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61.
Matthew J. Bauer Catherine S. Snyder Christopher C. Bowland Amanda M. Uhl Maeve A. K. Budi Maria Villancio‐Wolter Henry A. Sodano Jennifer S. Andrew 《Journal of the American Ceramic Society》2016,99(12):3902-3908
Barium titanate nanofibers were uniaxially aligned by electrospinning onto a rotating copper wire drum and alignment was maintained during calcination of the fibers. Two methods for maintaining alignment during calcination were tested, by either using carbon tape or a peeling off method to remove the aligned fibers from the mandrel followed by calcination. The carbon tape removal method led to the formation of shorter aligned nanowires while the peeling off method resulted in longer nanofibers. Additionally, the effects of calcination temperature and time on crystal structure were also examined. The degree of tetragonality in the barium titanate nanofibers increased at higher calcination temperatures and times. Piezoelectricity was confirmed in the nanofibers calcined using piezoeresponse force microscopy, yielding a d33 value of 15.5 pm/V. Using the methods presented here, large quantities of aligned piezoelectric barium titanate and other ceramic fibers or wires can be produced to fulfill their demand in novel microelectronics. 相似文献
62.
Amanda J. Cox Hillary N. Bengtson Dr. Yulia V. Gerasimova Dr. Kyle H. Rohde Dr. Dmitry M. Kolpashchikov 《Chembiochem : a European journal of chemical biology》2016,17(21):2038-2041
Some natural enzymes increase the rate of diffusion‐limited reactions by facilitating substrate flow to their active sites. Inspired by this natural phenomenon, we developed a strategy for efficient substrate delivery to a deoxyribozyme (DZ) catalytic sensor. This resulted in a three‐ to fourfold increase in sensitivity and up to a ninefold improvement in the detection limit. The reported strategy can be used to enhance catalytic efficiency of diffusion‐limited enzymes and to improve sensitivity of enzyme‐based biosensors. 相似文献
63.
Cover Picture: DNA Antenna Tile‐Associated Deoxyribozyme Sensor with Improved Sensitivity (ChemBioChem 21/2016) 下载免费PDF全文
64.
Interrogating the Tailoring Steps of Pactamycin Biosynthesis and Accessing New Pactamycin Analogues 下载免费PDF全文
Dr. Mostafa E. Abugrain Dr. Wanli Lu Dr. Yuexin Li Dr. Jeffrey D. Serrill Corey J. Brumsted Andrew R. Osborn Prof. Dr. Adam Alani Prof. Dr. Jane E. Ishmael Prof. Dr. Jane X. Kelly Prof. Dr. Taifo Mahmud 《Chembiochem : a European journal of chemical biology》2016,17(17):1585-1588
Pactamycin is a bacteria‐derived aminocyclitol antibiotic with a wide‐range of biological activity. Its chemical structure and potent biological activities have made it an interesting lead compound for drug discovery and development. Despite its unusual chemical structure, many aspects of its formation in nature remain elusive. Using a combination of genetic inactivation and metabolic analysis, we investigated the tailoring processes of pactamycin biosynthesis in Streptomyces pactum. The results provide insights into the sequence of events during the tailoring steps of pactamycin biosynthesis and explain the unusual production of various pactamycin analogues by S. pactum mutants. We also identified two new pactamycin analogues that have better selectivity indexes than pactamycin against malarial parasites. 相似文献
65.
Mallory Batty Rachel Pugh Ilampirai Rathinam Joshua Simmonds Edwin Walker Amanda Forbes Shailendra Anoopkumar-Dukie Catherine M. McDermott Briohny Spencer David Christie Russ Chess-Williams 《International journal of molecular sciences》2016,17(8)
This review evaluates the role of α-adrenoceptor antagonists as a potential treatment of prostate cancer (PCa). Cochrane, Google Scholar and Pubmed were accessed to retrieve sixty-two articles for analysis. In vitro studies demonstrate that doxazosin, prazosin and terazosin (quinazoline α-antagonists) induce apoptosis, decrease cell growth, and proliferation in PC-3, LNCaP and DU-145 cell lines. Similarly, the piperazine based naftopidil induced cell cycle arrest and death in LNCaP-E9 cell lines. In contrast, sulphonamide based tamsulosin did not exhibit these effects. In vivo data was consistent with in vitro findings as the quinazoline based α-antagonists prevented angiogenesis and decreased tumour mass in mice models of PCa. Mechanistically the cytotoxic and antitumor effects of the α-antagonists appear largely independent of α 1-blockade. The proposed targets include: VEGF, EGFR, HER2/Neu, caspase 8/3, topoisomerase 1 and other mitochondrial apoptotic inducing factors. These cytotoxic effects could not be evaluated in human studies as prospective trial data is lacking. However, retrospective studies show a decreased incidence of PCa in males exposed to α-antagonists. As human data evaluating the use of α-antagonists as treatments are lacking; well designed, prospective clinical trials are needed to conclusively demonstrate the anticancer properties of quinazoline based α-antagonists in PCa and other cancers. 相似文献
66.
