Performance of Composite Shear Walls Subjected to In-plane Cyclic Loading - A Numerical Parametric Study

An RC shear wall (wall1), a composite shear wall composed of a single external steel plate connected to a concrete panel (wall2), a composite shear wall constructed from two external steel plates connected to an internal concrete panel (wall3) and finally a composite shear wall fabricated with a single internal steel plate embedded within a concrete panel (wall4) are considered in this study and their behavior are assessed and compared under the effect of an in-plane cyclic load. Variation of the three functions include shear load capacity, energy absorption and shear stiffness of the walls are evaluated numerically using the ABAQUS finite element software. The performance of numerical models is validated against to the experimental results. The effects of four parameters consisting of compressive strength of concrete, yield strength of steel plate, height-to-length ratio of the wall and the thickness of the steel plate are investigated on the above-mentioned functions. Obtained results show that the wall4 has the best performance among all four types of shear walls. For instance, the energy absorption capacity of the wall4 is approximately two times greater than that of wall1 and wall2

Assessment of the influence of whole body vibration on Cochlear function

Background: Whole body vibration (WBV) is a potentially harmful consequence resulting from the dissipation of energy by industrial machineries. The result of WBV exposure on the auditory system remains unknown. The objective of the present research was to evaluate the influence of WBV on cochlear function, in particular outer hair cell function. It is hypothesized that WBV impairs cochlear function resulting in decreased Distortion Product Otoacoustic Emission (DPOAE) levels (Ldp) in rabbits subjected to WBV. Methods. Twelve rabbits were equally divided into vibration and control groups. Animals in vibration group were exposed to 1.0ms-2 r.m.s vertical WBV at 4-8Hz for 8h/day during 5 consecutive days. Outer hair cell function was assessed by comparing repeated-measurements of DPOAE levels (Ldp) across a range of f2 frequencies in rabbits both exposed and unexposed to WBV. DPOAE level shifts (LSdp) were compared across ears, frequencies, groups, and times. Results: No differences were seen over time in DPOAE levels in the non-exposed rabbits (p=0.082). Post-exposure Ldp in rabbits exposed to WBV were significantly increased at all test frequencies in both ears compared to baseline measures (p=0.021). The greatest increase in Ldp following exposure was seen at 5888.5Hz (mean shift=13.25dB). Post-exposure Ldp in rabbits exposed to WBV were not significantly different between the right and left ears (p=0.083). Conclusion: WBV impairs cochlear function resulting in increased DPOAE responses in rabbits exposed to WBV. DPOAE level shifts occurred over a wide range of frequencies following prolonged WBV in rabbits. © 2012 Moussavi-Najarkola et al.; licensee BioMed Central Ltd

Effects of whole body vibration on outer hair cells' hearing response to distortion product otoacoustic emissions

Whole body vibration (WBV) is one of the most vexing problems in industries. There is a debate about the effect of WBV exposure on hearing system as vibration-induced hearing loss. The purpose of this study was to investigate outer hair cells' (OHCs') hearing response hearing response to distortion product otoacoustic emissions (DPOAEs) in rabbits exposed to WBV. It was hypothesized that the DPOAE response amplitudes (A dp) in rabbits exposed to WBV would be lower than those in control rabbits not exposed to WBV. New Zealand white (NZW) rabbits as vibration group (n�=�6, exposed to WBV in the z-axis at 4-8 Hz and 1.0 ms-2 root mean square for 8 h per day during five consecutive days) and NZW rabbits as control group (n�=�6, not exposed to any WBV) were participated. A dp and noise floor levels (L nf) were examined on three occasions: day 0 (i.e., baseline), day 8 (i.e., immediately 1 h after exposure), and day 11 (i.e., 72 h following exposure) with f 2 frequencies ranging from 500 to 10,000 Hz and primaries L 1 and L 2 levels of 65 and 55 dB sound pressure level, respectively. Main effects were statistically found to be significant for group, time, and frequency (p�<�0.05). DPOAE amplitudes were significantly larger for rabbits exposed to WBV, larger on day 8 and larger for mid to high f 2 frequencies (at and above 5,888.50 Hz). Main effects were not statistically found to be significant for ear (p�>�0.05). Also, four statistically significant interactions including time by ear, time by frequency, group by frequency, and group by time were detected (p�<�0.05). Contrary to the main hypothesis, DPOAE amplitudes were significantly larger for rabbits exposed to WBV. WBV exposure significantly led to enhanced mean A dp at mid to high frequencies rather than at low ones. © 2012 The Society for In Vitro Biology

