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991.
Hugo Santos Lucas A. Zeoly Rafael Rebechi João Arantes Fernando Coelho Manoel T. Rodrigues Jr. 《Advanced Synthesis \u0026amp; Catalysis》2024,366(4):884-891
Polysubstituted carbazoles were efficiently synthesized through direct benzannulation reaction between 1,4-dicarbonyl compounds and indoles with catalytic amount of inexpensive zirconium(IV) chloride. This transformation proved to be regioselective and furnishes 1,4-disubstituted and 1,2,4-trisubstituted carbazoles with yields ranging from 26% to 91% and broad substrate scope. Moreover, this protocol benefits from using readily accessible starting materials without the need of their pre-functionalization. The synthetic utility of the products was exemplified by functionalization of an iodocarbazole by means of Suzuki-Miyaura reactions and by the synthesis of a 3-deaza-derivative of the natural product canthin-6-one. 相似文献
992.
Hyeonmu Jeon Uk Jo Mingyu Jo Nammoon Kim Youngok Kim 《Wireless Personal Communications》2013,69(4):1535-1550
In recent years, the indoor positioning technologies have been recognized as core technologies for realizing smart space, a ubiquitous society, context awareness, and various location-based services. There are several approaches for positioning with radio signals, but the received signal strength (RSS)-based technology is considered a promising scheme because of its simplicity and practicality in implementation. In this paper, the positioning performance of the RSS value-based scheme is analyzed with respect to the location of access points (APs) and the number of APs in an indoor environment. An adaptive AP selection scheme and a base AP changing scheme are then proposed to enhance the positioning accuracy. In order to estimate the RSS characteristics, RSS values are measured as the distance between the AP and the receiver increases. The positioning performance is evaluated with differing AP numbers, which form a triangle or a quadrilateral. The performance of the proposed schemes is evaluated via experiments using wireless local area network APs. Results show that the performance of proposed schemes is enhanced compared to that of conventional scheme. 相似文献
993.
Pícoli LC Dias FJ Issa JP Ogawa K Ciena A Iyomasa MM Lopes RA Watanabe IS 《Microscopy research and technique》2011,74(12):1154-1160
The fine structure of submandibular glands of mouse were analyzed using light microscopy (LM), high resolution scanning electron microscopy (HRSEM), and transmission electron microscopy (TEM) methods. For LM, the specimens were embedded in Spurr resin, stained by toluidin blue solutions. For TEM, the tissues of submandibular salivary glands were fixed with modified Karnovsky solution and postfixed with osmium tetroxide. For HRSEM, the tissues were fixed with 2% osmium tetroxide solution in 1/15M sodium phosphate buffer (pH 7.4). The samples were immersed successively in dymethylsulphoxide and freeze cracked. The maceration was made in diluted osmium tetroxide for 24-48 h. The samples were examined by high resolution scanning electron microscopy. The intracellular components of acinar and ductal cells revealed clearly the Golgi apparatus, rough endoplasmic reticulum, secretory granules, and mitochondria. The end bulbs of Golgi lamellae and flattened cisterns of rough endoplasmic reticulum showed the luminal surface. A few mitochondria were identified intermingling between the rough endoplasmic reticulum and the mitochondriales cristae in three-dimensional HRSEM images. Secretory granules were numerous and presented different sizes. Small granules of ribosomes were attached on cistern surface, measuring 20-25 nm in diameter. Numerous arranged microvilli were found on the luminal surface of secretory canaliculus. The contact surfaces of acinar cells revealed complicated interdigitations by cytoplasmic processes. The mitochondria of duct cells were disposed vertically and surrounded by basal infoldings of plasma membranes. Basement membrane showed a spongy-like structure having an irregular surface with various strands and meshes of fine collagen fibrils. 相似文献
994.
