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41.
High polymer poly(ester ethers) are rapidly synthesized in good yield employing the interfacial polycondensation reaction system. Infrared spectroscopy shows the formation of new bands derived from the Sn–O and Sn–O(CO) linkages. It also shows that the products exist as alternating Sn–O and Sn–O(CO) linkages. MALDI MS shows formation of ion fragment clusters several units in length. The products show reasonable inhibition of a variety of cancer cell lines including two pancreatic cancer cell lines.  相似文献   
42.
Three batches of yoghurts were made from goat's milk with different enrofloxacin concentrations (0, 50, 100 and 150 μg/kg). Quality parameters were analysed at 1, 7, 14 and 28 days at 5 °C. Drug residues were also quantified by HPLC. Coagulation time and most yoghurt properties remained unaffected by the presence of enrofloxacin in goat's milk. However, quality parameters were affected by the storage period. 74.9–99.2% of enrofloxacin initially added to goat's milk remained in the yoghurt throughout its entire shelf life, potentially posing a risk to consumer health. Therefore, an enrofloxacin maximum residue limit in yoghurt should be established.  相似文献   
43.
Vegetable oils are very heterogeneous materials with a wide distribution of triacylglycerol structures and double‐bond contents. The hydrogenation of epoxidized soybean oil (ESO) produces polyols having a functionality distribution related to that of soybean oil. Therefore, these polyols are convenient substances for studying the impact of structural heterogeneity on network formation and properties. Polyols of hydroxyl numbers ranging from 225 to 82 mg KOH/g and weight‐average functionalities ranging from 4.4 to 2.7 were obtained by the variation of the time of hydrogenation of ESO. An analysis of the functionality distribution in polyols shows that gel points with diisocyanates vary from 54 to 76% conversion. The molecular weights of the network chains of polyurethanes prepared from these polyols and diphenyl methane diisocyanate varied from 688 to 1993. Polyols with hydroxyl numbers above 200 mg KOH/g gave glassy polymers, whereas those below that value gave rubbers. The heterogeneity of polyols had a negative effect on the elastic properties only at low crosslinking densities. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   
44.
The primary purpose of this study was to examine relations between trauma exposure, post-resettlement stressors, perceived discrimination, and mental health symptoms in Somali adolescent refugees resettled in the U.S. Participants were English-speaking Somali adolescent refugees between the ages of 11 and 20 (N = 135) who had resettled in the U.S. Participants were administered an interview battery comprising self-report instruments that included the UCLA Posttraumatic Stress Disorder (PTSD) Index, the War Trauma Screening Scale, the Every Day Discrimination scale, the Adolescent Post-War Adversities Scale, and the Acculturative Hassles Inventory. Results indicated that cumulative trauma was related to PTSD and depression symptoms. Further, post-resettlement stressors, acculturative stressors, and perceived discrimination were also associated with greater PTSD symptoms after accounting for trauma, demographic, and immigration variables. Number of years since resettlement in the US and perceived discrimination were significantly related to depressive symptoms, after accounting for trauma, demographic, and immigration variables. Further research elucidating the relations between post-resettlement stressors, discrimination, and mental health of refugee adolescents may inform intervention development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
45.
Catalytic microwave pyrolysis of peanut shell (PT) using Fe3O4, Na2CO3, NaOH, and KOH for production of phenolic-rich bio-oil was investigated. The effects of catalyst type, pyrolysis temperature, and biomass/catalyst ratio on product distribution and composition were studied. Among four catalysts tested, Na2CO3 significantly increased the selectivity of phenolic compounds in bio-oil during microwave pyrolysis. The highest phenolics concentration of 57.36% (area) was obtained at 500 °C and PT:Na2CO3 ratio of 8: 1. The catalytic effect to produce phenolic compounds among all the catalysts tested can be summarized in the order Na2CO3>Fe3O4>KOH>NaOH. Using KOH and NaOH as catalyst resulted in formation of bio-oil with enhanced higher heating value (HHV) and lower oxygen content, indicating that these catalysts enhanced the deoxygenation of bio-oil. The scanning-electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis of char particles showed the melting of magnetite and vaporizationcondensation of mineral salt catalysts on char particle, which was attributed to extremely high local temperatures during microwave heating.  相似文献   
46.
