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61.
Justin D. Chaffin Sachidananda Mishra Douglas D. Kane Darren L. Bade Keara Stanislawczyk Kristen N. Slodysko Kevin W. Jones Eric M. Parker Erica L. Fox 《Journal of Great Lakes research》2019,45(2):277-289
Lake Erie western basin (WB) cyanobacterial blooms are a yearly summer occurrence; however, blooms have also been reported in the offshore waters of the central basin (CB), and very little is known about what drives these blooms or their potential for cyanobacterial toxins. Cyanobacteria Index was quantified using MODIS and MERIS data for the CB between 2003 and 2017, and water samples were collected between 2013 and 2017. The goals were to 1) quantify cyanobacteria, 2) determine environmental drivers of CB blooms, and 3) determine the potential for cyanobacterial toxins in the CB. Dolichospermum (Anabaena) occurred in the CB during July before the onset of the WB bloom, and then in August and September, the cyanobacteria community shifted towards Microcystis. The largest Dolichospermum blooms (2003, 2012, 2013, and 2015) were associated with reduced water clarity (Secchi disk depth?<?4?m), whereas large CB Microcystis blooms (2011 and 2015) were associated with large WB blooms. Dolichospermum blooms occurred in high nitrate concentrations (>20?μmol/L) and high nitrogen-to?phosphorus ratios (>100), which indicate nutrient concentrations or ratios did not select for Dolichospermum. Additionally, the sxtA gene, but not mcyE or microcystins, were detected in the CB during July 2016 and 2017. The mcyE gene and microcystins were detected in the CB during August 2016 and 2017. The results indicate the CB's potential for cyanotoxins shifts from saxitoxins to microcystins throughout the summer. Continued monitoring of cyanobacteria and multiple cyanobacterial toxins is recommended to ensure safe drinking water for CB coastal communities. 相似文献
62.
63.
Ramsook Darren Hosein Patrick Hosein Nicholas 《Multimedia Tools and Applications》2022,81(6):7957-7967
Multimedia Tools and Applications - Summarization techniques have traditionally achieved good performance results when summarizing sentences and documents. However, their application to instant... 相似文献
64.
Graham J. Hutchings Peter Johnston Darren F. Lee Craig D. Williams 《Catalysis Letters》1993,21(1-2):49-53
The catalytic activity of the proton forms of zeolite and ZSM-5 are compared for the conversion of acetone. Zeolite demonstrates markedly enhanced selectivity to isobutene and selectivities of >80% can be achieved for conversions up to 65%. In contrast high selectivities to isobutene with ZSM-5 can be attained only at very low conversions (5%). 相似文献
65.
The theme of a more compact city has been a central feature of planning policy for Sydney's development over the last two decades. Urban consolidation, in the form of attached dwellings in medium- and high-density configurations, has become the predominant form of new residential development since the early 1990s. One of the largely untested claims for this policy is that it provides more housing choice for an increasingly diverse population and that simply building larger amounts of smaller housing in high-density concentrations will be sufficient to meet that demand. As a result, planning for higher density housing has been undertaken with little explicit recognition of the housing sub-markets higher density housing caters for or their specific spatial characteristics within the city. These issues are examined by an analysis of the socio-economic characteristics of areas with high concentrations of attached housing. These data are processed by factor analysis to identify and locate the range of sub-markets within attached housing and additional small area data used to fill out the market profiling. The results reveal that a range of specific housing needs are met by this form of housing with discriminative characteristics in certain locations. In other words, higher density housing is associated with a range of locationally specific and spatially distinctive sub-markets. These findings are particularly relevant and timely as a new metropolitan strategy is in preparation for Sydney where an estimated 60–70 per cent of new dwelling provision in the next 30 years will take place within existing suburbs through higher density redevelopment. Planning for such development must take into account the local markets for such accommodation which have very different characteristics in different parts of the city. 相似文献
66.
67.
Flaherty TJ Timmons JC Wrobleski DA Orler EB Langlois DA Wurden KJ Williams DL 《Applied spectroscopy》2007,61(6):608-612
The spectral signatures of nitro attack of the aromatic portion of thermoplastic urethanes (TPU) were determined. Eight fragment molecules were synthesized that represent the nitrated and pristine methylenediphenyl section common to many TPUs. Infrared (IR) and Raman (785 nm illumination) spectra were collected and modeled using the B3LYP/6-31G(d)//B3LYP/6-31G(d) model chemistry. Normal mode animations were used to fully assign the vibrational spectra of each fragment. The vibrational assignment was used to develop a diagnostic method for aromatic nitro attack in thermoplastic urethanes. The symmetric NO(2) stretch coupled out of phase with the C-NO(2) stretch (1330 cm(-1)) was found to be free from spectral interferences. Spectral reference regions that enable correction for physical differences between samples were determined. The carbonyl stretch at 1700 cm(-1) was the best IR reference region, yielding a limit of quantitation (LOQ) of 0.66 +/- 0.02 g N/100 g Estane. Secondary IR reference regions were the N-H stretch at 3330 cm(-1) or the urethane nitrogen deformation at 1065 cm(-1). The reference region in the Raman was a ring stretching mode at 1590 cm(-1), giving an LOQ of 0.69 +/- 0.02 g N/100 g Estane. Raman spectroscopy displayed a larger calibration sensitivity (slope = 0.110 +/- 0.004) than IR spectroscopy (slope = 0.043 +/- 0.001) for nitration determination due to the large nitro Raman cross-section. The full spectral assignment of all eight molecules in the infrared and Raman is presented as supplemental material. 相似文献
68.
