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排序方式: 共有130条查询结果,搜索用时 12 毫秒
1.
Rizwan Ullah Khan Haojie Yu Li Wang Lisong Teng Zain-ul-Abdin Ahsan Nazir Shah Fahad Tarig Elshaarani Fazal Haq Di Shen 《应用聚合物科学杂志》2020,137(46):49424
The development of safe drug carriers is cardinal in cancer therapy, which can target the cancer cells and release the loaded drug on-demand without damaging the healthy cells of the body. In our work, we synthesized three different biodegradable polymers, poly[(ethyl aminobezoate) (ethyl glycinato) phosphazenes] (PABGPs), in different mole ratio of side groups. The successful synthesis of these PABGPs was confirmed by 1H NMR, 31P NMR, FT-IR, and gel permeation chromatography. These PABGPs were fabricated into drug (camptothecin, CPT, a hydrophobic anticancer drug) loaded nanoparticles. These drug-loaded nanoparticles showed good drug release behaviors under normal physiological conditions (pH 7.4 and temperature 37°C). These PABGPs-based nanoparticles may find their application as effective drug carriers for cancer therapy. 相似文献
2.
P. Naga Srinivasu Shakeel Ahmed Abdulaziz Alhumam Akash Bhoi Kumar Muhammad Fazal Ijaz 《计算机、材料和连续体(英文)》2021,69(3):3303-3319
In the digestion of amino acids, carbohydrates, and lipids, as well as protein synthesis from the consumed food, the liver has many diverse responsibilities and functions that are to be performed. Liver disease may impact the hormonal and nutritional balance in the human body. The earlier diagnosis of such critical conditions may help to treat the patient effectively. A computationally efficient AW-HARIS algorithm is used in this paper to perform automated segmentation of CT scan images to identify abnormalities in the human liver. The proposed approach can recognize the abnormalities with better accuracy without training, unlike in supervisory procedures requiring considerable computational efforts for training. In the earlier stages, the CT images are pre-processed through an Adaptive Multiscale Data Condensation Kernel to normalize the underlying noise and enhance the image’s contrast for better segmentation. Then, the preliminary phase’s outcome is being fed as the input for the Anisotropic Weighted–-Heuristic Algorithm for Real-time Image Segmentation algorithm that uses texture-related information, which has resulted in precise outcome with acceptable computational latency when compared to that of its counterparts. It is observed that the proposed approach has outperformed in the majority of the cases with an accuracy of 78%. The smart diagnosis approach would help the medical staff accurately predict the abnormality and disease progression in earlier ailment stages. 相似文献
3.
Nazish Jahan Saba Aslam Khalil ur Rahman Tuba Fazal Fareeha Anwar Rubab Saher 《Journal of Experimental Nanoscience》2016,11(1):72-80
Nanotechnology is a promising technique to increase the bioavailability of herbal medicines. This paper presents the nanosuspension approach for increasing the aqueous solubility and thereby bioactivity of important herbal extracts. Nanosuspensions of the seeds of three plants extract (Silybum marianum, Elettaria cardamomum and Coriandrum sativum) were prepared by using polyvinyl alcohol (1.5% w/v) as a stabiliser. Prepared nanoparticles were characterised by scanning electron microscope. Activity of nanosuspension formulation was assessed by using four in vitro antioxidant assays. S. marianum, E. cardamomum and C. sativum particle size was observed to fall in range of 446.1 ± 112.6, 456.63 ± 339.2 and 432.1 ± 172.8 nm, respectively, most of the particles were having spherical shape and smooth topology. These synthesised nanoparticles were found to be more effective against quenching free radical than their crude extracts and standards [butylated hydroxyl toluene and ascorbic acid]. C. sativum nanosuspension showed most free radical scavenging potential against 2,2-diphenyl-1-picrylhdrazyl (DPPH) and superoxide free radical scavenging assays (IC50 0.59 ± 0.01 and 0.81 ± 0.11 mg/ml). S. marianum nanosuspension was found to be most effective against DPPH radicals scavenging (IC50 0.34 ± 0.02 mg/ml). It was concluded that nanosuspension of herbal medicines potentiates the antioxidant potential. 相似文献
4.
