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951.
Unsymmetrical dimethylhydrazine and monomethylhydrazine are the two well‐known liquid propellants. Substantial amounts of sodium chloride present in the aqueous unsymmetrical dimethylhydrazine and monomethylhydrazine reaction liquors. Pervaporation experiments have been conducted using dense chitosan membrane for desalting of these reaction liquors. The effect of membrane thickness, salt concentration in the feed, and permeate pressures on flux and % rejection have been studied and discussed to optimize the conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 141–149, 1999 相似文献
952.
Thin polymer films were prepared under ultraviolet radiation with a triacrylated aliphatic urethane oligomer that was diluted with reactive monomers such as N‐vinyl pyrrolidone and tripropylene glycol diacrylate. These films were characterized. The effect of incorporation of a minute amount (>0.15%) of a titanium–pyridine complex and its ligands on the characterization of these polymers was investigated. Cotton and jute yarns were treated with the solutions containing these materials under the UV radiation. The change in tensile properties of the treated natural polymers (cotton and jute) was evaluated, and it was found that the titanium–pyridine‐based complex substantially enhanced the tensile strengths (tenacity) for both cotton and jute. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1131–1138, 1999 相似文献
953.
Sydney L. Lane Jason C. Parks Jennifer E. Russ Shaihla A. Khan William B. Schoolcraft Ye Yuan Mandy G. Katz-Jaffe 《International journal of molecular sciences》2021,22(23)
Ovarian aging is associated with elevated oxidative stress and diminished oocyte developmental competence. We aimed to determine the impact of systemic antioxidant treatment in aged mice. Female outbred CF-1 mice were aged for 9 months prior to an 8-week 45 mg Euterpe oleracea (açaí) daily supplement. The açaí treatment induced a threefold increase in serum antioxidant power (FRAP) compared to both young and aged mice (p < 0.0001). Compared to young mice, aged mice had fewer oocytes and reduced blastocyst development (p < 0.0001); açaí did not affect the oocyte numbers, but improved blastocyst formation (p < 0.05). Additionally, açaí alleviated the aging-related decrease in implantation potential (p < 0.01). The aged mice showed evidence of elevated ovarian ER stress (increased whole-ovary PDIA4 expression, granulosa cell and oocyte GRP78 expression, and oocyte PDIA4 protein), reduced oocyte mitochondrial quality (higher PRKN activation and mitochondrial DNA oxidative damage), and dysregulated uterine glandular epithelium. Antioxidant intervention was sufficient to lessen these effects of ovarian aging, likely in part by the upregulation of NRF2. We conclude that açaí treatment is a promising strategy to improve ER and mitochondrial function in the ovaries, thereby ameliorating the decreased oocyte competence that occurs with ovarian aging. 相似文献
954.
Zachary Welsh Matthew J. Simpson Md Imran H. Khan M. A. Karim 《Comprehensive Reviews in Food Science and Food Safety》2018,17(5):1293-1308
Plant‐based food materials are mostly porous in nature and heterogeneous in structure with huge diversity in cellular orientation. Different cellular environments of plant‐based food materials, such as intercellular, intracellular, and cell wall environments, hold different proportions of water with different characteristics. Due to this structural heterogeneity, it is very difficult to understand the drying process and associated morphological changes during drying. Transport processes and morphological changes that take place during drying are mainly governed by the characteristics of and the changes in the cells. Therefore, to predict the actual heat and mass transfer process that occurs in the drying process and associated morphological changes, development of multiscale modeling is crucial. Multiscale modeling is a powerful approach with the ability to incorporate this cellular structural heterogeneity with microscale heat and mass transfer during drying. However, due to the huge complexity involved in developing such a model for plant‐based food materials, the studies regarding this issue are very limited. Therefore, we aim in this article to develop a critical conceptual understanding of multiscale modeling frameworks for heterogeneous food materials through an extensive literature review. We present a critical review on the multiscale model formulation and solution techniques with their spatial and temporal coupling options. Food structure, scale definition, and the current status of multiscale modeling are also presented, along with other key factors that are critical to understanding and developing an accurate multiscale framework. We conclude by presenting the main challenges for developing an accurate multiscale modeling framework for food drying. 相似文献
955.
Luqman Jameel Rather Shahid-ul-Islam Mohd Shabbir Mohd Nadeem Bukhari Mohd Ali Khan 《Journal of Natural Fibers》2018,15(4):611-623
This study was undertaken to propose an alternative use of Adhatoda vasica leaves extract as a potential source of natural dye for the coloration of woolen yarn/fibers. Premordanting technique was adopted with double metal salt combinations of ferrous sulfate, stannous chloride, and potassium aluminum sulfate and double biomordant combinations of gallnut, pomegranate, and babool, to achieve dyed textile materials of acceptable colorimetric and fastness properties. Sixty-three sober and elegant shades were developed on wool by varying the nature and the concentration of mordants involved in the combinations. The hue of color developed was found to be in yellow-red coordinate of color space diagram. All the dyed samples presented excellent color strength (K/S) values and highest values were found in case of gallnut + pomegranate peel extract (PPE) combination. Biomordants produced altogether different behavior in comparison to metal mordants in the development of ecofriendly shades of different hue and tune. Majority of the dyed samples showed excellent fastness properties with respect to light, washing, and rubbing which confirmed the possibility of using A. vasica leaves extract as an effective yellow natural dye. 相似文献
956.
