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991.
Souzan Saad Latif Abd El‐Alim Andrea Lugasi Judit Hvri Ern Dworschk 《Journal of the science of food and agriculture》1999,79(2):277-285
The effect of dried spices and the ethanol extract of those spices was studied on the stability of fresh chicken minced meat, and fresh and cooked pork patties pretreated with NaCl during refrigerated and frozen storage. The antioxidant activities of the spices were measured by thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) in meat samples. The lipid oxidation was effectively inhibited in the chicken meat treated with several dry spices diminishing the TBARS to a range of 32% and 83% of those found in the control samples in frozen stored meat for 6 months. Marjoram, wild marjoram and caraway were the most effective dry spices. Ethanolic extracts of the same spices were more potent as antioxidants by lowering the concentration of the TBARS to a range of 20–27% of those found in the control samples. Addition of sodium salt to the minced pork resulted very high concentrations of the oxidation products originated from the polyunsaturated fatty acids. The treatment with ethanolic extract of spices (sage, basil, thyme and ginger) significantly inhibited the lipid peroxidation in refrigerated and chilled pork patties pretreated with NaCl by reducing both POV and TBARS. Heat treatment with microwaves produced significantly elevated levels of both lipid peroxides and TBARS, but the amount of these oxidation products was less than 10% in spice‐treated salted meat samples compared to that in untreated ones. Lipid peroxidation also grew continuously during the storage period at −18°C in raw and cooked samples. Ethanolic extracts of spices had a very strong antioxidative effect inhibiting lipid peroxidation in heat‐treated meat products during frozen storage. The highest antioxidant activity was observed in the case of ginger. High correlation coefficients were found between TBARS and POV both in raw and cooked pork patties (0.86, 0.91, respectively) during frozen storage. It is supposed that these compounds originated from the polyunsaturated fatty acids during oxidation processes but at different stages. Utilization of spices, spice mixtures or spice extracts in semi‐prepared meat products intended to be frozen for up to 6 months or more before consumption is proved to be advantageous in regard of shelf life of the food, as well as of human health, because of the beneficial effect of spices in inhibition of lipid peroxidation during heat treatment and chilling storage. © 1999 Society of Chemical Industry 相似文献
992.
Kinetics of free and glycosylated B6 vitamers,thiamin and riboflavin during germination of pea seeds
The effect of germination on the free and glycosylated B6 vitamers (pyridoxine, pyridoxal, pyridoxamine and glycosylated pyridoxine), thiamin and riboflavin content in pea seed (Pisum sativum L, var Esla) was investigated. In raw peas, the total vitamin B6 content (sum of all vitamers expressed as pyridoxine) was 2.183 mg kg−1 DM. Pyridoxine was found to be the predominant B6 vitamer, while only a little amount of glycosylated pyridoxine, the vitamer with the lowest boiavailability, was observed. Thiamin and riboflavin content in raw peas was found to be 7.614 and 2.110 mg kg −1 DM, respectively. After 6 days of germination, carried out at 20°C, in the dark and with daily rinsing, a significant increase of the total vitamin B6 content, mainly due to the increase of glycosylated pyridoxine, was observed. The content of pyridoxal and riboflavin increased in peas 7.5 and 2 times, respectively, whereas pyridoxine, pyridoxamine and thiamin decreased by 83, 24 and 25%, respectively, at the end of the experiment. Results obtained for these vitamins during pea germination were fitted to modelling curves in order to predict vitamin content for different germination periods. © 1999 Society of Chemical Industry 相似文献
993.
Christopher B Watkins Juan E Manzano‐Mendez Jacqueline F Nock Jianzhi Zhang Kevin E Maloney 《Journal of the science of food and agriculture》1999,79(6):886-890
The influence of cultivar on responses of strawberry fruit to 20 kPa CO2 or air storage at 2 °C was measured for 7 days. CO2 storage increased firmness of all cultivars over air storage, but the degree of increase was affected by cultivar and days in storage. CO2‐treated fruit were lighter colored and less intensely red than air‐treated fruit. Accumulations of acetaldehyde, ethanol and ethyl acetate in CO2‐treated fruit were strongly affected by cultivar, with those in ‘Annapolis’ having the lowest and those in ‘Governor Simcoe’ having the highest concentrations. Genetic variation in this response provides useful material for investigating the metabolic basis of CO2 effects in strawberry fruit. © 1999 Society of Chemical Industry 相似文献
994.
