1,471 research outputs found
James J. Kaput (1942–2005) imagineer and futurologist of mathematics education
Jim Kaput lived a full life in mathematics education and we have many reasons to be grateful to him, not only for his vision of the use of technology in mathematics, but also for his fundamental humanity. This paper considers the origins of his ‘big ideas’ as he lived through the most amazing innovations in technology that have changed our lives more in a generation than in many centuries before. His vision continues as is exemplified by the collected papers in this tribute to his life and work
Investigating photoexcitation-induced mitochondrial damage by chemotherapeutic corroles using multimode optical imaging
We recently reported that a targeted, brightly fluorescent gallium corrole (HerGa) is highly effective for breast tumor detection and treatment. Unlike structurally similar porphryins, HerGa exhibits tumor-targeted toxicity without the need for photoexcitation. We have now examined whether photoexcitation further modulates HerGa toxicity, using multimode optical imaging of live cells, including two-photon excited fluorescence, differential interference contrast (DIC), spectral, and lifetime imaging. Using two-photon excited fluorescence imaging, we observed that light at specific wavelengths augments the HerGa-mediated mitochondrial membrane potential disruption of breast cancer cells in situ. In addition, DIC, spectral, and fluorescence lifetime imaging enabled us to both validate cell damage by HerGa photoexcitation and investigate HerGa internalization, thus allowing optimization of light dose and timing. Our demonstration of HerGa phototoxicity opens the way for development of new methods of cancer intervention using tumor-targeted corroles
Recent Developments: The Uniform Arbitration Act
Since 1983, this annual Article 2 has been prepared to provide a survey of recent developments in the case law interpreting and applying the various state versions of the Uniform Arbitration Act3. The purpose is to promote uniformity in the interpretation of the U.A.A. by developing and explaining the underlying principles and rationales courts have applied in recent cases.
Cardiac myocyte-specific knock-out of calcium-independent phospholipase A2γ (iPLA2γ) decreases oxidized fatty acids during ischemia/reperfusion and reduces infarct size
Calcium-independent phospholipase A(2)γ (iPLA(2)γ) is a mitochondrial enzyme that produces lipid second messengers that facilitate opening of the mitochondrial permeability transition pore (mPTP) and contribute to the production of oxidized fatty acids in myocardium. To specifically identify the roles of iPLA(2)γ in cardiac myocytes, we generated cardiac myocyte-specific iPLA(2)γ knock-out (CMiPLA(2)γKO) mice by removing the exon encoding the active site serine (Ser-477). Hearts of CMiPLA(2)γKO mice exhibited normal hemodynamic function, glycerophospholipid molecular species composition, and normal rates of mitochondrial respiration and ATP production. In contrast, CMiPLA(2)γKO mice demonstrated attenuated Ca(2+)-induced mPTP opening that could be rapidly restored by the addition of palmitate and substantially reduced production of oxidized polyunsaturated fatty acids (PUFAs). Furthermore, myocardial ischemia/reperfusion (I/R) in CMiPLA(2)γKO mice (30 min of ischemia followed by 30 min of reperfusion in vivo) dramatically decreased oxidized fatty acid production in the ischemic border zones. Moreover, CMiPLA(2)γKO mice subjected to 30 min of ischemia followed by 24 h of reperfusion in vivo developed substantially less cardiac necrosis in the area-at-risk in comparison with their WT littermates. Furthermore, we found that membrane depolarization in murine heart mitochondria was sensitized to Ca(2+) by the presence of oxidized PUFAs. Because mitochondrial membrane depolarization and calcium are known to activate iPLA(2)γ, these results are consistent with salvage of myocardium after I/R by iPLA(2)γ loss of function through decreasing mPTP opening, diminishing production of proinflammatory oxidized fatty acids, and attenuating the deleterious effects of abrupt increases in calcium ion on membrane potential during reperfusion
Mobilization of pro-inflammatory lipids in obese Plscr3-deficient mice
Metabolic profiling of mice deficient in phospholipid scramblase 3 reveals a possible molecular link between obesity and inflammation
Targeting of Rac GTPases blocks the spread of intact human breast cancer
High expression of Rac small GTPases in invasive breast ductal carcinoma is associated with poor prognosis, but its therapeutic value in human cancers is not clear. The aim of the current study was to determine the response of human primary breast cancers to Rac-based drug treatments ex vivo. Three-dimensional organotypic cultures were used to assess candidate therapeutic avenues in invasive breast cancers. Uniquely, in these primary cultures, the tumour is not disaggregated, with both epithelial and mesenchymal components maintained within a three-dimensional matrix of type I collagen. EHT 1864, a small molecule inhibitor of Rac GTPases, prevents spread of breast cancers in this setting, and also reduces proliferation at the invading edge. Rac1+ epithelial cells in breast tumours also contain high levels of the phosphorylated form of the transcription factor STAT3. The small molecule Stattic inhibits activation of STAT3 and induces effects similar to those seen with EHT 1864. Pan-Rac inhibition of proliferation precedes down-regulation of STAT3 activity, defining it as the last step in Rac activation during human breast cancer invasion. Our data highlights the potential use of Rac and STAT3 inhibition in treatment of invasive human breast cancer and the benefit of studying novel cancer treatments using three-dimensional primary tumour tissue explant cultures
Isotopic constraints on the genesis and evolution of basanitic lavas at Haleakala, Island of Maui, Hawaii
© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 195 (2016): 201-225, doi:10.1016/j.gca.2016.08.017.To understand the dynamics of solid mantle upwelling and melting in the Hawaiian
plume, we present new major and trace element data, Nd, Sr, Hf, and Pb isotopic
compositions, and 238U-230Th-226Ra and 235U-231Pa-227Ac activities for 13 Haleakala
Crater nepheline normative basanites with ages ranging from ~900 to 4100 yr B.P..