Biodiesel, as an alternative fuel, is gradually receiving more popularity for use in internal combustion engines. However questions continue to arise with regard to its compatibility with elastomeric materials. The present work aims to investigate the comparative degradation of physical properties for different elastomers [e.g. ethylene propylene diene monomer (EPDM), silicone rubber (SR), polychloroprene (CR), polytetrafluroethylene (PTFE) and nitrile rubber (NBR)] upon exposure to diesel and palm biodiesel. Static immersion tests in B0(diesel), B10 (10% biodiesel in diesel), B20, B50 and B100(biodiesel) were carried out at room temperature (25 °C) for 1000 h. Different physical properties like, changes in weight and volume, hardness and tensile strength were measured at every 250 h of immersion time. Compositional changes in biodiesel due to exposure of different elastomers were investigated by Gas chromatography mass spectroscopy (GCMS). The overall sequence of compatible elastomers in palm biodiesel is found to be PTFE > SR > NBR > EPDM > CR. 相似文献
5.
Abul Fazal M. Arif 《Journal of Mechanical Science and Technology》2009,23(10):2603-2611
Laser shock processing (LSP) involves high-energy laser radiation combined with suitable overlays to generate high-pressure
pulses on the surface of the metal. The stress wave generated due to high pressure pulses propagates into the material causing
the surface layer to yield and plastically deform, and thereby, develop a significant residual compressive stress in the surface
region of the substrate material. The developed compressive stress field is beneficial to improve surface properties such
as fatigue, wear, and corrosion. To improve the understanding of the shock hardening process, investigation into the physical
processes involved is necessary. In the first part of this paper, the temporal variation in the pressure intensity and spot
size is calculated by using a two-dimensional recoil pressure prediction model. Using an explicit non-linear FEA code, ANSYS
LS-DYNA, the deformation behavior and residual stresses in the substrate material are predicted. In the second part, a probabilistic
approach to the modeling and analysis of LSP is presented in this paper. Various factors that affect the probabilistic performance
of the LSP are grouped into categories and a select number of factors known to be significant, for which the variability could
be assessed, are modeled as random variables (such as recoil pressure, laser beam spot size, substrate material properties
and others). The potential of the probabilistic approach in predicting the structural integrity of the laser-shocked components
is addressed. 相似文献
6.
Fazal I. Kumar S. Yunchu Li Christen L. Saghari P. Langrock C. Fejer M.M. Willner A.E. 《Lightwave Technology, Journal of》2008,26(12):1690-1695
We demonstrate a novel method of wavelength conversion in a periodically poled lithium niobate (PPLN) waveguide using polarization modulation and amplitude modulation of its pump. Polarization-insensitive, all-optical, intensity-to-polarization conversion in a semiconductor optical amplifier (SOA) is used to reduce the waveguide's polarization sensitivity from >30 dB to <1 dB. We demonstrate BER measurements of the converted signal at 2.5 Gb/s. We also demonstrate polarization modulation of the PPLN waveguide pump using cross-polarization modulation in highly nonlinear fiber (HNLF) at 10 Gb/s. 相似文献
7.
Elastically prestressed polymeric matrix composites (EPPMCs) are produced by stretching fibers (e.g., glass) within the composite during matrix curing. The resulting prestress can enhance mechanical performance, without increasing section dimensions or weight. Viscoelastically prestressed polymeric matrix composites (VPPMCs) can provide similar benefits, these being produced by subjecting polymeric fibers (e.g., nylon 6,6) to a creep load, which is released prior to molding. Although VPPMCs offer simplified processing and flexibility in product geometry, long‐term viscoelastic activity within the prestressing fibers is sensitive to time‐temperature limitations. In this study, nylon 6,6 fiber‐polyester resin samples were subjected to accelerated ageing. Using time‐temperature superposition, the samples were maintained at 70°C for 2,298 h, representing a 20‐fold ageing increase over previous work. Subsequent Charpy impact testing (at 20°C) demonstrated that the VPPMC samples absorbed ∼40% more energy than corresponding control (unstressed) counterparts; i.e., no deterioration in impact performance was observed, over a duration equivalent to ∼25 years at 50°C. In contrast, the longevity of EPPMCs remains unknown, but it is suggested that progressive localized matrix creep at the fiber‐matrix interface regions may cause a deterioration in elastically generated prestress with time and/or elevated ambient temperatures. POLYM. COMPOS., 37:2092–2097, 2016. © 2015 Society of Plastics Engineers 相似文献
8.