Governments use incentive programmes to attract new businesses. Due to limited resources, there are questions about which incentives are most effective. Using establishment data from California, and data on the location of disbursements through two federal programmes, we consider the effectiveness of different programmes in attracting new businesses. We find that the amount of funding through the New Markets Tax Credit programme has a significant impact on business activity but find no evidence of an effect from the Community Development Financial Institutions programme. Our results suggest that the effectiveness of these programmes depends on how they provide assistance. 相似文献
67.
The behavior of electrospun polyvinyl alcohol (PVA) and polyethylene oxide (PEO) nanofibers embedded with urea is studied as a function of various process parameters. Our results show that three‐dimensional nanofiber networks can be obtained when high concentrations of urea in the solution are used during electrospinning. The nanofibers are characterized using both scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The stability of the nanofiber as a function of electric field has also been studied. The successful formation of three‐dimensional nanofiber networks can open new trends toward applications in fertilizers containing nanofibers in the nanoagricultural field. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39840. 相似文献
68.
Lawhorn J. Osborn D. Caspary J. Nickell B.M. Larson D. Lasher W. Rahman M.Ea. 《Power and Energy Magazine, IEEE》2009,7(6):76-88
The challenge of integrating large amounts of renewable energy resources into the electric sector requires updated transmission analysis techniques. Economic planning, primarily in the form of value-based planning over interconnectionwide areas, is needed before performing the traditional single-hour, capacity-based reliability analyses. 相似文献
69.
Twambo Hachibamba Linda Dykes Joseph Awika Amanda Minnaar Kwaku G. Duodu 《International Journal of Food Science & Technology》2013,48(12):2638-2649
Consumption of diets rich in phenolic compounds has been associated with reduced risk of chronic diseases. The effect of cooking and simulated gastrointestinal digestion on phenolic compounds and antioxidant properties of two cowpea (Vigna unguiculata) types was determined. Phenolic acids, flavan‐3‐ols and flavonols were the main groups of phenolic compounds identified. Cooking and simulated enzyme digestion of the cooked cowpea samples rendered some phenolics less extractable (possibly by promoting binding with other food components) or more extractable (possibly by release of bound forms). Total phenolic contents and radical scavenging properties of the cowpeas were reduced upon cooking, but increased upon simulated enzyme digestion. Cowpea extracts inhibited human LDL oxidation at a concentration of 2 mg mL?1 possibly due to their phenolic content. Phenolic compounds in cowpea can potentially protect against cardiovascular diseases for which LDL oxidation is a risk factor. 相似文献
70.
Amanda Seemungal Andrea Petróczi Declan P. Naughton 《European Food Research and Technology》2011,233(5):781-789
Several studies have assessed total anti-oxidant activity of wine or individual components in isolation using chemical-based
assays. In this study, a quantitative approach was developed to assess the relative anti-oxidant efficacies of selected red
wine phenolics via peak reduction, using reversed-phase HPLC. Both intact red wine and phenolic standard solutions were challenged
with five oxidant model systems as follows: (1) hydrogen peroxide (H2O2); redox-active metal ions (2) Fe3+ and (3) Cu2+; and the Fenton reagents (4) H2O2 + Fe2+; and (5) H2O2 + Cu+. Treatment with oxidants (1–3) resulted in loss of 47–60% of phenolic standards, which increased to 66–89% for treatment
with the Fenton systems, with quercetin exhibiting the optimal anti-oxidant activity. For intact red wine, treatment with
oxidants (1–3) led to all phenolic compounds being oxidised (27–77% loss), with caffeic acid and quercetin as the most effective
anti-oxidants. For both Fenton systems (4–5), activities in red wine were considerably enhanced for caffeic acid and quercetin,
which exhibited the highest anti-oxidant efficacies with 100% peak reduction, while p-coumaric acid and gallic acid were less effective anti-oxidants with peak reductions of 60–68%. The ranking, facilitated
by this new quantitative approach, allows comparison of the individual efficacies of the anti-oxidants in a complex matrix. 相似文献