Effect of kenaf and EFB fiber hybridization on physical and thermo-mechanical properties of PLA biocomposites     

Md. Saiful Islam  Irmawati Binti Ramli  M. R. Hasan  Md. Moynul Islam  Kh. Nurul Islam  Mahbub Hasan  Ahmad Saffian Harmaen 《Fibers and Polymers》2017,18(1):116-121

Kenaf/empty fruit bunch/polylactic acid (kenaf/EFB/PLA) hybrid biocomposites were prepared using hot press technique. The ratio of fiber to polylactic acid was set at 60:40 with 1:1 ratio between kenaf and empty fruit bunch fibers. Physical, mechanical and thermal properties of hybrid biocomposites were subsequently characterized using Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, tensile and water absorption tests. Test results indicated that mechanically stronger fiber was able to support the weaker fiber. Hybrid fiber biocomposite had higher crystallinity as compared to single fiber biocomposite. Water absorption of hybrid composite was higher as compared to single fiber composite. Thermal result revealed that hybridization of fiber was not significantly influence the thermal properties of composites. However, the presence of two different fibers proposed good wettability properties, which could reduce the formation of voids at the fibers-polymer interface and produce composites with high stiffness and strength.  相似文献   

Nitrogen fertilization degrades soil aggregation by increasing ammonium ions and decreasing biological binding agents on a Vertisol after 12 years     

Zichun GUO  Wei LI  Mahbub UL ISLAM  Yuekai WANG  Zhongbin ZHANG  Xinhua PENG 《土壤圈》2022,32(4):629-636

Degraded soil aggregation arising from nitrogen(N) fertilization has been reported in many studies; however, the mechanisms have not yet been clarified.Elucidating the impact of N fertilization on soil aggregation would help to improve soil structure and sustain high crop production. The objective of this study was to determine the impact of long-term N fertilization on soil aggregation and its association with binding and dispersing agents. A 12-year(2008–2019) N fertilization field experiment ...  相似文献   

从陈旧血液提取基因组DNA的改进方法     

古丽娜·艾山  木耶赛尔  马合木提·哈力克 《畜禽业》2010,(12)

目的:建立一种快速、有效、陈旧血样基因组DNA的提取方法。方法:采用SDS,EDTA,Tris,蛋白酶K作细胞裂解剂裂解细胞和细胞核,用Tris饱和酚和氯仿:异戊醇(24:1)直接提取基因组DNA。结果该方法提取陈旧血样基因组DNA的纯度高。结论:本法简便、有效,适用于批量陈旧血样的处理。  相似文献   

Effects of two dietary probiotics (Bacillus subtilis or licheniformis) with two prebiotics (mannan or fructo oligosaccharide) in Japanese eel,Anguilla japonica     

Youngjin Park  Haham Kim  Seonghun Won  Ali Hamidoghli  Md Tawheed Hasan  In‐Soo Kong  Sungchul C. Bai 《Aquaculture Nutrition》2020,26(2):316-327

A 12‐week feeding trial was conducted to investigate the effects of two dietary probiotics; Bacillus subtilis KCTC 2217 or Bacillus licheniformis KCCM 11775 with two prebiotics; mannan oligosaccharide (MOS) or fructooligosaccharide (FOS) in Japanese eel. Fish averaging 12.8 ± 0.47 g (mean ± SD) were randomly distributed into five treatments with triplicate tanks. A basal control diet (CON) and four synbiotic diets supplementing B. subtilis + MOS (BSM), B. subtilis + FOS (BSF), B. licheniformis + MOS (BLM), and B. licheniformis + FOS (BLF). Weight gain and specific growth rate of fish fed all synbiotic diets were higher than those of fish fed CON. Immune‐related gene expression of heat shock protein 70 and immunoglobulin M of fish fed BSF and BLM were significantly higher than those of fish fed CON. Fish fed BSF and BLM had significantly higher intestinal villi length than those of fish fed BLF and CON (p < .05). Disease resistance against Aeromonas hydrophila of fish fed all synbiotic diets were significantly higher than those of fish fed CON (p < .05). Therefore, these results indicated that dietary B. subtilis with FOS (BSF) and B. licheniformis with MOS (BLM) could have beneficial effects on intestinal morphology, and immune‐related gene expression in Japanese eel.  相似文献   

