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181.
Takuro Hirai Kei Sawata Ali Awaludin Yoshihisa Sasaki Takeyoshi Uematsu 《Journal of Wood Science》2012,58(2):128-134
Shaking table tests of the wall-floor joints of wooden light-frame constructions under forced harmonic vibrations are conducted
in this study so as to observe the dynamic responsive characteristics. The principal results are as follows: The responsive
characteristics of timber constructions under strong earthquakes cannot be directly correlated with their resonant frequencies
under free or forced vibrations with low input accelerations, because they behave as continuous bodies when the input accelerations
are less than the apparent frictional limits of structural joints. The apparent frictional limits are reduced by periodic
fluctuation of the effective vertical loads as a result of the vertical motion of the specimens. The characteristic dynamic
responses of wall-floor joints depend clearly upon the frequency and input accelerations of forced vibrations. These dependencies
arise from the nonlinear load-slip relationship of the wall-floor joints. The equivalent stiffness in their successive transient
phases decreases as joint slip increases, which gradually changes the resonant frequencies of the wall-floor joints. This
indicates that the frequency components dominant to ultimate or safety-limit resistance should be distinguished from those
dominant to allowable or serviceability-limit resistance. 相似文献
182.
Bahador Bagheri Bahram Sohrabi Ali Akbar Movassaghpour Simin Mashayekhi Afagh Garjani Mehriar Shokri Masoud Pezeshkian Alireza Garjani 《Iranian Biomedical Journal》2014,18(2):76-81
Bacground: Evidence from several lines of investigations suggests that Toll-like receptor 4 (TLR4) is involved in atherosclerosis as a bridge between innate and acquired immunity. Percutaneous coronary intervention (PCI) can trigger inflammation through activation of human TLR4 (hTLR4) on monocytes. Hydrocortisone as an anti-inflammatory and immuno-suppressant agent has multiple mechanisms of action. In this study, we aimed at assessing the effects of hydrocortisone on monocyte expression and activity of hTLR4 in patients underwent PCI. Methods: Blood samples were taken from a total of 71 patients with chronic stable angina who were scheduled for a PCI, before the intervention. Thirty patients received 100 mg hydrocortisone prior to the procedure. Control group was composed of 41 patients underwent PCI without receiving hydrocortisone. Blood collection was repeated 2 and 4 h after PCI. The expression of hTLR4 on the surface of CD14+ monocytes and the serum levels of TNF-α and IL-1β were measured using flowcytometry and Sandwich ELISA. Results: Compared with controls, hydrocortisone significantly reduced monocyte expression of hTLR4 in test group (P<0.01). In addition, it had a significant effect on reduction of serum concentrations of TNF-α and IL-1β in test group in a time-dependent manner (P<0.01). Conclusion: In this study, hydrocortisone was able to reduce the hTLR4/CD14 positive monocytes and its related pro-inflammatory cytokines, thus it can decrease inflammatory responses following PCI. Key Words: Toll-like receptor 4, Cytokines, Hydrocortisone 相似文献
183.
184.
Studying the impregnation and distribution of oil-based preservative in dried wood is complicated as wood is a nonhomogeneous, hygroscopic and porous material, and especially of anisotropic nature. However, this study is important since it has influence on the durability of wood. To enhance the durability of thermally modified wood, a new method for preservative impregnation is introduced, avoiding the need for external pressure or vacuum. This article presents a study on preservative distribution in thermally treated Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) sapwood using computed tomography scanning, light microscopy, and scanning electron microscopy. Secondary treatment of thermally modified wood was performed on a laboratory scale by impregnation with two types of preservatives, viz. Elit Träskydd (Beckers) and pine tar (tar), to evaluate their distribution in the wood cells. Preservative solutions were impregnated in the wood using a simple and effective method. Samples were preheated to 170 °C in a drying oven and immediately submerged in preservative solutions for simultaneous impregnation and cooling. Tar penetration was found higher than Beckers, and their distribution decreased with increasing sample length. Owing to some anatomical properties, uptake of preservatives was low in spruce. Besides, dry-induced interstitial spaces, which are proven important flow paths for seasoned wood, were not observed in this species. 相似文献
185.
Sajjad Mansouri Ali Ashraf Mehrabi Danial Kahrizi 《Journal of Crop Science and Biotechnology》2013,16(3):197-200
A collection of sixty-three accessions of Ae. tauschii belonging to different eco-geographical regions were used to evaluate its genetic diversity by 15 morphological characters. The data recorded were analyzed on all accessions using multivariate analyses. Principal component analysis (PCA) indicated that first six principal components with eigenvalues more than 1 explained 77.2% of the variability amongst accessions. Through cluster analysis according to Euclidian distance and UPGMA method, accessions divided into three groups. Knowledge of genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources. 相似文献
186.
