Effects of nano-silver impregnation on brittleness, physical and mechanical properties of heat-treated hardwoods   总被引：1，自引：1，他引：0  

Hamid Reza Taghiyari  Aliakbar Enayati  Hadi Gholamiyan 《Wood Science and Technology》2013,47(3):467-480

The present study investigates the effect of heat treatment of untreated and nano-silver-impregnated Populus nigra, Populus deltoides and Fagus orientalis on the physical and mechanical properties. Specimens were impregnated with a 200-ppm aqueous silver nanoparticles suspension. Heat treatment was carried out at temperatures of 135 ± 3 °C and 185 ± 3 °C. Nano-silver impregnation aggravated the effects of heat treatment. Although significant in some cases, nano-silver impregnation did not seem to have great effect on physical properties. It may be concluded that although NS impregnation aggravated the effects of heat treatment on solid woods, other factors may also be involved such as the species and density of the wood.  相似文献   

Homocysteine Induces Heme Oxygenase-1 Expression via Transcription Factor Nrf2 Activation in HepG2 Cells     

Monireh Mani  Taghi Golmohammadi  Shahnaz Khaghani  Zahra Zamani  Kayhan Azadmanesh  Reza Meshkani  Parvin Pasalar 《Iranian Biomedical Journal》2013,17(2):93-100

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Bone Marrow Stromal Cell Transdifferentiation into Oligodendrocyte-Like Cells Using Triiodothyronine as a Inducer with Expression of Platelet-Derived Growth Factor α as a Maturity Marker     

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   

Mesenchymal Stem Cells as an Alternative for Schwann Cells in Rat Spinal Cord Injury     

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   

Aberrant Promoter Methylation Profile of Niemann-Pick Type C1 Gene in Cardiovascular Disease     

Masoumeh Afzali  Alireza Nakhaee  Seyed Payman Tabatabaei  Kourosh Tirgar-Fakheri  Mohammad Hashemi 《Iranian Biomedical Journal》2013,17(2):77-83

Background: The protein of Niemann-pick type C1 (NPC1) gene promotes the egress of cholesterol from late endosomes and lysosomes to other cellular compartments and contributes to a process known as reverse cholesterol transport. This study aimed to examine whether promoter methylation of NPC1 is associated with risk of cardiovascular disease (CVD). Methods: Fifty CVD patients and 50 healthy subjects as the control group were recruited in this study. Promoter methylation of NPC1 gene was defined using a nested-methylation specific polymerase chain reaction method. Statistical analyses were done using the chi-square, t-test or ANOVA tests. Results: Our study showed that the frequency of semi-methylated promoter (methylated/unmethylated status) was significantly higher in CVD patients than that in controls (OR = 6.521, 95% CI = 2.211-19.215, P = 0.008). However, a completely methylated promoter (methylated/methylated status) was not detected in any subjects in either of the two groups tested. Additionally, the analysis of clinical data according to the methylation status of NPC1 gene demonstrated that serum levels of total cholesterol, total triglycerides, high low-density lipoprotein cholesterol (LDL-C) and low high-density lipoprotein cholesterol (HDL-C) are influenced by NPC1 methylation, so that subjects with a completely unmethylated promoter (Unmethylated/unmethylated status) held lower levels of total triglycerides, total cholesterol, LDL-C and higher levels of HDL-C. Conclusion: Our findings propose that the NPC1 promoter methylation is a probable mechanism that can result in reduced/impaired NPC1 expression/activity and may thus contribute to progression of CVD. Key Words: Niemann-pick type C1 (NPC1), Promoter methylation, cardiovascular disease  相似文献   

Synthesis and characterization of nanocrystalline CoWO4@silk fibers with antibacterial activity under ultrasound irradiation     

Azadeh Azadbakht  Amir Reza Abbasi  Nourolah Noori  Ezzat Rafiee  Mojtaba Taran 《Fibers and Polymers》2013,14(4):687-692

The present investigation reports the novel synthesis of CoWO₄ nanoparticles@silk fiber under ultrasound irradiation. The effect of temperature, power of ultrasound irradiation and sequential dipping steps in growth of the CoWO₄ particles were studied. Results show a decrease in the particles size as the temperature and power of irradiation decreased. The fibers containing CoWO₄ nanoparticles were tested for their antibacterial efficacy against E. coli and S. aureus and were found to possess significant antibacterial activity. The results show the CoWO₄ nanoparticles@silk with strongest fluorescence characteristics can be obtained in this method. The physicochemical properties of the nanoparticles were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy.  相似文献   

Effect of various parameters on the chemical grafting of amide monomers to poly(lactic acid)     

Abolfazl Zare  Mohammad Morshed  Rouhollah Bagheri  Keikhosro Karimi 《Fibers and Polymers》2013,14(11):1783-1793