Thyroid hormone‐induced swim bladder and eye maturation are transduced by IGF‐1 in zebrafish embryos     

Mohammad Habibur Rahman Molla  Md T. Hasan  Won J. Jang  Cesar D. Soria Diaz  Patrick Appenteng  Haliliy Marufchoni  Bushra Jahan  Christopher L. Brown 《Aquaculture Research》2019,50(11):3462-3470

Maternally derived thyroid hormones (THs) deposited in yolk promote fish embryogenesis and survival, and understanding early regulatory mechanisms could lead to improved seedstock production. We have tested the hypothesis that some thyroid actions may be mediated by insulin‐like growth factor I (IGF‐1), another promoter of embryo development. Differentiation and performance were assessed in embryos treated with THs in the presence or absence of an IGF‐1 receptor blocking peptide. Treatment with the TH triiodothyronine (T₃) promoted IGF‐1 gene expression at days 1 and 5, and advanced swim bladder and eye development, but blocking the IGF‐1 receptor eliminated the swim bladder and eye effects. Growth and survival at 1 week of age were impaired by the IGF‐1 receptor blocking peptide alone, but concurrent treatment with T₃ partially restored these indices. Our results confirm interaction of T₃ and IGF‐1 regulatory signalling in zebrafish embryogenesis and transduction by IGF‐1 of thyroid‐driven swim bladder and eye maturation.  相似文献   

Stock assessment and management implications of anchovy kilka (Clupeonella engrauliformis) in Iranian waters of the Caspian Sea     

Hasan Fazli  Chang Ik Zhang  Douglas Edward Hay  Chun-Woo Lee 《Fisheries Research》2009,100(2):103-108

Recent changes in sea level of the Caspian Sea and ecological impacts caused by the invasive ctenophore (Mnemiopsis leidyi) have altered the ecosystem. A consequence is the changes in the absolute and relative abundance of the commercially important anchovy kilka (Clupeonella engrauliformis) in Iranian waters. To adjust to this change more rigorous management of this fishery is required. This paper examines the maximum sustainable yield (MSY) and fishing intensity at MSY. The paper presents estimates of f_MSY, yield-per-recruit and spawning biomass-per-recruit under various harvest strategies of F_max, F_0.1 and F_40%. We propose a method for estimating acceptable biological catch (ABC) that accounts for large differences in the quality and quantity of information and available data. The MSY and f_MSY were estimated 44,652 mt (metric tons) and 18,609 vessel × nights (a unit of effort). The ABC was estimated at 2190 mt in 2004. In 2005, however, the catch of anchovy kilka was about 4300, over twice the estimated ABC. In 2008 (from January to October) the catch declined to 220 mt. The analyses indicate that overfishing, especially between 2005 and 2008, is the main reason of the collapse of anchovy kilka in the Caspian Sea.  相似文献   

Employment volatility in lagging and advanced regions: The Italian case     

Hasan Engin Duran  Ugo Fratesi 《Growth and change》2020,51(1):207-233

The presence of cycles characterizes all economic systems, but economic cycles have differentiated spatial impacts. Some regions have broader cycles with respect to the country, while others tend to be less responsive to shocks and hence have narrower cycles. Being exposed to broader cycles, that is, greater volatility, may increase the strain on a regional economic system. This paper investigates the different responsiveness to cyclical forces and volatility of regions in the long run. It does so by using quarterly employment data for the Nuts2 Italian regions over almost 40 years before and during the period 1978–2016. Explored in particular are the cross-regional variations in employment volatility and the reasons for the patterns observed, as well as whether they have changed the following different macroeconomic policy regimes. The paper identifies the break dates of different regimes, and these regime changes will be related to policy modifications, such as the implementation of the European Monetary Union. The determinants of this regional volatility appear to be quite stable, so that the changes in volatility are explained by how these determinants have changed overtime and how they are unevenly distributed in space. In particular, the lagging regions of the country suffer, in addition to lower production and income, from higher volatility due to a structure which is weaker and more unstable. Volatility can hence be an additional issue for lagging regions.  相似文献   

