Incorporation of surface modified graphene nanoplatelets for development of shape memory PLA nanocomposite     

Mohsen Keramati  Ismaeil Ghasemi  Mohammad Karrabi  Hamed Azizi  Mohammad Sabzi 《Fibers and Polymers》2016,17(7):1062-1068

In this study, a temperature sensitive shape memory polymer (SMP) system based on polylactic acid (PLA) has been developed and the effect of graphene nanoplatelets (GNPs) on the shape memory properties was evaluated. Dispersion of GNPs in PLA was improved with the aid of a zwitterionic surfactant. X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the surface modified graphene nanoplatelets (SMGNPs) were exfoliated and homogenously dispersed in the PLA matrix due to enhancement of the polymer-graphene interaction. Mechanical properties of the samples namely stiffness and elasticity were increased upon incorporation of graphene nanoplatelets accompanied by their good dispersion in the PLA matrix. Furthermore, differential scanning calorimetry (DSC) revealed that the nucleation effect of graphene promote the crystallization and noticeably enhanced the degree of crystallinity. Finally, prominent mechanical properties along with high degree of crystallization due to fine dispersion of surface modified graphenes, resulted in drastic improvement in shape memory performance.  相似文献   

In vivo evaluation of gelatin/hyaluronic acid nanofiber as Burn-wound healing and its comparison with ChitoHeal gel     

Bahman Ebrahimi-Hosseinzadeh  Mirsepehr Pedram  Ashrafalsadat Hatamian-Zarmi  Soheila Salahshour-Kordestani  Mahtab Rasti  Zahra Beagom Mokhtari-Hosseini  Mohammad Mir-Derikvand 《Fibers and Polymers》2016,17(6):820-826

The study aims at performing a comparative assessment of two types of burn wound treatment. The present study was designed to prepare crosslinked and blended two natural polymers nanofiber scaffolds using gelatin (GE) and hyaluronic acid (HA). The GE/HA composite nanofibrous membranes with varied GE/HA weight ratio have also been successfully fabricated by an electrospinning method. The average diameter of GE/HA fibers was in the range of 20 to 150 nm. In vivo efficacy was also investigated based on a deep second degree burns model for Wistar rats. At 14 days post-operation, the dermal defect basically recovered its normal condition. A percentage of wound closure of GE/HA composite nanofibrous membranes and ChitoHeal gel reached up to 81.9 % and 77.8 % respectively, compared with 65 % of the untreated control (p<0.05). Also, histological parameters were assessed on postoperative day 7 and 14. The results of in vivo experiments showed that more epidermis was formed in the gel and scaffold groups compared to the control group. The numbers of inflammatory cells in these two groups were also smaller as compared with the control group, which could well be the reason for the delayed healing in the control group.  相似文献   

Wood anatomical changes due to uptake of cadmium and lead from contaminated soils in Acer velutinum seedlings     

Zeynab Shahpoori  Vilma Bayramzadeh  Vahid Reza Safdari  Manoochehr Khan Zarinkafsh  Roghayeh Jirrodnejad  Pedram Attarod 《林业研究》2012,23(3):473-479

We investigated wood anatomical changes due to uptake and accumulation of cadmium and lead from contaminated soils in Acer velutinum Boiss seedlings. Two-year old seedlings were exposed for 180 days to soil concentrations with varying cadmium and lead concentrations. We measured three wood anatomical traits, average vessel area(μm2), vessel number per square millimetre, and vessel lumen area percentage (%). For assessing the cadmium and lead accumulation, we measured the concentrations in the soil, leaf, stem, and root. Average vessel area and vessel lumen area percentage were similar (p>0.05) incontrol and treated seedlings. Vessel number per square millimetre showed a decreasing trend from pith to bark in control and treated seedlings, and the trend was more pronounced in treated seedlings. We conclude that vessel number per square millimetre in A. velutinum is influenced by soil contamination. A. velutinum Boiss is not a suitable species for remediation of soils contaminated by cadmium and lead but it can beused as an indicator of the soil lead contamination, because lead concentrations in seedlings increased with increasing amount of lead in the soil.  相似文献   

The effect of number of joints on bending properties of laminated lumber made from poplar (Populus nigra)     

Ali BAYATKASHKOLI  Mohammad SHAMSIAN  Marjan MANSOURFARD 《中国林学(英文版)》2012,14(3):246-250

Connection plays an important role in structural components and end jointing is one of the most common connections in structural applications.This study was designed to investigate some mechanical properties (MOE and MOR) of solid wood samples manufactured from poplar (Populus nigra),joined together through end jointing.As well,we studied combinations of lumber manufactured from 10-mm veneer,using a polyvinyl acetate adhesive.The results show that non-jointed lumber (control samples) have better bending properties (MOE and MOR) than jointed specimens and lumber made from laminated layers.On the whole,side-byside joints have a negative effect on the MOR and MOE of laminated products,which is more pronounced in the MOR.By increasing the number of joints,the properties of combination of three-ply,i.e.,bending strength and modulus of elasticity,decreased.  相似文献   

Gummosis Disease of Mango and Its Control     

UDDIN Mohammad Sorof  FENG Jiaxun  HE Xinhua  SUN Wenli  CHENG Qi 《中国林业科技(英文版)》2012,(4):25-32