These basanites of the Hana Volcanics exhibit an enrichment in incompatible trace
elements and a more depleted isotopic signature than similarly aged Hawaiian
shield lavas from Kilauea and Mauna Loa. Here we posit that as the Pacific
lithosphere beneath the active shield volcanoes moves away from the center of the
Hawaiian plume, increased incorporation of an intrinsic depleted component with
relatively low 206Pb/204Pb produces the source of the basanites of the Hana
Volcanics. Haleakala Crater basanites have average (230Th/238U) of 1.23 (n=13),
average age-corrected (226Ra/230Th) of 1.25 (n=13), and average (231Pa/235U) of 1.67
(n=4), significantly higher than Kilauea and Mauna Loa tholeiites. U-series modeling
shows that solid mantle upwelling velocity for Haleakala Crater basanites ranges
from ~0.7 to 1.0 cm/yr, compared to ~10 to 20 cm/yr for tholeiites and ~1 to 2
cm/yr for alkali basalts. These modeling results indicate that solid mantle upwelling
rates and porosity of the melting zone are lower for Hana Volcanics basanites than
for shield-stage tholeiites from Kilauea and Mauna Loa and alkali basalts from
Hualalai. The melting rate, which is directly proportional to both the solid mantle
upwelling rate and the degree of melting, is therefore greatest in the center of the
Hawaiian plume and lower on its periphery. Our results indicate that solid mantle
upwelling velocity is at least 10 times higher at the center of the plume than at its
periphery under Haleakala.Funding for this project was provided by NSF grants EAR-0001924 and EAR-9909473 to KWWS.2018-08-2
Next-generation sequencing of advanced prostate cancer treated with androgen-deprivation therapy
<b>Background:</b>
Androgen-deprivation therapy (ADT) is standard treatment for locally advanced or metastatic prostate cancer (PCa). Many patients develop castration resistance (castration-resistant PCa [CRPC]) after approximately 2–3 yr, with a poor prognosis. The molecular mechanisms underlying CRPC progression are unclear.<p></p>
<b>Objective:</b>
To undertake quantitative tumour transcriptome profiling prior to and following ADT to identify functionally important androgen-regulated pathways or genes that may be reactivated in CRPC.<p></p>
<b>Design, setting, and participants:</b>
RNA sequencing (RNA-seq) was performed on tumour-rich, targeted prostatic biopsies from seven patients with locally advanced or metastatic PCa before and approximately 22 wk after ADT initiation. Differentially regulated genes were identified in treatment pairs and further investigated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) on cell lines and immunohistochemistry on a separate CRPC patient cohort. Functional assays were used to determine the effect of pathway modulation on cell phenotypes.<p></p>
<b>Outcome measurements and statistical analysis:</b>
We searched for gene expression changes affecting key cell signalling pathways that may be targeted as proof of principle in a CRPC in vitro cell line model.<p></p>
<b>Results and limitations:</b>
We identified ADT-regulated signalling pathways, including the Wnt/β-catenin signalling pathway, and observed overexpression of β-catenin in a subset of CRPC by immunohistochemistry. We validated 6 of 12 (50%) pathway members by qRT-PCR on LNCaP/LNCaP-AI cell RNAs, of which 4 (67%) demonstrated expression changes consistent with RNA-seq data. We show that the tankyrase inhibitor XAV939 (which promotes β-catenin degradation) reduced androgen-independent LNCaP-AI cell line growth compared with androgen-responsive LNCaP cells via an accumulation of cell proportions in the G0/G1 phase and reduction in the S and G2/M phases. Our biopsy protocol did not account for tumour heterogeneity, and pathway inhibition was limited to pharmacologic approaches.<p></p>
<b>Conclusions:</b>
RNA-seq of paired PCa samples revealed ADT-regulated signalling pathways. Proof-of-principle inhibition of the Wnt/β-catenin signalling pathway specifically delays androgen-independent PCa cell cycle progression and proliferation and warrants further investigation as a potential target for therapy for CRPC.<p></p>
Long-Term GPS Tracking of Ocean Sunfish Mola mola Offers a New Direction in Fish Monitoring
Satellite tracking of large pelagic fish provides insights on free-ranging behaviour, distributions and population structuring. Up to now, such fish have been tracked remotely using two principal methods: direct positioning of transmitters by Argos polar-orbiting satellites, and satellite relay of tag-derived light-level data for post hoc track reconstruction. Error fields associated with positions determined by these methods range from hundreds of metres to hundreds of kilometres. However, low spatial accuracy of tracks masks important details, such as foraging patterns. Here we use a fast-acquisition global positioning system (Fastloc GPS) tag with remote data retrieval to track long-term movements, in near real time and position accuracy of <70 m, of the world's largest bony fish, the ocean sunfish Mola mola. Search-like movements occurred over at least three distinct spatial scales. At fine scales, sunfish spent longer in highly localised areas with faster, straighter excursions between them. These ‘stopovers’ during long-distance movement appear consistent with finding and exploiting food patches. This demonstrates the feasibility of GPS tagging to provide tracks of unparalleled accuracy for monitoring movements of large pelagic fish, and with nearly four times as many locations obtained by the GPS tag than by a conventional Argos transmitter. The results signal the potential of GPS-tagged pelagic fish that surface regularly to be detectors of resource ‘hotspots’ in the blue ocean and provides a new capability for understanding large pelagic fish behaviour and habitat use that is relevant to ocean management and species conservation
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