Effects of soil tillage,canola (Brassica napus L.) cultivars and planting date on canola yield,and oil and some biological and physical properties of soil     

Hossein Torabi  Hasan Ali Naghdibadi  Hossein Omidi  Heshmat Amirshekari 《Archives of Agronomy and Soil Science》2013,59(2):175-188

Determination of different agronomical properties including soil-related parameters for enhanced canola (Brassica napus L.) production can be of great significance. Hence, the objectives were to determine the effects of different tillage systems, canola cultivars and different planting dates on: (i) canola yield and oil, and (ii) soil moisture and microbial carbon (C) and nitrogen (N). Two field experiments were planned as split-plot experiments in three replicates. The main plots were different tillage systems including no-tillage (NT), minimum tillage (MT) and conventional tillage (CT), and the subplots were the combination of different canola cultivars (PF and Hyola 401) and different planting dates (PD): 8 and 23 September and 7 October. Soil moisture under CT and PF was significantly less than that of MT and NT, and Hyola 401, respectively. Carbon and N microbial biomass was the highest at NT and on the first PD. The tillage method and planting date also significantly affected canola yield, oil content and the amount, and the number of earthworms. We may conclude that although the amount of yield was the highest at CT, it may be more agronomically sustainable to plant canola under NT or MT earlier during the autumn growing season.  相似文献   

Insecticide resistance compromises the control of Aedes aegypti in Bangladesh     

Hasan Mohammad Al-Amin  Narayan Gyawali  Melissa Graham  Mohammad Shafiul Alam  Audrey Lenhart  Leon E Hugo  Gordana Rašić  Nigel W Beebe  Gregor J Devine 《Pest management science》2023,79(8):2846-2861

BACKGROUND

With no effective drugs or widely available vaccines, dengue control in Bangladesh is dependent on targeting the primary vector Aedes aegypti with insecticides and larval source management. Despite these interventions, the dengue burden is increasing in Bangladesh, and the country experienced its worst outbreak in 2019 with 101 354 hospitalized cases. This may be partially facilitated by the presence of intense insecticide resistance in vector populations. Here, we describe the intensity and mechanisms of resistance to insecticides commonly deployed against Ae. aegypti in Dhaka, Bangladesh.

RESULTS

Dhaka Ae. aegypti colonies exhibited high-intensity resistance to pyrethroids. Using CDC bottle assays, we recorded 2–24% mortality (recorded at 24 h) to permethrin and 48–94% mortality to deltamethrin, at 10× the diagnostic dose. Bioassays conducted using insecticide–synergist combinations suggested that metabolic mechanisms were contributing to pyrethroid resistance, specifically multi-function oxidases, esterases, and glutathione S-transferases. In addition, kdr alleles were detected, with a high frequency (78–98%) of homozygotes for the V1016G mutation. A large proportion (≤ 74%) of free-flying and resting mosquitoes from Dhaka colonies survived exposure to standard applications of pyrethroid aerosols in an experimental free-flight room. Although that exposure affected the immediate host-seeking behavior of Ae. aegypti, the effect was transient in surviving mosquitoes.

CONCLUSION

The intense resistance characterized in this study is likely compromising the operational effectiveness of pyrethroids against Ae. aegypti in Dhaka. Switching to alternative chemical classes may offer a medium-term solution, but ultimately a more sustainable and effective approach to controlling dengue vectors is required. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Antibacterial activity and cytotoxicity of extractives from Uvaria hamiltonii stem bark   总被引：2，自引：0，他引：2  

Asha KN  Chowdhury R  Hasan CM  Rashid MA 《Fitoterapia》2003,74(1-2):159-163

The extracts as well as piperolactum C, goniopedaline, 6beta-hydroxystigmasta-4,22-dien-3-one and a mixture of cis- and trans-4-hydroxymelleins obtained from Uvaria hamiltonii stem bark exhibited mild to moderate in vitro antibacterial activity. The results obtained were compared with a standard antibiotic, kanamycin. In a brine shrimp lethality bioassay the pet-ether, dichloromethane, methanol extracts and a major alkaloid, piperolactum C were found to exhibit mild to moderate cytotoxicity.  相似文献