Gummosis is the most serious disease of mango all around the world,which is becoming epidemic in different regions of these countries,can infect almost all the commercial and indigenous varieties of mango,and has been regarded as a new serious threat of mango trees at an alarming ratio.This article reviewed causal organisms,current status,future prospects,and management practices of mango gummosis disease.  相似文献   

Evidence-Based Use of Prokinetic Drugs for Abomasal Disorders in Cattle     

Peter D. Constable  Mohammad Nouri  Ismail Sen  Aubrey N. Baird  Thomas Wittek 《Veterinary Clinics of North America: Food Animal Practice》2012

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Effect of feeding olive-pulp ensiled with additives on feedlot performance and carcass attributes of fat-tailed lambs     

Mohammad Reza Taheri  Mohammad Javad Zamiri  Ebrahim Rowghani  Amir Akhlaghi 《Tropical animal health and production》2012,45(1):345-350

Feed cost has a significant effect on the economic efficiency of feedlot lambs; therefore, the use of low-cost non-conventional feedstuffs, such as olive pulp (OP), has the potential to decrease the production costs. Because optimum inclusion of OP-treated silages has not been determined in feedlot lambs, an experiment was conducted to determine the effect of inclusion of OP ensiled with additives in the diet on the feedlot performance and carcass attributes of feedlot lambs. Ram lambs of Mehraban and Ghezel breeds (n?=?50 lambs per breed) were randomly allotted to 10 groups and fed with one of the nine diets containing OP silage or a control diet. Silage treatments were: (1) OP silage without additives (OPS), (2) OP ensiled with 8 % beet molasses and 0.4 % formic acid (OP-MF), and (3) OP ensiled with 8 % beet molasses, 0.4 % formic acid and 0.5 % urea (OP-MFU). The control diet contained 50 % alfalfa hay and 50 % barley grain. Three levels from each silage were chosen to replace the barley grain (10, 20, or 30 % dry matter basis). The lambs were slaughtered after 92 days, and the average daily gain (ADG), feed conversion ratio (FCR), and carcass characteristics were determined. Feeding OPS to fat-tailed lambs, at an inclusion level of 30 %, decreased the carcass dressing percentage, mainly as a result of decreased brisket percentage, but the ADG and FCR values were not adversely affected. Ghezel lambs had higher ADG than Mehraban lambs, but the visceral fat weight percentage, flap weight percentage, and back fat depth were higher in Mehraban. The crude protein content in the longissimus dorsi (LD) muscle was higher in Ghezel, but the dry matter percentage was higher in Mehraban (P?<?0.05). Other attributes were not significantly affected by breed (P?>?0.05). Most carcass characteristics, including major cuts, were not affected by OPS feeding; therefore, feeding OPS (up to 30 %) can be economical for feedlot lambs. Most carcass characteristics, including major cuts, were not affected by OPS levels used in this experiment; therefore, inclusion of OPS (up to 30 %) in the diet may reduce the cost of raising feedlot lambs. This also could help alleviate the problem of storage of OP in oil factories.  相似文献   

Factors affecting calf mortality in Iranian Holstein dairy herds     

Azizzadeh M  Shooroki HF  Kamalabadi AS  Stevenson MA 《Preventive veterinary medicine》2012,104(3-4):335-340

The objective of this study was to document mortality reasons and risk factors for mortality in dairy calves in the northeast of Iran. This was a prospective cohort study of calves born on ten commercial dairy herds from 21 March 2009 to 20 March 2010. A total of 4097 live calves were followed for 90 days after birth. For each calf details of sex, parity of the dam, type of parturition and season of birth were recorded. The interval (in days) from the date of birth to the date of death and the reason for death was recorded for those calves that died before 90 days of age. A Cox proportional hazards model, including a frailty term to account for unmeasured herd-level effects was developed to quantify the effect of factors associated with time to death. Two hundred and sixty-six (6.5%, 95% CI: 5.8-7.3%) of the 4097 live-born calves died or were euthanised before 90 days of age. The most important reasons for death were digestive tract disorders (58% of all deaths, 95% CI: 52-64%) followed by respiratory diseases (13% of all deaths, 95% CI: 9-17%). Calves exposed to dystocia at birth had 2.09 (95% CI: 1.49-2.92) times the daily hazard of death compared with calves born from a normal calving. The daily hazard of death for calves born in the summer was 1.93 (95% CI: 1.41-2.64) times greater than the hazard for those calves born in the autumn. Inclusion of the herd-level frailty term had a significant effect on hazard estimates indicating that the study herds were heterogeneous in the distribution of unmeasured herd-level factors influencing calf survival. Our results show that diarrhoea is the most important cause of calf mortality in dairy herds in this area of Iran and that environmental and management factors affect calf mortality rate.  相似文献   

Geostatistical Assessment of the Spatial Distribution of Some Chemical Properties in Calcareous Soils   总被引：2，自引：0，他引：2  

Asma Najafian  Mahmood Dayani  Hamid Reza Motaghian  Habibolah Nadian 《中国农业科学(英文版)》2012,(10):1729-1737

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Influence of Diazotrophic Bacteria on Antioxidant Enzymes and Some Biochemical Characteristics of Soybean Subjected to Water Stress     

Hamed Zakikhani  Mohammad Reza Ardakani  Farhad Rejali  Majid Gholamhoseini  Aydin Khodaei Joghan  Aria Dolatabadian 《中国农业科学(英文版)》2012,11(11):1828-1835

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