The widespread usage of technology for service provision to customers has created a new and challenging environment for the
design of interactive systems, with the emergence of technology enabled multi-channel services. Requirements engineers involved
in the design of such service systems must actively work together with interaction designers and service managers to better
integrate customer service experience and technology components, requiring unifying methods and tools within the emerging
field of service science management and engineering. This paper proposes the service experience blueprint (SEB), a multidisciplinary
method for the design of technology enabled multi-channel service systems and illustrates its application in two examples
of redesign of banking services that involved an extensive study with more than 4,000 bank customers. The SEB method is based
on concepts and tools from RE and interaction design, such as goal-oriented analysis and conceptual modeling, but also uses
methods developed in the service and marketing fields, such as service blueprinting. SEB brings marketing research methods
to the requirements process, as they can provide a useful contribution for the elicitation of customer experience requirements
in service environments. By bringing together goal-oriented modeling and use case modeling from requirements engineering,
with service blueprinting from service design, the SEB method contributes to creating a shared understanding and a unifying
language to better support the design of new technology enabled multi-channel service systems, where technology and service
issues are deeply intertwined. 相似文献
995.
Determination of ethyl carbamate in cachaças produced by selected yeast and spontaneous fermentation 下载免费PDF全文
João Guilherme Pereira Mendonça Maria Das Graças Cardoso Wilder Douglas Santiago Leonardo Milani Avelar Rodrigues David Lee Nelson Rafaela Magalhães Brandão Bruno Leuzinger da Silva 《Journal of the Institute of Brewing》2016,122(1):63-68
Cachaça is a beverage produced by the distillation of fermented must from sugarcane. During the manufacturing steps, producers commonly use naturally occurring yeasts in the preparation of the fermentation broth, resulting in spontaneous fermentation. The composition of the resulting beverages can vary greatly, especially if various species and strains of yeast are present. The beverages produced with selected yeast strains are an alternative, leading to the production of more standardized beverages. Ethyl carbamate, which is highly toxic and has carcinogenic potential, is among the possible contaminants. The objectives of this study were to determine the levels of ethyl carbamate in cachaça produced by different types of fermentation and follow its formation during the production stages. The cachaças that contained rice bran as a nutrient during the fermentation stage contained the highest levels of ethyl carbamate throughout the production process and storage. Copyright © 2016 The Institute of Brewing & Distilling 相似文献
996.
Tâmmila Venzke Klug Júnia Novello Daniela Comparsi Laranja Tanira A. S. Aguirre Alessandro de Oliveira Rios Eduardo Cesar Tondo Rinaldo Pires dos Santos Renar João Bender 《Food and Bioprocess Technology》2017,10(2):275-283
Lettuce is often involved in foodborne outbreaks caused by pathogenic Escherichia coli. Current control strategies have often proved ineffective to ensure safe food production. For that reason, the present study compared the efficacy of tannin extracts and chlorine treatments on the reduction of E. coli ATCC 25922 adhered to lettuce leaves. E. coli was inoculated artificially on leaf surfaces of fresh crisp lettuce. Effectiveness of water, chlorine (200 mg/L), and three commercial available tannin extracts from Acacia mearnsii De Wild. (tannin AQ (2 %, w/v), tannin SG (1 %, v/v) and tannin SM (1 %, v/v)) treatments was evaluated using the viable plate count method and scanning electron microscopy (SEM). SEM results revealed that bacterial cells are attached as individual cells and in clusters to the leaf surface after 2 h of incubation. Biofilm formation was observed after 24 h of incubation. The tannin SM treatment was able to reduce counts in approximately 2 log CFU/cm2 on leaf segments. However, treatment was less effective in the reduction of E. coli counts after 24 h of incubation when compared to 2 h incubation of the same extract. The results suggest that the tannin SM extract diminishes E. coli counts adhered to and under biofilm formation on lettuce leaves and its effect is similar to the use of chlorine solutions. 相似文献
997.
Jung Jun Bae Seong Chu Lim Gang Hee Han Young Woo Jo Dinh Loc Doung Eun Sung Kim Seung Jin Chae Ta Quang Huy Nguyen Van Luan Young Hee Lee 《Advanced functional materials》2012,22(22):4819-4826
In spite of recent successful demonstrations of flexible and transparent graphene heaters, the underlying heat‐transfer mechanism is not understood due to the complexity of the heating system. Here, graphene/glass defoggers are fabricated and the dynamic response of the temperature as a function of input electrical power is measured. The graphene/glass defoggers reveal shorter response times than Cr/glass defoggers. Furthermore, the saturated temperature of the graphene/glass defoggers is higher than for Cr/glass defoggers at a given input electrical power. The observed dynamic response to temperature is well‐fitted to the power‐balance model. The response time of graphene/glass defogger is shorter by 44% than that of the Cr/glass defogger. The convective heat‐transfer coefficient of graphene is 12.4 × 10?4 W cm?2 °C?1, similar to that of glass (11.1 × 10?4 W cm?2 °C?1) but smaller than that of chromium (17.1 × 10?4 W cm?2 °C?1). The graphene‐based system reveals the lowest convective heat‐transfer coefficient due to its ideal flat surface compared to its counterparts of carbon nanotubes (CNTs) and reduced graphene oxide (RGO)‐based systems. 相似文献
998.
