatogonial stem cells (SSCs) in vitro. Methods: Isolated SSCs from neonate mice were cultured in DMEM culture medium with 10% fetal bovine serum (FBS). In the first phase of the study, the temperature was controlled by low intensity pulsed ultrasound stimulation (LIPUS) of the plate that contained the culture medium. In the next phase, SSCs were stimulated by LIPUS with 200 mW/cm² with 20% and 40% duty cycle for five days. Proliferation and colonization of SSCs were on the seventh day. Results: LIPUS treatment of mouse SSCs increased the proliferation rate and colonization of SSCs in the experimental groups compared to the control group. Average proliferation rate in the 20% duty cycle group was 1.46±0.06, in the 40% duty cycle group it was 2.00±0.1 and for the control group, it was 1.26±0.06. The average number of colonies in the 20% duty cycle group was 24±7.7, whereas the 40% duty cycle group had 62±1.4 colonies and the control group had an average of 19±5.5 colonies. Average colony diameters were as follows: 186.6±2.07 µm (20% duty cycle group), 185.3±4.4 µm (40% duty cycle group) and 190.0±2.0 µm (control group). Our results showed a significant increase in proliferation rate and number of colonies in the experimental groups compared to the control group (P<0.05), whereas no significant differences were observed between groups in colony diameters. Conclusion: These results suggested that LIPUS treatment can be an efficient, cost-effective method to improve proliferation and colonization of SSCs during in vitro culture.

---

Pulse wave velocity often used as an indicator clinically for diagnosis of cardiovascular diseases. This assumption is well grounded in the physics of pulsatile flow of an incompressible fluid where it is fully established that a pulse wave travels faster in a tube of stiffer wall, the wave speed becoming infinite in the mathematical limit of a rigid wall. in this paper we point out that pulse wave velocity in a stiffer tube is strictly valid only when the wall is free from outside constraints, Which is used as the outer boundary condition (tethering: the degree to which the vessel wall is surrounded by tissue). In this paper, using the equations of blood fluid and vessel walls and using analytical solutions and the use of tethering as outer boundary conditions pulse wave velocity is investigated. In previous research pulse wave velocity has been obtained just for the tethering zero and one, But in the study pulse wave velocity investigated for tethering different degrees of tethering and for three different material wall viscoelastic, elastic and stiff. With this research, it is clear the changes of pulse wave velocity with change of degrees of tethering and change of material wall ,This results is a great help for use of pulse wave velocity as an clinical index to predict arterial stiffness.

---

In the present study, a finite element model has been presented using both the in-vivo geometry of a healthy man carotid artery, which was extracted from consecutive transverse ultrasound images and the pulse pressure waveform and Kelvin viscoelastic model parameters that were obtained from processing the consecutive longitudinal ultrasound images. Extracting the internal diameter waveform from longitudinal ultrasonic image processing and calibrating it via an exponential equation, blood pressure waveform of the carotid artery was extracted. A Gaussian function was fitted to the blood pressure waveform. Differentiating the fitted Gaussian equation resulted in the pressure differentiation of the carotid artery over the cardiac cycle. Kelvin viscoelastic parameters were estimated using an optimization method. Finite element model of the carotid artery was reconstructed in ADINA software and implemented by loading over three cardiac cycles. To validate the model, radial displacement waveform resulted from finite element model and that resulted from image processing were compares in nearly the same spatial position. Percentage of the mean proportional differences between the radial displacement resulted from finite element model and that from consecutive ultrasound images was 9.3. Since the appropriate mechanical models can calculate true stress/strain distribution of the carotid artry wall and plaque and distinguish the location of the plaque areas prone to vulnireability; and because of the capability of the ultrasonic model proposed in this study for describing the pulsatile behavior of artery wall accurately, it is expected that the introduced dynamic model to be applied for accurate evaluation of the arterial disease.