Radical melt graft copolymerizations of poly (lactic acid) (PLA) with amide monomers using benzoyl peroxide as an initiator during reactive extrusion is studied. The effects of two monomer types at various concentrations, reaction temperatures and initiator concentrations on the grafting yield are investigated. The results showed that percentage of grafting was significantly enhanced by increasing benzoyl peroxide concentrations up to 12 mpm and then decreased by an increase in the initiator concentration. Furthermore, increasing each monomer concentration up to 450 mpm, improved the grafting yield significantly. Further increase brings about a marked fall in the grafting yield. Fourier Transform Infrared Spectroscopy (FTIR), back titration and nitrogen analyses confirmed that monomers of acrylamide and methacrylamide were successfully grafted onto PLA. The Gel Permeation Chromatography (GPC) data showed that the molecular weight of the grafted PLA samples under optimum conditions does not show any dramatic drop of PLA molecular weight by thermal degradation or hydrolysis of polyester chains, while the polydispersity index is poorly affected by the chemical modification of PLA. Also, the monomer structures affected the grafting yield as well as polymer chain combination. In addition under the same conditions, the grafting yield of acrylamide was more than that of methacrylamide. Thermal properties, molecular weight, density, moisture regain and tensile properties of the samples were also measured.  相似文献   

The effect of carbon black nanoparticles on some properties of air plasma printed cotton/polyamide 6 fabrics     

Mohammad Khajeh Mehrizi  Sayed Majid Mortazavi  Shadpour Mallakpour  Seyed Mansour Bidoki  Michel Vik  Martina Vikova 《Fibers and Polymers》2013,14(10):1620-1626

In this study, cotton/nylon blended fabrics were treated with atmospheric air plasma at various times (30–60 s) and were subsequently printed with pastes containing carbon black nanoparticles. Properties of plasma treated fabrics such as visible-near infrared (Vis-NIR) reflectance, water contact angle, air permeability, and color fastness were measured. It was shown that increasing plasma treatment time decreases reflection level of treated fabrics in Vis-NIR region. Plasma treatment also enhanced the hydrophobicity of cotton/nylon fabrics observed by an increase in water contact angle. Plasma treated samples for 60 s demonstrated lower air permeability than those treated for 30 s. Furthermore, printed samples possessed acceptable levels of fastness against washing, light and crocking.  相似文献   

A comparative study on behavioral,physiological, and adrenal changes in buffaloes during the first stage of labor with normal and difficult parturition     

Derar Refaat Ibraheem Mohammad  Mootaz Ahmad Mohammad Abdel-Rahman 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(1):46-50

The present study was primarily carried out to trace the behavioral, physiological, and adrenal changes during the first stage of labor in cases of dystocia, either in parturient buffalo heifers or cows, and their clinical significance. Of the 118 investigated buffalo herds, 40 cows (dystocia = 20 and eutocia = 20) and 40 heifers (dystocia = 20 and eutocia = 20) were used in this study. Cows approaching actual birth were transferred to a calving box with straw bedding. Behavior of the studied animals was recorded from the time that the animal was moved to the calving box until the emergence of the fetal limbs in the vulval lips. If no progress in parturition was observed within two hours after the rupture of fetal sacs (end of the first stage), these cases were considered as suffering dystocia. As the fetal limbs emerged from the birth canal, animals were examined clinically to determine their average pulse and respiratory rates as well as body temperature. Blood samples were collected to determine the cow/heifers cortisol level. Results of the present study indicated that dystocia was accompanied by disturbed physiological status and cortisol levels. Practical monitoring system of parturient animals, through observing behavioral, physiological, and adrenal aspects during calving, should be regarded to expect dystocia and provide help for the animal in the appropriate time.  相似文献   

Accumulation of heavy metal in Platanus orientalis, Robinia pseudoacacia and Fraxinus rotundifolia     

Sajjad Hosseinzadeh Monfared  Mohammad Matinizadeh  Anoushirvan Shirvany  Ghavamedin Zahedi Amiri  Reza Mousavi Fard  Fariba Rostami 《林业研究》2013,24(2):391-395

Plants are capable of reducing environmental pollutions through uptaking contaminants in their tissues. In the study site, twenty one-year-old leaves and shoots as well as twenty soil samples were sampled and analyzed by Inductively Coupled Plasma (ICP). We investigated the uptaking ability of lead (Pb) and cadmium (Cd) by the leaves and shoots of Platanus orientalis, Robinia pseudoacacia and Fraxinus rotundifolia in Karaj city, the western Tehran, Iran. We also evaluated the total metal accumulation capacity by using metal accumulation index (MAI). Results indicated that there was no significant difference in uptaking contents of Cd and Pb in the leaves among the trees. However accumulation of Cd in shoots of F. rotundifolia and R. pseudoacacia was significantly higher than that of P. orientalis. The accumulation of Pb in shoots of R. pseudoacacia was significantly higher than the other species. The amount of Pb in the soil of the study area was significantly higher than Cd. Concentrations of Cd and Pb in leaves of the three species are in the ranges of 2.4 2.7 mg Kg-1 and 7.1 14.4 mg Kg-1 , respectively. R. pseudoacacia had the highest MAI value for leaves (2.21) and F. rotundifolia had the highest MAI value for shoots (2.4).  相似文献