The surface charge of a biomaterial represents a promising tool to direct cellular behavior, which is crucial for therapeutic approaches in regenerative medicine. To expand the understanding of how the material surface charge affects protein adsorption and mesenchymal stem cell behavior, differently charged surfaces with zeta potentials spanning from ?25?mV to +15?mV were fabricated by the conjugation of poly(amidoamine) to alginate-based hydrogels. We showed that the increase of the biomaterials surface charge resulted in enhanced quantities of biologically available, surface-attached proteins. Since different surface charges were equalized after protein adsorption, mesenchymal stem cells interacted rather with diverse protein compositions instead of different surface features. Besides an enhanced cell attachment to increasingly positively charged surfaces, the cell spreading area and the expression of adhesion-related genes integrin α5 and tensin 1 were found to be increased after adhesion. Moreover, first results indicate a potential impact of the surface charge on mesenchymal stem cell differentiation towards bone and fat cells. The improved understanding of surface charge-related cell behavior has significant impact on the design of biomedical devices and artificial organs.  相似文献   
47.
Biomarkers are greatly needed in the fields of neurology and psychiatry, to provide objective and earlier diagnoses of CNS conditions. Proteomics and other omics MS-based technologies are tools currently being utilized in much recent CNS research. Saliva is an interesting alternative biomaterial for the proteomic study of CNS disorders, with several advantages. Collection is noninvasive and saliva has many proteins. It is easier to collect than blood and can be collected by professionals without formal medical training. For psychiatric and neurological patients, supplying a saliva sample is less anxiety-provoking than providing a blood sample, and is less embarrassing than producing a urine specimen. The use of saliva as a biomaterial has been researched for the diagnosis of and greater understanding of several CNS conditions, including neurodegenerative diseases, autism, and depression. Salivary biomarkers could be used to rule out nonpsychiatric conditions that are often mistaken for psychiatric/neurological conditions, such as fibromyalgia, and potentially to assess cognitive ability in individuals with compromised brain function. As MS and omics technology advances, the sensitivity and utility of assessing CNS conditions using distal human biomaterials such as saliva is becoming increasingly possible.  相似文献   
48.
Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[13C9, 15N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in 13C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), 13C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and 13C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of 13C-labeled flavones and flavonol (4′,7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically promote hydrolysis of isoflavone conjugates.  相似文献   
49.
A number of aza‐heterocyclic compounds, which share the 5,6‐dihydropyrrolo[2,1‐a]isoquinoline (DHPIQ) scaffold with members of the lamellarin alkaloid family, were synthesized and evaluated for their ability to reverse in vitro multidrug resistance in cancer cells through inhibition of P‐glycoprotein (P‐gp) and/or multidrug‐resistance‐associated protein 1. Most of the investigated DHPIQ compounds proved to be selective P‐gp modulators, and the most potent modulator, 8,9‐diethoxy‐1‐(3,4‐diethoxyphenyl)‐3‐(furan‐2‐yl)‐5,6‐dihydropyrrolo[2,1‐a]isoquinoline‐2‐carbaldehyde, attained sub‐micromolar inhibitory potency (IC50: 0.19 μm ). Schiff bases prepared by the condensation of some 1‐aryl‐DHPIQ aldehydes with p‐aminophenol also proved to be of some interest, and one of them, 4‐((1‐(4‐fluorophenyl)‐5,6‐dihydro‐8,9‐dimethoxypyrrolo[2,1‐a]isoquinolin‐2‐yl)methyleneamino)phenol, had an IC50 value of 1.01 μm . In drug combination assays in multidrug‐resistant cells, some DHPIQ compounds, at nontoxic concentrations, significantly increased the cytotoxicity of doxorubicin in a concentration‐dependent manner. Studies of structure–activity relationships and investigation of the chemical stability of Schiff bases provided physicochemical information useful for molecular optimization of lamellarin‐like cytotoxic drugs active toward chemoresistant tumors as well as nontoxic reversers of P‐gp‐mediated multidrug resistance in tumor cells.  相似文献   
50.
An interdisciplinary design research collaborative led by Alisa Andrasek, CONTINUUM emerged from a series of design research seminars at Columbia University's graduate school of architecture. Working collaboratively with Robert Aish, Andresek's workshops explored the potential of the new Bentley Systems' GenerativeComponents design software, which at the time was in beta testing. CONTINUUM was formed to extend the possibilities of such collaborations and has expanded its network, occupying an interesting and unique territory of intersecting interests between academia, corporate practice and the companies that create design tools. Traditionally understood as antagonistic, commercial and progressive interests and intentions find common ground in their shared need for research into advanced design software that will enable the retooling of architectural practice. Here, Pia Ednie-Brown, with illustrations by Alisa Andrasek, examines the unique ways in which CONTINUUM enfolds diverse professional and academic practices. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
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