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排序方式: 共有1842条查询结果,搜索用时 31 毫秒
41.
Pooja Sarker Sapan Kumar Sen M.N.H. Mia M.F. Pervez A.A. Mortuza Sazzad Hossain M.F. Mortuza M.H. Ali Salahuddin Nur Humayun Kabir M.A.M. Chowdhury 《Ceramics International》2021,47(3):3626-3633
This study reports the influences of gamma irradiation (GI) in the range of 20–100 kGy on CuO thin films via thermal spray pyrolysis technique on the glass substrates. The results demonstrate significant influences of GI on the crystallographic, microstructural and optical characteristics of CuO thin films. The obtained XRD results showed that the crystallinity of the films deteriorates by gradually decreasing crystallite size (from 59.13 to 46 nm) as applied gamma doses increases. However, the basic monoclinic crystal structure remains same. The dislocation density and lattice strain increased with the rise of GI absorbed dose due to the creation of defects. The values of number of crystallites per unit surface area increased as dose increased indicating the abundance of crystallization of nano CuO thin films. A UV–Vis–NIR spectrophotometer was utilized to determine the optical properties and obtained results indicated that the optical energy band gap (OBG) energies reduced from 2.00 to 1.72 eV as the doses increased from 0 to 100 kGy. No distinctions of the monoclinic phase of virgin CuO thin film have been perceived under applied absorbed doses, notwithstanding the slight deterioration of the crystallinity and narrowing the OBG. 相似文献
42.
Xin Jin Chang‐Sei Kim Guy A. Dumont J. Mark Ansermino Jin‐Oh Hahn 《International Journal of Adaptive Control and Signal Processing》2017,31(2):240-254
This paper presents a semi‐adaptive control approach to closed‐loop medication infusion problems. The rationale underlying this approach is to design a controller that can adapt model parameters with a large impact on the model's fidelity while fixing the remaining parameters at nominal values. In this paper, a control‐oriented model for this purpose is derived via system identification and sensitivity analysis of a low‐order model capturing the direct dose‐response relationship Using the model thus derived, a model‐reference adaptive controller and a composite adaptive controller are designed and compared with each other. In‐silico simulation results using remifentanil's effect on respiratory rate as an example indicate that both controllers can regulate the output at commanded set points. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
43.
《Journal of Nuclear Science and Technology》2013,50(11):836-838
Flow around a circular, square and trapezoid-type turbulence promoter was studied putting it in a center of channels or on a wall for low Reynolds number. Frequencies and power spectrum intensities of shedding vortices behind a promoter were measured. Results show that vortices behind the trapezoid cylinder were the strongest and the widest. Flow characteristics behind the trapezoid cylinder were similar to that behind the circular cylinder. Vortices behind the square cylinder were the weakest and the narrowest. Adequate shape of turbulence promoter for augmentation of heat transfer was discussed. 相似文献
44.
《Drug development and industrial pharmacy》2013,39(12):1504-1511
Objectives: To evaluate physicochemical properties of two micronized drugs, salbutamol sulfate (SS) and beclomethasone dipropionate (BDP) prepared as dry powder inhalation physical blends. Methods: Five different blends of SS:BDP ratios of 0:100, 25:75, 50:50, 75:25, and 100:0 (w/w) were prepared. Aerosolization performance was evaluated using a multistage impinger and a Rotahaler® device. Results: The median SS particle diameter was larger than BDP (4.33?±?0.37 µm compared to 2.99?±?0.15 µm, respectively). The SS appeared to have a ribbon-like morphology, while BDP particles had plate-like shape with higher cohesion than SS. This was reflected in the aerosolization performance of the two drugs alone, where SS had a significantly higher fine particle fraction (FPF) than BDP (12.3%, 3.1% and 2.9%, 0.2%, respectively). The study of cohesion versus adhesion for a series of SS and BDP probes on SS and BDP substrates suggested both to be moderately adhesive, verified using scanning Raman microscopy, where a physical association between the two was observed. A plot of loaded versus emitted dose indicated that powder bed fluidization was significantly different when the drugs were tested individually. Furthermore, the FPF of the two drugs from the binary blends, at all three ratios, were similar. Conclusions: Such observations indicate that when these two drugs are formulated as a binary system, the resulting powder structure is altered and the aerosolization performance of each drug is not reflective of the individual drug performance. Such factors could have important implications and should be considered when developing combination dry powder inhalation systems. 相似文献
45.
Paul M. Young Rania O. Salama Bing Zhu Gary Phillips John Crapper Hak-Kim Chan 《Drug development and industrial pharmacy》2015,41(5):859-865
A series of co-engineered macrolide–mannitol particles were successfully prepared using azithromycin (AZ) as a model drug. The formulation was designed to target local inflammation and bacterial colonization, via the macrolide component, while the mannitol acted as mucolytic and taste-masking agent. The engineered particles were evaluated in terms of their physico-chemical properties and aerosol performance when delivered via a novel high-payload dry powder Orbital? inhaler device that operates via multiple inhalation manoeuvres. All formulations prepared were of suitable size for inhalation drug delivery and contained a mixture of amorphous AZ with crystalline mannitol. A co-spray dried formulation containing 200?mg of 50:50?w/w AZ: mannitol had 57.6%?±?7.6% delivery efficiency with a fine particle fraction (≤6.8?µm) of the emitted aerosol cloud being 80.4%?±?1.1%, with minimal throat deposition (5.3?±?0.9%). Subsequently, it can be concluded that the use of this device in combination with the co-engineered macrolide–mannitol therapy may provide a means of treating bronchiectasis. 相似文献
46.