Mazurek J Salehi E Propes D Holt J Bannerman T Nicholson LM Bundesen M Duffy R Moolenaar RL 《Journal of food protection》2004,67(10):2165-2170
In December 2002, the Ohio Department of Health was notified of two children with Salmonella infection. Both had a history of drinking raw milk from a combination dairy-restaurant-petting zoo (dairy). The dairy was the only establishment in Ohio licensed to sell raw milk and reported 1.35 million visitors annually. We investigated to determine the extent of the outbreak and identify illness risk factors. A case patient was any person with pulsed-field gel electrophoresis-matched Salmonella enterica serotype Typhimurium from 30 November 2002 to 18 February 2003. Sixty-two met the confirmed case definition. Forty dairy case patient patrons were included in a case-control study; 56 controls were their well meal companions. Consumption of raw milk was found to be associated with illness (odds ratio, 45.1; 95% confidence interval, 8.8 to 311.9). The dairy discontinued selling raw milk. Because 27 other states still allow the sale of raw milk, awareness of the hazards of its consumption should be raised and relevant regulations carefully reviewed. 相似文献
999.
Santanu Karan Manuela Nania Zhiwei Jiang Alexandra E. Porter Andrew G. Livingston João T. Cabral 《Advanced functional materials》2017,27(37)
The structure and hydration of polyamide (PA) membranes are investigated with a combination of neutron and X‐ray reflectivity, and their performance is benchmarked in reverse osmosis water desalination. PA membranes are synthesized by the interfacial polymerization of m‐phenylenediamine (MPD) and trimesoyl chloride (TMC), varying systematically reaction time, concentration, and stoichiometry, to yield large‐area exceptionally planar films of ≈10 nm thickness. Reflectivity is employed to precisely determine membrane thickness and roughness, as well as the (TMC/MPD) concentration profile, and response to hydration in the vapor phase. PA film thickness is found to increase linearly with reaction time, albeit with a nonzero intercept, and the composition cross‐sectional profile is found to be uniform, at the conditions investigated. Vapor hydration with H2O and D2O from 0 to 100% relative humidity results in considerable swelling (up to 20%), but also yields uniform cross‐sectional profiles. The resulting film thickness is found to be predominantly set by the MPD concentration, while TMC regulates water uptake. A favorable correlation is found between higher swelling and water uptake with permeance. The data provide quantitative insight into the film formation mechanisms and correlate reaction conditions, cross‐sectional nanostructure, and performance of the PA active layer in RO membranes for desalination. 相似文献
1000.
Min-Oh Suk Sung-Koo Jo Seon-Hyo Kim Jeong-Sik Kim Sang-Chul Shim 《Metallurgical and Materials Transactions B》2004,35(6):1087-1095
An equilibrium experiment was carried out at 1873 K to investigate the effect of carbon in CaO-SiO2-Al2O3-MgO-MnO-Fe
t
O slag systems on their Fe
t
O and MnO activity coefficients, representing the slag’s thermodynamic potential for steel reoxidation. The activity coefficients
of Fe
t
O and MnO showed not only a sharp increment but also a simultaneous slow decrement with increasing carbon content in slag,
suggesting opposite roles of the carbon in slag according to its stable forms. X-ray photoelectron spectroscopy (XPS) was
introduced to determine the stable forms of carbon in slag. The XPS results proved that carbon dissolves in slag as carbonate,
and carbide ions under oxidizing and reducing atmospheres, respectively. The simultaneous consideration of the activity coefficients
of Fe
t
O and MnO and stable carbon forms showed that carbonate ions increase the activity coefficients of Fe
t
O and MnO, but that carbide decreases them. This article suggests an application method of the present results to actual ladle
refining processes, in order to enhance steel cleanliness with maintaining (Fe
t
O + MnO) in slag to some allowable amount. 相似文献