53 research outputs found
Biophysical Phenotyping and Modulation of ALDH+ Inflammatory Breast Cancer StemâLike Cells
Cancer stemâlike cells (CSCs) have been shown to initiate tumorigenesis and cancer metastasis in many cancer types. Although identification of CSCs through specific marker expression helps define the CSC compartment, it does not directly provide information on how or why this cancer cell subpopulation is more metastatic or tumorigenic. In this study, the functional and biophysical characteristics of aggressive and lethal inflammatory breast cancer (IBC) CSCs at the singleâcell level are comprehensively profiled using multiple microengineered tools. Distinct functional (cell migration, growth, adhesion, invasion and selfârenewal) and biophysical (cell deformability, adhesion strength and contractility) properties of ALDH+ SUM149 IBC CSCs are found as compared to their ALDHâ nonâCSC counterpart, providing biophysical insights into why CSCs has an enhanced propensity to metastasize. It is further shown that the cellular biophysical phenotype can predict and determine IBC cellsâ tumorigenic ability. SUM149 and SUM159 IBC cells selected and modulated through biophysical attributesâadhesion and stiffnessâshow characteristics of CSCs in vitro and enhance tumorigenicity in in vivo murine models of primary tumor growth. Overall, the multiparametric cellular biophysical phenotyping and modulation of IBC CSCs yields a new understanding of IBCâs metastatic properties and how they might develop and be targeted for therapeutic interventions.This study comprehensively profiles the biophysical characteristics of inflammatory breast cancer stemâlike cells to delineate the soâcalled âbiophysical phenotypeâ of the model of the most metastatic breast cancer subtype. Evidence indicates that the cellular biophysical phenotype can predict and determine cancer cellsâ tumorigenic ability.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/1/smll201802891_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/2/smll201802891.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/3/smll201802891-sup-0001-S1.pd
Ultra-high-rate pseudocapacitive energy storage in two-dimensional transition metal carbides
The use of fast surface redox storage (pseudocapacitive) mechanisms can enable devices that store much more energy than electrical double-layer capacitors (EDLCs) and, unlike batteries, can do so quite rapidly. Yet, few pseudocapacitive transition metal oxides can provide a high power capability due to their low intrinsic electronic and ionic conductivity. Here we demonstrate that two-dimensional transition metal carbides (MXenes) can operate at rates exceeding those of conventional EDLCs, but still provide higher volumetric and areal capacitance than carbon, electrically conducting polymers or transition metal oxides.We applied two distinct designs for MXene electrode architectures with improved ion accessibility to redox-active sites. A macroporous Ti3C2Tx MXene film delivered up to 210 F g-1 at scan rates of 10Vs-1, surpassing the best carbon supercapacitors known. In contrast, we show that MXene hydrogels are able to deliver volumetric capacitance of 1,500 F cm-3 reaching the previously unmatched volumetric performance of RuO2
Understanding and improving model representation of aerosol optical properties for a Chinese haze event measured during KORUS-AQ
KORUS-AQ was an international cooperative air quality field study in South Korea that measured local and remote sources of air pollution affecting the Korean Peninsula during MayâJune 2016. Some of the largest aerosol mass concentrations were measured during a Chinese haze transport event (24 May). Air quality forecasts using the WRF-Chem model with aerosol optical depth (AOD) data assimilation captured AOD during this pollution episode but overpredicted surface particulate matter concentrations in South Korea, especially PM2.5, often by a factor of 2 or larger. Analysis revealed multiple sources of model deficiency related to the calculation of optical properties from aerosol mass that explain these discrepancies. Using in situ observations of aerosol size and composition as inputs to the optical properties calculations showed that using a low-resolution size bin representation (four bins) underestimates the efficiency with which aerosols scatter and absorb light (mass extinction efficiency). Besides using finer-resolution size bins (8â16 bins), it was also necessary to increase the refractive indices and hygroscopicity of select aerosol species within the range of values reported in the literature to achieve better consistency with measured values of the mass extinction efficiency (6.7âm2âgâ1 observed average) and light-scattering enhancement factor (f(RH)) due to aerosol hygroscopic growth (2.2 observed average). Furthermore, an evaluation of the optical properties obtained using modeled aerosol properties revealed the inability of sectional and modal aerosol representations in WRF-Chem to properly reproduce the observed size distribution, with the models displaying a much wider accumulation mode. Other model deficiencies included an underestimate of organic aerosol density (1.0âgâcmâ3 in the model vs. observed average of 1.5âgâcmâ3) and an overprediction of the fractional contribution of submicron inorganic aerosols other than sulfate, ammonium, nitrate, chloride, and sodium corresponding to mostly dust (17â%â28â% modeled vs. 12â% estimated from observations). These results illustrate the complexity of achieving an accurate model representation of optical properties and provide potential solutions that are relevant to multiple disciplines and applications such as air quality forecasts, health impact assessments, climate projections, solar power forecasts, and aerosol data assimilation
Orally Active Multi-Functional Antioxidants Are Neuroprotective in a Rat Model of Light-Induced Retinal Damage
Progression of age-related macular degeneration has been linked to iron dysregulation and oxidative stress that induce apoptosis of neural retinal cells. Since both antioxidants and chelating agents have been reported to reduce the progression of retinal lesions associated with AMD in experimental animals, the present study evaluates the ability of multi-functional antioxidants containing functional groups that can independently chelate redox metals and quench free radicals to protect the retina against light-induced retinal degeneration, a rat model of dry atrophic AMD.Proof of concept studies were conducted to evaluate the ability of 4-(5-hydroxypyrimidin-2-yl)-N,N-dimethyl-3,5-dioxopiperazine-1-sulfonamide (compound 4) and 4-(5-hydroxy-4,6-dimethoxypyrimidin-2-yl)-N,N-dimethyl-3,5-dioxopiperazine-1-sulfonamide (compound 8) to reduce retinal damage in 2-week dark adapted Wistar rats exposed to 1000 lx of light for 3 hours. Assessment of the oxidative stress markers 4- hydroxynonenal and nitrotyrosine modified proteins and Thioredoxin by ELISA and Western blots indicated that these compounds reduced the oxidative insult caused by light exposure. The beneficial antioxidant effects of these compounds in providing significant functional and structural protection were confirmed by electroretinography and quantitative histology of the retina.The present study suggests that multi-functional compounds may be effective candidates for preventive therapy of AMD
A Co(OH)2-graphene nanosheets composite as a high performance anode material for rechargeable lithium batteries
A Co(OH)2âgraphene nanosheets (Co(OH)2âGNS) composite as a high performance anode material was firstly prepared through a simultaneous hydrothermal method. The structure, morphology and electrochemical performance of the obtained samples were systematically investigated by X-ray diffraction (XRD), transmission electron microscope (TEM) and electrochemical measurements. According to the TEM analysis, the surface of the Co(OH)2 is surrounded with GNS in the Co(OH)2âGNS composite. The specific discharge (lithiation) and charge (delithiation) capacities of Co(OH)2âGNS attain to 1599 and 1120Â mAh/g at a current density of 200Â mA/g in the first cycle, respectively. After 30 cycles, the reversible capacity of Co(OH)2âGNS is still 910Â mAh/g with the retention of 82%. The particular structure of Co(OH)2 particles surrounded by the GNS could limit the volume change during cycling and provide an excellent electronic conduction pathway, which could be the main reason for the remarkable improvement of electrochemical performance. Keywords: Cobalt hydroxide, Graphene, Simultaneous hydrothermal synthesis, Anode, Lithium batterie
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