Zahra Bakhtiary Jaleh Barar Ayuob Aghanejad Amir Ata Saei Elhameh Nemati 《Drug development and industrial pharmacy》2017,43(8):1244-1253
Non-small cell lung cancer (NSCLC) patients with sensitizing mutations in the exons 18–21 of the epithelial growth factor receptor (EGFR) gene show increased kinase activity of EGFR. Hence, tyrosine kinase inhibitors (TKIs) such as erlotinib (ETB) have commonly been used as the second line therapeutic option for the treatment of metastatic NSCLC. While the ETB is available as an oral dosage form, the local delivery of this TKI to the diseased cells of the lung may ameliorate its therapeutic impacts. In the current study, we report on the development of ETB-loaded solid lipid nanoparticle (SLN) based formulation of dry powder inhaler (ETB-SLN DPI). ETB-SLNs were formulated using designated amount of compritol/poloxamer 407. The engineered ETB-SLNs showed sub-100?nm spherical shape with an encapsulation efficiency of 78.21%. MTT assay and DAPI staining revealed that the ETB-SLNs enhanced the cytotoxicity of cargo drug molecules in the human alveolar adenocarcinoma epithelial A549 cells as a model for NSCLC. To attain the ETB-SLN DPI, the ETB-SLNs were efficiently spray dried into microparticles (1–5?μm) along with mannitol. The ETB-SLN DPI powder displayed suitable flowability and aerodynamic traits. The Carr's Index, Hausner ratio and Next Generation Impactor (NGI) analyses confirmed deep inhalation pattern of the formulation. Based on these findings, we propose the ETB-SLN DPI as a promising treatment modality for the NSCLC patients. 相似文献
47.
《Drug development and industrial pharmacy》2013,39(3):205-212
The aim of this study was to compare, using gamma scintigraphy, the lung deposition of a novel mucoactive agent, Nacystelyn (NAL), administered as a dry powder inhaler (DPI) in six healthy volunteers, six adult patients with cystic fibrosis (CF), and six children and adolescents patients with CF. The correlation between in vitro and in vivo results was also tested. It was first demonstrated that the method of labeling of NAL with 99mTc was reliable as tested by three in vitro methods (multistage liquid impinger, multistage cascade impactor, and 2-stage glass impinger). The deposition of unlabeled NAL, labeled NAL, and the radiolabel was similar in all stages of each device. Furthermore, the fine particle fraction (FPF) was the same on all apparatuses. The mean lung deposition obtained in volunteers was 27.5 ± 13.5%. The results are approximately three times higher than the results obtained previously in healthy volunteers with NAL metered-dose inhalers (MDIs). As expected, the lung deposition observed in patients with CF was lower, e.g., 23.5 ± 7.0% for adults and 16.5 ± 5.9% for children and adolescents. A significant correlation was found between lung deposition and both the patient weight (p < 0.02) and height (p < 0.04). Surprisingly, the peripheral:central (P:C) ratio was similar for the three populations, indicating that the presence of mucus in moderately ill patients with CF does not modify the lung distribution of NAL. The FPF measured in vitro was similar to that obtained in volunteers but higher than that found in both patient populations. The DPI formulation of NAL developed will probably improve patient compliance and comfort in future clinical trials and postmarketing use of the drug. 相似文献
48.
49.
为了研究电子辐照导致CCD参数退化的损伤机理,以及CCD内不同沟道宽长比的NMOSFET的辐射效应,将与CCD同时流片的两种不同沟道宽长比的深亚微米NMOSFET进行电子辐照实验。分析了电子辐照导致NMOSFET阈值电压和饱和电流退化的情况,以及器件的辐射损伤敏感性。实验结果表明,电子辐照导致两种NMOSFET器件的参数退化情况以及辐射损伤敏感性类似。导致器件参数退化的主要原因是界面陷阱电荷,同时氧化物陷阱电荷表现出了一定的竞争关系。实验结果为研究CCD电子辐照导致的辐射效应提供了基础数据支持。 相似文献
50.
N. G. Shiva Prasad G. V. Ashok H. M. Mahesh 《The International journal of environmental studies》2013,70(1):83-92
Potable waters from various locations of the Bangalore environment were investigated for their 222Rn concentrations by the emanometry method. About 94 groundwater (borewell) samples were analysed for 222Rn concentrations and found to vary in the range 5.3–283.4 Bq L?1 with a mean value of 87 Bq L?1. Frequency distribution showed the 222Rn concentration in a large number of samples in the range of 0–50 Bq L?1. From the measured concentrations, the effective doses (lung and stomach) for the population of the region were estimated. The effective dose was found to vary from 42.6 to 2280.2 µSv y?1 with a mean value 702.5 µSv y?1. The effect of boiling of water showed a drastic reduction in the 222Rn concentration. The results of the present investigation are systematically analysed, compared with the literature values and discussed. 相似文献