Anodic oxidation is accompanied by stressgeneration during the growth of the oxide. The presentstudy focuses on the stress-generation mechanism onaluminum as a function of the applied current density in acidic solutions of sulfuric acid ofdifferent strengths giving variable pH. Abeam-deflection technique was utilized for thedetermination of the magnitude and direction of stressesgenerated during the anodic oxidation process. Generally,thickness of the oxide determines whether the stress iscompressive or tensile in nature. The results have beeninterpreted in terms of the formation and annihilation of anion (O2-) and cation(Al3+) vacancies. A reduction in thealuminum-ion vacancy concentration (V
Al
3
) results in a compressive stressdeflection, whereas tensile-stress deflection isintroduced by an increase in the oxygen vacancy(Vo2+) concentration. The mechanism isfurther elucidated by current-density jump/dropexperiments. The results show that stress in this caseis affected by the dissolution of the oxide at the oxide-electrolyteinterface. 相似文献
9.
Comparative corrosive characteristics of petroleum diesel and palm biodiesel for automotive materials 总被引:1,自引:0,他引:1
Corrosive characteristics of biodiesel are important for long term durability of engine parts. The present study aims to compare the corrosion behavior of aluminum, copper and stainless steel in both petroleum diesel and palm biodiesel. Immersion tests in biodiesel (B100) and diesel (B0) were carried out at 80 °C for 1200 h. At the end of the test, corrosion characteristic was investigated by weight loss measurements and changes on the exposed metal surface. Surface morphology was examined by optical microscope and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDS). Fuels were analyzed by using TAN analyzer, FTIR, GCMS and ICP in order to investigate the acid concentration, oxidation level with water content, compositional characteristics and presence of metal species respectively. Results show that the extent of corrosion and change in fuel properties upon exposure to metals are more in biodiesel than that in diesel. Copper and aluminum were susceptible to attack by biodiesel whereas stainless steel was not. 相似文献
10.
Saba Gul Mushtaq Ahmad Muhammad Zafar Saraj Bahadur Shazia Sultana Najla Begum Syed Nasar Shah Wajid Zaman Fazal Ullah Asma Ayaz Uzma Hanif 《Microscopy research and technique》2019,82(7):1021-1031
The present study is insight into pollen morphology for characterizing species and their utility in the taxonomic separation of certain taxa of subfamily Nepetoideae (Lamiaceae) from Pakistan. The pollen micromorphology of 11 species of the Nepetoideae was analyzed and documented using light microscopy and scanning electron microscopy (SEM) for both qualitative and quantitative characteristics. Most species have hexazonocolpate pollen grains but trizonocolpate and tetrazonocolpate pollen with circular and oval amb were also rarely observed in Mentha spicata. The basic pollen shape in most of the studied species was subspheroidal but prolate grains were also observed in M. spicata, S. coccinea, and S. plebeia. The exine sculpturing of Nepetoideae pollen was taxonomically very informative particularly at subfamily level. Observations of exine sculpturing with SEM revealed various types of pollen grains: reticulate, bireticulate, microreticulate, perforate, aerolate, and gammate. The bireticulate type further subdivided into three subtypes based on the number of secondary lumina in each primary lumen and is characterized by varying characteristics of the secondary reticulum and primary muri. A significant variation was observed in colpus surface ornamentation. The maximum polar diameter was found in O. americanum (58 ± 5.8 μm) and the maximum equatorial diameter observed in O. basilicum (50.25 ± 1.37 μm). Pollen features of the studied species were discussed and compared based on the current taxonomical concepts. The results showed that pollen traits of the subfamily Nepetoideae was found significant to classify the taxa. Furthermore, pollen features provide additional evidence to distinguish macromorphologically similar taxa from each other. 相似文献