Lyons RE Lesieur E Kim M Wong DC Huson MG Nairn KM Brownlee AG Pearson RD Elvin CM 《Protein engineering, design & selection : PEDS》2007,20(1):25-32
Resilin is an elastic protein found in specialized regions of the cuticle of insects, which displays unique resilience and fatigue lifetime properties. As is the case with many elastomeric proteins, including elastin, gliadin and spider silks, resilin contains distinct repetitive domains that appear to confer elastic properties to the protein. Recent work within our laboratory has demonstrated that cloning and expression of exon 1 of the Drosophila melanogaster CG15920 gene, encoding a putative resilin-like protein, results in a recombinant protein that can be photochemically crosslinked to form a highly resilient, elastic biomaterial (Rec1 resilin). The current study describes a recursive cloning strategy for generating synthetic genes encoding multiple copies of consensus polypeptides, based on the repetitive domains within resilin-like genes from D. melanogaster and Anopheles gambiae. A simple non-chromatographic purification method that can be applied to these synthetic proteins and Rec1 is also reported. These methods for the design and purification of resilin-like periodic polypeptides will facilitate the future investigation of structural and functional properties of resilin, and the development of novel highly resilient biomaterials. 相似文献
69.
Somayeh S. Tarighat Fei Fei Eun Ji Joo Hisham Abdel-Azim Lu Yang Huimin Geng Khuchtumur Bum-Erdene I. Darren Grice Mark von Itzstein Helen Blanchard Nora Heisterkamp 《International journal of molecular sciences》2021,22(22)
Environmentally-mediated drug resistance in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) significantly contributes to relapse. Stromal cells in the bone marrow environment protect leukemia cells by secretion of chemokines as cues for BCP-ALL migration towards, and adhesion to, stroma. Stromal cells and BCP-ALL cells communicate through stromal galectin-3. Here, we investigated the significance of stromal galectin-3 to BCP-ALL cells. We used CRISPR/Cas9 genome editing to ablate galectin-3 in stromal cells and found that galectin-3 is dispensable for steady-state BCP-ALL proliferation and viability. However, efficient leukemia migration and adhesion to stromal cells are significantly dependent on stromal galectin-3. Importantly, the loss of stromal galectin-3 production sensitized BCP-ALL cells to conventional chemotherapy. We therefore tested novel carbohydrate-based small molecule compounds (Cpd14 and Cpd17) with high specificity for galectin-3. Consistent with results obtained using galectin-3-knockout stromal cells, treatment of stromal-BCP-ALL co-cultures inhibited BCP-ALL migration and adhesion. Moreover, these compounds induced anti-leukemic responses in BCP-ALL cells, including a dose-dependent reduction of viability and proliferation, the induction of apoptosis and, importantly, the inhibition of drug resistance. Collectively, these findings indicate galectin-3 regulates BCP-ALL cell responses to chemotherapy through the interactions between leukemia cells and the stroma, and show that a combination of galectin-3 inhibition with conventional drugs can sensitize the leukemia cells to chemotherapy. 相似文献
70.
Darren J. Martin Gordon F. Meijs Gordon M. Renwick Simon J. Mccarthy Pathiraja A. Gunatillake 《应用聚合物科学杂志》1996,62(9):1377-1386
A series of eight thermoplastic polyurethane elastomers were synthesized from 4,4′-methylene diphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender, with poly(hexamethylene oxide) (PHMO) macrodiol soft segments. The soft segment molecular weights employed ranged from 433 g/mol to 1180 g/mol. All materials contained 60% (w/w) of the soft segment macrodiol. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), wide angle x-ray diffraction (WAXD), and small angle x-ray scattering (SAXS) techniques were employed to characterize morphology. Tensile and Shore hardness tests were also performed. Materials were tested in the annealed state. It was found that an increase in segment length was accompanied by an increase in the degree of microphase separation, average interdomain spacing, hard domain order, hardness, stiffness, and opacity. DSC experiments showed the existence of several hard segment melting regions that were postulated to result from the disordering or melting of various hard segment length populations. For the system and composition ratio employed, it was found that optimum tensile properties (UTS and breaking strain) were achieved when a PHMO molecular weight of between 650 and 850 was utilized. © 1996 John Wiley & Sons, Inc. 相似文献