Hojjat-Allah Abbaszadeh Taki Tiraihi Ali Reza Delshad Majid Saghedi Zadeh Taher Taheri 《Iranian Biomedical Journal》2013,17(2):62-70
Background: The present study investigated the functional maturity of oligodendrocyte derived from rat bone marrow stromal cells (BMSC). Methods: The BMSC were isolated from female Sprague-Dawley rats and evaluated for different markers, such as fibronectin, CD106, CD90, Oct-4 and CD45. Transdifferentiation of OLC from BMSC was obtained by exposing the BMSC to DMSO and 1 µM all-trans-retinoic acid during the pre-induction stage and then induced by heregulin (HRG), platelet-derived growth factor AA (PDGFR-α), fibroblast growth factor and T3. The neuroprogenitor cells (NPC) were evaluated for nestin, neurofilament 68, neurofilament 160 and glial fibrillary acidic protein gene expression using immunocytochemistry. The OLC were assessed by immunocytochemistry for O4, oligo2, O1 and MBP marker and gene expression of PDGFR-α was examined by RT-PCR. Results: Our results showed that the fibronectin, CD106, CD90, CD45 and Oct-4 were expressed after the fourth passage. Also, the yield of OLC differentiation was about 71% when using the O1, O4 and oligo2 markers. Likewise, the expression of PDGFR-α in pre-oligodendrocytes was noticed, while MBP expression was detected in oligodendrocyte after 6 days of the induction. Conclusion: The conclusion of the study showed that BMSC can be induced to transdifferentiate into mature OLC. Key Words: Bone marrow stromal cell, Triiodothyronine, Platelet-derived growth factor α 相似文献
187.
Arash Zaminy Mohammad Ali Shokrgozar Yousef Sadeghi Mohsen Noroozian Mohammad Hassan Heidari Abbas Piryaei 《Iranian Biomedical Journal》2013,17(3):113-122
Background: Spinal cord has a limited capacity to repair; therefore, medical interventions are necessary for treatment of injuries. Transplantation of Schwann cells has shown a great promising result for spinal cord injury (SCI). However, harvesting Schwann cell has been limited due to donor morbidity and limited expansion capacity. Furthermore, accessible sources such as bone marrow stem cells have drawn attentions to themselves. Therefore, this study was designed to evaluate the effect of bone marrow-derived Schwann cell on functional recovery in adult rats after injury. Methods: Mesenchymal stem cells were cultured from adult rats’ bone marrow and induced into Schwann cells in vitro. Differentiation was confirmed by immunocytochemistry and RT-PCR. Next, Schwann cells were seeded into collagen scaffolds and engrafted in 3 mm lateral hemisection defects. For 8 weeks, motor and sensory improvements were assessed by open field locomotor scale, narrow beam, and tail flick tests. Afterwards, lesioned spinal cord was evaluated by conventional histology and immunohistochemistry. Results: In vitro observations showed that differentiated cells had Schwann cell morphology and markers. In this study, we had four groups (n = 10 each): laminectomy, control, scaffold and scaffold + Schwann cells. Locomotor and sensory scores of cell grafted group were significantly better than control and scaffold groups. In histology, axonal regeneration and remyelination were better than control and scaffold groups. Conclusion: This study demonstrates that bone marrow-derived Schwann cells can be considered as a cell source for Schwann cells in SCI treatment. Key Words: Rats, Spinal cord injuries (SCI), Bone marrow, Schwann cells, Cell transdifferentiation 相似文献
188.
Samira Daniali Arezo Nahavandi Zahra Madjd Ali Shahbazi Somayeh Niknazar Delavar Shahbazzadeh 《Iranian Biomedical Journal》2013,17(3):134-139
Background: Ritalin has high tendency to be abused. It has been the main indication to control attention deficit hyperactivity disorder. The college students may seek for it to improve their memory, decrease the need for sleep (especially during exams), which at least partially, can be related to serotonergic system. Therefore, it seems worthy to evaluate the effect of Ritalin intake on mature brain. There are many studies on Ritalin effect on developing brain, but only few studies on adults are available. This study was undertaken to find Ritalin effect on serotonin transporter (SERT) density in medial frontal cortex (MFC) of mature rat. Methods: Thirty male Wistar rats were used in the study. Rats were assigned into five groups (n = 6 per group): one control, two Ritalin and two vehicle groups. Twelve rats received Ritalin (20 mg/kg/twice a day) orally for eleven continuous days. After one week of withdrawal and another two weeks of rest, in order to evaluate short-term effects of Ritalin, six rats were sacrificed. Another six rats were studied to detect the long-term effects of Ritalin; therefore, they were sacrificed 12 weeks after the previous group. The immunohistochemistry was performed to evaluate the results. Results: Immunohistochemistry studies showed a higher density of SERT in both 2 and 12 weeks after withdrawal from Ritalin intake in MFC of rat and there was no significant difference between these two groups. Conclusions: Our findings demonstrated both short- and long-term effects of Ritalin on frontal serotonergic system after withdrawal period.Key Words: Ritalin, Serotonin, Rats 相似文献
189.
Delamination is the most common failure mode in laminated composites due to the reduced strength in the through-the-thickness direction. Air-jet texturing was used to provide more surface contact between the fibres and the resin by producing bulk and loops in the yarn. The development and characterization of core-and-effect textured glass yarns and the effect of texturing on the mechanical properties of laminated composites were presented in the previous papers. This paper describes the effect of texturing on the inter-laminar fracture toughness (Mode I) of glass laminated composites. The composites of twill weave fabrics were developed from both the textured and non-textured yarn and fracture toughness is tested in warp and weft directions. Significant improvement was observed in the Mode I fracture toughness of the composites after texturing. The bulkier, loopy structure of the textured yarn provided more surface contact between the fibre and the resin and significantly improved the bonding strength. 相似文献
190.