Jieqiong Qin Jianmei Gao Xiaoyu Shi Junyu Chang Yanfeng Dong Shuanghao Zheng Xiao Wang Liang Feng Zhong‐Shuai Wu 《Advanced functional materials》2020,30(16)
Planar integrated systems of micro‐supercapacitors (MSCs) and sensors are of profound importance for 3C electronics, but usually appear poor in compatibility due to the complex connections of device units with multiple mono‐functional materials. Herein, 2D hierarchical ordered dual‐mesoporous polypyrrole/graphene (DM‐PG) nanosheets are developed as bi‐functional active materials for a novel prototype planar integrated system of MSC and NH3 sensor. Owing to effective coupling of conductive graphene and high‐sensitive pseudocapacitive polypyrrole, well‐defined dual‐mesopores of ≈7 and ≈18 nm, hierarchical mesoporous network, and large surface area of 112 m2 g?1, the resultant DM‐PG nanosheets exhibit extraordinary sensing response to NH3 as low as 200 ppb, exceptional selectivity toward NH3 that is much higher than other volatile organic compounds, and outstanding capacitance of 376 F g?1 at 1 mV s?1 for supercapacitors, simultaneously surpassing single‐mesoporous and non‐mesoporous counterparts. Importantly, the bi‐functional DM‐PG‐based MSC‐sensor integrated system represents rapid and stable response exposed to 10–40 ppm of NH3 after only charging for 100 s, remarkable sensitivity of NH3 detection that is close to DM‐PG‐based MSC‐free sensor, impressive flexibility with ≈82% of initial response value even at 180°, and enhanced overall compatibility, thereby holding great promise for ultrathin, miniaturized, body‐attachable, and portable detection of NH3. 相似文献
995.
Ming‐Fong Hsu Tsang‐Yi Wang Chao‐Tang Yu 《Wireless Communications and Mobile Computing》2015,15(9):1368-1375
Cognitive radio (CR) is a newly developed technology for increasing spectral efficiency in wireless communication systems. In the CR networks, there exist two traditional spectrum‐sharing technologies called spectrum overlay and spectrum underlay. A new hybrid overlay/underlay paradigm has also been discussed in the literature. In this work, we create a unified spectrum sensing and throughput analysis model, which is suitable for overlay, underlay, and hybrid overlay/underlay paradigms in the CR networks. In the proposed model, the energy detection scheme is employed for the spectrum sensing in the network in which the co‐channel interference is present among primary users and secondary users (SUs). The SUs' throughput in the proposed CR system model is then analyzed. The simulations are also carried out for demonstrating the performance of overlay, underlay, and hybrid overlay/underlay paradigms. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
996.
Xiao‐Hua Qin Krystyna Labuda Jie Chen Veronika Hruschka Anna Khadem Robert Liska Heinz Redl Paul Slezak 《Advanced functional materials》2015,25(42):6606-6617
Several hemostatic strategies rely on the use of blood components such as fibrinogen and thrombin, which suffer from high cost and short shelf‐life. Here, a cost‐effective synthetic biomaterial is developed for rapid local hemostasis. Instead of using thrombin, thrombin‐receptor‐agonist‐peptide‐6 (TRAP6) is covalently engineered in polyvinyl alcohol (PVA) hydrogels. Soluble PVA‐TRAP6 is first prepared by covalent attachment of cysteine‐containing TRAP6 onto the backbone of PVA‐norbornenes (PVA‐NB) through photoconjugation. Cytotoxicity studies using C2C12 myoblasts indicate that PVA‐NB and PVA‐TRAP6 are nontoxic. Thromboelastography reveals that hemostatic activity of TRAP6 is retained in conjugated form, which is comparable to free TRAP6 solutions with equal concentrations. A 0.1% PVA‐TRAP6 solution can shorten the clotting time (CT) to ca. 45% of the physiological CT. High platelet‐activating efficiency is further confirmed by platelet aggregation assay and flow cytometry (FACS). For potential clinical applications, TRAP6‐presenting hydrogel particulates (PVA‐TRAP6‐P) are developed for local platelet activation and hemostasis. PVA‐TRAP6‐P is prepared by biofunctionalization of photopolymerized PVA‐NB hydrogel particulates (PVA‐NB‐P) with TRAP6. It is demonstrated that PVA‐TRAP6‐P can effectively shorten the CT to ca. 50%. FACS shows that PVA‐TRAP6‐P can activate platelets to a comparable extent as soluble TRAP6 control. Altogether, PVA‐TRAP6‐P represents a promising class of biomaterials for safe hemostasis and wound healing. 相似文献
997.