Kinetics of murine decidual dendritic cells

Dendritic cells (DCs) are professional antigen presenting cells (APC) capable of induction of primary immune responses as well as immunologic tolerance. Myeloid and lymphoid subsets of murine DCs are able to shift cytokine responses of T cells toward Th2 and Th1 profiles respectively. Thus, DCs would be suitable candidates to mediate the balance of maternal immune responses to conception. We analyzed pregnancy-related variations in uterus and splenic DCs in a murine model. C57BL/6-mated Balb/c female mice with vaginal plugs were scarified at early, middle, and late pregnancy. Frozen sections of uterus and spleen at each stage of pregnancy were immunostained with CD11c- and MHC-II-specific antibodies. Two-color immunohistochemistry was also carried out using anti-CD11c and one of the antibodies against CD11b, CD8α, CD86, and DEC-205. Using morphometric analysis, the average density of DCs and relative percentage of myeloid (CD11c+, CD11b+) and lymphoid DCs (CD11c+, CD8α+) were determined at each stage. Our results showed that DCs are present throughout the pregnancy in decidua. The average density of decidual DCs at early pregnancy was significantly higher relative to middle and late gestation or to those of endometrial DCs of non-pregnant mice. Interestingly, the average density of decidual and splenic DCs, followed the same variations at different stages of pregnancy. The relative percentage of decidual lymphoid DCs (LDC) was significantly higher at mid-gestation when compared with other stages of pregnancy or non-pregnant mice. Inversely, the frequency of myeloid DCs (MDC) and the MDC/LDC ratio were statistically lower at the middle stage of pregnancy. A majority of decidual DCs expressed MHC-II and CD86. At early pregnancy, DCs were more concentrated subadjacent to the luminal epithelial layers, whereas at mid- or late gestation, DCs were randomly distributed in the stroma and around the epithelium. Mid-pregnancy period was a critical point with regard to splenic DCs kinetics, as both the average density of DCs and the frequency of MDCs decreased significantly when compared with early or late pregnancy, although the relative percentage of splenic LDCs did not change. Our data suggest that the balance of MDC and LDC is finely tuned throughout pregnancy, pointing an eminent immunoregulatory role of DCs in the maintenance of pregnacy. © 2007 Society for Reproduction and Fertility

Noise-induced outer hair cells' dysfunction and cochlear damage in rabbits

Background: Outer hair cells' (OHCs') dysfunctions as the extent of temporary and permanent threshold shifts (TTS and PTS) and cochlear damage were assessed in rabbits exposed to continuous noise. Methods: Twelve New Zealand white rabbits were studied in noise (N) (n=6; exposed to continuous noise; 95 dB SPL, 500-8000 Hz for 8 h per day during 5 consecutive days) and control (C) (n=6; not exposed to noise). OHCs' functions were assessed by distortion product otoacoustic emission (DPOAE) level (Ldp) measurements in different periods and comparing TTS and PTS. Animals were anaesthetized by CO2; cochleae were extracted, fixed in 10 formaldehyde for 48 hours, decalcified by 10 nitric acid for 24 hours, and dehydrated, embedded, sectioned 5 \am thickness and stained by Hematoxylin and Eosin for light microscopy. Results: The most and least Ldp or TTS or PTS were related to 5888.50 Hz and 588.00 Hz respectively in noise subjected rabbits (P0.05). Severely vacuolated OHCs, pyknotic IHCs, swollen SC, and slightly thickened BM were found. Conclusion: Continuous noise extensively led to OHCs' dysfunctions as decreased Ldp (both TTS and PTS) and highly damage to cochlea. © Iranian Red Crescent Medical Journal

The Morphological Expression of Endometrial Pinopodes During Implantation in Mice After Ovarian Stimulation and Progesterone Injection

Introduction: The aim of this study was to evaluate the expression of pinopodes as animplantation marker after ovarian hyper stimulation and progesterone injection using scanningelectron microscopic studies. Material and Methods: Three groups of NMRI adult female mice were used in the experiment. The control group (Group A) were untreated pseudopregnant mice. Group B mice were made pseudopregnant after super ovulation treatment with hMG and hCG. Group C micewere treated the same as Group B and then received progesterone daily from day 1 of pseudopregnancy. Animals were sacrificed by cervical dislocation 3.5 and 4.5 days after hCG injection. Tissues were obtained from the middle 1/3 part of uterine horns and processed for scanning electron microscopic studies. Results: In the control group there were some pinopodes at 3.5 days of pseudopregnancy and the apical surface of all cells expressed these projections on day four. In the hyperstimulated group without progesterone injection no pinopodes were seen 3.5 days after hCG injection and some appeared on day 4. In the hyper stimulated and progesterone-injected group well developed pinopodes were expressed 3.5 days after stimulation and they became much smaller on day 4 after hCG injection. Conclusion: The results showed that the life span of pinopodes is short and changeable during hyper stimulation and that progesterone causes premature expression of the pinopodes, suggesting that the implantation after ovarian stimulation might depend upon the timing of the pinopode expression