957.
Harikishor Kumar Meghanshu Vashista Mohd. Zaheer Khan Yusufzai 《Transactions of the Indian Institute of Metals》2018,71(8):2025-2033
Although copper has its use in many industrial and functional applications, but its low wear resistance limits its potential application. Hard particulates are generally reinforced in bulk copper to increase its wear resistance but it tend to decrease its toughness. Thus the present research focuses on synthesis of copper based surface composite by friction stir processing. Zircon sand was used as reinforcement in copper as it is hard and fairly inexpensive. To prepare the composites, a groove of defined dimension was machined in the copper plate for compaction of zircon sand (18 vol%) at the centre of the plate. After filling the zircon sand in grooves, friction stir processing technique was employed to reinforce it in copper. For microstructure analysis, XRD, microhardness and wear characterization, specimens were cut from the processed portion of the plate. The micrograph obtained by optical and scanning electron microscope revealed equiaxed and fine grain structure in stir zone with no sign of concentration gradient, aggregation and segregation of particles. XRD pattern revealed no peaks corresponding to intermetallics or interfacial reaction products. The microhardness and wear resistance of fabricated surface composite improved significantly as compared to pure copper. The micrograph of worn surface was also analysed to investigate the predominant wear mechanisms. Adhesion and delamination wear were predominant wear mechanisms in pure copper whereas these wear mechanism was not significant in Cu/Zircon composite. 相似文献
958.
In this paper, we propose a novel coverless image steganographic scheme based on a generative model. In our scheme, the secret image is first fed to the generative model database, to generate a meaning-normal and independent image different from the secret image. The generated image is then transmitted to the receiver and fed to the generative model database to generate another image visually the same as the secret image. Thus, we only need to transmit the meaning-normal image which is not related to the secret image, and we can achieve the same effect as the transmission of the secret image. This is the first time to propose the coverless image information steganographic scheme based on generative model, compared with the traditional image steganography. The transmitted image is not embedded with any information of the secret image in this method, therefore, can effectively resist steganalysis tools. Experimental results show that our scheme has high capacity, security and reliability. 相似文献
959.
Ruth T. Chepchirchir Ibrahim Macharia Alice W. Murage Charles A. O. Midega Zeyaur R. Khan 《Food Security》2017,9(6):1359-1372
The paper evaluates the impact of adoption of push-pull technology (PPT) on household welfare in terms of productivity, incomes and poverty status measured through per-capita food consumption in eastern Uganda. Push-pull is a habitat management strategy for the integrated management of stemborers, striga weeds and poor soil fertility involving the use of a natural repellent (push) and an attractant (pull). This biological technology simultaneously reduces the impact of three major production constraints to cereal-livestock farming in Africa ? pests, weeds and poor soil. Cross sectional survey data were collected from 560 households in four districts in the region (Busia, Tororo, Bugiri and Pallisa), in November and December 2014. Generalized propensity scoring (GPS) was used to determine the intensity of adoption of the technology (i.e., land area allocated to PPT) and also to estimate the dose-response function (DRF) relating intensity of adoption and household welfare. Results revealed that with increased intensity of reported adoption of PPT, the probability of being poor declined through increased maize yield per unit area, incomes, and per capita food consumption. However, its impact varied with the intensity of adoption. With an increase in the area allocated to PPT from 0.025 to 1 acre, average maize yield per unit area increased from 27 kg to 1400 kg, average household income increased from 135 US$ (Uganda Shilling (USh) 370,000) to 273 US$ (USh 750,000) and per capita food consumption increased from 15 US$ (USh 40,000) to 27 US$ (USh 75,000). The average probability of a household being poor (below a rural poverty line of US$ 12.71) declined from 48% to 28%. These findings imply that increased investment in the dissemination and expansion of PPT is essential for poverty reduction among smallholder farmers in Uganda. 相似文献
960.
Huiquan Wu Erik Read Maury White Brittany Chavez Kurt Brorson Cyrus Agarabi Mansoor Khan 《Frontiers of Chemical Science and Engineering》2015,9(3):386-19
Compared to small molecule process analytical technology (PAT) applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufacturing biotechnology drug products. However, the use of inline Fourier transform infrared (FTIR) spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites (including glucose, glutamine, lactate, and ammonia) and protein yield at increasing levels of complexity (simple binary system, fully formulated media, actual bioreactor cell culture process) was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares (PLS) calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2nd derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed. 相似文献