Surface Chemistry of Vitamin: Pyridoxal 5′‐Phosphate (Vitamin B6) as a Multifunctional Compound for Surface Functionalization 下载免费PDF全文
Jung Seung Lee Kyuri Kim Kihong Lee Joseph P. Park Kisuk Yang Seung‐Woo Cho Haeshin Lee 《Advanced functional materials》2015,25(30):4754-4760
Vitamins are non‐toxic compounds that perform a variety of biological functions and also available in a large quantity. Other than the usage as food supplements, few attempts have been made to use them as functional materials. In this study, we report that vitamin B6, pyridoxal 5′‐phosphate (PLP), is a multi‐functional molecule for oxide surface chemistry. PLP‐immobilized surfaces exhibit superhydrophilicity and even hemophilicity, enhancing proliferation, migration, and differentiation of mammalian cells. Unlike existing molecules used so far in surface modification, PLP has an intrinsic chemical reactivity toward biomacromolecules due to the presence of the aldehyde group. In fact, RGD peptide is covalently tethered onto PLP surfaces directly in one step without any chemical activation. Furthermore, PLP‐functionalized implant device showed rapid bone healing. As vitamin B6 is a FDA approved molecule for human usage, the surface chemistry of vitamin B6 potentially allows a fast route for surface functionalized medical devices into clinic. 相似文献
998.
J. William Boley Edward L. White George T.‐C. Chiu Rebecca K. Kramer 《Advanced functional materials》2014,24(23):3501-3507
In this paper, a direct writing method for gallium‐indium alloys is presented. The relationships between nozzle inner diameter, standoff distance, flow rate, and the resulting trace geometry are demonstrated. The interaction between the gallium oxide layer and the substrate is critically important in understanding the printing behavior of the liquid metal. The difference between receding and advancing contact angles demonstrates that the adhesion of the oxide layer to the substrate surface is stronger than the wetting of the surface by the gallium‐indium alloy. This further demonstrates why free‐standing structures such as the traces described herein can be realized. In addition to the basic characterization of the direct writing process, a design algorithm that is generalizable to a range of trace geometries is developed. This method is applied to the fabrication of an elastomer‐encapsulated strain gauge that displays an approximately linear behavior through 50% strain with a gauge factor of 1.5. 相似文献
999.
Can Bayram John A. Ott Kuen‐Ting Shiu Cheng‐Wei Cheng Yu Zhu Jeehwan Kim Manijeh Razeghi Devendra K. Sadana 《Advanced functional materials》2014,24(28):4492-4496
A method of forming cubic phase (zinc blende) GaN (referred as c‐GaN) on a CMOS‐compatible on‐axis Si (100) substrate is reported. Conventional GaN materials are hexagonal phase (wurtzite) (referred as h‐GaN) and possess very high polarization fields (~MV/cm) along the common growth direction of <0001>. Such large polarization fields lead to undesired shifts (e.g., wavelength and current) in the performance of photonic and vertical transport electronic devices. The cubic phase of GaN materials is polarization‐free along the common growth direction of <001>, however, this phase is thermodynamically unstable, requiring low‐temperature deposition conditions and unconventional substrates (e.g., GaAs). Here, novel nano‐groove patterning and maskless selective area epitaxy processes are employed to integrate thermodynamically stable, stress‐free, and low‐defectivity c‐GaN on CMOS‐compatible on‐axis Si. These results suggest that epitaxial growth conditions and nano‐groove pattern parameters are critical to obtain such high quality c‐GaN. InGaN/GaN multi‐quantum‐well structures grown on c‐GaN/Si (100) show strong room temperature luminescence in the visible spectrum, promising visible emitter applications for this technology. 相似文献
1000.
Hans J. Liebe George A. Hufford Takeshi Manabe 《Journal of Infrared, Millimeter and Terahertz Waves》1991,12(7):659-675
Experimental permittivity data of liquid water, compiled from the open literature, were selectively applied to support a modeling strategy. Frequencies up to 1 THz and atmospheric temperatures are covered with an expression made up by two relaxation (Debye) terms. The double-Debye model reduces to one term when the high frequency limit is set at 100 GHz, and the model can be extended to 30 THz by adding two resonance (Lorentzian) terms. The scheme was carried out by employing nonlinear least-squares fitting routines to data we considered reliable. 相似文献